Philips TEA0677T Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TEA0677T

Dual pre-amplifier and equalizer for
reverse tape decks

Product specification
File under Integrated Circuits, IC01

August 1993

Philips Semiconductors Product specification

Dual pre-amplifier and equalizer for

TEA0677T

reverse tape decks

FEATURES

• Head pre-amplifiers

• Reverse head switching

• Equalization with electronically switched time constants

• 0 dB = 387.5 mV

• Pin compatible to TEA0675 Dolby B, music search IC.

QUICK REFERENCE DATA

SYMBOL PARAMETER MIN. TYP. MAX. UNIT

V

CC

I

CC

(S + N)/N signal-plus-noise to noise ratio 68 74 − dB

supply voltage 7.6 10 12 V
supply current − 23 26 mA

GENERAL DESCRIPTION

The TEA0677T is a monolithic bipolar integrated circuit
intended for applications in car radios. It includes head and
equalization amplifiers with electronically switchable time
constants. Furthermore it includes electronically
switchable inputs for tape drives with reverse heads. The
device is intended to replace the regular TEA0675T in
low-cost car radios using the same PCB. External
components that are necessary for Dolby B and music
search features can be omitted.

The device will operate with power supplies in the range of

7.6 V to 12.0 V, output overload level increasing with
increase in supply voltage. Current drain varies with
supply voltage, so it is advisable to use a regulated power
supply or a supply with a long time constant.

ORDERING INFORMATION

EXTENDED TYPE

NUMBER

TEA0677T 24 SO plastic SOT137A

Note

1. SOT137-1; 1996 August 27.

PINS PIN POSITION MATERIAL CODE

PACKAGE

(1)

August 1993 2

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August 1993 3

Philips Semiconductors Product specification

Dual pre-amplifier and equalizer for

reverse tape decks

Instead of potentiometers at EQ AMP
fixed resistors may be used. The value
depends on applied heads.

TEA0677T

Fig.1 Block and application diagram.

Philips Semiconductors Product specification

Dual pre-amplifier and equalizer for
reverse tape decks

PINNING

SYMBOL PIN DESCRIPTION

OUTA 1 output channel A
n.c. 2 not connected
n.c. 3 not connected
n.c. 4 not connected
n.c. 5 not connected
n.c. 6 not connected
EQA 7 equalizing output channel A
EQFA 8 equalizing input channel A
V

CC

INA1 10 input channel A1 (forward or

V

REF

INA2 12 input channel A2 (reverse or

INB2 13 input channel B2 (reverse or

HS 14 head switch input
INB1 15 input channel B1 (forward or

GND 16 ground
EQFB 17 equalizing input channel B
EQB 18 equalizing output channel B
EQS 19 equalizing switch input
n.c. 20 not connected
ACUR 21 auxiliary current
n.c. 22 not connected
n.c. 23 not connected
OUTB 24 output channel B

9 supply voltage

reverse)

11 reference voltage

forward)

forward)

reverse)

TEA0677T

Fig.2 Pin configuration.

FUNCTIONAL DESCRIPTION
Head switching is achieved when pin 14 (HS) is

connected to GND via a 27 kΩ resistor (inputs INA2, INB2
active), or left open-circuit (inputs INA1, INB1 active).
The 10 µF capacitor at pin 14 sets the time constant for
smooth switching.

August 1993 4

Time constant switching for equalization

(70 µs/120 µs) is achieved when pin 19 (EQS) is
connected to ground via an 18 kΩ resistor (120µs) or left
open-circuit (70 µs).