Datasheet LTC2424, LTC2428 (Analog Devices)

LTC2424/LTC2428 4-/8-Channel 20-Bit µPower No Latency ∆ΣTM ADCs
U FEATURES DESCRIPTIO
■
Pin Compatible 4-/8-Channel 20-Bit ADCs
The LTC®2424/LTC2428 are 4-/8-channel 2.7V to 5.5V ■
8ppm INL, No Missing Codes at 20 Bits
micropower 20-bit A/D converters with an integrated ■
4ppm Full-Scale Error and 0.5ppm Offset
oscillator, 8ppm INL and 1.2ppm RMS noise. They use ■
1.2ppm Noise
delta-sigma technology and provide single cycle digital ■
Digital Filter Settles in a Single Cycle. Each
filter settling time (no latency delay) for multiplexed
Conversion is Accurate, Even After Changing
applications. The first conversion after the channel is
Channels
changed is always valid. Through a single pin the LTC2424/ ■
Fast Mode: 16-Bit Noise, 12-Bit TUE at 100sps
LTC2428 can be configured for better than 110dB rejec- ■ Internal Oscillator—No External Components tion at 50Hz or 60Hz ±2%, or can be driven by an external Required oscillator for a user defined rejection frequency in the ■ 110dB Min, 50Hz/60Hz Notch Filter range 1Hz to 800Hz. The internal oscillator requires no ■ Reference Input Voltage: 0.1V to V external frequency setting components. CC ■ Live Zero—Extended Input Range Accommodates The converters accept any external reference voltage from 12.5% Overrange and Underrange 0.1V to VCC. With their extended input conversion range of ■ Single Supply 2.7V to 5.5V Operation –12.5% VREF to 112.5% VREF (VREF = FSSET – ZSSET) the ■ Low Supply Current (200µA) and Auto Shutdown LTC2424/LTC2428 smoothly resolve the offset and ■ Can Be Interchanged with 24-Bit LTC2404/LTC2408 overrange problems of preceding sensors or signal con- if ZSSET Pin is Grounded ditioning circuits.
U APPLICATIO S
The LTC2424/LTC2428 communicate through a flexible 4-wire digital interface which is compatible with SPI and ■ Weight Scales MICROWIRETM protocols. ■ Direct Temperature Measurement , LTC and LT are registered trademarks of Linear Technology Corporation. ■ Gas Analyzers No Latency ∆Σ is a trademark of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation. ■ Strain-Gage Transducers ■ Instrumentation ■ Data Acquisition ■ Industrial Process Control ■ 4-Digit DVMs
U TYPICAL APPLICATIO Total Unadjusted Error (3V Supply)
10 0.1V TO VCC 2.7V TO 5.5V VCC = 3V 8 7 4 3 2, 8 VREF = 2.5V 1µF MUXOUT ADCIN FS 6 SET VCC 9 CH0 SERIAL DATA LINK 4 MICROWIRE AND 10 CH1 23 CSADC SPI COMPATABLE 2 11 CH2 20 CSMUX ANALOG 0 12 CH3 25 20-BIT SCK INPUTS 4-/8-CHANNEL 13 CH4* + 19 ∆Σ ADC –2 –0.12V CLK MPU ERROR (ppm) REF TO MUX 1.12V 21 REF 14 CH5* D –4 – IN T 15 CH6* 24 A = –55°C, –45°C, 25°C, 90°C SDO –6 17 CH7* LTC2424/LTC2428 VCC –8 = INTERNAL OSC/50Hz REJECTION 5 ZSSET 26 = EXTERNAL CLOCK SOURCE GND FO –10 = INTERNAL OSC/60Hz REJECTION 0 0.5 1.0 1.5 2.0 2.5 24248 TA01 1, 6, 16, 18, 22, 27, 28 INPUT VOLTAGE (V) *THESE PINS ARE NO CONNECTS ON THE LTC2404 24248 G01 1