Ver: 1.6

Aug 04, 2005

TEL: 886-3-5788833

http://www.gmt.com.tw

16

G1421

Global Mixed-mode Technology Inc.

Pin Description

PIN

NAME

I/O

FUNCTION

1,12,13,24

GND/HS

Ground connection for circuitry, directly connected to thermal pad.

2

TJ

O

Source a current inversely to the junction temperature. This pin should be left uncon-

nected during normal operation. For more information, see the junction temperature

measurement section of this document.

3

LOUT+

O

Left channel + output in BTL mode, + output in SE mode.

4

LLINE IN

I

Left channel line input, selected when HP/ pin is held low.

5

LHP IN

I

Left channel headphone input, selected when HP/pin is held high.

6

LBYPASS

Connect to voltage divider for left channel internal mid-supply bias.

7

LVDD

I

Supply voltage input for left channel and for primary bias circuits.

8

SHUTDOWN

I

Shutdown mode control signal input, places entire IC in shutdown mode when held

9

MUTE OUT

O

Follows MUTE IN pin, provides buffered output.

10

LOUT-

O

Left channel - output in BTL mode, high impedance state in SE mode. Supply VDD/2 to

the phone jacket in HP-IN mode.

11

MUTE IN

I

Mute control signal input, hold low for normal operation, hold high to mute.

14

SE/

I

Mode control signal input, hold low for BTL mode, hold high for SE mode.

15

ROUT-

O

Right channel - output in BTL mode, high impedance state in SE mode.

16

HP/

I

MUX control input, hold high to select headphone inputs (5,20), hold low to select line

inputs (4,21).

17

HP-IN

This pin can activate the HP-IN mode to supplied the VDD/2 at LOUT- onto the phone

jacket. So the DC blocking capacitors can be removed in HP-IN type (like SE mode

except no DC blocking capacitors). Hold high to activate this function. If this function is

not used, it should be strongly tied to low.

18

RVDD

I

Supply voltage input for right channel.

19

RBYPASS

Connect to voltage divider for right channel internal mid-supply bias.

20

RHP IN

I

Right channel headphone input, selected when HP/pin is held high.

21

RLINE IN

I

Right channel line input, selected when HP/pin is held low.

22

ROUT+

O

Right channel + output in BTL mode, + output in SE mode.

23

VOL

I

The output power can be clamped by setting a low bound voltage to this pin. The high

bound voltage will be generated internally. The output voltage will be clamped between

high/low bound voltages. Then the output power is limited. It is weakly pull-low inter-

nally, let this pin floating or tied to GND can deactivate this function.

Thermal Pad

Recommend connecting the Thermal Pad to the GND for excellent power dissipation.