TA8157AF/AFN
2002-10-30
1
TOSHIBA Bipolar Linear Integrated Circuit Silicon Monolithic
TA8157AF,TA8157AFN
Stereo Headphone Power Amplifier (1.5V USE)
The TA8157AF and TA8157AFN are developed for play−back
stereo headphone equipments at low voltage operation (1.5V use).
Those are built in bass boost function.
Features
· OCL (output condenser less)
· Built−in ripple filter
· Output power (VCC = 1.5V, f = 1kHz, THD = 10%, RL = 16Ω)
Po = 9mW (typ.)
· Voltage gain: GV = 24dB (typ.)
· Built−in boost amplifier
· Built−in power switch
· Built−in muting circuit
· Low quiescent supply current (Ta = 25°C)
ICCQ = 8mA (typ.)
· Excellent ripple rejection ratio: RR = 55dB (typ.)
· Low noise: Vno = 25µVrms (typ.)
· Operating supply voltage range (Ta = 25°C)
VCC (opr) = 0.9~2.2V
Block Diagram
Weight
SSOP24−P−300−1.00: 0.32g (typ.)
SSOP24−P−300−0.65A: 0.14g (typ.)
TA8157AF/AFN
2002-10-30
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Te rminal Explanation
(terminal voltage: Typical terminal voltage at no signal with test circuit, VCC = 1.2V,
Ta = 25°C)
Terminal
No. Name
Function Internal Circuit
Terminal
Voltage
(V)
1 BST SW
Boost amplifier on / off switch
(synchronized with equalizer
circuit)
V
CC / OPEN: BST amp. ON
GND: BST amp. OFF
―
2 EQA
9 EQB
Equalizer circuit
(controlled by BST SW)
On resistance: 60Ω (typ.)
―
4 VREF Reference voltage
0.75
5 INA
7 INB
Input of power amplifier
(This terminal is common with
input of adder amplifier.)
0.75
3 NFA
8 NFB
NF of power amplifier 0.75
20 OUTA
18 OUTB
Output of power amplifier
0.6
6 PRE GND ― ― 0
10 MT SW
Muting switch for power
amplifier
V
CC: Power amp. ON
GND / OPEN: Power amp. OFF
―
11 PW SW
Power switch
V
CC: Power ON
GND / OPEN: Power OFF
―
TA8157AF/AFN
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Terminal
No. Name
Function Internal Circuit
Terminal
Voltage
(V)
12 RF IN Ripple filter terminal
1.2
13 RF OUT
Output of ripple filter
Ripple filter circuit supplies
VREF circuit, adder amplifier
and boost amplifier with power
source.
1.13
14 COMP
Phase-compensation terminal
for a ripple filter circuit 0.7
15 Base
Base biasing terminal of
transistor for ripple filter
0.5
16 VCC ― ― 1.2
17 PW GND ― ― 0
19 OUTC Output of center amplifier 0.6
24 INC Input of center amplifier
0.75
21 ADD OUT
Output of adder amplifier
Input of adder amplifier is
common with input of power
amplifier.
0.6
TA8157AF/AFN
2002-10-30
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Terminal
No. Name
Function Internal Circuit
Terminal
Voltage
(V)
22 BST IN Input of boost amplifier 0.75
23 BST OUT
Output of boost amplifier
(controlled by boost switch)
BST ON: BST amp. ON
BST OFF: BST amp. OFF
(cut off input signal of BST
amp.)
0.6
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2002-10-30
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Application Note
(1) PW SW
It is necessary to connect an external pull-down resistor with terminal PW SW (pin(11)), in case that this
IC is turned on due to external noise etc.
(2) MT SW
The leak current flows through the terminal of MT SW (pin(10)), in case that this terminal is connected
with VCC line independently, even though this IC is off-mode (the terminal of PW SW (pin(11)) is off-mode).
It is necessary to connect an external pull-down resistor with terminal MT SW, in case that this IC is
turned on due to external noise etc.
(3) BST SW
The leak current never flows through the terminal of BST SW (pin(1)) even though this terminal is at any
condition, because the ripple filter circuit supplies the BST SW circuit with power source. The terminal of
BST SW should not be applied higher voltage than VCC, to prevent IC from destruction. It is necessary to
connect an external pull-up resistor with terminal BST SW, in case that this IC doesn't operate normally
due to external noise etc.
In case that boost amplifier is on, BST SW terminal should be appliied VCC ~(VCC-0.3V).
(4) Input of amplifier
Each input signal should be applied through a condenser. In case that DC current or DC voltage is applied
to each amplifier, the internal circuit has unbalance and the each amplifier doesn't operate normally.
It is advised that input signal refer to voltage of VREF, in order to reduce a pop sound.
(5) Ripple filter
It is necessary to connect a transistor for ripple filter, because this IC doesn't have transistor for ripple
filter. Care should be taken to stabilize the ripple filter circuit, because the ripple filter circuit supplies
VREF circuit, adder amplifier and boost amplifier with power source.
TA8157AF/AFN
2002-10-30
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Maximum Ratings (Ta = 25°C)
Characteristic Symbol Rating Unit
Supply voltage VCC 4.5 V
Output current IO (Peak) 100 mA
TA8157AF 400
Power dissipation
TA8157AFN
PD (Note)
500
mW
Operating temperature Topr -25~75
Storage temperature Tstg -55~150
°C
(Note) Derated above Ta = 25°C in the proportion of 3.2mW / °C for TA8157AF, and of
4mW / °C for TA8157AFN.
Electrical Characteristics
Unless Otherwise Specified : VCC = 1.2V, RL = 16Ω, Rg = 600Ω, f = 1kHz, Ta = 25°C
SW1: a, SW2: a, SW3: b, SW4: a, SW5: a
SW6: a, SW7: ON, SW8: OPEN
Characteristic Symbol
Test
Cir-
cuit
Test Condition Min. Typ. Max. Unit
ICC1 Power OFF, SW1: b
SW2: b ― 0.1 5 µA
ICC2 Power amp. OFF, SW2: b ― 2.4 4.0
Quiescent supply current
ICC3
1
Vin = 0 ― 8 11.5
mA
Voltage gain 1 GV1 22 24 26
Channel balance CB1
2 Vo (A) = Vo (B) = -22dBV
― 0 1.5
dB
Output power 1 Po1 VCC = 1.5V
THD (A) = THD (B) = 10% 5 9 ―
Output power 2 Po2
2 VCC = 1.5V
THD (A) = THD (B) = 10%
Vin (A) = Vin (B) = -Vin (C)
f = 100Hz, * BTL operation
SW3: a, SW5: b
8 14 ―
mW
Total harmonic
distortion THD 2 Po (A) = Po (B) = 1mW ― 0.6 1 %
Output noise voltage Vno 2 BPF = 20Hz~20kHz, SW4: b ― 25 40 µVrms
Cross talk CT 2 Vo = -22dBV, SW4: b 35 42 ―
Ripple rejection ratio RR1 2 VCC = 1.0V, fr = 100Hz
Vr = -32dBV, SW7: OPEN 45 55 ―
Power amplifier stage
Muting attenuation ATT1 2 Vo = -22dBV, SW2: a→b ― 73 ―
dB
TA8157AF/AFN
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Characteristic Symbol
Test
Cir-
cuit
Test Condition Min. Typ. Max. Unit
ADD amp. voltage
gain GV2 2
Vin (A) = Vin (B), RL = 12kΩ
Vo (ADD) = -22dBV
SW3: a / b
15 17.5 20 dB
ADD amp.
maximum output
voltage Vom2 2
Vin (A) = Vin (B), RL = 12kΩ
THD (ADD) = 1%, SW3: a / b 80 130 ― mVrms
BST amp. voltage
gain GV3 2
Vo = -37dBV, RL = 16kΩ
SW6: b 14 16.5 19 dB
BST amp.
maximum output
voltage
Vom3 2
THD (BST) = 3%, RL = 16kΩ
SW6: b 55 90 ― mVrms
Bass
boost
function
stage
BST amp.
attenuation ATT3 2
Vo = -32dBV, SW3: a→b
SW6: b ― 73 ― dB
Ripple filter output voltage VRF OUT 2 VCC = 1V，IRF = 20mA 0.9 0.93 ― V
Ripple rejection ratio RR4 2
VCC = 1V，IRF = 20mA
fr = 100Hz, Vr = -37dBV
SW7: OPEN
35 43 ― dB
Equalizer on resistance RON 1
IEQ = 100µA, SW3: a
SW8: ON ― 60 ― Ω
On current I11 1
VCC = 0.9V, V4 ≥ 0.5V
SW1: c, SW2: b 5 ― ― µA
Power
switch
Off voltage V11 1
VCC = 0.9V, V4 ≤ 0.2V
SW1: d, SW2: b 0 ― 0.3 V
Off current I10 1
VCC = 0.9V, ICC ≥ 4.5mA
SW2: c 5 ― ― µA
Mute
switch
On voltage V10 1
VCC = 0.9V, ICC ≤ 3.5mA
SW2: d 0 ― 0.3 V
Off current I1 1
VCC = 0.9V, IEQ = 100µA
V2 ≥ 0.7V, SW3: c, SW8: ON 5 ― ― µA
Boost
switch
On voltage V1 1
VCC = 0.9V, IEQ = 100µA
V2 ≤ 0.2V, SW3: d, SW8: ON 0.6 ― 0.9 V
TA8157AF/AFN
2002-10-30
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Test Circuit 1
(*) Tantalum condenser
TA8157AF/AFN
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Test Circuit 2
(*) Tantalum condenser
TA8157AF/AFN
2002-10-30
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Characteristic Curves
Unless Otherwise Specified: VCC = 1.2V, RL = 16Ω, Rg = 600Ω, f = 1kHz, Ta = 25°C
TA8157AF/AFN
2002-10-30
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TA8157AF/AFN
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TA8157AF/AFN
2002-10-30
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Package Dimensions
Weight: 0.32g (typ.)
TA8157AF/AFN
2002-10-30
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Package Dimensions
Weight: 0.14g (typ.)
TA8157AF/AFN
2002-10-30
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RESTRICTIONS O N PRODUCT USE
