TOSHIBA TA2145AF Technical data

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TOSHIBA Bipolar Lin ear I nt egrated Circuit Silicon Monolith ic

TA2145AF

3 V Stereo Headphone Amplifier (3 V USE)

The TA2145AF is developed for play-back stereo headphone equipments (3 V USE). It is built in dual preamplifiers, dual OCL power amplifiers, motor governor, DC volume control and preamplifier on/off switch etc.

Features

· Built-in preamplifier

Input coupling condenser-less Built-in input capacitor for reducing buzz noise Low noise: V Preamplifier on/off switch.

· Built-in power amplifier

OCL (Output condenser-less) Voltage gain: G

· Built-in motor governor (Current proportion type)

· Built-in DC volume control function

ATT = 82dB (Ta = 25°C, typ.)

· Built-in bass boost function

· Low supply current (V

· Quiescent supply current

PRE + PW: I GVN: ICC = 2.5 mA

· 0.1 mW × 2 ch output I

CC1

I

CC2

· 0.5 mW × 2 ch output I

CC3

I

CC4

· Operating supply voltage range (Ta = 25°C) V

CC (opr)

GVN V

CC (opr)

= 1.2 µVrms (typ.)

ni

= 31 dB (typ.)

V

= 3 V, f = 1 kHz, PRE OUT = 100 mVrms, Ta = 25°C, typ.)

CC

= 8.5 mA

CCQ

= 9.8 mA (RL = 32 Ω) = 10.5 mA (RL = 16 Ω)

= 14.0 mA (RL = 32 Ω) = 16.5 mA (RL = 16 Ω)

= 1.8~3.6 V

= 2.1~3.6 V (Motor voltage = 1.8 V)

Weight: 0.32 g (typ.)

TA2145AF

1

2002-04-19

Block Diagram

TA2145AF

M

PRE: OFF

V

REF

IN

23

NFB

B

22 24

PRE

B

PRE OUT

PW IN

B

RIPPLE FILTER

RF IN

PRE

SW

PRE SW

V

CC

GVN V

161718192021

Rt

CC

15 14 13

GVN CTL

GVN OUT

VOL.

V

REF

VOL.

PRE

A

VOL.

PWB PWA PWC

CONTROL

1

PRE GND

2 3

IN

A

NFA

4 5

PRE OUT

A

6 7 8

PW IN

V

CTL

A

OUT

B

OUT

9

A

C

10

OUT

PW IN

C

11 12

PW GND

GVN GND

OUT

A

RL

OUT

C

B

V

REF

BST SW

BST: OFF

RL

2

2002-04-19

TA2145AF

Terminal Explanation

circuit, V

No. Name

1 PRE GND

2 INA

23 INB

3 NFA

22 NFB

4 PRE OUTA

21 PRE OUTB

7 OUTB

8 OUTA

==== 3 V, Ta ==== 25°C)

CC

Terminal

The GND, except for power drive stage and motor governer stage.

Input of preamplifier 1.2

NF of preamplifier

Output of preamplifier

Output of power amplifier

(Terminal Voltage: Typical terminal voltage at no signal with test

Terminal

Function Internal Circuit

¾ 0

RF

500 W

3

500 W

2

V

REF

V

CC

4

Voltage

(v)

1.2

9 OUTC

5 PW INA

20 PW INB

6 V

The terminal of DC volume control

CTL

Input of power amplifier

5

RF

10 kW

V

REF

VCC

1.2

V

REF

6

¾

3

2002-04-19

TA2145AF

Terminal

No. Name

10 PW INC Input of center amplifier

11 PW GND GND for power drive stage ¾ 0 12 GVN GND GND for motor governor stage ¾ 0

13 GVN OUT Motor terminal ¾

Function Internal Circuit

20 kW

10

V

REF

30 kW

V

2 kW

REF

M

Terminal

Voltage

1.2

(v)

1416 15

14 GVN CTL The terminal of motor speed control ¾

15 Rt

16 GVN VCC VCC for motor governor stage

17 VCC

18 PRE SW

The terminal of amateur compensation resistor

for preamplifier stage and

V

CC

power amplifier stage.

Muting switch of preamplifier

Preamp. on: “L” level/open Preamp. off: “H” level

Refer to application note

¾ 3

18

13

¾

3

4

2002-04-19

TA2145AF

Terminal

No. Name

19 RF IN Ripple filter of power supply 2.5

Reference voltage

24 V

REF

Preamplifier and power amplifier operate on this reference.

Function Internal Circuit

19 24

VCC

4 kW

4.7 kW 1.3 kW

10 kW

Terminal

Voltage

(v)

1.2

5

2002-04-19

TA2145AF

Application Note

· VCC and GND

This IC has two V

terminals and three GND terminals. Pattern layout should be designed carefully to

CC

reduce the common impedance.

· V

CC

V

(pin 17) -----------------Preamplifier stage and power amplifier stage.

CC

GVN V

(pin 16) --------- Motor governor stage.

CC

· GND PRE GND (pin 1)------------Preamplifier stage, and power amplifier stage except for the power drive stage. PW GND (pin 11) -----------Power drive stage of power amplifier. GVN GND (pin 12) ---------Motor governor stage.

· V

REF

It is necessary to stabilize the V

circuit, because the internal circuit operate on this reference.

REF

· RF IN As this terminal is an input terminal of the ripple filter, it cannot supply a power supply to other ICs etc.

· Preamplifier Input signal should be applied to V

standard, otherwise pop noise become bigger when VCC is turned on

REF

and off.

· Power amplifier It is necessary to insert the coupling capacitor through the PW IN terminal. In case that DC current or DC

voltage is applied to the PW IN terminal, the internal circuit has unbalance and the power amplifier doesn’t operate normally.

· Operating supply voltage range of motor governor stage As for the minimum of operating supply voltage range, the motor voltage is 1.8 V.

In case that it is more than 1.8 V, the low voltage performance becomes bad.

· PRE SW sensitivity (Ta = 25°C)

PRE SW

4

(V)

18

3

2

1.8 V

1.5 V

1

Terminal DC voltage V

0.5 V

0 1.5 2.0 2.5 3.5 4.0 3.0

Supply voltage VCC (V)

“H”

PRE AMP: OFF

3.6 V

3.0 V

1.2 V

6

2002-04-19