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AOZ1375DI
ECPower™ 20V 5A Bidirectional Load Switch
with Over-Voltage and Over-Current Protection
General Description
The AOZ1375DI is a bidirectional current-limited load
switch intended for applications that require circuit protec-
tions. The device operates from voltages between 3.4V
and 23V and features two power terminals, VINT and
VBUS, which are rated at 28V Absolute Maximum. When
used as source switch, the internal current limiting circuit
protects the supply from large load current. The current
limit can be set with an external resistor. The back-to-back
switch configuration blocks any leakage between VINT
and VBUS pins when the device is disabled.
The AOZ1375DI provides over-voltage protection, short-
circuit protection and thermal protection function that limit
excessive power dissipation. The over-voltage protection
threshold is selectable by an external resistor. The internal
soft start circuitry controls inrush current due to highly
capacitive loads. The soft start can be adjusted using an
external capacitor. It consumes less than 5µA in shut-
down.
The AOZ1375DI is available in a 3mm x 3mm DFN-12L
package which can operate over -40
C to +85
C
temperature range.
Features
17.8m typical ON resistance
3.4V to 23V operating input voltage
VINT and VBUS are both rated 28V
Bidirectional operation
Reverse blocking to completely isolate VINT and
VBUS when disabled
Programmable current limit
Short circuit protection
Selectable Over-Voltage-Protection
Programmable soft start
Under-voltage lockout
Over-voltage lockout
Thermal shutdown protection
±4kV HBM ESD rating
±8kV HBM ESD rating for VBUS and VINT
3mm x 3mm DFN-12L package
UL pending
Applications
Thunderbolt/USB Type-C PD power switch
Notebook/desktop
Monitors
Docking station/dongles
Typical Application
RFLTB
VBUS
C
INT
AOZ1375DI
ON
OFF
VINT
CSN
FLTB
ILIM
EN SS
C
BUS
CSP
RLIM
C
SS
GND
5V
R
SENSE
10mΩ
ROVP
POVP
AOZ1375DI
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Ordering Information
All AOS products are offered in packages with Pb-free plating and compliant to RoHS standards.
Please visit www.aosmd.com/media/AOSGreenPolicy.pdf for additional information.
Pin Configuration
3mm x 3mm DFN-12L
Top Transparent View
Pin Description
Part Number Fault Recovery Temperature Range Package Environmental
AOZ1375DI-01 Auto-Restart -40°C to +85°C 3mm x 3mm DFN-12L RoHS
AOZ1375DI-02 Latch-Off -40°C to +85°C 3mm x 3mm DFN-12L RoHS
Pin Number Pin Name Pin Function
1, 2 VBUS Adapter supply input or output to periphery. Connect to VBUS Connector
3 POVP Programmable over voltage protection. Connect a resistor ROVP from POVP to GND.
4 FLTB Fault Indicator, Open Drain output. Active Low when fault condition occurs.
5 EN Enable Input.
6 GND Ground.
7 SS Soft start pin. Connect a capacitor CSS from SS to GND to set the soft start time.
8 ILIM Current limit set pin. Connect a resistor RLIM from ILIM to GND to set the switch current limit.
9 CSP Current sense positive input, connect to a 10m for accurate current sensing. Short to VINT
if current limit is not required
10 CSN Current sense negative input, connect to a 10m for accurate current sensing. Short to VINT
if current limit is not required
11, 12 VINT Connect to internal power source or load.
EXP EXP Exposed Pad. Connect to GND.
VBUS
VBUS
POVP
FLTB
EN
GND
VINT
VINT
CSN
CSP
ILIM
SS
`
EXP
AOZ1375DI
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Absolute Maximum Ratings(1)
Exceeding the Absolute Maximum ratings may damage the
device.
Note:
1.Devices are inherently ESD sensitive, handling precautions are
required. Human body model is a 100pF capacitor discharging
through a 1.5k resistor.
Recommend Operating Ratings
The device is not guaranteed to operate beyond the Maximum
Operating Ratings.
Parameter Rating
VINT, VBUS, CSP, CSN, to GND -0.3V to +28V
VINT-CSP, VINT-CSN, CSP-CSN -0.3V to +0.3V
EN, ILIM, SS, FLTB, POVP to GND -0.3V to +6V
Junction Temperature (TJ) +150°C
Storage Temperature (TS) -65°C to +150°C
ESD Rating HBM All Pins ±4kV
ESD Rating HBM VBUS/VINT ±8kV
Parameter Rating
Supply Voltage (VINT, VBUS) 3.4V to 23V
EN, FLTB 0 to 5.5V
POVP 0 to 3V
Switch Current (ISW) 0A to 6A
Ambient Temperature (TA) -40°C to +85°C
Package Thermal Resistance
3x3 DFN-12 (JA)50°C/W
Electrical Characteristics
TA = 25°C, VIN = 20V, unless otherwise specified.
Symbol Parameter Conditions Min. Typ. Max. Units
VVINT Input Supply Voltage VINT is input and VBUS is output 3.4 23 V
VVBUS VBUS is input and VINT is output 3.4 23
VUVLO Under-voltage Lockout Threshold VINT Rising, VBUS is output 3.0 3.35 V
VBUS Rising, VINT is output 3.0 3.35
VUVLO_HYS Under-voltage Lockout Hysteresis VINT Falling, VBUS is output 0.25 V
VBUS Falling, VINT is output 0.25
VOVLO_VINT
VOVLO_VBUS
Overvoltage Lockout Threshold
ROVP = 20k23.0 24.0 25.0
V
ROVP = 75k16.8 17.4 18.0
ROVP = 125k10.0 10.4 10.8
ROVP = 180k6.2 6.4 6.6
VOVLO_HYS Overvoltage Lockout Hysteresis VINT and VBUS 300 mV
tD_OVP Overvoltage Turn-off Delay VINT and VBUS 1 µs
IVINT_ON Input Quiescent Current VINT = 20V, IVBUS = 0A, EN = 5V 550 µA
IVBUS_ON VBUS = 20V, IVINT = 0A, EN = 5V
IVINT_OFF Input Shutdown Current VINT = 20V, VBUS = Float, EN=OFF 2 5 µA
IVBUS_OFF Output Leakage Current VBUS = 20V, VINT = Float, EN=OFF 2 5 µA
RON Switch On Resistance VINT = 20V, IVBUS = 1A, RLIM = 30k17.8 m
VINT = 5V, IVBUS = 1A, RLIM = 30k18.2 m
ILIMIT Current Limit(2)
RLIM = 68k (1% Tolerance)
RSENSE =10m (1% Tolerance) 2.02.352.7
A
RLIM = 47k (1% Tolerance)
RSENSE =10m (1% Tolerance) 3.0 3.4 3.8
RLIM = 30k (1% Tolerance)
RSENSE =10m (1% Tolerance) 5.0 5.3 5.6
AOZ1375DI
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Note:
2. Configured such that VINT is input and VBUS is output.
Functional Block Diagram
VEN_H Enable Input High Voltage 1.4 V
VEN_L Enable Input Low Voltage 0.6 V
IEN_BIAS Enable Input Bias Current EN = 1.8V 4 10 µA
VFLTB_LO Fault Pull-down Voltage ISINK = 3mA 0.3 V
tD_ON Turn-On Delay Time
EN to VBUS (10%)
EN to 10% of VBUS, VINT=20V,
CVBUS = 68F, CSS = 1nF 1600
µs
tON
Turn-On Rise Time
VBUS from 10% to 90%
VBUS rising from 10% to 90%,
VINT=20V, CVBUS = 68F, CSS =
1nF
400
VSCP Short Circuit Protection VINT - VBUS when VINT = 20V 5 V
TSD Thermal Shutdown Threshold 140 °C
TSD_HYS Thermal Shutdown Hysteresis 35
tOCP Over Current Response Time Over current to switch disabled 1 ms
tD_FLTB FLTB Delay The time of occurrence of over
current to FLTB going low 500 µs
tREC FLTB Recover Time Fault is removed 64 ms
Electrical Characteristics
TA = 25°C, VIN = 20V, unless otherwise specified.
Symbol Parameter Conditions Min. Typ. Max. Units
Control Logic
Gate Drive &
Charge Pump
UVLO
SCP
OVLO
Soft Start
Current
Limit
VBUS
POVP
VINT
CSN
CSP
ILIM
FLTB
GND
VINT
VBUS
VCC
VCC
EN
SS
AOZ1375DI
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Timing Diagrams
Figure 1. Turn-on Delay and Turn-on Time
Figure 2. OVP Delay and Recovery Time (AOZ1375DI-01)
Figure 3. OCP and FLTB Time
EN
VBUS
tD_ON
tON
VINT
VBUS
tREC
FLTB
tD_OVP
400µs
IOUT
tD_FLTB
FLTB
VBUS
tOCP
tREC
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Typical Performance Curves
Turn-On by EN (VINT=20V) Turn-On by EN (VINT=5V)
Turn-Off by EN (VINT=20V) Turn-Off by EN (VINT=5V)
VINT OVP Operation with ROVP=20kVINT OVP Operation with ROVP=180k
VINT
VBUS
IVBUS
EN
VINT
VBUS
IVBUS
EN
VINT
VBUS
IVBUS
EN
VINT
VBUS
IVBUS
EN
VINT
VBUS
IVINT
FLTB
VINT
VBUS
IVINT
FLTB
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Typical Performance Curves (continued)
Over-Current Protection (VINT=20V, RLIM=30k) Over-Current Protection (VINT=5V, RLIM=30k)
Short-Circuit Protection (VINT=20V, RLIM=30k)
(Auto-Restart)
Short-Circuit Protection (VINT=5V, RLIM=30k)
(Auto-Restart)
VINT
VBUS
IVINT
FLTB
VINT
VBUS
IVINT
FLTB
VINT
VBUS
IVINT
FLTB
VINT
VBUS
IVINT
FLTB
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AOZ1375DI
Typical Characteristics
TA = 25°C, unless otherwise specified.
Figure 4. VINT Quiescent Current vs. VINT Voltage Figure 5. VBUS Quiescent Current vs. VBUS Voltage
Figure 6. VINT Shutdown Current vs. VINT Voltage Figure 7. VBUS Shutdown Current vs. VBUS Voltage
Figure 8. VINT Quiescent Current vs.Temperature
(VINT=20V)
Figure 9. VBUS Quiescent Current vs.Temperature
(VBUS=20V)
IVINT_ON (µA)
VINT (V)
550
500
450
400
350
300
0 5 10 15 20 25
IVBUS_ON (µA)
VBUS (V)
550
500
450
400
350
300
0 5 10 15 20 25
IVINT_OFF (µA)
VINT (V)
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
0 5 10 15 20 25
IVBUS_OFF (µA)
VBUS (V)
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
0 5 10 15 20 25
IVINT_ON (µA)
Temperature (°C)
700
600
500
400
300
-40 -10 25 55 85
IVBUS_ON (µA)
Temperature (°C)
700
600
500
400
300
-40 -10 25 55 85
AOZ1375DI
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Typical Characteristics (Continued)
TA = 25°C, unless otherwise specified
Figure 10. VINT Shutdown Current vs.Temperature
(VINT=20V)
Figure 11. VBUS Shutdown Current vs.Temperature
(VBUS=20V)
Figure 12. Enable Input Low Voltage vs. Temperature Figure 13. Enable Input High Voltage vs.Temperature
Figure 14. UVLO Rise Voltage (VINT) vs. Temperature Figure 15. UVLO Rise Voltage (VBUS) vs. Temperature
IVINT_OFF (µA)
Temperature (°C)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
-40 -10 25 55 85
IVBUS_OFF (µA)
Temperature (°C)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
-40 -10 25 55 85
VEN_L (V)
Temperature (°C)
2.0
1.5
1.0
0.5
0
-40 -10 25 55 85
VEN_H (V)
Temperature (°C)
2.0
1.5
1.0
0.5
0
-40 -10 25 55 85
IUVLO (µA)
Temperature (°C)
3.30
3.25
3.20
3.15
3.10
-40 -10 25 55 85
VUVLO (V)
Temperature (°C)
3.30
3.25
3.20
3.15
3.10
-40 -10 25 55 85
AOZ1375DI
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Typical Characteristics (Continued)
TA = 25°C, unless otherwise specified
Figure 16. UVLO Hysteresis Voltage (VINT)
vs. Temperature
Figure 17. UVLO Hysteresis Voltage (VBUS)
vs. Temperature
Figure 18. VINT OVP vs. Temperature Figure 19. VBUS OVP vs. Temperature
VUVLO_HYS (mV)
Temperature (°C)
300
280
260
240
220
200
-40 -10 25 55 85
VUVLO_HYS (mV)
Temperature (°C)
300
280
260
240
220
200
-40 -10 25 55 85
VOVLO (V)
Temperature (°C)
30
25
20
15
10
5
0
-40 -20 20 40 60
ROVP=75kOhm
ROVP=20kOhm
ROVP=125kOhm
ROVP=180kOhm
0
-60 80 100
VOVLO (V)
Temperature (°C)
30
25
20
15
10
5
0
-40 -20 20 60 80
ROVP=75kOhm
ROVP=20kOhm
ROVP=125kOhm
ROVP=180kOhm
040
-60 100
AOZ1375DI
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Detailed Description
AOZ1375DI is a high-side load switch with adjustable
soft start, over current limit, over-voltage, over
temperature and short circuit protections. It is capable of
operating from 3.4V to 23V and rated up to 5A.
AOZ1375DI can be operated as bidirectional switch. As a
source switch it can pass power from VINT to the VBUS.
As a sink switch, it can pass supply from VBUS to VINT.
The devices automatically selects power from either
VINT or VBUS whichever is higher.
The power switch consists of 2 back-to-back connected
N-channel MOSFETs. When switch is enabled, the
overall resistance between VINT and VBUS is only
17.8m in typical condition, minimizing power lose and
thermal dissipation. The back-to-back configuration of
switches completely isolates between VINT and VBUS
when turned off, preventing leakage between the two
pins.
Enable
The EN pin is the ON/OFF control for the power switch.
The device is enabled when EN pin is high and device is
not in UVLO lockout state. The EN pin must be driven to
a logic high or logic low state to guarantee operation.
While disabled, the AOZ1375DI only draws about 2A
supply current.
Input Under-Voltage Lockout (UVLO)
The internal circuitry of AOZ1375DI is powered from
either VBUS or VINT. The under-voltage lockout (UVLO)
circuit of AOZ1375DI monitors the voltage at both pins
and only allows the power switches to turn on when VINT
or VBUS is higher than 3.4V. If both pins are below 3.4V,
the device is in under-voltage lockout state.
Programmable Over-Voltage Protection (OVP)
The voltages at both VINT and VBUS pins are
constantly monitored once the device is enabled. In
case voltage on either pin exceeds the programmed
threshold, over-voltage protection is activated:
1) If the power switch is on, it will be turned off
immediately to isolate VINT from VBUS;
2) OVP will prevent power switch to be turned on if it is
in off state.
In either case FLTB pin is pulled low to report the fault
condition.
An external resistor ROVP connected between POVP
and GND pins sets the over-voltage protection thresh-
old. An internal 8µA current source biases POVP pin.
The voltage drop across resistor ROVP is detected by
comparators that sets the OVP threshold based on the
table below:
Programmable Over-Current Protection (OCP)
AOZ1375DI implemented current limit to ensure that the
current through the switch does not exceed the
programmed value. The current passes through the
switch is sensed using external sense resistor RSENSE.
Current limit is programmed by an external resistor RLIM
connected between ILIM and GND. If over-load occur,
the internal circuitry will limit the output current based
on the value of RLIM.
The current limit threshold can be calculated according to
equation below for RSENSE=10m:
Current Limit = 160kV/RLIM (A)
For example, for 5.3A current limit, a 30k RLIM should
be selected.
Figure 20. Current Limit vs RLIM
The current limit threshold should be within 1A to 6A.
Current limit accuracy or functionality is not guaranteed
beyond this range. 1% resistors are recommended for
both RSENSE and RLIM.
When AOZ1375DI is under current-limiting, FLTB is
pulled low after 500µs delay. The load switch will then
open if the device is still current-limiting after an
additional 500µs delay.
ROVP Resistor Value OVP Threshold
20K 24V
75K 17.4V
125K 10.4V
180K 6.4V
Table 1. OVP Setting by External Resistor
AOZ1375DI
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There is no current limiting function when configured as
sink switch (current flow from VBUS to VINT), but VINT
startup rise time is still controlled by the SS pin.
If current limit function is not used, both CSP and CSN
pins must be connected to VINT.
Short-Circuit Protection (SCP)
AOZ1375DI implemented short circuit protection to
quickly turn off the power switch when output is severely
overloaded. A comparator monitors the voltage drop
between VINT and VBUS when switch is closed. Short-
circuit protection is activated when the above voltage
difference reaches approximately 75% of VIN. Short-
circuit protection functions in either sourcing or sinking
configuration.
Short-circuit protection is not active until soft start is com-
pleted.
Thermal Shutdown Protection
During current limit or short circuit, the power switch
resistance is increased to limit the load current. This
increases device power dissipation dramatically and
causes the die temperature to rise. When the die temper-
ature reaches 140°C the power switch is turned off.
There is a 35°C hysteresis. Over-temperature fault is
removed when die temperature drops below approxi-
mately 105°C.
Soft Start
When EN pin is asserted high, the soft start control
circuitry applies voltage on the gate of the power switch
in a manner such that the output voltage is ramped up
linearly until it reaches input voltage level. The soft start
can be adjusted by an external capacitor CSS connected
between SS pin and ground. The soft start can be
approximately set by the following equation:
Soft start of Output=VIN*2µA/Css -100µs
The actual soft start also depends on the output capaci-
tance and current limit setting if in-rush current reaches
current-limit level.
System Startup
The device is enabled when EN1.4V and either VBUS
or VINT is higher than UVLO threshold. The OVP thresh-
old is first selected by sensing POVP voltage set by
ROVP
. The device will then check if fault condition exist.
When no fault exists, the power switch is turned on and
the output is then ramped up, controlled by the soft start
and current limiting circuitry till it reaches input voltage.
Fault Protection
AOZ1375DI protects its load from the following fault
conditions: over-voltage, over-current, short circuit, and
over-temperature.
When device is first enabled, the power switch is off and
fault conditions are checked. If voltage at VBUS or VINT
is higher than the OVP threshold, or die temperature is
higher than thermal shutdown threshold. FLTB pin is
pulled low to report to host controller.
After the power switch turned on, device continuously
monitors all fault conditions. The switch is turned off
when OVP, short-circuit, or over-temperature is detected.
FLTB pin is pulled low.
In case of over-current, the device will limit the current
pass-through the switch to the value set by RLIM. The
switch is turned off if over-current last approximately
1ms. FLTB pin is pulled low about 500µs after OCP is
detected.
Auto-restart or Latch-off
AOZ1375DI-01 (auto-restart version): The device will
try to restart 64ms after the power switch is turned off
due to fault protection.
AOZ1375DI-02 ( latch-o ff versio n): The device keeps off
after fault occurs. It can only be re-enabled by either
toggle EN pin or recycle the power.
Input Capacitor Selection
The input capacitor prevents large voltage transients
from appearing at the input, and provides the instanta-
neous current needed each time the switch turns on to
charge output capacitors and to limit input voltage drop.
It is also to prevent high-frequency noise on the power
line from passing through to the output. The input
capacitor should be located as close to the pin as possi-
ble. A 10F ceramic capacitor is recommended. How-
ever, higher capacitor values further reduce the
transient voltage drop at the input.
Output Capacitor Selection
The output capacitor has to supply enough current for a
large load that it may encounter during system
transient. This bulk capacitor must be large enough to
supply fast transient load in order to prevent the output
from dropping.
There is an upper limit for output capacitor to ensure it
can be charged fully during start-up. This upper limit is
set by the current limit level and soft start time.
Output Capacitor (Max) = Current Limit * (t
ON
/ Input Voltage)
AOZ1375DI
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If output capacitor is too large that output voltage can’t
reach 75% of the input voltage at the end of soft start
time, short-circuit protection will be triggered.
Power Dissipation Calculation
Calculate the power dissipation for normal load condition
using the following equation:
Power Dissipated = RON × (IOUT)2
The worst case power dissipation occurs when the load
current hits the current limit due to over-current or short
circuit fault. The power dissipation under these conditions
can be calculated using the following equation:
Power Dissipated = |VINT – VBUS| × Current Limit
Layout Guidelines
Good PCB layout is important for improving the thermal
and overall performance of AOZ1375DI. To optimize the
switch response time to output short-circuit conditions,
keep all traces as short as possible to reduce the effect
of unwanted parasitic inductance. Place the input and
output bypass capacitors as close as possible to the
VINT and VBUS pins. The input and output PCB traces
should be as wide as possible for the given PCB space.
Use a ground plane to enhance the power dissipation
capability of the device.
AOZ1375DI
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Package Dimensions, DFN3x3B_12L, EP1_S
AOZ1375DI
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Tape and Reel Dimensions, DFN3x3B_12L, EP1_S
Carrier Tape
Reel
AOZ1375DI
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Tape and Reel Dimensions, DFN3x3B_12L, EP1_S
DFN3x3 EP TAPE
Leader / Trailer & Orientation
AOZ1375DI
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Part Marking
Part Number Description Code
AOZ1375DI-01 Green Product AA01
AOZ1375DI-02 Green Product AA02
YWLT
AA00
Part Number Code
Assembly Lot Code
Year & Week Code
DFN 3x3
Option Code
Special Code
As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant into
the body or (b) support or sustain life, and (c) whose
failure to perform when properly used in accordance
with instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of
the user.
2. A critical component in any component of a life
support, device, or system whose failure to perform can
be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or
effectiveness.
LEGAL DISCLAIMER
Alpha and Omega Semiconductor makes no representations or warranties with respect to the accuracy or complete-
ness of the information provided herein and takes no liabilities for the consequences of use of such information or
any product described herein. Alpha and Omega Semiconductor reserves the right to make changes to such informa-
tion at any time without further notice. This document does not constitute the grant of any intellectual property rights
or representation of non-infringement of any third party’s intellectual property rights.
LIFE SUPPORT POLICY
ALPHA AND OMEGA SEMICONDUCTOR PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL
COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS.