MOSA ELECTRONICS

MS8870

DTMF Receiver

－ 2 －

Pin Description

Pin #

Name

Description

1

IN +

Non-inverting op-amp input.

2

IN -

Inverting op-amp input.

3

GS

Gain select. Gives access to output of front end differential amplifier for connection

of feedback resistor.

4

2).

5

IC

Internal connection. Must be tied to Vss.

6

IC

Internal connection. Must be tied to Vss.

7

OSC1

Clock input.

8

OSC2

Clock output. A 3.5795 MHz crystal connected between OSC1 and OSC2 completes

the internal oscillator circuit.

9

Vss

Negative power supply input.

10

TOE

3-state output enable (input). Logic high enables the outputs Q1-Q4 Internal pull up.

11-14

Q1-Q4

3-state data output. When enable by TOE, provide the code

corresponding to the last

valid tone-pair received (see Fig. 5).

15

StD

Delayed steering output. Presents a logic high when a received tone-pair has been

registered and the output latch updated; return to logic low when the voltage on St/GT

16

ESt

Early steering output. Presents a logic high once the digital algorithm has detected a

valid tone pair (signal condition). Any momentary loss of signal condition will cause

ESt to return to a logic low.

17

St/GT

at St causes the device to register the detected tone pair and update the output latch. A

to reset the external steering time-constant; its state is a function of ESt and the

voltage on St.

18

Positive power supply input.

Absolute Maximum Ratings

Parameter

Min

Max

Units

1

6

V

2

Voltage on any pin

Vss - 0.3

V

3

Current at any pin

10

mA

4

Operating temperature

-40

+85

℃

5

Storage temperature

-65

+150

℃

6

Package power dissipation

1000

mW