GMT G1421 Datasheet

Global Mixed-mode Technology Inc.

G1421

2W Stereo Audio Amplifier With No Headphone
Coupling Capacitor Function

Features

Depop Circuitry Integrated



Output Power at 1% THD+N, VDD=5V



--1.8W/CH (typical) into a 4

--1.2W/CH (typical) into a 8
Eliminates Headphone Amplifier Output Cou-



Load

ΩΩΩΩ

Load

ΩΩΩΩ

pling Capacitors
Maximum Output Power Clamping Circuitry



Integrated
Bridge-Tied Load (BTL), Single-Ended (SE),



and Stereo Headphone Amplifier (HP-IN) modes
Supported
Stereo Input MUX



Mute and Shutdown Control Available



Surface-Mount Power Package



24-Pin TSSOP-P

Applications

Stereo Power Amplifiers for Notebooks or



Desktop Computers
Multimedia Monitors



Stereo Power Amplifiers for Portable Audio



Systems

General Description

G1421 is a stereo audio power amplifier in 24pin
TSSOP thermal pad package. It can drive 1.8W con­tinuous RMS power into 4Ω load per channel in
Bridge-Tied Load (BTL) mode at 5V supply voltage. Its
THD is smaller than 1% under the above operation
condition. To simplify the audio system design in the
notebook application, G1421 supports the Bridge-Tied
Load (BTL) mode for driving the speakers, Single-End
(SE) mode for driving the headphone. In the HP-IN
mode, it can support a DC value to the phone-jacket
and drive the headphone without the audio amplifier
outputs coupling capacitors. G1421 can mute the
output when Mute-In is activated. For the low current
consumption applications, the SHDN mode is sup­ported to disable G1421 when it is idle. The current
consumption can be further reduced to below 5µA.

G1421 also supports two input paths, that means two
different gain loops can be set in the same PCB and

choosing either one by setting HP/
hances the hardware designing flexibility. G1421 also
supports an extra function -- the maximum output
power clamping function to protect the speakers or
headphones from burned-out.

LINE pin. It en-

Pin Configuration

GND/HS

GND/HS

LOUT+

LOUT+

LLINEIN

LLINEIN

LHPIN

LHPIN

LBYPASS

LBYPASS

SHUTDOWN

SHUTDOWN

MUTE OUT

MUTE OUT

LOUT-

LOUT-

MUTE IN

MUTE IN

GND/HS

GND/HS

TJ

TJ

LVDD

LVDD

1

1

2

2
3

3

4

4

5

5

6

6

7

7
8

8

9

9

10

10

11

11

12

12

Ordering Information

PART NUMBER TEMP. RANGE PIN-PACKAGE

G1421 -40°C to +85°C 24 TSSOP

G1421

G1421

GND/HS

GND/HS

24

24

23

23

VOL

VOL

22

22

ROUT+

ROUT+

RLINEIN

RLINEIN

21

21

20

20

RHPIN

RHPIN

Thermal

19

19

RBYPASS

RBYPASS

RVDD

RVDD

18

18

HP-IN

HP-IN

17

17

HP/LINE

HP/LINE

16

16

ROUT-

ROUT-

15

15

SE/BTL

SE/BTL

14

14

13

13

GND/HS

GND/HS

Top View Bottom View

Top View Bottom View

24Pin TSSOP

24Pin TSSOP

Thermal

Pad

Pad

14

14

Ver: 0.7 Preliminary

Dec 20, 2002

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G1421

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 high,

I

= 5µA.

DD

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

Ver: 0.7 Preliminary

Dec 20, 2002

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Absolute Maximum Ratings

Supply Voltage, VCC…………………..…...…….……...6V
Operating Ambient Temperature Range
T

…….…………………………….……….-40°C to +85°C

A

Maximum Junction Temperature, T
Storage Temperature Range, T
Soldering Temperature, 10seconds, T

…..……….….150°C

J

….….-65°C to+150°C

STG

……….……300°C

S

Power Dissipation

T
T

T
Electrostatic Discharge, V
Human body mode

(1)

≤ 25°C…………………………………………..2.7W

A

≤ 70°C…………………………………………..1.7W

A

≤ 85°C………………….……………………….1.4W

A

ESD

G1421

Lout- pin………………………..…………-8000 to 8000V
Other pins………………………………...-3000 to 3000

Note:

(1)

: Recommended PCB Layout.

(2)

: Human body model : C = 100pF, R = 1500Ω, 3 positive pulses plus 3 negative pulses

Electrical Characteristics

DC Electrical Characteristics, TA=+25°C

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT

Supply Current IDD

DC Differential Output Voltage V

Supply Current in Mute Mode I

IDD in Shutdown ISD VDD = 5V 2 5 µA

VDD =3.3V HP-IN 5.5 7
VDD = 5V HP-IN 6.5 8

VDD =3.3V

V

= 5V

DD

VDD = 5V,Gain = 2 5 25 mV

O(DIFF)

VDD = 5V

DD(MUTE)

Stereo BTL 7 9
Stereo SE 3.5 5.6
Stereo BTL 8 11
Stereo SE 4 6.5

Stereo BTL 8 11
HP-IN 6.5 8
Stereo SE 4 6.5

mA

mA

(2)

(AC Operation Characteristics, VDD = 5.0V, TA=+25°C, RL = 4

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT

THD = 1%, BTL, RL = 4Ω 1.8
THD = 1%, BTL, RL = 8Ω 1.12
THD = 10%, BTL, RL = 4Ω 2
THD = 10%, BTL, RL = 8Ω 1.4

Output power (each channel) see Note P

Total harmonic distortion plus noise THD+N

Maximum output power bandwidth BOM G = 10, THD < 1% >20 kHz
Phase margin RL = 4Ω, Open Load 71
Power supply ripple rejection PSRR f = 120Hz 75 dB
Mute attenuation 85 dB
Channel-to-channel output separation f = 1kHz 82 dB
Line/HP input separation 80 dB
BTL attenuation in SE mode 85 dB
Input impedance ZI 2 MΩ
Signal-to-noise ratio PO = 500mW, BTL 90 dB
Output noise voltage Vn Output noise voltage 55 µV (rms)

Note :Output power is measured at the output terminals of the IC at 1kHz.

(OUT)

THD = 1%, SE, RL = 4Ω 500
THD = 1%, SE, RL = 8Ω 320
THD = 10%, SE, RL = 4Ω 650
THD = 10%, SE, RL L = 8Ω 400
THD = 0.5%, SE, R
PO = 1.6W, BTL, RL = 4Ω 500
PO = 1W, BTL, RL = 8Ω 150
PO = 75mW, SE, RL = 32Ω 20

= 1V, RL = 10KΩ, G = 1 10

V

I

, unless otherwise noted)

ΩΩΩΩ

= 32Ω 90

L

W

mW

m%

°

Ver: 0.7 Preliminary

Dec 20, 2002

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Global Mixed-mode Technology Inc.

G1421

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT POWER

10

5

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
3m 35m 10m 20m 50m 100m 200m 500m 1 2

1kHz

20 Hz

20kHz

W

VDD=5V
RL=3

Ω

BTL

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

5

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10k

Po=1.5W

Po=1.8W

Hz

VDD=5V
RL=3

Ω

BTL
Av=-2V/V

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT POWER

10

5

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
3m 35m 10m 20m 50m 100m 200m 500m 1 2

1kHz

20 Hz

20kHz

W

VDD=5V
RL=4

Ω

BTL

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

5

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10k

Av=-2V/V

Av=-1V/V

Hz

Av=-4V/V

VDD=5V
RL=4

Ω

BTL
Po=1.5W

Ver: 0.7 Preliminary

Dec 20, 2002

TEL: [phone]

http://www.gmt.com.tw

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Global Mixed-mode Technology Inc.

G1421

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

VDD=5V

5

RL=4

Ω

BTL

2

Av=-2V/V

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10k

Po=0.25W

Hz

Po=1.5W

Po=0.75W

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT POWER

10

5

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
3m 35m 10m 20m 50m 100m 200m 500m 1 2

20kHz

1kHz

20Hz

VDD=5V
RL=8

Ω

BTL
Av=-2V/V

W

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

5

VDD=5V
RL=8

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10k

Ω

BTL
Av=-2V/V

Po=1W

Po=0.25W

Po=0.5W

Hz

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

5

VDD=5V
RL=8

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01

Ω

BTL
Po=1W

Av=-2V/V

20 20k50 100 200 500 1k 2k 5k 10k

Hz

Av=-4V/V

Av=-1V/V

Ver: 0.7 Preliminary

Dec 20, 2002

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Global Mixed-mode Technology Inc.

G1421

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT POWER

10

5

2

1

0.5

%

0.2

0.1

VDD=3.3V

0.05

RL=3

Ω

BTL

0.02

0.01

1m 12m 5m 10m 20m 50m 100m 200m 500m

20kHz

1kHz

20Hz

W

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT POWER

10

5

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
1m 12m 5m 10m 20m 50m 100m 200m 500m

1kHz

VDD=3.3V
RL=4

Ω

BTL

20Hz

20kHz

W

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

5

VDD=3.3V
RL=4

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10k

Ω

BTL
Po=0.65W

Av=-2V/V

Hz

Av=-4V/V

Av=-1V/V

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

VDD=3.3V

5

RL=4

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10k

Ω

BTL
Av=-2V/V

Po=0.7W

Po=0.1W

Po=0.35W

Hz

Ver: 0.7 Preliminary

Dec 20, 2002

TEL: [phone]

http://www.gmt.com.tw

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Global Mixed-mode Technology Inc.

G1421

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT POWER

10

W

VDD=3.3V
RL=8

Ω

BTL

5

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
1m 12m 5m 10m 20m 50m 100m 200m 500m

20kHz

1kHz

20Hz

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

5

VDD=3.3V
RL=8

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10 k

Ω

BTL
Po=0.4W

Av=-4V/V

Av=-2V/V

Av=-1V/V

Hz

TOTAL HARAMONIC DISTORTION PLUS NOISE
vs OUTPUT FREQUENCY

10

VDD=3.3V

5

RL=8

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
20 20k50 100 200 500 1k 2k 5k 10k

Ω

BTL
Av=-2V/V

Po=0.4W

Po=0.1W

Po=0.25W

Hz

TOTAL HARMONIC DISTORTION PLUS NOISE
vs OUTPUT POWER

10

VDD=5V

5

RL=4

Ω

SE

2

1

0.5

%

0.2

0.1

0.05

0.02

0.01
1m 12m 5m 10m 20m 50m 100m 200m 500m

100Hz

20kHz

1kHz

W

Ver: 0.7 Preliminary

Dec 20, 2002

TEL: [phone]

http://www.gmt.com.tw

7