TMS3471C

2/3-INCH NTSC TIMER

SOCS028B – AUGUST 1991

4

POST OFFICE BOX 655303

Terminal Functions (Continued)

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

S1

24

O

Serial clock 1

S2,3

25

O

Serial clock 2, 3

T

23

O

Transfer-gate clock

VCC

22

DC power

VD

16

O

Vertical drive

VDS

41

I

Vertical-dump speed. When VDS is high, the vertical-dump frequency is 2 MHz; when VDS is low, the

vertical-dump frequency is 1 MHz. VDS can also function as a timer reset by dropping the voltage on

VDS from VCC to VCC/2 and then raising it back to VCC.

VGATE

19

O

Decoded V count signal. VGATE is a test point and is not used in normal operation.

WHTA

17

O

WHTA is a test point and is not used in normal operation.

WHTB

18

O

WHTB is a test point and is not used in normal operation.

X1

34

Crystal oscillator (see Figure 1)

X2

35

Crystal oscillator (see Figure 1)

X1

X2

34

35

C1

≈ 40 pF

C2

≈ 40 pF

TMS3471C

NOTE: The TMS3471C is designed for use with

a crystal oscillator. The X1 and X2

terminals should not connect directly to

external driver outputs.

Figure 1. Connection of an External Crystal Oscillator to the TMS3471C