8-Channel Cold-Cathode

Fluorescent Lamp Controller

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7

Pin Description

PINS BY CHANNEL (n = 1–8)

NAME

CH 1

CH 2

CH 3

CH 4

CH 5

CH 6

CH 7

CH 8

DESCRIPTION

GAn

1

5

9

14

19

25

29

33

MOSFET A Gate Drive. Connect directly to logic-

level mode n-channel MOSFET. Leave open if

channel is unused.

GBn

2

6

10

15

20

26

30

34

MOSFET B Gate Drive. Connect directly to logic-

level mode n-channel MOSFET. Leave open if

channel is unused.

LCMn

37

11

16

21

27

31

35

Lamp Current Monitor Input. Lamp current is

monitored by measuring a voltage across a

resistor placed in series with the low-voltage side

of the lamp. Leave open if channel is unused.

OVDn

48

12

17

22

28

32

36

Overvoltage Detection. Lamp voltage is

monitored through a capacitor-divider placed on

the high-voltage side of the transformer. Leave

open if channel is unused.

NAME

PIN

DESCRIPTION

GND

13, 18,

24, 45

Ground Connection

23, 48

Power-Supply Connection

SDA

37

Serial Data Input/Output. I

levels.

SCL

38

Serial Clock Input. I

FAULT

39

Fault Output. Active-low, open-drain, requires external pullup resistor to realize high logic levels.

LSYNC

40

Lamp Frequency Input/Output. This pin is the input for an externally sourced lamp frequency when the

DS3988 is configured as a lamp frequency receiver. If the DS3988 is configured as a lamp frequency source

(i.e., the lamp frequency is generated internally), the frequency is output on this pin for use by other lamp

frequency receiver DS3988s.

LOSC

41

Lamp Oscillator Resistor Adjust. A resistor to ground on this lead sets the frequency of the lamp oscillator.

A0

42

Address Select Input. Determines the DS3988’s I

PSYNC

43

DPWM Input/Output. This pin is the input for an externally generated DPWM signal when the DS3988 is

configured as a DPWM receiver. If the DS3988 is configured as a DPWM source (i.e., the DPWM signal is

generated internally), the DPWM signal is output on this pin for use by other DPWM receiver DS3988s.

POSC

44

DPWM Oscillator Resistor Adjust. A resistor to ground on this lead sets the frequency of the DPWM oscillator

(dimming clock). This lead can optionally accept a 22.5Hz to 440Hz clock as the source timing for the

internal DPWM signal.

BRIGHT

46

Analog Brightness Control Input. Used to control DPWM dimming. Ground when using a PWM signal at

PSYNC to control brightness.

SVM

47

Supply Voltage Monitor Input. Used to monitor the inverter voltage for undervoltage conditions.