_______________General Description
The MAX913 single and MAX912 dual high-speed,
low-power comparators have differential inputs and
complementary TTL outputs. Fast propagation delay
(10ns typ), extremely low supply current, and a wide
common-mode input range that includes the negative
rail make the MAX912/MAX913 ideal for low-power,
high-speed, single +5V (or ±5V) applications such as
V/F converters or switching regulators.
The MAX912/MAX913 outputs remain stable through
the linear region. This feature eliminates output instability
common to high-speed comparators when driven with a
slow-moving input signal.
The MAX912/MAX913 can be powered from a single
+5V supply or a ±5V split supply. The MAX913 is an
improved plug-in replacement for the LT1016. It pro-
vides significantly wider input voltage range and equiva-
lent speed at a fraction of the power. The MAX912 dual
comparator has equal performance to the MAX913 and
includes independent latch controls.
________________________Applications
Zero-Crossing Detectors
Ethernet Line Receivers
Switching Regulators
High-Speed Sampling Circuits
High-Speed Triggers
Extended Range V/F Converters
Fast Pulse Width/Height Discriminators
____________________________Features
♦Ultra Fast (10ns)
♦Single +5V or Dual ±5V Supply Operation
♦Input Range Extends Below Negative Supply
♦Low Power: 6mA (+5V) Per Comparator
♦No Minimum Input Signal Slew-Rate Requirement
♦No Power-Supply Current Spiking
♦Stable in the Linear Region
♦Inputs Can Exceed Either Supply
♦Low Offset Voltage: 0.8mV
______________Ordering Information
* Dice are specified at T
A
= +25°C, DC parameters only.
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
________________________________________________________________
Maxim Integrated Products
1
1
2
3
4
8
7
6
5
V+
IN+
IN-
V-
Q
Q
GND
LE
DIP/SO
MAX913
+
-
TOP VIEW
___________________________________________________________Pin Configurations
Call toll free 1-800-998-8800 for free samples or literature.
19-0157; Rev 1; 1/94
PART TEMP. RANGE PIN-PACKAGE
MAX912CPE 0°C to +70°C 16 Plastic DIP
MAX912CSE 0°C to +70°C 16 Narrow SO
MAX912C/D 0°C to +70°C Dice*
MAX912EPE -40°C to +85°C 16 Plastic DIP
MAX912ESE -40°C to +85°C 16 Narrow SO
MAX912MJE -55°C to +125°C 16 CERDIP
N.C.
V-
INA-
LEB
N.C.
V+
INB-
DIP/Narrow SO
116QA
GND
LEA
QB
GND
MAX912
89INA+ INB+
+
-
QA QB
+
-
AB
4
5
6
7
13
12
11
10
2
3
15
14
MAX913CPA 0°C to +70°C 8 Plastic DIP
MAX913CSA 0°C to +70°C 8 SO
MAX913C/D 0°C to +70°C Dice*
MAX913EPA -40°C to +85°C 8 Plastic DIP
MAX913ESA -40°C to +85°C 8 SO
MAX913MJA -55°C to +125°C 8 CERDIP
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Positive Supply Voltage............................................................7V
Negative Supply Voltage ........................................................-7V
Differential Input Voltage .....................................................±15V
Input Voltage (Referred to V-)..................................- 0.3V to 15V
Latch Pin Voltage.............................................Equal to Supplies
Continuous Output Current...............................................±20mA
Continuous Power Dissipation (TA= +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ...727mW
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C)........640mW
16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)...842mW
16-Pin Narrow SO (derate 8.70mW/°C above +70°C) ...696mW
16-Pin CERDIP (derate 10.00mW/°C above +70°C)....800mW
Operating Temperature Ranges:
MAX91_ C_ _ ......................................................0°C to +70°C
MAX91_ E_ _....................................................-40°C to +85°C
MAX91_ MJ_ .................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec).............................+300°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.
PARAMETER
RS≤100Ω
SYMBOL MIN TYP MAX
TA= TMIN to TMAX
UNITS
TA= +25°C
3
TA= TMIN to TMAX
Offset Drift TCVOS 2 µV/°C
Input Offset Current (Note 1) IOS 0.3 0.5 µA
TA= +25°C
0.8
TA= +25°C
Input Bias Current IB
35
µA
C, E temp. ranges 8
M temp. range 10
CONDITIONS
Input Offset Voltage (Note 1) VOS 0.8 2 mV
Single +5V C, E temp. ranges
Power-Supply Rejection Ratio PSRR
M temp. range
Positive supply: 4.5V ≤V+ ≤5.5V 60 85
M temp. range
-5.0 +3.5
-5.0V ≤VCM ≤+3.5V
dB
IOUT = 1mA
VOL
-0.2 +3.5
Negative supply: -2V ≥V- ≥-7V
Common-Mode Rejection Ratio CMRR
80 100
0 +3.5 dB
C, E temp. ranges
IOUT = 10mA
80 110
Small-Signal Voltage Gain AV1V ≤VQ≤2V, TA= +25°C 1500 3500 V/V
Output Voltage VOH V+ ≥4.5V 2.7 3.4
V
2.4 3.0
ISINK = 4mA 0.3 0.5
TA= +25°C, ISINK = 10mA 0.4
Input Voltage Range VCM
-5.2 +3.5
V
ELECTRICAL CHARACTERISTICS
(V+ = +5V, V- = -5V, VQ= 1.4V, VLE = 0V, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
12
C, E temp. ranges 610
Positive Supply Current Per
Comparator I+ M temp. range 12 mA
Latch-Pin High Input Voltage VIH
I- 0.4 2 mA
2.0 V
Latch-Pin Current IIL VLE = 0V
Latch-Pin Low Input Voltage VIL 0.8 V
-20 µA
Negative Supply Current Per
Comparator
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = +5V, V- = -5V, VQ= 1.4V, VLE = 0V, TA= TMIN to TMAX, unless otherwise noted).
TA = +25°C
TA= TMIN to TMAX
∆VIN = 100mV,
VOD = 20mV 912
T
A
= +25°C
Propagation Delay (Note 2) tPD+, tPD-
∆VIN = 100mV,
VOD = 5mV 10 14
ns
16
15
TA= TMIN to TMAX
Note 1: Input Offset Voltage (VOS) is defined as the average of the two input offset voltages, measured by forcing first one output,
then the other to 1.4V. Input Offset Current (IOS) is defined the same way.
Note 2: Propagation Delay (tPD) and Differential Propagation Delay (∆tPD) cannot be measured in automatic handling equipment
with low input overdrive values. The MAX912/MAX913 are sample tested to 0.1% AQL with a 1V step and 500mV overdrive
at +25°C only. Correlation tests show that tPD and ∆tPD can be guaranteed with this test, if additional DC tests are per-
formed to guarantee that all internal bias conditions are correct. For low overdrive conditions, VOS is added to the over-
drive. Differential Propagation Delay is defined as: ∆tPD = tPD+ – tPD-.
Note 3: Input latch setup time (tSU) is the interval in which the input signal must be stable prior to asserting the latch signal.
The hold time (tH) is the interval after the latch is asserted in which the input signal must be stable. These parameters are
guaranteed by design.
Note 4: Latch Propagation Delay (tLPD) is the delay time for the output to respond when the latch-enable pin is deasserted.
See Timing Diagram.
CONDITIONS
PARAMETER SYMBOL UNITSMIN TYP MAX
TA=
+25°C
∆VIN = 100mV,
VOD = 5mV 23
ns
20t
SU
∆tPD
Latch Setup Time (Note 3) ns
Differential Propagation Delay
(Note 2)
TA= +25°C
∆VIN = 100mV,
VOD = 5mV
(MAX912 only) 500 ps
Channel-to-Channel
Propagation Delay
(Note 2)
32t
H
Latch Hold Time (Note 3) ns
7tLPD
Latch Propagation Delay (Note 4) ns
__________________________________________Typical Operating Characteristics
(V+ = 5V, V- = -5V, VLE = 0V, CL= 15pF, TA = +25°C, unless otherwise noted.)
51 10 100
PROPAGATION DELAY
vs. INPUT OVERDRIVE
INPUT OVERDRIVE (mV)
PROPAGATION DELAY (ns)
6
7
8
9
10
tPD(-)
tPD(+)
MAX912-01
VOD = 10mV 50
01 100 10,000
PROPAGATION DELAY
vs. SOURCE RESISTANCE
10
MAX912-02
SOURCE RESISTANCE (Ω)
PROPAGATION DEALY (ns)
20
30
40
10 1000
tPD(-)
tPD(+)
VOD = 10mV
PROPAGATION DELAY
vs. LOAD CAPACITANCE
PROPAGATION DELAY (ns)
610 20 30 40 50
LOAD CAPACITANCE (pF)
MAX912-03
7
8
9
10
11
tPD(-)
tPD(+)
VOD = 10mV
MAX913 35MAX912
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
4 _______________________________________________________________________________________
____________________________Typical Operating Characteristics (continued)
(V+ = 5V, V- = -5V, VLE = 0V, CL= 15pF, TA = +25°C, unless otherwise noted.)
PROPAGATION DELAY
vs. TEMPERATURE
PROPAGATION DELAY (ns)
TEMPERATURE (°C)
6-55
MAX912-04
-15 25 105 12565
7
8
9
10
11 Q OUTPUT
tPD(-)
Q OUTPUT
tPD(-)
Q OUTPUT
tPD(+)
Q OUTPUT
tPD(+)
VOD = 10mV
POSITIVE SUPPLY CURRENT
(PER COMPARATOR)
vs. POSTIVE SUPPLY VOLTAGE
I+ (PER COMPARATOR)
2
4
6
8
10
34567
V+ (V)
MAX912-07
TA = +125°C
TA = +25°C
TA = -55°C
V- = 0V TO -5V
NEGATIVE SUPPLY CURRENT
(PER COMPARATOR)
vs. NEGATIVE SUPPLY VOLTAGE
I- (PER COMPARATOR)
V- (V)
0.2 0
MAX912-08
1234567
0.4
0.6
0.8
1.0
1.2
TA = +125°C
TA = +25°C
TA = -55°C
OFFSET VOLTAGE
vs. TEMPERATURE
VOS (µV)
0-55 TEMPERATURE (°C)
MAX912-11
-15 25 65 105 125
200
400
800
1000
600
INPUT BIAS CURRENT
vs. TEMPERATURE
IB (µA)
2
TEMPERATURE (°C)
MA912-12
-55 -15 25 65 105 125
3
4
5
6
VCM = -5.2V
VCM = 0V
VCM = +3.5V
OUTPUT VOLTAGE
vs. DIFFERENTIAL INPUT VOLTAGE
OUTPUT VOLTAGE (V)
DIFFERENTIAL INPUT VOLTAGE (mV)
0-3
MAX912-14
-2 -1 1 2 30
1
2
3
4
5
TA = +125°C
TA = +25°C
TA = -55°C
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
_______________________________________________________________________________________ 5
____________________________Typical Operating Characteristics (continued)
(V+ = 5V, V- = -5V, VLE = 0V, CL= 15pF, TA = +25°C, unless otherwise noted.)
POSITIVE-TO-NEGATIVE PROPAGATION DELAY
INPUT
100mV/div
OUTPUT
Q
1V/div
Q
5ns/div
NEGATIVE-TO-POSITIVE PROPAGATION DELAY
INPUT
100mV/div
OUTPUT
Q
1V/div
Q
5ns/div
MAX912/MAX913 RESPONSE TO
50MHz (+10mVP-P) SINE WAVE
INPUT
10mV/div
OUTPUT
Q
2V/div
10ns/div
INDUSTRY STANDARD
686 RESPONSE
INPUT
20mV/div
OUTPUT
Q
1V/div
Q
20µs/div
1V/div
MAX912/MAX913 RESPONSE
INPUT
20mV/div
OUTPUT
Q
1V/div
Q
20µs/div
1V/div
MAX912/MAX913 RESPONSE TO SLOW-MOVING TRIANGLE WAVE
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
6 _______________________________________________________________________________________
____________________________________________________________Pin Descriptions
PIN
MAX912 NAME FUNCTION
1 QA Comparator A TTL output
2–
Q
–AComparator A complementary TTL output
3, 14 GND Logic ground. Connect both GND pins to ground.
4 LEA
5, 12 N.C. Not internally connected
6 V- Negative power supply: -5V for dual supplies (bypass to GND with a 0.1µF capacitor), or GND for a
single supply
7 INA- Comparator A inverting input
8 INA+ Comparator A noninverting input
9 INB+ Comparator B noninverting input
10 INB- Comparator B inverting input
11 V+ Positive power supply, +5V. Bypass to GND with a 0.1µF capacitor.
13 LEB
15 –
Q
–BComparator B complementary TTL output
16 QB Comparator B TTL output
PIN
MAX913 NAME FUNCTION
1 V+ Positive power supply. Bypass to GND with a 0.1µF capacitor.
2 IN+ Noninverting input
3 IN- Inverting input
4 V- Negative power supply: -5V for dual supplies (bypass to GND with a 0.1µF capacitor), or GND for a
single supply
5 LE
6 GND Logic ground
7 Q TTL output
8–
Q
–Complementary TTL output
Comparator A latch enable. QA and –
Q
–A are latched when LEA is high or floating.
Comparator A latch is transparent when LEA is low.
Comparator B latch enable. QB and –
Q
–B are latched when LEB is high or floating.
Comparator B latch is transparent when LEB is low.
Latch enable. Q and –
Q
–are latched when LE is TTL high or floating. The comparator latch is
transparent when LE is low.
_______________Detailed Description
The MAX913 (single) and MAX912 (dual) high-speed
comparators have a unique design that prevents oscil-
lation when the comparator is in its linear region. No
minimum input slew rate is required.
Many high-speed comparators oscillate in the linear
region, as shown in the
Typical Operating
Characteristics’
industry-standard 686 response graph.
One way to overcome this oscillation is to sample the
output after it has passed through the unstable region.
Another practical solution is to add hysteresis. Either
solution results in a loss of resolution and bandwidth.
Because the MAX912/MAX913 do not need hysteresis,
they offer high resolution to all signals—including low-
frequency signals.
The MAX912/MAX913 provide a TTL-compatible latch
function that holds the comparator output state (Figure 1).
As long as Latch Enable (LE) is high or floating, the input
signal has no effect on the output state. With LE low, the
outputs are controlled by the input differential voltage and
the latch is transparent.
Input Amplifier
A comparator can be thought of as having two sec-
tions: an input amplifier and a logic interface. The
MAX912/MAX913’s input amplifier is fully differential,
with input offset voltage trimmed to below 2.0mV at
+25°C. Input common-mode range extends from
200mV below the negative supply rail to 1.5V below the
positive power supply. The total common-mode range
is 8.7V when operating from ±5VDC supplies.
The MAX912/MAX913’s amplifier has no built-in hys-
teresis. For highest accuracy, do not add hysteresis.
Figure 2 shows how hysteresis degrades resolution.
Resolution
A comparator’s ability to resolve small signal differ-
ences—its resolution—is affected by various factors.
As with most amplifiers, the most significant factors are
the input offset voltage (VOS) and the common-mode
and power-supply rejection ratios (CMRR, PSRR). If
source impedance is high, input offset current can be
significant. If source impedance is unbalanced, the
input bias current can introduce another error.
For high-speed comparators, an additional factor in reso-
lution is the comparator’s stability in its linear region. Many
high-speed comparators are useless in their linear region
because they oscillate. This makes the differential input
voltage region around 0V unusable, as does a high VOS.
Hysteresis does not cure the problem, but acts to keep
the input away from its linear range (Figure 2).
The MAX912/MAX913 do not oscillate in the linear region,
which greatly enhances the comparator’s resolution.
__________Applications Information
Power Supplies and Bypassing
The MAX912/MAX913 are tested with ±5V power sup-
plies that provide an input common-mode range (VCM)
of 8.7V (-5.2V to +3.5V). Operation from a single +5V
supply provides a common-mode input range of 3.7V
(-0.2V to +3.5V). Connect V- to GND for single-supply
operation. The MAX912/MAX913 will operate from a
minimum single-supply voltage of +4.5V.
The V+ supply provides power to both the analog input
stage and digital output circuits, whereas the V- supply
only powers the analog section. Bypass V+ and V- to
ground with 0.1µF to 1.0µF ceramic capacitors in parallel
with 10µF or greater tantalum capacitors. Connect the
ceramic capacitors very close to the MAX912/MAX913’s
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
_______________________________________________________________________________________ 7
tSU
tH
tPD+
∆tPD
tPD-
tLPDR
Q
Q
VIN
(DIFFERENTIAL)
LATCH
ENABLE (LE)
Figure 1. Timing Diagram
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.
8
___________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600
© 1994 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
MAX912/MAX913
Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
HYSTERESIS
BAND*
IN+
IN-
Q
* WHEN HYSTERESIS IS ADDED, A COMPARATOR CANNOT RESOLVE ANY INPUT SIGNAL WITHIN THE HYSTERESIS BAND.
WITH HYSTERESIS
IDEAL (WITHOUT HYSTERESIS)
.
.
.
.
.
.
.
.
.
.
.
.
..
Figure 2. Effect of Hysteresis on Input Resolution
supply pins, keeping leads short to minimize lead
inductance. For particularly noisy applications, use fer-
rite beads on the power-supply lines.
Board Layout
As with all high-speed components, careful attention to
layout is essential for best performance.
1) Use a printed circuit board with an unbroken
ground plane.
2) Pay close attention to the bandwidth of bypass
components and keep leads short.
3) Avoid sockets; solder the comparator and other
components directly to the board to minimize
unwanted parasitic inductance and capacitance.
Input Slew Rate
The MAX912/MAX913 design eliminates the input slew-
rate requirement imposed on many standard compara-
tors. As long as LE is high after the maximum propaga-
tion delay and the input is greater than the compara-
tor’s total DC error, the output will be valid without oscil-
lations.
Maximum Clock (LE) and Signal Rate
The maximum clock and signal rate is 70MHz, based
on the comparator’s rise and fall time with a 5mV over-
drive at +25°C (Figure 1). With a 20mV overdrive, the
maximum propagation delay is 12ns and the clock and
signal rate is 85MHz.
__________________________________________________________Chip Topographies
V-
LEA
LEB
GND
INB-
QB
0.071"
(1.80mm)
0.080"
(2.03mm)
INB+
INA+
INA-
GND
QB QA QA
V+ V+
V-
LE
IN-
0.056"
(1.42mm)
0.058"
(1.47mm)
IN+ V+
Q
GND Q
MAX913
MAX912
TRANSISTOR COUNT: 100;
SUBSTRATE CONNECTED TO V-.
TRANSISTOR COUNT: 197;
SUBSTRATE CONNECTED TO V-.
