Datasheet AD7298 (Analog Devices)

8-Channel, 1 MSPS, 12-Bit SAR ADC with Temperature Sensor AD7298 FEATURES FUNCTIONAL BLOCK DIAGRAM 12-bit SAR ADC VDD GND 8 single-ended inputs Channel sequencer functionality VREF Fast throughput of 1 MSPS REF BUF Analog input range: 0 V to 2.5 V 12-bit temperature-to-digital converter 12-BIT VIN0 SUCCESSIVE Temperature sensor accuracy of ±1°C T/H APPROXIMATION Temperature range: −40°C to +125°C ADC Specified for VDD: 2.8 V to 3.6 V INPUT V AD7298 IN7 MUX Logic voltage VDRIVE : 1.65 V to 3.6 V Power-down current: <10 μA SEQUENCER SCLK Internal 2.5 V reference DOUT CONTROL Internal power-on reset DIN TEMP LOGIC CS High speed serial interface SPI SENSOR 20-lead LFCSP VDRIVE
1 0 0 4-
PD/RST T
75
SENSE_BUSY
08 Figure 1.
GENERAL DESCRIPTION PRODUCT HIGHLIGHTS
The AD7298 is a 12-bit, high speed, low power, 8-channel, 1. Ideally Suited to Monitoring System Variables in a Variety successive approximation ADC with an internal temperature of Systems. This includes telecommunications, and process sensor. The part operates from a single 3.3 V power supply and and industrial control. features throughput rates up to 1 MSPS. The device contains a 2. High Throughput Rate of 1 MSPS with Low Power low noise, wide bandwidth track-and-hold amplifier that can Consumption. handle input frequencies in excess of 30 MHz. 3. Eight Single-Ended Inputs with a Channel Sequencer. The AD7298 offers a programmable sequencer, which enables A consecutive sequence of channels can be selected on the selection of a preprogrammable sequence of channels for which the ADC cycles and converts. conversion. The device has an on-chip, 2.5 V reference that can 4. Integrated Temperature Sensor with 0.25°C Resolution. be disabled to allow the use of an external reference. The AD7298 includes a high accuracy band gap temperature sensor, which is monitored and digitized by the 12-bit ADC to give a resolution of 0.25°C. The device offers a 4-wire serial interface compatible with SPI and DSP interface standards. The AD7298 uses advanced design techniques to achieve very low power dissipation at high throughput rates. The part also offers flexible power/throughput rate management options. The part is offered in a 20-lead LFCSP package.
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Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM PRODUCT HIGHLIGHTS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION THERMAL RESISTANCE PIN CONFIGURATION AND FUNCTION DESCRIPTION TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY CIRCUIT INFORMATION CONVERTER OPERATION ANALOG INPUT ADC Transfer Function TEMPERATURE SENSOR OPERATION TEMPERATURE SENSOR AVERAGING Temperature Value Format VDRIVE THE INTERNAL OR EXTERNAL REFERENCE CONTROL REGISTER MODES OF OPERATION TRADITIONAL MULTICHANNEL MODE OF OPERATION REPEAT OPERATION POWER-DOWN MODES Normal Mode Partial Power-Down Mode Full Power-Down Mode POWERING UP THE AD7298 RESET SERIAL INTERFACE TEMPERATURE SENSOR READ LAYOUT AND CONFIGURATION POWER SUPPLY BYPASSING AND GROUNDING TEMPERATURE MONITORING OUTLINE DIMENSIONS ORDERING GUIDE