TS636

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DIGITAL INPUTS

SIMPLIFIED SCHEMATIC

The TS636 consists of two independent channels.

Each channel has two stages. The first is a very low noise digitally controlled variable gain amplifier (range

0 to 18dB).

The TS636 features a high input impedance and a low noise current. To minimize the overall noise figure,

the source impedance must be less than 3k

Ω.

This value gives an equal contribution of voltage and current noises.

The second stage is a gain/attenuation stage (+12dB to -9dB) featuring a low output impedance.

This output stage can drive loads as low as 500

Ω.

POWER DOWN MODE POSITION

Pin

Parameter

Min.

Typ.

Max.

Unit

GC1, GC2, GC3

and GC4

Low Level

0

0.8

V

High Level

2

3.3

Power Down

Thershold Voltage for Power

Down Mode (high level active)

0

0.8

V

23.3

+

_

_

+

+

_

_

+

v

v

GAIN CONTROL

LOGIC DECODER

Input1

+

_

_

+

v

Input2

+Vcc2

Digital GND

(DGND)

Ouput2

Ouput1

+Vcc1

-Vcc

Analog GND

(AGND)

GC2

GC1

GC3

GC4

v

v

v

Power

Down

+Vcc

-Vcc

+Vcc

-Vcc

Power Down

Input

Output