LTC221/LTC222

1

2212fa

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Micropower Operation

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Single 5V or ±15V Supply Operation

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Low Charge Injection

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Low Leakage

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Guaranteed Break Before Make

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Latch Resistant Design

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TLL/CMOS Compatible

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Improved Second Source for DG221/DG222

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Microprocessor Bus Compatible

The LTC

analog switches which typically dissipate only 250µW

from ±15V supplies and 40µW from a single 5V supply.

Onboard latches allow the LTC221 and LTC222 to inter-

face directly to most microprocessor buses. The switches

have 65Ω typical on resistance and a very high off resis-

tance. A break before make characteristic is inherent in

these switches to prevent the shorting of two channels.

The signal range is ±15V with a supply voltage of ±15V and

0V to 5V with a single 5V supply. The switches have special

charge compensation circuitry which greatly reduces

charge injection to a maximum of ±25pC (±15V supplies).

The LTC221 and LTC222 are designed for applications

such as microprocessor controlled programmable gain

amplifiers, automatic test equipment, communication

systems, and data acquisition systems. The LTC221 is

normally closed and the LTC222 is normally open as

shown in the Logic Table.

Micropower, Low Charge

Injection, Quad CMOS Analog

Switches with Data Latches

, LTC and LT are registered trademarks of Linear Technology Corporation.

FEATURES

DESCRIPTIO

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Charge Injection

±15V Supplies ................................. ±25pC Max

Single 5V Supply .................................. 2pC Typ

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Signal Range ..................................................... ±15V

Two-Channel, 12-Bit, Self Calibrating Data Acquisition System

KEY SPECIFICATIO S

LTC221/222 • TA01

5V

R1

15V

IN

–IN

10k

150k

100k

120Ω

270Ω

GND

IN3

IN4

WR

WR

TO MICROPROCESSOR

e.g. TMS320C25

IN2

IN1

CS

CLK

GND

D1

S1

D2

S2

OV TO 5V

D3

S3

D4

S4

5V

–15V

15V

LTC221/LTC222

LT1006

+

–

LOGIC

DECODER

LTC1292

12-BIT

ADC

SERIAL PORT

DATA BUS B0 – B3

ADDRESS BUS

LT1027

TYPICAL APPLICATIO