Sanyo LA-4485 Service manual

Ordering number: EN3680C

Monolithic Linear IC

LA4485

5 W, Two-channel Power Amplifier with Very Few

External Parts

Overview

The LA4485 is a 5 W, two-channel power amplifier IC that
requires a minimum of external parts, making it ideal for radio
cassette players and car stereo equipment.

The LA4485 eliminates the need for bootstrap capacitors,
negative feedback capacitors, and oscillation prevention CR
parts, all of which were necessities for power ICs previously.
All of these functions are now on chip, keeping the number of
external parts to an absolute minimum. The LA4485 is part of
the Power (Stylish Power) Series, and supports two modes:
dual and BTL.

Features

.

5W×2 output power in dual mode, and 15 W in BTL mode

.

Minimum external parts for the Power Series count:
4 or 5 parts in dual mode; 3 or 4 parts in BTL mode

.

Protection circuits

Overvoltage protection
Thermal protection
DC output short-circuit protection (to V

.

Circuitry designed to handle +VCCapplied to the outputs

.

Pop noise reduction

.

Standby switch

.

Muting function

and to GND)

CC

Package Dimensions

unit : mm

3107-SIP13H

[LA4485]

SANYO : SIP13H

Specifications

Maximum Ratings at Ta = 25°C

Parameter Symbol Conditions Ratings Unit
Maximum supply voltage V
Surge supply voltage V
Peak output current I
Allowable power dissipation Pd max With infinite heat sink 15 W
Operating temperature Topr –30 to +80 °C
Storage temperature Tstg –40 to +150 °C

*: By the π type B check point method.

max No signal 24 V

CC

surge * Based on the JASO standard 50 V

CC

peak Per channel 3.3 A

O

Operating Conditions at Ta = 25°C

Parameter Symbol Conditions Ratings Unit
Recommended supply voltage V
Supply voltage range V

Recommended load resistance range R

CC

CC

op Must not be over package Pd 7.5 to 18 V

L

Dual 2 to 8 Ω
BTL 4to8 Ω

13.2 V

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN

73096HA(II)/D2893TS/9041TS No.3680-1/20

LA4485

Operating Characteristics at Ta = 25°C, VCC= 13.2 V, RL=4Ω,Rg=600Ω,f=1kHz, Dual

Parameter Symbol Conditions min typ max Unit
Standby current Ist Pin 9 to GND, Standby switch OFF 10 µA
Quiescent supply current I

Voltage gain

Output power

CCO

VG1 Dual: V
VG2 BTL: V

P

O

P

O

Total harmonic distortion THD P
Channel separation CH sep V
Output noise voltage V

NO

Ripple rejection ratio SVRR

*: PO1 = 6 W (typ) when VCC= 14.4 V
Voff ± 250 mV for BTL-mode

Rg = 0 40 80 160 mA

= 0 dBm 43 45 47 dB

O

= 0 dBm 51 dB

O

1* Dual: THD = 10% 4 5 W

2 BTL: THD = 10% 11 15 W

= 1 W 0.15 0.8 %

O

= 0 dBm, Rg = 0 45 55 dB

O

Rg = 0, 20 Hz to 20 kHz bandpass filter 0.15 0.5 mV
Rg = 0, 20 Hz to 20 kHz bandpass filter,

f

= 100 Hz, VR= 0 dBm, decoupling capacitor

R

connected

40 50 dB

Pd max – Ta

Al heat sink
mounting

Infinite heat sink

conditions

Mounting

torque

39 Nvcm.

Flat washer

with silicone

grease

applied

No heat sink

Allowable power dissipation, Pd max – W

Ambient temperature, Ta – °C

Equivalent Circuit Block Diagram

CH1 IN

Small signal GND

BTL IN

CH2 IN

FILTER

Input
amp
CH1

REF
amp

Input
amp
CH2

Filter

Large signal

V

CC

Output-to-ground
short-circuit
protection

Pre
drive
amp

Output-to-supply
short-circuit
protection

Thermal shutdown

Output-to-supply
short-circuit

Pre
drive
amp

protection

Output-to-ground
short-circuit
protection

Standby switch

Small signal
V

CC

protection

Overvoltage
protection

Output
amp

Output
amp

Mute

CH1 OUT

Large signal GND

CH2 OUT

BTL OUT

STANDBY

MUTE

No.3680-2/20

LA4485

Recommended LA4485 External Parts Arrangement (Dual-mode)

95.0 × 67.0 mm

2

IC Usage Notes

Maximum ratings

Care must be taken when operating the LA4485 close to the maximum ratings as small changes in the operating conditions can
cause the maximum ratings to be exceeded, thereby breakdown will be caused.

Printed circuit board connections

Care must be taken when designing the circuit of printed board so as not to form feedback loops, particularly with the small-signal
and large-signal ground connections.

Notes on LA4485 heatsink mounting

1. Mounting torque must be in the range 39 to 59 Nvcm.

2. The spacing of the tapped holes in the heatsink must match the spacing of the holes in the IC tab.

3. Use screws with heads equivalent to truss head machine screws and binding head machine screws stipulated by JIS for the
mounting screws. Furthermore, washers must be used to protect the surface of the IC tab.

4. Make sure that there is no foreign matter, such as cutting debris, between the IC tab and the heatsink. If a heat conducting
compound is applied between the contact surfaces, make sure that it is spread uniformly over the entire surface.

5. Because the heatsink mounting tab and the heatsink are at the same electric potential as the chip’s GND (large signal GND),
care must be taken when mounting the heatsink on more than one device.

6. The heatsink must be mounted before soldering the pins to the PCB.

Comparison of External Parts Required

External parts Existing device LA4485
Output coupling capacitors Yes Yes
Input coupling capacitors Yes Yes
Bootstrap capacitors Yes No
Feedback capacitors Yes No
Filter capacitor Yes Optional
Phase compensating capacitor Yes No
Oscillation-quenching mylar capacitors Yes No
Oscillation-quenching resistors Yes No
Others No Optional
Total (for dual-mode) 15 to 16 parts 4 to 6 parts

Note: Supply capacitors, contained within the power IC, are not counted in both existing and new devices.

No.3680-3/20

LA4485

Operating Pin Voltages at VCC= 13.2 V

Pin No. Name Function Pin voltage (Reference value)

1 CH1 IN Channel 1 input. 1.4 V (2 V
2 CH2 IN Channel 2 input. 1.4 V (2 V
3 SS GND Small-signal ground 0 V
4 BTL IN BTL-mode feedback input. 45 mV
5 BTL OUT BTL-mode feedback output. 3.1 V (61/4 V
6 FILTER Filter capacitor connection. 6.6 V (61/2 V
7LSV
8SSV

9 STANDBY Standby control input. 5 V
10 MUTE Mute control input. 0 V
11 CH2 OUT Channel 2 output. 6.3 V
12 LS GND Large-signal ground 0 V
13 CH1 OUT Channel 1 output. 6.3 V

Large-signal supply 13.2 V (VCC)

CC

Small-signal supply 13.2 V (VCC)

CC

Note: Each pin is so arranged lest the IC should be broken even if inserted reversely.

BE
BE

)
)

)

CC

)

CC

LA4485 Sample Application Circuit

No.3680-4/20

LA4485

–V

N

Output pin voltage, V

Supply voltage, VCC–V

CVCC= 0.15 µF (mylar)
Rg = 0
Standby to GND

VN–V

CC

=4Ω(dual)

R

L

Rg = 0 standby + 5 V

Overvoltage cutoff

VCC= 7.5 V
Cutoff for waveform carrying signal

Muting on

lst–V

CC

–mA

CCO

Quiescent supply current, I

VCC= 13.2 V
R

f = 1 kHz
Rg = 600 Ω

–W

O

L

I

CCO–VCC

Muting on

Supply voltage, VCC–V

P

=4Ω

O–VIN

=4Ω

R

L

Rg=0

I

CCO

Standby current, Ist – µA

Supply voltage, VCC–V

THD–P

O

Total harmonic distortion, THD – %

Output power, PO–W

f Response

Output power, P

Input voltage, VIN–mV

THD–f

Total harmonic distortion, THD – %

Frequency,f–Hz

THD–V

CC

Response – dB

Total harmonic distortion, THD – %

Frequency,f–Hz

Supply voltage, VCC–V

No.3680-5/20

LA4485

–W

O

Output power, P

Dual
RL=2Ω

PO–V

CC

Supply voltage, VCC–V

Pd–P

O

(2CH) – A

Current drain, I

CC

I

CC–PO

Dual
Rg = 600 Ω
f = 1 kHz

Output power, PO(1CH) – W

Pd–P

O

Dual
RL=3Ω

Power dissipation, Pd (2CH) – W

Power dissipation, Pd (2CH) – W

Output power, PO(1CH) – W

Pd–P

O

Output power, PO(1CH) – W

Pd–P

O

Dual
R

=4Ω

L

Dual
RL=8Ω

Power dissipation, Pd (2CH) – W

Power dissipation, Pd (2CH) – W

Output power, PO(1CH) – W

Pd–P

Output power, PO(1CH) – W

Pd max – V

Dual
Ta = 25°C

O

Dual
RL=6Ω

CC

Power dissipation, Pd (2CH) – W

Output power, PO(1CH) – W

–W

Allowable power dissipation, Pd max (2CH)

Supply voltage, VCC–V

No.3680-6/20