6-20

Figure 2 - Pin Connections

Pin Description

Pin Name

Description

CSTi

Control ST-BUS In is a TTL-compatible digital input used to control the function of the filter/codec.

(GNDD), or an 8-bit serial word, depending on the logic states of CA and F1i.

Functions controlled are: powerdown, filter gain adjust, loopback, chip testing, SD outputs.

DSTi

Data ST-BUS In accepts the incoming 8-bit PCM word. Input is TTL-compatible.

C2i

Clock Input is a TTL-compatible 2.048 MHz clock.

DSTo

Data ST-BUS Out is a three-state digital output driving the PCM bus with the outgoing 8-bit PCM

word.

Positive power Supply (+5V).

F1i

Synchronization Input is an active low digital input enabling (in conjunction with CA) the PCM input,

PCM output and digital control input. It is internally sampled on every positive edge of the clock, C2i,

and provides frame and channel synchronization.

CA

Control Address is a three-level digital input which enables PCM input and output and determines

into which control register (A or B) the serial data, presented to CSTi, is stored.

SD3

System Drive Output is an open drain output of an N-channel transistor which has its source tied to

GNDA. Inactive state is open circuit.

SD4-5

System Drive Outputs are open drain outputs of N-channel transistors which have their source tied

to GNDD. Inactive state is open circuit.

SD0-2

state is logic low.

Negative power supply (-5V).

Voice Transmit is the analog input to the transmit filter.

ANUL

Auto Null is used to integrate an internal auto-null signal. A 0.1

µF capacitor must be connected

between this pin and GNDA.

Voice Receive is the analog output of the receive filter.

GNDA

Analog ground (0V).

Voltage Reference input to D to A converter.

GNDD

Digital ground (0V).

1

2

3

4

5

6

7

8

9

10

11

12

20

19

18

17

16

15

14

13

20 PIN PDIP/SOIC

CSTi

DSTi

C2i

DSTo

VDD

SD5

SD4

F1i

CA

SD3

GNDD

VRef

GNDA

VR

ANUL

VX

VEE

SD0

SD1

SD2

1

2

3

4

5

6

7

8

9

10

18

17

16

15

14

13

12

11

18 PIN CERDIP/PDIP

CSTi

DSTi

C2i

DSTo

VDD

F1i

CA

SD3

SD2

GNDD

VRef

GNDA

VR

ANUL

VX

VEE

SD0

SD1

MT8960/61/64/65

MT8962/63/66/67