L9954 / L9954XP Block diagram and pin description
Doc ID 14279 Rev 4 7/37
3
4
5
OUT1
OUT2
OUT3
Half-bridge-output 1,2,3
The output is built by a highside and a lowside switch, which are
internally connected. The output stage of both switches is a power
DMOS transistor. Each driver has an internal parasitic reverse diode
(bulk-drain-diode: highside driver from output to VS, lowside driver
from GND to output). This output is over-current and open load
protected.
6, 7, 14, 25,
28, 32
V
S
Power supply voltage (external reverse protection required)
For this input a ceramic capacitor as close as possible to GND is
recommended.
Important: for the capability of driving the full current at the outputs all
pins of VS must be externally connected.
8DI
Serial data input
The input requires CMOS logic levels and receives serial data from the
microcontroller. The data is an 24bit control word and the least
significant bit (LSB, bit 0) is transferred first.
9
CM/PWM2
Current monitor output/PWM2 input
Depending on the selected multiplexer bits of Input Data Register this
output sources an image of the instant current through the
corresponding highside driver with a ratio of 1/10.000. This pin is
bidirectional. The microcontroller can overdrive the current monitor
signal to provide a second PWM input for the output OUT5.
10 CSN
Chip select not input / testmode
This input is low active and requires CMOS logic levels. The serial data
transfer between L9954 and micro controller is enabled by pulling the
input CSN to low level.
11 DO
Serial data output
The diagnosis data is available via the SPI and this tristate-output. The
output will remain in tristate, if the chip is not selected by the input CSN
(CSN = high)
12 V
CC
Logic supply voltage
For this input a ceramic capacitor as close as possible to GND is
recommended.
13 CLK
Serial clock input
This input controls the internal shift register of the SPI and requires
CMOS logic levels.
26 CP
Charge pump output
This output is provided to drive the gate of an external n-channel power
MOS used for reverse polarity protection.
27 PWM1
PWM1 input
This input signal can be used to control the drivers OUT1-OUT4 and
OUT6 by an external PWM signal.
Table 2. Pin definitions and functions (continued)
Pin Symbol Function
