The ADS8881 is an 18-bit, 1-MSPS, true-differential input, analog-to-digital converter (ADC). The device operates with a 2.5-V to 5-V external reference, offering a wide selection of signal ranges without additional input signal scaling. The reference voltage setting is independent of, and can exceed, the analog supply voltage (AVDD).
The device offers an SPI-compatible serial interface that also supports daisy-chain operation for cascading multiple devices. An optional busy-indicator bit makes synchronizing with the digital host easy.
The device supports unipolar, true-differential analog input signals with a differential input swing of –VREF to VREF. This true-differential analog input structure allows for a common-mode voltage of any value in the range of 0 V to VREF (when both inputs are within the operating input range of –0.1 V to VREF
+ 0.1 V).
Device operation is optimized for very low-power operation. Power consumption directly scales with speed. This feature makes the ADS8881 excellent for lower-speed applications.
PART NUMBER | PACKAGE | BODY SIZE (NOM) |
---|---|---|
ADS8881x | VSSOP (10) | 3.00 mm × 3.00 mm |
VSON (10) | 3.00 mm × 3.00 mm |
Changes from C Revision (July 2014) to D Revision
Changes from B Revision (December 2014) to C Revision
Changes from A Revision (July 2013) to B Revision
Changes from * Revision (May 2013) to A Revision
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PIN | I/O | DESCRIPTION | |
---|---|---|---|
NAME | NO. | ||
AINN | 4 | Analog input | Inverting analog signal input |
AINP | 3 | Analog input | Noninverting analog signal input |
AVDD | 2 | Analog | Analog power supply. This pin must be decoupled to GND with a 1-μF capacitor. |
CONVST | 6 | Digital input | Convert input. This pin also functions as the CS input in 3-wire interface mode; see the Description and Timing Requirements sections for more details. |
DIN | 9 | Digital input | Serial data input. The DIN level at the start of a conversion selects the mode of operation (such as CS or daisy-chain mode). This pin also serves as the CS input in 4-wire interface mode; see the Description and Timing Requirements sections for more details. |
DOUT | 7 | Digital output | Serial data output |
DVDD | 10 | Power supply | Digital interface power supply. This pin must be decoupled to GND with a 1-μF capacitor. |
GND | 5 | Analog, digital | Device ground. Note that this pin is a common ground pin for both the analog power supply (AVDD) and digital I/O supply (DVDD). The reference return line is also internally connected to this pin. |
REF | 1 | Analog | Positive reference input. This pin must be decoupled with a 10-μF or larger capacitor. |
SCLK | 8 | Digital input | Clock input for serial interface. Data output (on DOUT) are synchronized with this clock. |
Thermal pad | — | Thermal pad | Exposed thermal pad (only for the DRC package option). Texas Instruments recommends connecting the thermal pad to the printed circuit board (PCB) ground. |