LTC221 Datasheet, PDF (1/12 Pages) Linear Technology – Micropower, Low Charge Injection, Quad CMOS Analog Switches with Data Latches

LTC221/LTC222
Micropower, Low Charge
Injection, Quad CMOS Analog
Switches with Data Latches
FEATURES
■ _{Micropower Operation}
■ _{Single 5V or ±15V Supply Operation}
■ _{Low Charge Injection}
■ _{Low RON}
■ _{Low Leakage}
■ _{Guaranteed Break Before Make}
■ _{Latch Resistant Design}
■ _{TLL/CMOS Compatible}
■ _{Improved Second Source for DG221/DG222}
■ _{Microprocessor Bus Compatible}
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KEY SPECIFICATIO S
■ _{Supply Current ..................... I}⁺ _{= 40µA, I}^– _{= 5µA Max}
■ _{Charge Injection}
±15V Supplies ................................. ±25pC Max
Single 5V Supply .................................. 2pC Typ
■ _{RON ............................................................... 65ΩTyp}
■ _{Signal Range ..................................................... ±15V}
DESCRIPTIO
The LTC^®221 and LTC222 are micropower, quad CMOS
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATIO
Two-Channel, 12-Bit, Self Calibrating Data Acquisition System
LTC221/LTC222
WR
V⁺
5V
IN4
GND
IN3
V^–
IN2
IN1
V_FS ^S1
D1
S2
D2
V_IN
OV TO 5V
S3
D3
S4
D4
LOGIC
DECODER
ADDRESS BUS
DATA BUS B0 – B3
15V
5V
LT1006
10k _IN
150k
–IN
GND
120Ω
–15V
LTC1292 CLK
12-BIT
ADC
D_OUT
CS
R1 V_REF
SERIAL PORT
100k
270Ω
LT1027
V_FS
WR
TO MICROPROCESSOR
e.g. TMS320C25
15V
LTC221/222 • TA01
2212fa
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