Datasheet AD7887 (Analog Devices)

2.7 V to 5.25 V, Micropower, 2-Channel, 125 kSPS, 12-Bit ADC in 8-Lead MSOP Data Sheet AD7887 FEATURES FUNCTIONAL BLOCK DIAGRAM Specified for VDD of 2.7 V to 5.25 V AD7887 Flexible power/throughput rate management AIN0 I/P T/H MUX Shutdown mode: 1 μA max One or two single-ended inputs AIN1/ VREF Serial interface: SPI®/QSPI™/MICROWIRE™/DSP compatible 2.5V COMP REF 8-lead narrow SOIC and MSOP packages AIN1/VREF Qualified for automotive applications V SOFTWARE DD BUF CONTROL LATCH APPLICATIONS GND CHARGE Battery-powered systems (personal digital assistants, REDISTRIBUTION DAC medical instruments, mobile communications) Instrumentation and control systems High speed modems SAR + ADC CONTROL LOGIC SPORT
01 -0
DIN CS DOUT SCLK
91 61 0 Figure 1.
GENERAL DESCRIPTION
The AD7887 is a high speed, low power, 12-bit analog-to-digital the reference voltage for the part is provided via the VDD pin. As converter (ADC) that operates from a single 2.7 V to 5.25 V a result, the input voltage range on both the AIN0 and AIN1 power supply. The AD7887 is capable of 125 kSPS throughput inputs is 0 to VDD. rate. The input track-and-hold acquires a signal in 500 ns and CMOS construction ensures low power dissipation of typically features a single-ended sampling scheme. The output coding for 2 mW for normal operation and 3 μW in power-down mode. the AD7887 is straight binary, and the part is capable of The part is available in an 8-lead, 0.15-inch-wide narrow body converting full power signals of up to 2.5 MHz. SOIC and an 8-lead MSOP package. The AD7887 can be configured for either dual- or single-channel
PRODUCT HIGHLIGHTS
operation via the on-chip control register. There is a default single-channel mode that allows the AD7887 to be operated as a 1. Smallest 12-bit dual-/single-channel ADC; 8-lead MSOP read-only ADC. In single-channel operation, there is one package. analog input (AIN0) and the AIN1/VREF pin assumes its VREF 2. Lowest power 12-bit dual-/single-channel ADC. function. This VREF pin allows the user access to the part’s 3. Flexible power management options, including automatic internal 2.5 V reference, or the VREF pin can be overdriven by an power-down after conversion. external reference to provide the reference voltage for the part. This external reference voltage has a range of 2.5 V to V 4. Read-only ADC capability. DD. The analog input range on AIN0 is 0 to VREF. 5. Analog input range from 0 V to VREF. In dual-channel operation, the AIN1/VREF pin assumes its AIN1 6. Versatile serial input/output port (SPI/QSPI/MICROWIRE/ function, providing a second analog input channel. In this case, DSP compatible).
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Document Outline Features Applications Functional Block Diagram General Description Product Highlights Table of Contents Revision History Specifications Timing Specifications6F Absolute Maximum Ratings ESD Caution Pin Configurations and Function Descriptions Typical Performance Characteristics Terminology Control Register Theory of Operation Circuit Information Converter Operation ADC Transfer Function Typical Connection Diagram Analog Input On-Chip Reference Power-Down Options Power-Up Times Power vs. Throughput Rate Modes of Operation Mode 1 (PM1 = 0, PM0 = 0) Mode 2 (PM1 = 0, PM0 = 1) Mode 3 (PM1 = 1, PM0 = 0) Mode 4 (PM1 = 1, PM0 = 1) Serial Interface Microprocessor Interfacing AD7887 to TMS320C5x AD7887 to ADSP-21xx AD7887 to DSP56xxx AD7887 to MC68HC11 AD7887 to 8051 AD7887 to PIC16C6x/PIC16C7x Application Hints Grounding and Layout Outline Dimensions Ordering Guide Automotive Products