L9945
Datasheet
Automotive fully configurable 8-channel High/Low side MOSFET pre-driver
suitable for 12 V and 24 V systems
Features
TQFP64 exposed pad down
GADG1606171506PS
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Product status link
L9945
Product summary
Order code
L9945
L9945TR
Package
TQFP64
(exposed
pad down)
Packing
Tray
Tape and
reel
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AEC-Q100 qualified
12 V and 24 V battery systems compliance
3.3 V and 5 V logic compatible I/O
8-channel configurable MOSFET pre-driver
–
High-side (N-channel and P-channel MOS)
–
Low-side (N-channel MOS)
–
H-bridge (up to 2 H-bridge)
–
Peak & Hold (2 loads)
Operating battery supply voltage 3.8 V to 36 V
Operating VDD supply voltage 4.5 V to 5.5 V
All device pins, except the ground pins, withstand at least 40 V
Programmable gate charge/discharge currents for improving EMI behavior
Individual diagnosis for:
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Short circuit to battery
–
Open load
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Short circuit to ground
Highly flexible overcurrent sensing implementation
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Possibility of monitoring external MOS drain to source voltage
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Possibility of monitoring voltage on external shunt resistor
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64 programmable overcurrent thresholds independent for each channel
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Ultra-fast output shutdown in case of overcurrent
Current limitation for H-Bridge configuration
32-bit SPI protocol available for configuration and diagnostics
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Failures latched even if they occur during diagnostics reading
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Daisy chain operation
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SDO protected against overvoltage
Safety features
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Fast switch off redundant output disable through two external pins
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Built In Self Test (BIST) for logic operation
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Hardware Self Check (HWSC) for VDD5 overvoltage comparator
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Configurable Communication Check (CC) watchdog timer available
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Disable feedback through bi-directional pin
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Highly redundant output monitoring through dedicated SPI registers
10-bit ADC for battery and die temperature measurements available through SPI
VDD5 monitoring for over/under voltage
VPS (battery) monitoring for under voltage
ISO26262 systems compatible
DS12275
-
Rev 8
-
December 2019
For further information contact your local STMicroelectronics sales office.
www.st.com
L9945
Description
The
L9945
is an 8-channel MOSFET pre-driver configurable for low-side, high-side,
peak and hold and H-Bridge load control. It is designed to comply with the
requirements of 12 V (passenger vehicle) and 24 V (commercial vehicle) battery
systems.
All outputs can be PWM controlled. Six outputs are capable of driving safety relevant
loads. One output can be dedicated to the actuation of safety relevant loads requiring
a dedicated enable pin (EN6).
The device offers the possibility of controlling two independent H-Bridges.
The device can also drive up to two loads requiring "peak & hold" control strategy.
The driver outputs are protected against short circuit condition.
The device protects the external MOS in case of an overcurrent event.
Each output provides full diagnostic information such as short to battery, short to
ground and open-load. Each output status can be constantly monitored through
dedicated SPI registers.
The voltage slew rate of the external transistors 1-8 is controlled during turn ON and
turn OFF in order to improve EMI behavior.
A double, redundant, external disable source is available through DIS and NDIS pins
in order to improve safety.
The device is configurable via SPI through a 32-bit protocol.
DS12275
-
Rev 8
page 2/151
L9945
Block diagram
1
Block diagram
Figure 1.
Block diagram
L9945
GNDCP
VIO
SDI
SDO
SCK
NCS
GNDIO
CH4
CH3
SPI
Watchdog
Charge Pump
CH2
CH1
VGBHI
BATT12
DRN1/2
VDD5
VPS
GND
Power
Supply
BIST
&
HWSC
Output Channels
OUT1
OUT2
GNSP1/2
SNGP1/2
BATT34
DRN3/4
GNSP3/4
SNGP3/4
DRN5/6
GNSP5/6
SNGP5/6
BATT56
DRN7/8
GNSP7/8
SNGP7/8
BATT78
PGND78
PGND56
PGND34
PGND12
GADG2302170914PS
OUT3
OUT4
NRES
DIS
NDIS
EN6
NON1
NON8
Battery
&
Temperature
Monitor
LOGIC
OUT5
OUT6
OUT7
OUT8
Channel
Diagnostics
DS12275
-
Rev 8
page 3/151
L9945
Applications
2
Applications
The device offers three different configuration options for the output channels: High-Side/Low-Side, Peak & Hold
and H-Bridge. P&H configuration requires 2 or 4 channels, while H-Bridge requires 4 or 8 channels. Channels not
used in P&H or H-Bridge are available for HS/LS usage. All the configurations involving channel 6 require the
output driver 6 to be enabled through the EN6 input.
2.1
High-Side / Low-Side, with configurable FET type (N channel or P channel)
Each channel features a dedicated SPI register where the user can specify:
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MOS side: High-Side or Low-Side, through the LS_HS_config_xx bit;
•
MOS type: NMOS or PMOS, through the N_P_config_xx bit;
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PMOS type is available only for High-Side.
The picture below shows an example of High-Side configuration with NMOS transistor on channel 1. Refer to this
schematic in order to understand how the external FET must be mounted with respect to the DRNx/GNSPx/
SNGPx/BATTx pins.
Figure 2.
Example of High-Side configuration with NMOS on channel 1
VBATT
BATT12
DRN1
C
M
R
M
C
BATT
GNSP1
R
G
GND
R
PD
SNGP1
D
FW
C
ESD
OUT1
LOAD
HS NMOS
R
SH
PGND12
GND
GND
GND
Note: the freewheeling diode is needed only in case of inductive load.
GADG2302171549PS
The following picture shows an example of High-Side configuration with PMOS transistor on channel 5. Refer to
this schematic in order to understand how the external FET must be mounted with respect to the DRNx/GNSPx/
SNGPx/BATTx pins.
DS12275
-
Rev 8
page 4/151
L9945
High-Side / Low-Side, with configurable FET type (N channel or P channel)
Figure 3.
Example of High-Side configuration with PMOS on channel 5
VBATT
BATT56
GNSP5
R
PU
SNGP5
R
G
GND
C
M
DRN5
D
FW
C
ESD
PGND56
R
M
OUT5
LOAD
R
SH
HS PMOS
C
BATT
GND
GND
GND
GADG2302171301PS
Note: the freewheeling diode is needed only in case of inductive load.
The picture below shows an example of Low-Side configuration with NMOS transistor on channel 3. Refer to this
schematic in order to understand how the external FET must be mounted with respect to the DRNx/GNSPx/
SNGPx/PGNDx pins.
Figure 4.
Example of Low-Side configuration with NMOS on channel 3
VBATT
BATT34
DRN3
C
M
R
M
D
FW
C
ESD
LOAD
GNSP3
R
G
GND
LS NMOS
R
PD
SNGP3
R
SH
PGND34
GND
Note: the freewheeling diode is needed only in case of inductive load.
GADG2302170929PS
DS12275
-
Rev 8
page 5/151
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