Datasheet AD7991, AD7995, AD7999 (Analog Devices)

4-Channel, 12-/10-/8-Bit ADC with I2C-Compatible Interface in 8-Lead SOT-23 AD7991/AD7995/AD7999 FEATURES FUNCTIONAL BLOCK DIAGRAM V 12-/10-/8-bit ADCs with fast conversion time: 1 μs typical DD 4 analog input channels/3 analog input channels with reference input VIN0 Specified for VDD of 2.7 V to 5.5 V VIN1 I/P 12-/10-/8-BIT T/H SAR Sequencer operation MUX VIN2 ADC Temperature range: −40°C to +125°C VIN3/VREF I2C-compatible serial interface supports standard, fast, CONTROL and high speed modes LOGIC AND SCL I2C 2 versions allow 2 I2C addresses SDA INTERFACE Low power consumption Shutdown mode: 1 μA maximum AD7991/AD7995/AD7999
01 0
8-lead SOT-23 package
1- 46
GND
06
APPLICATIONS
Figure 1.
System monitoring Battery-powered systems Data acquisition Medical instruments GENERAL DESCRIPTION PRODUCT HIGHLIGHTS
The AD7991/AD7995/AD7999 are 12-/10-/8-bit, low power, 1. Four single-ended analog input channels, or three single- successive approximation ADCs with an I2C®-compatible interface. ended analog input channels and one reference input channel. Each part operates from a single 2.7 V to 5.5 V power supply and 2. I2C-compatible serial interface. Standard, fast, and high features a 1 μs conversion time. The track-and-hold amplifier speed modes. allows each part to handle input frequencies of up to 14 MHz, 3. Automatic shutdown. and a multiplexer allows taking samples from four channels. 4. Reference derived from the power supply or external Each AD7991/AD7995/AD7999 provides a 2-wire serial reference. interface compatible with I2C interfaces. The AD7991 and 5. 8-lead SOT-23 package. AD7995 come in two versions and each version has an
Table 1. Related Devices
individual I2C address. This allows two of the same devices to be
Device Resolution Input Channels
connected to the same I2C bus. Both versions support standard, AD7998 12 8 fast, and high speed I2C interface modes. The AD7999 comes in AD7997 10 8 one version. AD7994 12 4 The AD7991/AD7995/AD7999 normally remain in a shutdown AD7993 10 4 state, powering up only for conversions. The conversion process AD7992 12 2 is controlled by a command mode, during which each I2C read operation initiates a conversion and returns the result over the I2C bus. When four channels are used as analog inputs, the reference for the part is taken from VDD; this allows the widest dynamic input range to the ADC. Therefore, the analog input range to the ADC is 0 V to VDD. An external reference, applied through the VIN3/VREF input, can also be used with this part.
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION PRODUCT HIGHLIGHTS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS AD7991 AD7995 AD7999 I2C TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY THEORY OF OPERATION CONVERTER OPERATION ADC Transfer Function TYPICAL CONNECTION DIAGRAM ANALOG INPUT INTERNAL REGISTER STRUCTURE CONFIGURATION REGISTER SAMPLE DELAY AND BIT TRIAL DELAY CONVERSION RESULT REGISTER SERIAL INTERFACE SERIAL BUS ADDRESS WRITING TO THE AD7991/AD7995/AD7999 READING FROM THE AD7991/AD7995/AD7999 PLACING THE AD7991/AD7995/AD7999 INTO HIGH SPEED MODE MODE OF OPERATION OUTLINE DIMENSIONS ORDERING GUIDE