Datasheet LTC221, LTC222 (Analog Devices)

LTC221/LTC222 Micropower, Low Charge Injection, Quad CMOS Analog Switches with Data Latches
U FEATURES DESCRIPTIO
■ Micropower Operation The LTC®221 and LTC222 are micropower, quad CMOS ■ Single 5V or ±15V Supply Operation analog switches which typically dissipate only 250µW ■ Low Charge Injection from ±15V supplies and 40µW from a single 5V supply. ■ Low RON Onboard latches allow the LTC221 and LTC222 to inter- ■ Low Leakage face directly to most microprocessor buses. The switches ■ Guaranteed Break Before Make have 65Ω typical on resistance and a very high off resis- ■ Latch Resistant Design tance. A break before make characteristic is inherent in ■ TLL/CMOS Compatible these switches to prevent the shorting of two channels. ■ Improved Second Source for DG221/DG222 The signal range is ±15V with a supply voltage of ±15V and ■ Microprocessor Bus Compatible 0V to 5V with a single 5V supply. The switches have special charge compensation circuitry which greatly reduces
U
charge injection to a maximum of ±25pC (±15V supplies).
KEY SPECIFICATIO S
The LTC221 and LTC222 are designed for applications ■ Supply Current ... I+ = 40µA, I– = 5µA Max such as microprocessor controlled programmable gain ■ Charge Injection amplifiers, automatic test equipment, communication ±15V Supplies ... ±25pC Max systems, and data acquisition systems. The LTC221 is Single 5V Supply .. 2pC Typ normally closed and the LTC222 is normally open as ■ RON ... 65ΩTyp shown in the Logic Table. ■ Signal Range ... ±15V , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO Two-Channel, 12-Bit, Self Calibrating Data Acquisition System
LTC221/LTC222 WR WR V+ IN4 5V LOGIC ADDRESS BUS DECODER GND IN3 V– IN2 DATA BUS B0 – B3 IN1 TO MICROPROCESSOR e.g. TMS320C25 S1 D1 15V 5V VFS S2 D2 + 10k V IN LTC1292 CLK IN LT1006 OV TO 5V D S3 D3 12-BIT OUT – ADC SERIAL PORT S4 D4 CS 150k R1 –IN V 100k REF GND 120Ω 270Ω –15V LT1027 15V VFS LTC221/222 • TA01 2212fa 1