1-/2-Channel 20-Bit µPower
No Latency ∆ΣTMADCs in MSOP-10
s 20-Bit ADCs in Tiny MSOP-10 Packages
s 1- or 2-Channel Inputs
s Single Supply 2.7V to 5.5V Operation
s Low Supply Current (200µA) and Auto Shutdown
s Automatic Channel Selection (Ping-Pong) (LTC2422)
s No Latency: Digital Filter Settles in a
Single Conversion Cycle
s 8ppm INL, No Missing Codes
s 4ppm Full-Scale Error
s 0.5ppm Offset
s 1.2ppm Noise
s Zero Scale and Full Scale Set for Reference
and Ground Sensing
s Internal Oscillator—No External Components Required
s 110dB Min, 50Hz/60Hz Notch Filter
s Reference Input Voltage: 0.1V to VCC
s Live Zero—Extended Input Range Accommodates
12.5% Overrange and Underrange
s Pin Compatible with LTC2401/LTC2402
s Weight Scales
s Direct Temperature Measurement
s Gas Analyzers
s Strain Gauge Transducers
s Data Acquisition
s Industrial Process Control
The LTC®2421/LTC2422 are 1- and 2-channel 2.7V to 5.5V
micropower 20-bit analog-to-digital converters with an
integrated oscillator, 8ppm INL and 1.2ppm RMS noise.
These ultrasmall devices use delta-sigma technology and
a new digital filter architecture that settles in a single cycle.
This eliminates the latency found in conventional ∆Σ
converters and simplifies multiplexed applications.
Through a single pin, the LTC2421/LTC2422 can be
configured for better than 110dB rejection at 50Hz or
60Hz ±2%, or can be driven by an external oscillator for
a user defined rejection frequency in the range 1Hz to
120Hz. The internal oscillator requires no external fre-
quency setting components.
These converters accept an external reference voltage
from 0.1V to VCC. With an extended input conversion
range of –12.5% VREF to 112.5% VREF (VREF = FSSET –
ZSSET), the LTC2421/LTC2422 smoothly resolve the off-
set and overrange problems of preceding sensors or
signal conditioning circuits.
The LTC2421/LTC2422 communicate through a 2- or
3-wire digital interface that is compatible with SPI and
, LTC and LT are registered trademarks of Linear Technology Corporation.
No Latency ∆Σ is a trademark of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
2.7V TO 5.5V
ZSSET + 0.1V TO VCC
ANALOG INPUT RANGE
ZSSET – 0.12VREF TO
FSSET + 0.12VREF
(VREF = FSSET – ZSSET)
0V TO FSSET – 100mV
= INTERNAL OSC/50Hz REJECTION
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION
Pseudo Differential Bridge Digitizer
FSSET SCK 9
2.7V TO 5.5V