Datasheet LTC2430, LTC2431 (Analog Devices)

LTC2430/LTC2431 20-Bit No Latency ∆ΣTM ADCs with Differential Input and Differential Reference
U FEATURES DESCRIPTIO
■
Low Supply Current (200
µ
A in Conversion Mode
The LTC®2430/LTC2431 are 2.7V to 5.5V micropower
and 4
µ
A in Autosleep Mode)
20-bit differential ∆Σ analog-to-digital converters with an ■
Differential Input and Differential Reference
integrated oscillator, 3ppm INL and 0.56ppm RMS noise.
with GND to V
They use delta-sigma technology and provide single cycle
CC Common Mode Range
■
3ppm INL, No Missing Codes
settling time for multiplexed applications. Through a ■
10ppm Full-Scale Error and 1ppm Offset
single pin, the LTC2430/LTC2431 can be configured for ■
0.56ppm Noise, 20.8 ENOBs
better than 110dB differential mode rejection at 50Hz or ■
No Latency: Digital Filter Settles in a Single Cycle.
60Hz ±2%, or they can be driven by an external oscillator
Each Conversion Is Accurate, Even After an
for a user-defined rejection frequency. The internal oscil-
Input Step
lator requires no external frequency setting components. ■ Single Supply 2.7V to 5.5V Operation The converters accept any external differential reference ■ Internal Oscillator—No External Components voltage from 0.1V to VCC for flexible ratiometric and Required remote sensing measurement configurations. The full- ■ 110dB Min, 50Hz/60Hz Notch Filter scale differential input range is from – 0.5VREF to 0.5VREF. ■ Pin Compatible with 24-Bit LTC2410/LTC2411 The reference common mode voltage, VREFCM, and the
U
input common mode voltage, VINCM, may be indepen-
APPLICATIO S
dently set anywhere within GND to VCC. The DC common ■ Direct Sensor Digitizer mode input rejection is better than 120dB. ■ Weight Scales The LTC2430/LTC2431 communicate through a flexible ■ Direct Temperature Measurement 3-wire digital interface that is compatible with SPI and ■ Gas Analyzers MICROWIRETM protocols. ■ Strain Gauge Transducers , LTC and LT are registered trademarks of Linear Technology Corporation. ■ Instrumentation No Latency ∆Σ is a trademark of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation. ■ Data Acquisition ■ Industrial Process Control ■ DVMs and Meters
U TYPICAL APPLICATIO S Total Unadjusted Error (V
(V
CC = 5V, VREF = 5V)
OUT + 0.25V) TO 20V 5 VOUT 6 4 VCC = 5V LT1790 3V TO 5V 4 VREF = 5V VINCM = VINCM = 2.5V 1 2 0.1µF 3 4.7µF FO = GND ) 2 VCC REF 25°C 85°C = INTERNAL OSC/50Hz REJECTION 1 VCC FO = EXTERNAL CLOCK SOURCE 0.1µF = INTERNAL OSC/60Hz REJECTION 0 LTC2431 REF+ –1 SCK –45°C TUE (ppm OF V –2 REF– 3-WIRE –3 ANALOG INPUT RANGE SPI INTERFACE IN+ SDO –0.5V –4 REF TO 0.5VREF IN– CS –5 GND –2.5 –2 –1.5 –1 – 0.5 0 0.5 1 1.5 2 2.5 24301 TA01 INPUT VOLTAGE (V) 24301 G01 24301f 1