l9942 STMicroelectronics, l9942 Datasheet - Page 7

• Manufacturer Part Number: l9942
• Description: Integrated Stepper Motor Driver For Bipolar Stepper Motors With Microstepping And Programmable Current Profile
• Manufacturer: STMicroelectronics

L9942
Table 2.
1, 12, 13,
3, 10, 15,
11, 14
2, 23
Pin
24
22
16
17
18
19
4
5
6
7
8
9
Pin description
QA1,QA
QB1,QB
Symbol
PGND
STEP
TEST
PWM
GND
CSN
VCC
CLK
DO
VS
CP
DI
2
2
Power ground: All pins PGND are internally connected to the heat slug.
Important: All pins of PGND must be externally connected!
Power supply voltage (external reverse protection required): For EMI
reason a ceramic capacitor as close as possible to PGND is recommended.
Important: All pins of VS must be externally connected!
Fullbridge-outputs An: The output is built by a high-side and a low-side
switch, which are internally connected. The output stage of both switches is
a power DMOS transistor. Each driver has an internal reverse diode (bulk-
drain-diode: highside driver from output to VS, low-side driver from PGND to
output). This output is over-current protected.
Fullbridge-outputs Bn: The output is built by a highside and a low-side
switch, which are internally connected. The output stage of both switches is
a power DMOS transistor. Each driver has an internal reverse diode (bulk-
drain-diode: highside driver from output to VS, low-side driver from PGND to
output). This output is over-current protected.
SPI clock input: The input requires CMOS logic levels. The CLK input has
a pull-down current. It controls the internal shift register of the SPI.
Serial data input: The input requires CMOS logic levels. The DI input has a
pull-down current. It receives serial data from the microcontroller. The data
is a 16bit control word and the least significant bit (LSB, bit 0) is transferred
first.
Chip Select Not input The input requires CMOS logic levels. The CSN
input has a pull-up current. The serial data transfer between device and
micro controller is enabled by pulling the input CSN to low level.
SPI data output: The diagnosis data is available via the SPI and it is a
tristate-output. The output is CMOS compatible will remain highly resistive,
if the chip is not selected by the input CSN (CSN = high)
PWM output This CMOS compatible output reflects the current duty cycle
of the internal PWM controller of bridge A. It is an high resistance output
until VCC has reached minimum voltage ore can switched off via the SPI
command.
Step clock input: The input requires CMOS logic levels. The STEP input
has a pull-down current. It is clock of up and down counter of control
register 0. Rising edge starts new PWM cycle to drive motor in next
position.
Charge Pump Output: A ceramic capacitor (e.g.100 nF) to VS can be
connected to this pin to buffer the charge-pump voltage.
Ground: Reference potential besides power ground e.g. for reference
resistor RREF. From this pin exist a resistive path via substrate to PGND.
Test input The TEST input has a pull-down current. Pin used for production
test only. In the application it must be connected to GND.
Logic supply voltage: For this input a ceramic capacitor as close as
possible to GND is recommended.
Function
Block diagram and pin information
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