![](/html/d9/d91d/d91dde89322cc532cd0cc5e79f58064ee5b8458ff9994d728394676c8c605b47/bg1.png)
INTEGRATED CIRCUITS
DATA SH EET
TEA0677T
Dual pre-amplifier and equalizer for
reverse tape decks
Product specification
File under Integrated Circuits, IC01
August 1993
![](/html/d9/d91d/d91dde89322cc532cd0cc5e79f58064ee5b8458ff9994d728394676c8c605b47/bg2.png)
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
![](/html/d9/d91d/d91dde89322cc532cd0cc5e79f58064ee5b8458ff9994d728394676c8c605b47/bg3.png)
This text is here in white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here in
_white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here inThis text is here in
white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader. white to force landscape pages to be ...
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.
![](/html/d9/d91d/d91dde89322cc532cd0cc5e79f58064ee5b8458ff9994d728394676c8c605b47/bg4.png)
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).