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AD7705BN
DIP16
2-Kanal 16-Bit Sigma-Delta-ADC

The AD7705/AD7706 are complete analog front ends for low
frequency measurement applications. These 2-/3-channel devices
can accept low level input signals directly from a transducer and
produce serial digital output. The devices employ a Σ-Δ
conversion technique to realize up to 16 bits of no missing codes
performance. The selected input signal is applied to a
proprietary, programmable-gain front end based around an
analog modulator. The modulator output is processed by an on-
chip digital filter. The first notch of this digital filter can be pro-
grammed via an on-chip control register, allowing adjustment of
the filter cutoff and output update rate.
The AD7705/AD7706 devices operate from a single 2.7 V to
3.3 V or 4.75 V to 5.25 V supply. The AD7705 features two fully
differential analog input channels; the AD7706 features three
pseudo differential input channels.
Both devices feature a differential reference input. Input signal
ranges of 0 mV to 20 mV through 0 V to 2.5 V can be
incorporated on both devices when operating with a VDD of 5 V
and a reference of 2.5 V. They can also handle bipolar input
signal ranges of ±20 mV through ±2.5 V, which are referenced to
the AIN(−) inputs on the AD7705 and to the COMMON input
on the AD7706.

3 V/5 V, 1 mW, 2-/3-Channel,
16-Bit, Sigma-Delta ADCs
AD7705/AD7706
Rev. C
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FEATURES
- AD7705: 2 fully differential input channel ADCs
- AD7706: 3 pseudo differential input channel ADCs
- 16 bits no missing codes
- 0.003% nonlinearity
- Programmable gain front end: gains from 1 to 128
- 3-wire serial interface
- SPI®-, QSPI™-, MICROWIRE™-, and DSP-compatible
- Schmitt-trigger input on SCLK
- Ability to buffer the analog input
- 2.7 V to 3.3 V or 4.75 V to 5.25 V operation
- Power dissipation 1 mW maximum @ 3 V
- Standby current 8 μA maximum