Datasheet AD7923 (Analog Devices)

4-Channel, 200 kSPS 12-Bit ADC with Sequencer in 16-Lead TSSOP Data Sheet AD7923 FEATURES FUNCTIONAL BLOCK DIAGRAM Fast throughput rate: 200 kSPS AVDD Specified for AVDD of 2.7 V to 5.25 V Low power REFIN 3.6 mW max at 200 kSPS with 3 V supply VIN0 7.5 mW max at 200 kSPS with 5 V supply • T/H • 12-BIT 4 (single-ended) inputs with sequencer • SUCCESSIVE • APPROXIMATION Wide input bandwidth • ADC • 70 dB Min SNR at 50 kHz input frequency I/P • MUX Flexible power/serial clock speed management • • No pipeline delays • • High speed serial interface SPI®-/QSPITM-/ • • MICROWIRETM-/DSP-compatible VIN3 Shutdown mode: 0.5 μA max SCLK 16-lead TSSOP package DOUT SEQUENCER CONTROL LOGIC Qualified for automotive applications DIN CS GENERAL DESCRIPTION AD7923 VDRIVE
The AD7923 is a 12-bit, high speed, low power, 4-channel, suc-
GND
03086-001 cessive approximation (SAR) ADC. It operates from a single Figure 1. 2.7 V to 5.25 V power supply and features throughput rates up to
PRODUCT HIGHLIGHTS
200 kSPS. It contains a low noise, wide bandwidth track-and-hold amplifier that can handle input frequencies in excess of 8 MHz. 1. High Throughput with Low Power Consumption. The AD7923 offers up to 200 kSPS throughput rates. At the The conversion process and data acquisition are controlled by maximum throughput rate with 3 V supplies, the AD7923 CS and the serial clock, allowing the device to easily interface dissipates just 3.6 mW of power. with microprocessors or DSPs. The input signal is sampled on 2. Four Single-Ended Inputs with a Channel Sequencer. the falling edge of CS; the conversion is also initiated at this point. 3. Single-Supply Operation with VDRIVE Function. The VDRIVE function allows the serial interface to connect The AD7923 uses advanced design techniques to achieve very directly to either 3 V or 5 V processor systems independent low power dissipation at maximum throughput rates. At of AVDD. maximum throughput rates, it consumes 1.2 mA maximum 4. Flexible Power/Serial Clock Speed Management. with 3 V supplies and 1.5 mA maximum with 5 V supplies. The conversion rate is determined by the serial clock, Through the configuration of the control register, the analog allowing the conversion time to be reduced through the input range can be selected as 0 V to REF serial clock speed increase. The part also features various IN or 0 V to 2 × REFIN, with either straight binary or twos complement output coding. shutdown modes to maximize power efficiency at lower The AD7923 features four single-ended analog inputs with a throughput rates. Current consumption is 0.5 μA channel sequencer to allow a preprogrammed selection of maximum when in full shutdown. channels to be converted sequentially. 5. No Pipeline Delay. The part features a SAR ADC with accurate control of the The conversion time for the AD7923 is determined by the serial sampling instant via a CS input and once off conversion clock, SCLK, frequency, since this is used as the master clock to control. control the conversion. The conversion time can be as short as 800 ns with a 20 MHz SCLK.
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Document Outline Specifications Timing Specifications Absolute Maximum Ratings ESD Caution Pin Configuration and Function Description Typical Performance Characteristics Terminology Control Register Descriptions Sequencer Operation Theory of Operation Circuit Information Converter Operation Analog Input ADC Transfer Function Handling Bipolar Input Signals Typical Connection Diagram Analog Input Selection Digital Inputs VDRIVE Reference Modes of Operation Normal Mode (PM1 = PM0 = 1) Full Shutdown (PM1 = 1, PM0 = 0) Auto Shutdown (PM1 = 0, PM0 = 1) Powering Up the AD7923 Power vs. Throughput Rate Serial Interface Writing Between Conversions Microprocessor Interfacing AD7923-to-TMS320C541 AD7923-to-ADSP-21xx AD7923-to-DSP563xx Application Hints Grounding and Layout Outline Dimensions Ordering Guide Automotive Products