Si9993CS

Vishay Siliconix

S-60752–Rev. A, 05-Apr-99

FaxBack 408-970-5600, request 70653

8

www.siliconix.com

18

PWMIN

Digital, Input

Digital input of stand-alone PWM driver

19

SRADJ

Analog, Input

Spindle Output drive slew rate control

20

DGND

Supply

Digital negative supply

21

VTEST

Analog, I/O

External charge storage node for spindle brake function. Also used as a

manufacturer’s test pin

22

VDD

Supply

+5 V digital power supply

23

SYSCLK

Digital, Input

System clock input (5Mhz) for onboard timers

24

FCOM

Digital, Output

Commutation clock output for external speed control

27

STEPCLK

Digital, Input

Clock input for spindle commutation state machine, used during spindle start-up

only

28

SENC

Analog, Input

Input to BEMF-sense circuitry; connect to 0-C

29

SENB

Analog, Input

Input to BEMF-sense circuitry, connect to 0-B

30

SENA

Analog, Input

Input to BEMF-sense circuitry, connect to 0-A

31

CT

Analog, Output

Center Tap

32

POR

Digital, Output

Power-on-reset pulse for entire drive electronics

33

ENCOM

Digital, Input

Enable input for onboard commutation clock generator

37

UVADJ

Analog, Output

External Undervoltage threshold adjust

38

IVCMS

Analog, Output

39

ISS-

Analog, Input

Negative input to spindle current sense amplifier

40

ISS+

Analog, Input

Positive input to spindle current sense amplifier

41

SPDACIN

Analog, Input

Spindle Input (from PWM DAC Out)

42

PWMREF

Analog I/O

Reference supply input for stand-alone PWM driver

43

VCC

Supply

+12 V analog power supply for the whole chip

44

PORCAP

Analog, Output

Connect to Power-on-reset timing capacitor

45

REFGND

Supply

Critical analog ground reference

46

AGND

Supply

Analog negative supply and ground reference

47

VREF(OUT)

Analog, Output

Reference supply output for stand-alone PWM DAC and VCM common

48

VREF/2

Analog, Output

Reference supply output for external VCM DAC

49

ISV+

Analog, Input

Positive input to VCM current sense amplifier

50

ISV-

Analog, Input

Negative input to VCM current sense amplifier

51

COMP1

Analog, Output

Connection for external VCM R/C compensation

52

COMP2

Analog, Input

Connection for external VCM R/C compensation

53

+VCMDACIN

Analog, Input

Positive VCM input (from +VCM DAC Out)

54

-VCMDACIN

Analog, Input

Negative VCM input (from -VCM DAC Out)

55, 56

VCLAMP

Supply

+12-V digital power supply for spindle PWM section; also, inductive flyback clamp

and emergency head retract power supply

57

PWRGND

Supply

Ground return referred to external VCM n-channel FETs; used to power VCM class

AB stage.

59

VCM+

Analog, I/O

Feedback from the positive output of VCM driver

60

VMOT

Supply

+12-V power supply referred to external VCM p-channel FETs; used to power VCM

class AB stage.

61

VCM-

Analog, I/O

Feedback from the negative output of VCM driver

62

HS+

Analog, Output

Connection to gate of positive VCM high-side driver

63

LS+

Analog, Output

Connection to gate of positive VCM low-side driver

PIN DESCRIPTION

Pin No.

Name

Type

Function