LTC2401/LTC2402 WUTYPICAL PERFOR A CE CHARACTERISTICSINL vs Output RateResolution vs Output Rate 24 24 VCC = 5V VREF = 5V FO = EXTERNAL 20 20 TA = –55°C TA = 90°C TA = 25°C 16 16 TA = –55°C INL (BITS) TA = 90°C RESOLUTION (BITS) 12 12 TA = 25°C VCC = 5V VREF = 5V FO = EXTERNAL 8 8 0 20 40 60 80 100 0 20 40 60 80 100 OUTPUT RATE (Hz) OUTPUT RATE (Hz) 24012 G28 24012 G29 UUUPIN FUNCTIONSVCC (Pin 1): Positive Supply Voltage. Bypass to GND be connected directly to a ground plane through a mini- (Pin␣ 6) with a 10µF tantalum capacitor in parallel with mum length trace or it should be the single-point-ground 0.1µF ceramic capacitor as close to the part as possible. in a single-point grounding system. FSSET (Pin 2): Full-Scale Set Input. This pin defines the CS (Pin 7): Active LOW Digital Input. A LOW on this pin full-scale input value. When VIN = FSSET, the ADC outputs enables the SDO digital output and wakes up the ADC. full scale (FFFFFH). The total reference voltage is Following each conversion, the ADC automatically enters FSSET – ZSSET. the Sleep mode and remains in this low power state as long as CS is HIGH. A LOW on CS wakes up the ADC. A CH0, CH1 (Pins 4, 3): Analog Input Channels. The input LOW-to-HIGH transition on this pin disables the SDO voltage range is – 0.125 • VREF to 1.125 • VREF. For digital output. A LOW-to-HIGH transition on CS during the VREF > 2.5V, the input voltage range may be limited by the Data Output transfer aborts the data transfer and starts a absolute maximum rating of – 0.3V to VCC + 0.3V. Conver- new conversion. sions are performed alternately between CH0 and CH1 for the LTC2402. Pin 4 is a No Connect (NC) on SDO (Pin 8): Three-State Digital Output. During the data the LTC2401. output period, this pin is used for serial data output. When the chip select CS is HIGH (CS = V ZS CC), the SDO pin is in a SET (Pin 5): Zero-Scale Set Input. This pin defines the high impedance state. During the Conversion and Sleep zero-scale input value. When VIN = ZSSET, the ADC periods, this pin can be used as a conversion status out- outputs zero scale (00000H). put. The conversion status can be observed by pulling CS GND (Pin 6): Ground. Shared pin for analog ground, LOW. digital ground, reference ground and signal ground. Should 8