
5/23
L9950
Table 2. Pin Description
Pin
Symbol
GND
Function
1, 18, 19,
36
Ground:
Reference potential
Important
:
For the capability of driving the full current at the outputs all pins of GND must
be externally connected !
Highside-driver-output 11:
The output is built by a highside switch and is intended for resistive loads, hence the
internal reverse diode from GND to the output is missing. For ESD reason a diode to GND
is present but the energy which can be dissipated is limited. The highside driver is a power
DMOS transistor with an internal parasitic reverse diode from the output to VS (bulk-drain-
diode). The output is over-current and open load protected.
Important
:
For the capability of driving the full current at the outputs both pins of OUT11
must be externally connected !
Halfbridge-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.
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 !
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.
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 outputs OUT9 and OUT10.
Chip Select Not input / Testmode :
This input is low active and requires CMOS logic levels. The serial data transfer between
L9950 and micro controller is enabled by pulling the input CSN to low level. If an input
voltage of more than 7.5V is applied to CSN pin the L9950 will be switched into a test
mode.
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)
Logic supply voltage:
For this input a ceramic capacitor as close as possible to GND is recommended.
Serial clock input:
This input controls the internal shift register of the SPI and requires CMOS logic levels.
Halfbridge-output 4,5,6:
→
see OUT1 (pin 3).
Important
:
For the capability of driving the full current at the outputs both pins of OUT4
(OUT5, respectively) must be externally connected !
Charge Pump Output:
This output is provided to drive the gate of an external n-channel power MOS used for
reverse polarity protection (see FIGURE 1)
PWM1 input:
This input signal can be used to control the drivers OUT1-OUT8 and OUT11 by an
external PWM signal.
Highside-driver-output 7,8,9,10:
The output is built by a highside switch and is intended for resistive loads, hence the
internal reverse diode from GND to the output is missing. For ESD reason a diode to GND
is present but the energy which can be dissipated is limited. The highside driver is a power
DMOS transistor with an internal parasitic reverse diode from the output to VS (bulk-drain-
diode). The output is over-current and open load protected.
2.35
OUT11
3
4
5
OUT1
OUT2
OUT3
6, 7, 14, 15,
23, 24, 25,
28, 29, 32
VS
8
DI
9
CM/PWM2
10
CSN
11
DO
12
VCC
13
CLK
16,17,
20,21,
22
OUT4
OUT5
OUT6
26
CP
27
PWM1
30
31
33
34
OUT7,
OUT8,
OUT9,
OUT10