NIPPON PRECISION CIRCUITS-3

SM8220/SM8221

PIN DESCRIPTIONS

Number

Name

i/o

Function

SM8220

SM8221

1

1

TIP

i

2

2

RING

i

3

-

AGND

o

4

-

RDIN

si

5

-

RDRC

od

6

-

RDET

o

7

3

PDWN

si

8

4

GND

-

9

5

OSCIN

i

/CLKIN

10

-

OSCOUT

o

11

6

CDET

o

12

-

NC

-

13

7

DOUT

o

14

-

DMIN

i

15

-

FOUT

o

16

8

VDD

-

(Note) si: Schmitt Triger Input, od: Open Drain Output.

Tip Input: This pin is connected to the tip side of the twisted pair telephone wires.

This pin must be DC isolated from the phone line.

Ring Input: This pin is connected to the ring side of the twisted pair telephone wires.

This pin must be DC isolated from the phone line.

µF capacitor.

Ring Detect Input: The attenuated ring signal is connected to this pin for the ring detection.

Ring Detect RC Terminal: An RC network will be connected to this pin to set time delays for

the ring signal detection.

Ring Detect Output: This pin is an output of a schmitt trigger buffer which input is connected

to RDRC pin. The low level at this pin indicates that the ring signal is detected.

Power Down Control: This pin must be kept at low level for the normal operation.

When it is high, the device will be in the power down.

Under the power down mode, OSCOUT, CDET and DOUT pins are set to high level and

AGND, FOUT pins are set to high impedance.

Device Ground: This pin is connected to the system ground.

Crystal Oscillator Input: A crystal will be connected between this pin and OSCOUT pin.

This pin may be driven from an external clock source.

Crystal Oscillator Output: A crystal will be connected between this pin and OSCIN pin.

This pin must be kept open when OSCIN pin is driven from an external clock source.

Carrier Detect Output: When low, this output indicates that a valid carrier present on the line.

No connection pin.

Data Out: This pin presents the output of the demodulator while CDET pin is low.

When CDET pin goes high, this pin is held high.

Demodulator Input: This pin is connected from FOUT pin through a 0.1

µF capacitor.

No other components should be connected to this pin.

Band Pass Filter Output: This pin is connected to DMIN pin through a 0.1

µF capacitor.

No other components should be connected to this pin.

Power Supply: Positive power supply pin.