General Description
The MAX11080 is a battery-pack fault-monitor IC capa-
ble of monitoring up to 12 lithium-ion (Li+) battery
cells. This device is designed to provide an overvolt-
age or undervoltage fault indication when any of the
cells cross the user-selectable threshold for longer
than the set program-delay interval. The overvoltage
levels are pin selectable from +3.3V to +4.8V in 100mV
increments, and have a guaranteed accuracy of
±25mV over the entire temperature range. The under-
voltage level is also user selectable from +1.6V to
+2.8V in 200mV increments. These levels are guaran-
teed to ±100mV over the entire temperature range.
Undervoltage detection can be disabled as one of the
user-configuration options.
The MAX11080 has a built-in level-shifter that allows up
to 31 MAX11080 devices to be connected in a daisy-
chain fashion to reduce the number of interface signals
needed for large stacks of series batteries. Each cell is
monitored differentially and compared to the overvolt-
age and undervoltage thresholds. When any of the cells
exceed this threshold for longer than the set program
delay interval, the MAX11080 inhibits the heartbeat sig-
nal from being passed down the daisy chain. Built-in
comparator hysteresis prevents threshold chattering.
The MAX11080 is designed to be the perfect comple-
ment to the MAX11068 high-voltage measurement IC
for redundant fault-monitoring applications. This device
is offered in a 9.7mm x 4.4mm, 38-pin TSSOP package
with 0.5mm pin spacing. The package is lead-free and
RoHS compliant with an extended operating tempera-
ture range of -40°C to +105°C.
Applications
High-Voltage, Multicell-Series-Stacked Battery
Systems
Electric Vehicles
Hybrid Electric Vehicles
Electric Bikes
High-Power Battery Backup
Solar Cell Battery Backup
Super-Cap Battery Backup
Features
oUp to 12-Cell Li+ Battery Voltage Fault Detection
oOperation from 6.0V to 72V
oPin-Selectable Overvoltage Threshold from +3.3V
to +4.8V in 100mV Increments
±25mV Overvoltage-Detection Accuracy
oPin-Selectable Undervoltage Threshold from
+1.6V to +2.8V in 200mV Increments
±100mV Undervoltage-Detection Accuracy
o300mV Over/Undervoltage-Threshold Detection
Hysteresis
oProgrammable Delay Time of Alarm Detection
from 3.0ms to 3.32s with an External Capacitor
oDaisy-Chained Alarm and Shutdown Functions
with Heartbeat Status Signal
Up to 31 Devices Can Be Connected
oUltra-Low-Power Dissipation
Operating-Mode Current Drain: 80µA
Shutdown-Mode Current: 2µA
oWide Operating Temperature Range from -40°C to
+105°C (AEC-Q100 Type 2)
o9.7mm x 4.4mm, 38-Pin TSSOP Package
oLead(Pb) Free and RoHS Compliant
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-4584; Rev 0; 5/09
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
PART TEMP RANGE
PIN-PACKAGE
MAX11080GUU+
-40°C to +105°C
38 TSSOP
MAX11080GUU/V+
-40°C to +105°C
38 TSSOP
Pin Configuration appears at end of data sheet.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(TA= TMIN to TMAX, unless otherwise noted. VDCIN = VGNDu= +6.0V to +72V, typical values are at TA= +25°C, unless otherwise
specified from -40°C to +105°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
HV, VDDU, GNDU, DCIN to AGND.........................-0.3V to +80V
HV to DCIN and C12 ................................................-0.3V to +6V
C2–C12 to AGND ....................................-0.3V to (VDCIN + 0.6V)
Cn+1 to Cn, where n = 2 to 12...............................-0.3V to +80V
C1 to C0 ...................................................-0.3V to +20V (Note 1)
C1 to AGND ..............................-0.3V to (VDCIN + 0.6V) (Note 2)
C0 to AGND...........................................................-0.3V to +0.9V
SHDN, VAA to AGND................................................-0.3V to +4V
VDDUto GNDU.........................................................-0.3V to +6V
OVSEL_, UVSEL_, TOPSEL to AGND ......-0.3V to (+VAA + 0.3V)
CD, ALRMLto AGND ...............................-0.3V to (+VAA + 0.3V)
ALRMUto GNDU...................................-0.3V to (+VDDU+ 0.3V)
CP+ to AGND ...........................(GNDU- 0.3V) to (VDDU+ 0.3V)
CP- to AGND...........................................-0.3V to (GNDU+ 0.3V)
CP- to VDDU.......................................................................+0.3V
ESD Rating
C_, REF, VAA, VDDUGNDU,
DCIN, SHDN, CP+, CP-, HV,
OVSEL_, UVSEL_, TOPSEL,
ALRMU, ALRML,
AGND, CD..............................±2kV (Human Body Model, Note 3)
Continuous Power Dissipation (TA= +70°C)
38-Pin TSSOP
(derating 15.9mW/°C above +70°C).........................1095.9mW
Operating Temperature Range .........................-40°C to +105°C
Storage Temperature Range .............................-55°C to +150°C
Junction Temperature (continuous).................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
C_ INPUTS
Common-Mode Input Range VCXIN Any two inputs Cn to Cn+1 for full
threshold accuracy (Note 4) 1.5 72 V
Input Current ICXIN VCELL = 3.0V -1 0.05 +1 µA
Overvoltage Threshold VOV +3.3 +4.8 V
Overvoltage-Threshold Accuracy ±5±25 mV
Undervoltage Threshold VUV +1.6 +2.8 V
Undervoltage-Threshold
Accuracy ±20 ±100 mV
Comparator Hysteresis VHYS 300 mV
CD PIN
CD Current ICD VCD = 0.4V 4.35 6.1 7.65 µA
CD Trip Voltage VCD Internal at comparator 1.23 V
Delay-Time Accuracy Excluding CDLY variation ±20 %
STATUS/CONTROL PORT
Shutdown Disable (SHDN High
Voltage) SHDN/VIH 2.1 V
Shutdown Asserted (SHDN Low
Voltage) SHDN/VIL 0.6 V
Note 1: The C1 to C0 differential input path is tolerant to 80V as long as the SHDN pin is deasserted.
Note 2: The C1 input is tolerant to a maximum VDCIN + 0.6V. If SHDN is asserted, 20V is the maximum rating.
Note 3: Human Body Model to Specification MIL-STD-883 Method 3015.7.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(TA= TMIN to TMAX, unless otherwise noted. VDCIN = VGNDu= +6.0V to +72V, typical values are at TA= +25°C, unless otherwise
specified from -40°C to +105°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
VDDU Output High VDDU
VOH
Output voltage of VDDU after the
20kΩ/200kΩ resistor-divider to SHDN
GNDU
+ 2.4 V
VDDU Output Low VDDU
VOL
Output voltage of VDDU after the
20kΩ/200kΩ r esi stor - d i vi d er for S H DN
GNDU
+ 0.3 V
ALRML Output-Voltage High ALRML
VOH ISOURCE = 150µA 2.4 V
ALRML Output-Voltage Low ALRML
VOL ISINK = 150µA 0.6 V
ALRMU Input-Voltage High ALRMU
VIH
Daisy-chained ALRMU signal as
coupled through a 3.3nF high-voltage
capacitor and a 150kΩ resistor as
referred to GNDU
GNDU
+ 2.1 V
ALRMU Input-Voltage Low ALRMU
VIL
Daisy-chained ALRMU signal as
coupled through a 3.3nF high-voltage
capacitor and a 150kΩ resistor as
referred to GNDU
GNDU
+ 0.9 V
Alarm Voltage Output “Heartbeat”
Frequency
ALRML
fOUT
Heartbeat clock rate with no alarm
condition 4032 4096 4157 Hz
Alarm Voltage Output Duty Cycle Heartbeat clock rate with no alarm
condition 49.0 51.0 %
LINEAR REGULATOR (VAA)
Input Voltage Range VDCIN 672V
Output Voltage VAAOUT 6V < VDCIN < 72V, ILOAD = 0 3.0 3.3 3.6 V
Short-Circuit Current IAA S H ORT C IR C U IT VAA = 0, 6V < VDCIN < 36V 50 mA
VAARESET Falling VAA 2.8
VAAVALID Rising VAA 3.0 V
Power-On-Reset Trip Level
(Note 4)
VAAHYS Hysteresis on rising VAA 37 mV
Thermal Shutdown TSHUT Rising temperature +145 °C
POWER-SUPPLY REQUIREMENTS (DCIN)
Operating mode, SHDN = 1, 12
battery cells, alarm inactive,
VDCIN = VGNDU = 36V
35 40
Current Consumption IDCIN
Shutdown mode, SHDN = 0, 12
battery cells, VDCIN = VGNDU = 36V 1.3 2
µA
IGNDu Operating Mode SHDN = 1, battery cells, alarm
inactive, VDCIN = VGNDU = 36V 35 40 µA
LOGIC INPUTS AND OUTPUTS
VIH UVSEL0/UVSEL1/UVSEL2, TOPSEL VAA -
0.1
Threshold Setting
VIL OVSELO/OVSEL1/OVSEL2/OVSEL3 0.1
V
Note 4: Guaranteed by design and not production tested.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
4 _______________________________________________________________________________________
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
UNDERVOLTAGE SET THRESHOLD
vs. TEMPERATURE
MAX11080 toc01
TEMPERATURE (°C)
UNDERVOLTAGE SET THRESHOLD (V)
800-20 6040
1.59
1.60
1.61
1.56
1.57
1.58
1.62
1.63
1.64
1.55
-40 20 100
1.6V SET POINT
MAX
MEAN
MIN
CD CURRENT DISTRIBUTION
MAX11080 toc02
CD PIN CURRENT (µA)
DEVICE COUNT
5.6 6.66.05.8 6.4
10
15
20
5
25
30
35
0
5.4 6.2
CD CHARGING CURRENT
vs. TEMPERATURE
MAX11080 toc03
TEMPERATURE (°C)
CD CURRENT (µA)
800-20 6040
6.00
6.01
6.02
5.97
5.98
5.99
6.03
5.96
-40 20 100
VCD = 0.4V
DCIN SUPPLY CURRENT vs. VDCIN
MAX11080 toc04
VDCIN (V)
IDCIN (µA)
50 804030
40
50
60
30
70
20
020 607010
4.8V OVERVOLTAGE THRESHOLD
VCELL = VDCIN/12
TA = +105°C
TA = +25°CTA = -40°C
GNDU SUPPLY CURRENT
vs. GNDU VOLTAGE
MAX11080 toc05
VGNDU (V)
IGNDU (µA)
50 804030
25
30
35
20
40
45
50
55
15
020 607010
TA = +105°C
TA = +25°C
TA = -40°C
OVERVOLTAGE CLEAR THRESHOLD
vs. TEMPERATURE
MAX11080 toc06
TEMPERATURE (°C)
OVERVOLTAGE CLEAR THRESHOLD (V)
800-20 6040
4.51
4.52
4.53
4.48
4.49
4.50
4.54
4.47
-40 20 100
4.8V SET POINT
MAX
MEAN
MIN
OVERVOLTAGE SET THRESHOLD
vs. TEMPERATURE
MAX11080 toc07
TEMPERATURE (°C)
OVERVOLTAGE SET THRESHOLD (V)
800-20 6040
4.800
4.802
4.804
4.794
4.796
4.798
4.806
4.792
-40 20 100
4.8V SET POINT
MAX
MEAN
MIN
UNDERVOLTAGE CLEAR THRESHOLD
vs. TEMPERATURE
MAX11080 toc08
TEMPERATURE (°C)
UNDERVOLTAGE CLEAR THRESHOLD (V)
800-20 6040
1.90
1.92
1.84
1.86
1.88
1.94
1.82
-40 20 100
1.6V SET POINT
MAX
MEAN
MIN
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
_______________________________________________________________________________________ 5
Pin Description
PIN NAME FUNCTION
1 DCIN DC Power-Supply Input. DCIN supplies the internal 3.3V regulator. This pin should be connected as shown
in the application diagrams.
2HV
High-Voltage Bias. HV is biased by the output of the charge pump to provide a DC supply above the DCIN
level. It is used internally to bias the cell-comparator circuitry. Bypass to DCIN with a 1µF capacitor.
3, 33 N.C. No Connection
4 C12 Cell 12 Plus Connection. Top of battery module stack.
5 C11 Cell 12 Minus Connection and Cell 11 Plus Connection
6 C10 Cell 11 Minus Connection and Cell 10 Plus Connection
7 C9 Cell 10 Minus Connection and Cell 9 Plus Connection
8 C8 Cell 9 Minus Connection and Cell 8 Plus Connection
9 C7 Cell 8 Minus Connection and Cell 7 Plus Connection
10 C6 Cell 7 Minus Connection and Cell 6 Plus Connection
11 C5 Cell 6 Minus Connection and Cell 5 Plus Connection
12 C4 Cell 5 Minus Connection and Cell 4 Plus Connection
13 C3 Cell 4 Minus Connection and Cell 3 Plus Connection
14 C2 Cell 3 Minus Connection and Cell 2 Plus Connection
15 C1 Cell 2 Minus Connection and Cell 1 Plus Connection
16 C0 Cell 1 Minus Connection
17 UVSEL0
18 UVSEL1
19 UVSEL2
Undervoltage Threshold Select 2 to 0. Used to select one of eight undervoltage alarm threshold settings.
The parts have internal pulldown; these pins should only be tied to VAA or AGND to set the logic state.
20 OVSEL0
21 OVSEL1
22 OVSEL2
23 OVSEL3
Overvoltage Threshold Select 3 to 0. Used to select one of 16 overvoltage alarm threshold settings.
The parts have internal pulldown; these pins should only be tied to VAA or AGND to set the logic state.
24 VAA +3.3V Analog Supply Output. Bypass with a 1µF capacitor to AGND.
25, 29,
30, 32 AGND Analog Ground. Should be connected to the negative terminal of cell 1.
26 SHDN
Active-Low Shutdown Input. This pin completely shuts down the MAX11080 internal regulator and
oscillators when the pin is less than 0.6V as referenced to AGND. The host controller should drive SHDN for
the first pack. SHDN for daisy-chained modules should be connected to the lower neighboring module’s
VDDU through a 20kΩ series resistor.
27 ALRML
Lower Port Alarm Output. This output is an alarm indicator for overvoltage, undervoltage, and setup faults.
The alarm signal is daisy chained and driven from the highest module down to the lowest. The alarm output
is nominally a clocked “heartbeat” signal that provides a 4kHz clock when no alarm is present. The ALRML
can also be configured as level signal and set to “low” for no alarm and “high” for alarm state. See the
TOPSEL Function section for details. This signal swings between VAA and AGND, and is active high in the
alarm state.
28 CD
Programmable Delay Time. Connect a capacitor from this pin to AGND to set the hold time required for a
fault condition before the alarm is set. The capacitor should be a ceramic capacitor in the 15nF to 16.5µF
range.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
6 _______________________________________________________________________________________
Pin Description (continued)
PIN NAME FUNCTION
31 TOPSEL Input to Indicate Topmost Device in the Daisy Chain. This pin should be connected to AGND for all devices
except the topmost. For the top device, this pin should be connected to VAA.
34 ALRMUUpper Port Alarm Input. This input receives the ALRML output signal from an upper neighboring module. It
swings between VDDU and GNDU.
35 GNDU
Level-Shifted Upper Port Ground. Upper port-supply return and supply input for the charge pump and HV
supplies. This pin should be connected to the DCIN takeoff point on the battery stack as shown in the
application diagrams.
36 VDDU
Level-Shifted Upper Port Supply. Upper port-supply output for the daisy-chained bus. This is a regulated
output voltage from the internal charge pump that is level-shifted above the DCIN pin voltage level. It
should be bypassed with a 1µF capacitor to GNDU.
37, 38 CP-, CP+ Charge-Pump Capacitor. Negative/positive input for the internal charge pump. Connect a 0.01µF high-
voltage capacitor between CP+ and CP-.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
_______________________________________________________________________________________ 7
MAX11080
CELL COMPARATORS
LDO
REGULATOR
CELL COMPARATORS
C12
HV DCIN
C11
C10
CELL COMPARATORS
CELL COMPARATORS
C9
C8
CELL COMPARATORS
CELL COMPARATORS
C7
C6
CELL COMPARATORS
CELL COMPARATORS
C5
C4
CELL COMPARATORS
CELL COMPARATORS
C3
C2
CELL COMPARATORS
CELL COMPARATORS
C1
C0
AGND CD
FAULT-STATE
MACHINE
AND
CONTROL LOGIC
FAULT
LOWER
PORT
ALRML
SHDN
OVSEL3
OVSEL2
OVSEL1
OVSEL0
UVSEL2
UVSEL1
UVSEL0
TOPSEL
UPPER
PORT
VDDU
ALRMU
GNDU
LEVEL
SHIFT
CP+
CP-
VAA
FAULT
Figure 1. Functional Diagram
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
8 _______________________________________________________________________________________
MAX11080
VDDU
ALRMU
AGND CD
HV DCIN
C3DC
3.3nF
630V
GNDU
CHV
1µF
6V R2DC
20kΩ
RDCIN
5kΩ
CDCIN
0.1µF
80V
CDLY
15nF TO 16.5µF CERAMIC CAP
CDD
1µF
6V
CP
0.01µF
100V
GNDU
GNDU
GNDU
DPROT
5.6V
SMCJ70
FUSE
C12
R13
C12CELL 12
MODULE+(N)
MODULE-(N)
MODULE-(N+1)
BUS BAR
BUS BAR
C11
R12
C11CELL 11
C10
R11
C10CELL 10
C9
R10
C9
CELL 9
C8
R9
C8CELL 8
C7
R8
C7CELL 7
C6
R7
C6CELL 6
C5
R6
C5CELL 5
C4
R5
C4CELL 4
C3
R4
C3CELL 3
C2
R3
C2CELL 2
C1
R2
C1CELL 1
C0
MODULE
N+1
CELL STACK
MODULE
N+1
GND REFERENCE
MODULE
N-1
CELL STACK
MODULE
N-1
GNDU TAKEOFF
LOCAL
GROUND
R1DC
150kΩ
RSHD2
20kΩ
RSHD
200kΩ
SHDN
ALRML
GNDU
CP+
CP-
CA
1µF
6V
VAA
ALRML
OVSEL3
OVSEL2
OVSEL1
OVSEL0
UVSEL2
UVSEL1
UVSEL0
TOPSEL
SHDN
DAISY-CHAIN BUS
TO UPPER MODULES
MODULE
N+1
ISOLATOR
AND
CONTROL
INTERFACE
SEE TEXT FOR GNDU
CONNECTION OPTIONS
VAA
JUMPER BANK
R2–R13 = 10kΩ
C1–C12 = 0.1µF/80V
Figure 2. Application Circuit Diagram for a 12-Cell System
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
_______________________________________________________________________________________ 9
MAX11080
VDDU
ALRMU
AGND CD
HV DCIN
C3DC
3.3nF
630V
GNDU
CHV
1µF
6V R2DC
20kΩ
RDCIN
5kΩ
CDCIN
0.1µF
80V
CDLY
15nF TO 16.5µF CERAMIC CAP
CDD
1µF
6V
CP
0.01µF
100V
GNDU
GNDU
GNDU
DPROT
5.6V
SMCJ70
FUSE
C12
R11
C10CELL 10
MODULE+(N)
MODULE-(N)
MODULE-(N+1)
BUS BAR
BUS BAR
C11
C10
C9
R10
C9
CELL 9
C8
R9
C8CELL 8
C7
R8
C7CELL 7
C6
R7
C6CELL 6
C5
R6
C5CELL 5
C4
R5
C4CELL 4
C3
R4
C3CELL 3
C2
R3
C2CELL 2
C1
R2
C1CELL 1
C0
MODULE
N+1
CELL STACK
MODULE
N+1
GND REFERENCE
MODULE
N-1
CELL STACK
MODULE
N-1
GNDU TAKEOFF
LOCAL
GROUND
R1DC
150kΩ
RSHD2
20kΩ
RSHD
200kΩ
SHDN
ALRML
GNDU
CP+
CP-
CA
1µF
6V
VAA
ALRML
OVSEL3
OVSEL2
OVSEL1
OVSEL0
UVSEL2
UVSEL1
UVSEL0
TOPSEL
SHDN
DAISY-CHAIN BUS
TO UPPER MODULES
MODULE
N+1
ISOLATOR
AND
CONTROL
INTERFACE
VAA
JUMPER BANK
R2–R11 = 10kΩ
C1–C10 = 0.1µF/80V
Figure 3. Application Circuit Diagram for a 10-Cell System
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
10 ______________________________________________________________________________________
MAX11080
VDDU
ALRMU
AGND CD
HV DCIN
C3DC
3.3nF
630V
GNDU
CHV
1µF
6V R2DC
20kΩ
RDCIN
5kΩ
CDCIN
0.1µF
80V
CDLY
15nF TO 16.5µF CERAMIC CAP
CDD
1µF
6V
CP
0.01µF
100V
GNDU
GNDU
GNDU
DPROT
5.6V
SMCJ70
FUSE
C12
R9
C8CELL 8
MODULE+(N)
MODULE-(N)
MODULE-(N+1)
BUS BAR
BUS BAR
C11
C10
C9
C8
C7
R8
C7CELL 7
C6
R7
C6CELL 6
C5
R6
C5CELL 5
C4
R5
C4CELL 4
C3
R4
C3CELL 3
C2
R3
C2CELL 2
C1
R2
C1CELL 1
C0
MODULE
N+1
CELL STACK
MODULE
N+1
GND REFERENCE
MODULE
N-1
CELL STACK
MODULE
N-1
GNDU TAKEOFF
LOCAL
GROUND
R1DC
150kΩ
RSHD2
20kΩ
RSHD
200kΩ
SHDN
ALRML
GNDU
CP+
CP-
CA
1µF
6V
VAA
ALRML
OVSEL3
OVSEL2
OVSEL1
OVSEL0
UVSEL2
UVSEL1
UVSEL0
TOPSEL
SHDN
DAISY-CHAIN BUS
TO UPPER MODULES
MODULE
N+1
ISOLATOR
AND
CONTROL
INTERFACE
VAA
JUMPER BANK
R2–R9 = 10kΩ
C1–C8 = 0.1µF/80V
Figure 4. Application Circuit Diagram for an 8-Cell System
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 11
MAX11068
VDDU
ALRMU
AGND REF
HV DCIN
DCIN
SCLU
CDCIN1
CDCIN2 DPROT2
SMCJ70
DPROT1
SMCJ70
DCIN
D1
FUSE
C1Q750
(1206)
C12
R13
C12CELL 12
MODULE+(N)
MODULE-(N)
MODULE-(N+1)
BUS BAR
BUS BAR
C11
R12
C11
CELL 11
C10
R11
C10
CELL 10
C9
R10
C9
CELL 9
C8
R9
C8CELL 8
C7
R8
C7CELL 7
C6
R7
C6CELL 6
C5
R6
C5CELL 5
C4
R5
C4CELL 4
C3
R4
C3CELL 3
C2
R3
C2CELL 2
C1
R2
R1 C1
C0
CELL 1
C0
THRM
AUXIN2
AUXIN1
MODULE
N+1
CELL STACK
MODULE
N+1
GND REFERENCE
MODULE N-1
CELL STACK
SDAU
GNDU
CP+
CP-
VDDL
SCLL
SDAL
ALRML
GNDL
GPIO1
GPIO2
GPIO0
VAA
SHDN
MAX11080
ALRMU
VDDU
C12
C11
C10
C9
C8
C7
C6
C5
C4
C3
C2
C1
C0
GNDU
CP+
CP-
TOPSEL
SHDN
CD
OVSEL0
ALRML
ISOLATOR
AND
CONTROL
INTERFACE
FOR FIRST
MODULE
R26 R25 R24 R23 R22 R21 R20 R19 R18 R17 R15R16
C24 C23 C22 C21 C20 C19 C18 C17 C16 C15 C14 C13
LOCAL GROUND
REFER TO EACH DEVICE'S APPLICATION REFERENCE CIRCUITS FOR COMPONENTS AND VALUES NOT SHOWN ON THIS SIMPLIFIED SYSTEM-LEVEL SCHEMATIC.
BATTERY
CONNECTOR
HV
DCIN
VAA
AGND
UVSEL1
UVSEL0
UVSEL2
OVSEL1
OVSEL2
OVSEL3
RDCIN2
D2
GPIO
ALRML
(MAX11080)
ALRML
(MAX11068)
SDAL
SCLL
SHDN
Figure 5. Battery Module System with Redundant Fault-Detection Application Schematic
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
12 ______________________________________________________________________________________
HV VDDU
CP+
ALRMU
GNDU
CP-
DCIN
C12
C0
AGND
C1 TO C11
6V
6V
4V
4V
80V
80V80V
6V
VAA
ALRML
TOPSEL
SHDN
CD
OVSEL0/1/2/3
UVSEL0/1/2
MAX11080
ESD DIODES
Figure 6. ESD Diode Diagram
Detailed Description
Figure 1 shows the functional diagram; Figure 2 shows
the application circuit diagram for a 12-cell system
while Figure 3 shows the application circuit design for a
10-cell system and Figure 4 for an 8-cell system. Figure
5 is the application schematic for the battery module
system with redundant fault detection.
Architectural Overview
The MAX11080 is a battery-pack fault-monitor IC capa-
ble of monitoring up to 12 Li+ battery cells. This device
is designed to provide an overvoltage or undervoltage
alarm indicator when any of the cells cross the user-
selectable threshold for longer than the configured
decision delay interval. The MAX11080 also incorpo-
rates a daisy-chain bus for use in high-voltage stacked-
battery operation. The daisy-chain bus relays shutdown
and alarm communication across up to 31 stacked
modules without the need for isolation between each
module. This results in a simplified system with reduced
cost. The MAX11080 is ideal as an ultra-low-power,
redundant cell fault monitor that is the perfect comple-
ment to the MAX11068 high-voltage battery measure-
ment IC. Both ICs in concert form a powerful Li+ battery
system monitor with redundant overvoltage and under-
voltage fault detection.
Overvoltage and Undervoltage Fault
Detection
Figure 7 summarizes the fault-detection mechanism for
a set of differential cell inputs in the MAX11080.
First, the differential cell inputs are attenuated by a fac-
tor of four while being level-shifted and converted to a
single-ended voltage referenced to AGND. The ground-
referenced voltage is then connected to a set of over-
voltage and undervoltage comparators. The threshold
references for the comparators are set by the UVSEL_
and OVSEL_ input pins. When one of the cell voltages
exceeds VOV or is below VUV when VUV is enabled, the
internal cell out-of-range signal for the given cell is set
and logically ORed with the same signal for the other
cell positions to create an overall out-of-range signal.
When any cells are out-of-range as indicated by the
internal out-of-range signal, an internal current source
begins to charge the capacitor CDLY connected to the
CD pin. If the voltage at the CD pin reaches VCD, the
ALRMLline is set to VAA (+2.4V minimum as referred to
AGND). Normally, the ALRMLline is a heartbeat signal
with pulses occurring every 250µs. If all cell voltages
transition from out-of-range to in-range before the volt-
age at pin CD reaches VCD, an internal switch clamps
the CD pin to GND. This action discharges CDLY and,
because the delay had not yet expired, no alarm
occurs. Discharging CDLY ensures that the full delay
time occurs for the next overvoltage or undervoltage
event. Figure 8 summarizes the CDLY circuit.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 13
75mV
HYSTERESIS
75mV
HYSTERESIS
SHORT-CIRCUIT
DETECTOR
UNDERVOLTAGE
COMPARATOR
ENABLE
CELL
OUT-OF-RANGE
11
OUT-OF-RANGE
VUV/4
VSC/4
VOV/4
VCELL/4
VCELL/4
VCELL RSHIFT
RIN*
40MΩ
TYP
2MΩ
TYP
AGND
+
-
+
-
VCELL
6MΩ
TYP
+
-
VCELL/(4 x RSHIFT)
CN
CELLS 2-12
CELL 1
CN+1
HV
Figure 7. Cell Differential Input and Comparator Block Diagram
11
CELL OUT-OF-RANGE
1 TO 12
OUT-OF-RANGE
VAA
ICD
6.1µA
VCD
THRESHOLD
ALARM
CD
CDLY
6kΩ
Figure 8. CDLY Circuit Block Diagram
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
14 ______________________________________________________________________________________
Once the ALRMLpin is forced high due to an alarm
(+2.4V minimum as referred to AGND), it transitions
back to a heartbeat signal only after all battery cells
meet the following condition:
(VOV - VHYS) > VCELL(ALL) > (VUV + VHYS)
Examples of cell-voltage readings and their effect on
the alarm status are shown in Figures 9 and 10 for sin-
gle- and multiple-cell systems. In the case where an
upper module is forwarding an active alarm condition
down the daisy chain, that condition continues to be
propagated toward the host regardless of the alarm
state of any lower module. Furthermore, to circumvent
the possibility of a short-circuited capacitor connected
to CD preempting the fault-time validation process, a
redundant built-in delay of 4s nominal is asserted as a
backup. If the VCD threshold is not reached within 4s of
an out-of-range event, the alarm becomes active.
Programmable Delay Time
The alarm trigger delay time is calculated according to
the following equations:
tDLY = (VCD x CDLY)/ICD
CDLY = (tDLY x ICD)/VCD
The effective ICD value of the current source is 6.1µA
typical and the threshold voltage, VCD, is 1.23V typical.
The VCD threshold is specified at an internal node prior
to the resistor in series with the CD pin as shown in
Figure 8. The threshold voltage seen at the pin is
approximately 1.18V due to the drop associated with
the typical ICD value and the 6kΩresistor. The
MAX11080 can operate with capacitor values from
15nF (3.0ms) to 16.5µF (3.32s). Each capacitor should
have a voltage tolerance of 5V minimum.
Cell-Voltage Threshold Selection
The overvoltage and undervoltage threshold selection
is configured through the OVSEL_ and UVSEL_ inputs.
The overvoltage selection can be configured from 3.3V
to 4.8V in 100mV increments. The undervoltage thresh-
old can be configured from 1.6V to 2.8V in 200mV
increments. The undervoltage detection can also be
disabled. See Tables 1 and 2 for the proper configura-
tion settings.
Immunity to unintended changes in the threshold volt-
age setting (due to accidental pin-to-pin short circuits,
for example) is provided. The customer-programmed
selection is sensed and stored at power-up and any
subsequent change to the input pin status is ignored.
OVERVOLTAGE SELECTION
THRESHOLD (V) OVSEL3 OVSEL2 OVSEL1 OVSEL0
3.3 0 0 0 0
3.4 0 0 0 1
3.5 0 0 1 0
3.6 0 0 1 1
3.7 0 1 0 0
3.8 0 1 0 1
3.9 0 1 1 0
4.0 0 1 1 1
4.1 1 0 0 0
4.2 1 0 0 1
4.3 1 0 1 0
4.4 1 0 1 1
4.5 1 1 0 0
4.6 1 1 0 1
4.7 1 1 1 0
4.8 1 1 1 1
Table 1. Overvoltage Threshold Selection
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 15
VOV
VOV - VHYS
VCD
CELL
VOLTAGE
CD
ALRML
ANY
CELL
Figure 9. Single-Cell Overvoltage Detection Example
VOV VOV - VHYS
VCD
CELL
VOLTAGE
CELL 12
CELL 1
CELL 11
CELL N
CD
ALRML
Figure 10. Multiple-Cell Overvoltage Detection Example
MAX11080
Internal Linear Regulator
The MAX11080 has an internal linear regulator for gen-
erating the internal supply from DCIN (Figure 11). The
regulator can accept a supply voltage on the DCIN pin
from +6.0V to +72V, which it regulates to 3.3V to run
the voltage-detection system, control logic, and low-
side alarm-pulse interface. When the SHDN pin is not
active and a sufficient voltage is applied to DCIN, the
output of the regulator becomes active. The regulator is
paired with a power-on-reset (POR) circuit that senses
its output voltage and holds the MAX11080 in a reset
state until the internal supply has reached a sustainable
threshold of +3.0V (±5%). The internal comparators
have built-in hysteresis that can reject noise on the sup-
ply line. Because secondary metal batteries are never
fully discharged to 0V, the MAX11080 is designed for a
hot-swap insertion of the battery cells. Once the POR
threshold is reached, approximately 1ms later the inter-
nal reset signal disables, the internal oscillator starts,
and the charge pump begins operating. The charge
12-Channel, High-Voltage Battery-Pack
Fault Monitor
16 ______________________________________________________________________________________
UNDERVOLTAGE SELECTION
THRESHOLD (V) UVSEL2 UVSEL1 UVSEL0
Disabled 0 0 0
1.6 0 0 1
1.8 0 1 0
2.0 0 1 1
2.2 1 0 0
2.4 1 0 1
2.6 1 1 0
2.8 1 1 1
Table 2. Undervoltage Threshold Selection
LINEAR
REGULATOR
+6.0V TO +72V INTERNAL +3.3V
CHARGE
PUMP
+3.3V TO GNDU
+3.0V ±5%
BANDGAP
REFERENCE
DIE OVERTEMPERATURE
DETECT
DCIN
SHDN
VAA
VDDU
GNDU
REGULATOR
ENABLE
CHARGE-PUMP
ENABLE
35mV
HYSTERESIS
POR
COMPARATOR
INTERNAL POR
POR THRESHOLD
Figure 11. Internal Linear Regulator Block Diagram
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 17
POR ACTIVE
VOLTAGE APPLIED
TO DCIN
FAULT THRESHOLDS
READ
16kHz OSCILLATOR
ENABLED
CHARGE-PUMP
ENABLED
POR CLEARED
REGULATOR
ENABLED
CHECK SHDN
TOP BOARD
IDENTIFIED
NUMBER OF CELLS
DETECTED
MAX11080 FULLY
FUNCTIONAL
OVERVOLTAGE
COMPARATOR
SELF-TEST
CHECK VAA
SHDN ACTIVE
VAA < 3.0V
1ms DELAY
3ms DELAY
Figure 12. Linear Regulator Power-Up Sequence
Figure 13. Low DCIN POR Event
pump reaches regulation in approximately 3ms. The
MAX11080 associated with the top module in the bat-
tery pack is identified as detailed in the
TOPSEL
Function
section. This is followed by a self-test of the
overvoltage comparators and detection of the number
of cells connected. At this time in the power-on
sequence, the MAX11080 is ready for operation. When
the charge pump achieves regulation of 3.3V between
VDDUand GNDU, it switches to a standby mode until
the voltage drops by about 35mV. The specified accu-
racy and full operation of the MAX11080 are not guar-
anteed until a minimum of 6.0V is applied to the DCIN
pin.
The linear regulator also incorporates a thermal shut-
down feature. If the MAX11080 die temperature rises
above +145°C, the device shuts down. After a thermal
shutdown, the die temperature must cool 15°C below
the shutdown temperature before the device restarts.
Figure 12 shows the linear regulator power-up sequence
and Figure 13 shows the low DCIN POR event.
MAX11080
DCIN and GNDUSupply Connections
A surge voltage is produced by the electric motor dur-
ing regenerative braking conditions. The MAX11080 is
designed to tolerate an absolute maximum of 80V
under this condition. The MAX11080 should be protect-
ed against higher voltages with an external voltage
suppressor such as the PBMB78AT3 on the DCIN con-
nection point. This protection circuit also helps to
reduce power spikes that can occur during the inser-
tion of the battery cells. During negative voltage excur-
sions, the protection circuit stores enough charge to
power the regulator through the transient. Figure 14
shows the clamp configuration to protect the DCIN sup-
ply input.
The DCIN input contains a comparator circuit to detect
an open circuit on this pin for fault-management pur-
poses. Whenever a nominal voltage of two silicon diode
drops appears between C12 and DCIN following the
power-up sequence, the ALRMLoutput is asserted as a
fault indication. This voltage drop must appear for at
least the delay time set by CDLY to result in a fault. The
voltage drop from C12 to DCIN during normal operation
should be kept at no more than 0.5V to prevent erro-
neous tripping of the DCIN open-circuit comparator
under worst-case circumstances (lowest silicon diode
forward bias voltage). The diode DDCIN is used to sup-
ply the transient current demanded at startup by the
decoupling circuit. In parallel with this diode, RDCIN
provides the supply path during normal operation. It is
selected to be 5kΩso that the maximum voltage drop
between C12 and DCIN is about 0.25V with nominal
supply currents.
High-power batteries are often used in noisy environ-
ments subject to high dV/dt or dI/dt supply noise and
EMI noise. For example, the supply noise of a power
inverter driving a high horse-power motor produces a
large square wave at the battery terminals, even though
the battery is also a high-power battery. Typically, the
battery dominates the task of absorbing this noise,
since it is impractical to put hundreds of farads at the
inverter.
The MAX11080 is designed with several mechanisms to
deal with extremely noisy environments. First, the major
power-supply inputs that see the full battery-stack volt-
age are 80V tolerant. This is high enough to handle the
large voltage changes on the battery stack that can
occur when the batteries transition between charge and
discharge conditions. Next, the linear regulator has
high PSRR to produce a clean low-voltage power sup-
ply for the internal circuitry. This allows DCIN to be con-
nected directly to the stack voltage. Finally, GNDU
serves two purposes. It supplies the internal charge
pump with its power and acts as the reference ground
for the upper alarm communication port. The charge
pump creates a secondary low-voltage supply that is
referenced to GNDU. Because the level-shifted supply
VDDUis referenced to GNDU, the entire upper alarm
communication port glides smoothly on GNDUand it is
effectively immune to noise on GNDU. The upper alarm
signal is internally shifted down to AGND level where it
is processed by the digital logic. There are two connec-
tion methods that can be used for GNDU depending on
application requirements.
For the top module in a system, or where GNDUcannot
be DC-coupled to the next higher module for other rea-
sons, GNDUshould be connected to the same location
as DCIN. This connection is valid as long as the voltage
difference between the top of Stack(n) and the bottom
of Stack(n+1) during worst-case conditions does not
exceed the margin of the alarm pin signaling levels.
When GNDUis not DC-coupled to the far side of the
bus bar, it can be AC-coupled to the far side to main-
tain alarm communication when the bus bar is open-cir-
cuit. In that case, the two sides of the AC-coupling
capacitor can be at different DC potentials, but the
alarm communication signal continues to be passed
across the capacitor connection. It is recommended
that an AC- or DC-coupled version of GNDUis paired
with the alarm signal through the communication bus
wiring, possibly by twisted pair wire, for maximum noise
immunity and minimum emissions.
The preferred connection to reject noise between mod-
ules is when a DC connection can be made from GNDU
to AGND of the next module. It is again recommended
that the DC-coupled GNDUsignal is routed adjacent to
the alarm signal as part of the communication bus for
maximum noise immunity and minimum emissions.
12-Channel, High-Voltage Battery-Pack
Fault Monitor
18 ______________________________________________________________________________________
TO DCIN INPUT
RDCIN
5kΩ
CDCIN
0.1µF
80V
PBMB78AT3
FUSE
TOP OF CELL STACK
SEE THE APPLICATION CIRCUIT DIAGRAMS (FIGURES 15 AND 16) FOR THE
PROPER CONNECTION LOCATION.
Figure 14. Battery Module Surge and Overvoltage Protection
Circuit
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 19
C12
C11
C2
C1
C0 AGND
DCIN
GNDU
MODULEN+1
C12
C11
C2
C1
C0 AGND
DCIN
GNDU
MODULEN
BUS BAR
OPTIONAL
TO MAINTAIN
ALARM
COMMUNICATION
Figure 15. GNDUConnection: AC-Coupled to Next Module,
DC-Coupled to Present Module
Figure 16. GNDUConnection: DC-Coupled with the
Communication Bus
MAX11080
Shutdown Control
The SHDN pin connections of the MAX11080 operate in
a manner that allows the shutdown/wake-up command
to trickle up through the series of daisy-chained packs.
Because the internal linear regulator is powered down
during shutdown, the shutdown function must operate
when VAA is absent and it, therefore, cannot depend on
a Schmitt trigger input. A special low-current, high-volt-
age circuit is used to detect the state of the SHDN pin.
The shutdown pin has a +1.8V minimum threshold for
the inactive state. When SHDN > 1.8V, the MAX11080
turns on and begins regulating VDDUand VDDL. If
SHDN < 0.6V, the MAX11080 shuts down. For automat-
ic shutdown when the pack is removed from the sys-
tem, connect a 200kΩresistor from SHDN to AGND.
Once SHDN is driven high, the power-up sequence fol-
lows that described for the internal linear regulator. The
SHDN signal of the next higher module should be con-
nected to VDDU through a 20kΩresistor pullup. This
connection ensures that the next module in the daisy
chain is enabled as VDDUof the lower module powers
up. This action propagates up the daisy chain until the
last battery module is enabled. The shutdown of a
VDDUsupply pulls the connected SHDN pin of the
upper module toward GNDLand propagates the shut-
down signal up the daisy chain.
A shutdown signal propagated from the first daisy-
chain device to the last incurs a certain amount of
delay. A deasserted shutdown signal is not propagated
to the next higher module until the charge pump has
regulated the level-shifted upper port supply, VDDU, to
a value greater than the SHDN VIH level. This time
depends on both the charge-pump capacitor used and
the value of the VDDUdecoupling capacitor. A typical
time delay of 10ms can be expected from the time the
SHDN pin reaches the deasserted state until VDDU
reaches its full specified value.
C1 Input Absolute Maximum Rating
The C1 input is limited to VDCIN - 0.6V above AGND or
a maximum of 20V if the SHDN pin is asserted. If an
application requires that the 20V restriction be removed
during active shutdown, then a 4.0V zener diode can
be added from VAA to AGND. This protects VAA and
allows the C1 input to go to VDCIN - 0.6V regardless of
the SHDN state. It also allows the differential C1 to C0
voltage to range from -0.3V to +80V.
Cell-Connection Detection
An individual MAX11080 can be connected to as many
as 12 series-connected cells. To accommodate configu-
rations with fewer cells, unused cell inputs must be short-
ed together. The designer can choose which cell inputs
to leave unused. The example application circuits in this
document have chosen to populate the uppermost cell
position and group the unused inputs just under this cell.
At power-up, the part compares the voltage applied to
each cell input with a nominal cell-detection threshold
voltage of 0.7V. If the cell voltage is less than the cell-
detection threshold, undervoltage detection is disabled
for that cell input. If the voltage at the input is 0.7V or
greater, undervoltage detection is specified by the
state of the UVSEL_ inputs. Overvoltage detection is
always enabled for all cell-voltage inputs. The cell-con-
nection detection occurs just before the MAX11080 is
fully functional as shown in Figure 12 under “Number of
Cells Detected.”
TOPSEL Function
The TOPSEL pin is used to indicate to a device whether
it is the top device in the daisy-chain stack. The top
daisy-chain device is responsible for generating the
heartbeat signal at the top of the ALRM_ pin bus. This
heartbeat propagates along the chain toward the host.
To designate a device as the top device, the TOPSEL
pin should be connected to VAA. For all other devices
in a daisy chain, this pin should be connected to
AGND. The TOPSEL pin has a weak internal pulldown
resistor, but this resistor should not be relied upon as
the sole means of setting the TOPSEL logic level. The
logic level of the TOPSEL pin is not latched internally at
startup and is continuously sampled during operation.
The ALRMUinput should be connected to GNDUfor the
top module as good design practice to prevent noise
pickup even though the input logic level is ignored.
For the single device application, the device enters the
“level” mode when the TOPSEL is connected to AGND.
The ALRMLshows the level of AGND for no alarm state
and VAA for alarm state. ALRMUhas to be tied to
GNDUfor this mode. The following table summarizes
the operation of TOPSEL and ALRML:
Internal Self-Test
The MAX11080 performs an internal self-test during
power-up according to the linear regulator power-up
flowchart (Figure 12). Each overvoltage comparator is
tested for the ability to detect an internally generated
overvoltage test condition. This is done by using the
ground voltage level as the threshold reference in place
of the usual threshold level. Figure 8 shows the connec-
12-Channel, High-Voltage Battery-Pack
Fault Monitor
20 ______________________________________________________________________________________
ALRML
TOPSEL ALRMUNo alarm alarm
0001
1X
Heartbeat 1
tion for this test-mode compare level. If all comparators
can detect the internally generated overvoltage test
event, part operation continues. If any comparator fails
to detect the internally generated overvoltage test
event, a fault is signaled using the ALRMLpin. The
device must be power cycled to retest the comparators
and attempt to clear this fault condition.
Failure Mode and Effects Analysis
High-voltage battery-pack systems can be subjected to
severe stresses during in-service fault conditions and
could experience similar conditions during the manu-
facturing and assembly process. The MAX11080 is
designed with high regard to these potential states.
Open and short circuits at the package level must be
readily detected for fault diagnosis and should be toler-
ated whenever possible. A number of circuits are
employed within the MAX11080 specifically to detect
such conditions and progress to a known device state.
Table 3 summarizes other conditions typical in a normal
manufacturing process along with their effect on the
MAX11080 device.
See Table 4 for the FEMA analysis of the MAX11080. If
the cell voltage is within the monitor range, the heart-
beatsignal on the ALRML resumes once the fault condi-
tion (either open or short) is removed, unless specified.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 21
CONDITION EFFECT DESIGN RECOMMENDATION
PCB or IC package open or short circuit—
no stack load
Refer to the pin-level FMEA analysis
spreadsheet available from the factory
The built-in features of the MAX11080
should ensure low FMEA risk in most
cases.
Random connection of cells to IC—
no stack load No effect
The series resistors on the cell inputs of
the MAX11080 as well as the internal
design ensure protection against random
power supply or ground connections.
Random connection of modules—
no stack load No effect
Each module is referenced to its neighbor,
so no special connection order is
necessary.
Random connect/disconnect of
communication bus—no stack load;
AC- or DC-coupled
Communication from host to the first break
in the daisy-chain bus
The level-shifted interface design of the
MAX11080 ensures that the SHDN, GNDU,
and ALRM_ communication bus can be
connected at any time with no load.
Random connect/disconnect of
communication bus—with stack load;
AC- or DC-coupled
Communication from host to the first break
in the daisy-chain bus
The level-shifted interface design of the
MAX11080 ensures that the SHDN, GNDU,
ALRM_ communication bus can be
connected at any time as long as the
power bus is properly connected.
Connect/disconnect module interconnect
(bus bar)—no stack load
No effect for DC- or AC-coupled
communication bus
A break in the power bus does not cause
a problem as long as there is no load on
the stack.
Removal/fault of module interconnect
(bus bar)—with stack load
No effect for AC-coupled communication
bus; device damage for DC-coupled bus
An AC-coupled bus with isolation on the
SHDN pin or a redundant bus-bar
connection should be used to protect
against this case.
Removal/fault of module interconnect
(bus bar)—with stack under charge
No effect for AC-coupled communication
bus; device damage for DC-coupled bus
An AC-coupled bus with isolation on the
SHDN pin or a redundant bus-bar
connection should be used to protect
against this case.
Table 3. System Fault Modes
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
22 ______________________________________________________________________________________
PIN
NUMBER NAME ACTION EFFECT
Open (or Disconnected) ALRML goes high (see Note 6).
1 DCIN Short to Pin 2 ALRML goes high.
Open (or Disconnected) ALRML goes high.
2HV
Short to Pin 3 No effect.
Open (or Disconnected) No effect.
3N.C.
Short to Pin 4 No effect.
Open (or Disconnected)
• If open occurs before power-up, the part works as if C12 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C12 to C11 is disabled and is
not enabled even if the pin is reconnected.
• If open occurs after power-up, it is considered a zero voltage input. ALRML
goes high when the undervoltage is enabled.
4 C12
Short to Pin 5
• If short occurs before power-up, the part works as if C12 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C12 to C11 is disabled and is
not enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C12 to C11. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high because it causes an overvoltage to the affected input pair
even if the overvoltage is set to the maximum.
5 C11
Short to Pin 6
• If short occurs before power-up, the part works as if C11 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C11 to C10 is disabled and is
not enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C11 to C10. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
6 C10
Short to Pin 7
• If short occurs before power-up, the part works as if C10 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C10 to C9 is disabled and is
not enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C10 to C9. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
7C9
Short to Pin 8
• If short occurs before power-up, the part works as if C9 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C9 to C8 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C9 to C8. ALRML goes high when the undervoltage is enabled.
Table 4. FEMA Analysis (Note 5)
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 23
PIN
NUMBER NAME ACTION EFFECT
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
8C8
Short to Pin 9
• If short occurs before power-up, the part works as if C8 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C8 to C7 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C8 to C7. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
9C7
Short to Pin 10
• If short occurs before power-up, the part works as if C7 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C7 to C6 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C7 to C6. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
10 C6
Short to Pin 11
• If short occurs before power-up, the part works as if C6 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C6 to C5 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C6 to C5. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
11 C5
Short to Pin 12
• If short occurs before power-up, the part works as if C5 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C5 to C4 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C5 to C4. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
12 C4
Short to Pin 13
• If short occurs before power-up, the part works as if C4 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C4 to C3 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C4 to C3. ALRML goes high when the undervoltage is enabled.
Table 4. FEMA Analysis (Note 5) (continued)
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
24 ______________________________________________________________________________________
PIN
NUMBER NAME ACTION EFFECT
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
13 C3
Short to Pin 14
• If short occurs before power-up, the part works as if C3 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C3 to C2 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C5 to C4. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
14 C2
Short to Pin 15
• If short occurs before power-up, the part works as if C2 does not exist
because the internal circuit detects the situation and assumes it is what the
application intended to do. The monitoring of C2 to C1 is disabled and is not
enabled even if the short is removed.
• If short occurs after power-up, the situation is treated as a zero voltage input
for C2 to C1. ALRML goes high when the undervoltage is enabled.
Open (or Disconnected) ALRML goes high as it causes an overvoltage to the affected input pair even if
the overvoltage is set to the maximum.
15 C1
Short to Pin 16 ALRML goes high irrespective of whether undervoltage is enabled/disabled
and before and after power-up.
Open (or Disconnected) ALRML goes high irrespective of whether undervoltage is enabled/disabled
and before and after power-up.
16 C0
Short to Pin 17
• ALRML goes high if pin 17 is pulled high by VAA. The part consumes a large
current as VAA is shorted to AGND (connected to C0).
• If pin 17 is tied to AGND, there is no effect.
Open (or Disconnected) The pin defaults to low due to the internal pulldown (see Note 7). The effect
depends on the intended undervoltage setting.
17 UVSEL0
Short to Pin 18
• If pin 17 and pin 18 have the same intended value, there is no effect for the
short.
• If pin 17 and pin 18 have a different setting, the VAA is shorted to AGND.
ALRML goes low.
Open (or Disconnected) The pin defaults to low due to the internal pulldown (see Note 7). The effect
depends on the intended undervoltage setting.
18 UVSEL1
Short to Pin 19
• If pin 18 and pin 19 have the same intended value, there is no effect for the
short.
• If pin 18 and pin 19 have a different setting, the VAA is shorted to AGND.
ALRML goes low.
Open (or Disconnected) The pin defaults to low due to the internal pulldown (see Note 7). The effect
depends on the intended undervoltage setting.
19 UVSEL2
Short to Pin 20
• If pin 19 and pin 20 have the same intended value, there is no effect for the
short.
• If pin 19 and pin 20 have the different setting, the VAA is shorted to. AGND
ALRML goes low.
Table 4. FEMA Analysis (Note 5) (continued)
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
______________________________________________________________________________________ 25
PIN
NUMBER NAME ACTION EFFECT
Open (or Disconnected) The pin defaults to low due to the internal pulldown (see Note 7). The effect
depends on the intended overvoltage setting.
20 OVSEL0
Short to Pin 21
• If pin 20 and pin 21 have the same intended value, there is no effect for the
short.
• If pin 20 and pin 21 have a different setting, the VAA is shorted to AGND.
ALRML goes low.
Open (or Disconnected) The pin defaults to low due to the internal pulldown (see Note 7). The effect
depends on the intended overvoltage setting.
21 OVSEL1
Short to Pin 22
• If pin 21 and pin 22 have the same intended value, there is no effect for the
short.
• If pin 21 and pin 22 have a different setting, the VAA is shorted to AGND.
ALRML goes low.
Open (or Disconnected) The pin defaults to low due to the internal pulldown (see Note 7). The effect
depends on the intended overvoltage setting.
22 OVSEL2
Short to Pin 23
• If pin 22 and pin 23 have the same intended value, there is no effect for the
short.
• If pin 22 and pin 23 have a different setting, the VAA is shorted to AGND.
ALRML goes low.
Open (or Disconnected) The pin defaults to low due to the internal pulldown (see Note 7). The effect
depends on the intended overvoltage setting.
23 OVSEL3
Short to Pin 24 • If pin 23 is set high, there is no effect for the short.
• If pin 23 is set low, the VAA is shorted to AGND. ALRML goes low.
Open (or Disconnected) ALRML goes high.
24 VAA Short to Pin 25 ALRML goes low.
Open (or Disconnected) VAA goes to approximately 100mV and ALRML is approximately 0.5V. There is
no heartbeat if there is a one before the opening.
25 AGND
Short to Pin 26 The device is in shutdown mode. ALRML is low.
Open (or Disconnected) The pin is internally pulled down and the device goes to the shutdown mode.
ALRML is low.
26 SHDN
Short to Pin 27
ALRML goes high and stays high even if the short is removed. The internal
detect circuit considers this a major failure and the part has to be repowered
up to come out of this state.
Open (or Disconnected) The signal at the ALRML cannot be seen by the host.
27 ALRMLShort to Pin 28
ALRML goes high and stays high even if the short is removed. The internal
detect circuit considers this a major failure and the part has to be repowered
up to come out of this state.
Open (or Disconnected) The delay between the fault condition and alarm setting (ALRML goes high)
goes to the minimum. This means there is almost no delay.
28 CD
Short to Pin 29 The delay between the fault condition and alarm setting (ALRML goes high) is
approximately 4s, which is set by the internal watchdog.
Table 4. FEMA Analysis (Note 5) (continued)
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
26 ______________________________________________________________________________________
PIN
NUMBER NAME ACTION EFFECT
Open (or Disconnected) No effect.
29 AGND Short to Pin 30 No effect.
Open (or Disconnected) No effect.
30 AGND Short to Pin 31
If pin TOPSEL is set high (VAA), it causes the short between VAA and AGND.
ALRML is low.
There is no effect if TOPSEL is set low.
Open (or Disconnected)
If the part is the topmost device in the daisy chain, the ALRML is set high as
the state of TOPSEL is low (internally pulled down).
There are no other effects as the state of the pin stays the same (both low).
31 TOPSEL
Short to Pin 32
No effect if TOPSEL is set low.
If TOPSEL is set high, it causes the short between VAA and AGND and ALRML
is low.
Open (or Disconnected) No effect.
32 AGND Short to Pin 33 No effect.
Open (or Disconnected) No effect.
33 N.C. Short to Pin 34 No effect.
Open (or Disconnected)
ALRMU is internally pulled up to VDDU. There is no effect to the topmost
device. Otherwise, the communication of the chain is broken and the alarm
signal from the parts close to the topmost device are not passed through.
Since ALRML is a reflection of ALRMU, the state of ALRML is high for the no-
alarm state.
34 ALRMU
Short to Pin 35
No effect for the topmost device. Otherwise, the communication of the chain is
broken and the alarm signal from the parts close to the topmost are not
passed through. Since ALRML is a reflection of ALRMU, the state of ALRML is
low for the no-alarm state.
Open (or Disconnected) The ALRML goes high. VDDU floats down approximately 4V. (See Note 8.)
35 GNDUShort to Pin 36 The ALRML is high. (See Note 8).
Open (or Disconnected) ALRML goes high. HV is approximately 0.4V below DCIN. (See Note 8.)
36 VDDUShort to Pin 37 ALRML goes high. VDDU is approximately 0.5V lower than GNDU.
(See Note 8.)
Open (or Disconnected) ALRML goes high. VDDU and HV collapse.
37 CP- Short to Pin 38 ALRML goes high. VDDU is approximately 0.5V lower than GNDU.
(See Note 8.)
38 CP+ Open (or Disconnected) ALRML goes high. VDDU and HV collapse. (See Note 8.)
Table 4. FEMA Analysis (Note 5) (continued)
Note 5: If the cell voltage is within the monitor range, the heartbeat signal on the ALRML resumes once the fault condition is
removed.
Note 6: The voltage level of high is equal to VAA and low is equal to AGND.
Note 7: Even if the pin has internal pulldown, the pulldown is very weak and the pin should be tied to AGND for logic 0 setting.
Note 8: VDDU- GNDU= 3.3 - V and HV - DCIN = 3.6V for the typical configuration. When VDDUand HV collapse, VDDU- GNDU≈
0 - V and HV - DCIN ≈-0.4V.
MAX11080
12-Channel, High-Voltage Battery-Pack
Fault Monitor
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________
27
© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Pin Configuration Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
38 TSSOP U38-1 21-0081