描述The ADS7870 (US patents 6140872, 6060874) is a complete low-power data acquisition system on a single chip. It consists of a 4-channel differential/8-channel single-ended multiplexer, precision programmable gain amplifier, 12-bit successive approximation analog-to-digital (A/D) converter, and a precision voltage reference.The programmable-gain amplifier provides high input impedance, excellent gain accuracy, good common-mode rejection, and low noise. For many low-level signals, no external amplification or impedance buffering is needed between the signal source and the A/D input. The offset voltage of the PGA is auto zeroed. Gains of 1, 2, 4, 5, 8, 10, 16, and 20 V/V allow signals as low as 125 mV to produce full-scale digital outputs.The ADS7870 contains an internal reference, which is trimmed for high initial accuracy and stability vs temperature. Drift is typically 10 ppm/°C. An external reference can be used in situations where multiple ADS7870s share a common reference. The serial interface allows the use of SPI?, QSPI?, Microwire?, and 8051-family protocols, without glue logic.特性PGA Gains: 1, 2, 4, 5, 8, 10, 16, 20V/V Programmable Input (Up to 4-channel Differential/Up to 8-channel Single-Ended or Some Combination) 1.15-V, 2.048-V or 2.5-V Internal Reference SPI/DSP Compatible Serial Interface (≤20 MHz) Throughput Rate: 52 kSamples/sec Error/Overload Indicator Programmable Output 2s Complement/Binary 2.7-V to 5.5-V Single-Supply Operation 4-Bit Digital I/O Via Serial Interface Pin Compatible With ADS7871 SSOP-28 Package APPLICATIONS Portable Battery-Powered Systems Low-Power Instrumentation Low-Power Control Systems Smart Sensor ApplicationsQSPI and SPI are trademarks of Motorola, Inc. Microwire is a trademark of National Semiconductor Corporation. All other trademarks are the property of their respective owners.