The 20-bit is highly integrated Delta-Sigma analog-to-digital (A/D) converters that include an instrumentation amplifier, a PGA (programmable gain amplifier), eight digital filters and self- and system-calibration circuitry.
The converters are designed to provide their own negative supply, which enables their on-chip instrumentation amplifiers to measure bipolar ground-referenced signals ?100 mV. By directly supplying NBV with -2.5 V and with VA+ at 5 V, ±2.5 V signals (with respect to ground) can be measured.
The digital filters provide programmable output update rates between 3.76 Hz to 202 Hz (XIN = 32.768 kHz). Output word rates can be increased by approximately 3x by using XIN = 100 kHz. Each filter is designed to settle to full accuracy for its output update rate in one conversion cycle. The filters with word rates of 15 Hz or less (XIN = 32.768 kHz) reject both 50 Hz and 60 Hz (±3 Hz) line interference simultaneously.
Low power, single-conversion settling time, programmable output rates and the ability to handle negative input signals make these single-supply products ideal solutions for isolated and non-isolated applications.
- Delta-Sigma A/D converters:
- Linearity error: 0.0015% FS
- Noise-free resolution: 18 bits
Bipolar/unipolar input ranges:
25 mV, 55 mV, 100 mV, 1 V, 2.5 V, and 5 V
Chopper-stabilized instrumentation amplifier
On-chip charge pump drive circuitry
4-bit output latch
Simple, 3-wire serial interface:
SPI™ and Microwire™ compatible
Schmitt Trigger on serial clock (SCLK)
Programmable output word rates:
3.76 Hz to 202 Hz (XIN = 32.768 kHz)
11.47 Hz to 616 Hz (XIN = 100 kHz)
Output settles in one conversion cycle
Simultaneous 50 Hz/60 Hz noise rejection
System- and self-calibration with read/write registers
Single +5 V analog supply; +3 V or +5 V digital supply
Low power mode consumption: 4.9 mW:
1.8 mW in 1 V, 2.5 V and 5 V input ranges
Package: 20-pin SSOP; lead-free assembly
