Datasheet AD7294 (Analog Devices) - 7

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Data Sheet AD7294 Parameter Min Typ Max Unit Test Conditions/Comments
TEMPERATURE SENSOR—INTERNAL Operating Range −40 +105 °C Accuracy ±2 °C Internal temperature sensor, TA = −30°C to +90°C ±2.5 °C Internal temperature sensor, TA = −40°C to +105°C Resolution 0.25 °C LSB size Update Rate 5 ms TEMPERATURE SENSOR—EXTERNAL External transistor is 2N3906 Operating Range −55 +150 °C Limited by external diode Accuracy ±2 °C TA = TDIODE = −40°C to +105°C Resolution 0.25 °C LSB size Low Level Output Current Source2 8 µA Medium Level Output Current Source2 32 µA High Level Output Current Source2 128 µA Maximum Series Resistance (RS) for 100 Ω For < ±0.5°C additional error, CP = 0, see Figure 31 External Diode2 Maximum Parallel Capacitance (CP) for 1 nF RS = 0, see Figure 30 External Diode2 CURRENT SENSE VPP = AVDD to 59.4 V VPP Supply Range AVDD 59.4 V Gain 12.4375 12.5 12.5625 Gain of 12.5 gives a gain error = 0.5% maximum; delivers ±200 mV range with +2.5 V reference RS(+)/RS(−) Input Bias Current 25 32 µA CMRR/PSRR2 80 dB Inputs shorted to VPP Offset Error ±50 ±340 µV Offset Drift 1 µV/°C Amplifier Peak-To-Peak Noise2 400 µV Referred to input VPP Supply Current 0.18 0.25 mA VPP = 59.4 V REFERENCE Reference Output Voltage 2.49 2.51 V ±0.2% maximum at 25°C only Reference Input Voltage Range 0.1 4.1 V For four uncommitted ADCs 1 AVDD − 2 For current sense DC Leakage Current ±2 μA VREF Output Impedance2 25 Ω Input Capacitance2 20 pF Reference Temperature Coefficient 10 25 ppm/°C 1 See the Terminology section for more details. 2 Sampled during initial release to ensure compliance, not subject to production testing. 3 VIN+ or VIN− must remain within GND/VDD. 4 VIN− = 0 V for specified performance. For full input range on VIN−, see Figure 40. Rev. I | Page 7 of 47 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS DAC SPECIFICATIONS ADC SPECIFICATIONS GENERAL SPECIFICATIONS TIMING CHARACTERISTICS I2C Serial Interface Timing and Circuit Diagrams ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY DAC TERMINOLOGY ADC TERMINOLOGY THEORY OF OPERATION ADC OVERVIEW ADC TRANSFER FUNCTIONS ANALOG INPUTS Single-Ended Mode Differential Mode Driving Differential Inputs Using an Op Amp Pair Pseudo Differential Mode CURRENT SENSOR Choosing RSENSE Current Sense Filtering Kelvin Sense Resistor Connection ANALOG COMPARATOR LOOP TEMPERATURE SENSOR Remote Sensing Diode Ideality Factor Base Emitter Voltage Base Resistance hFE Variation Series Resistance Cancellation DAC OPERATION Resistor String Output Amplifier ADC AND DAC REFERENCE VDRIVE FEATURE REGISTER SETTING ADDRESS POINTER REGISTER COMMAND REGISTER (0x00) RESULT REGISTER (0x01) ADC Channel Allocation TSENSE1, TSENSE2 RESULT REGISTERS (0X02 AND 0X03) TSENSEINT RESULT REGISTER (0X04) Temperature Value Format DACA, DACB, DACC, DACD, REGISTERS (0x01 TO 0x04) ALERT STATUS REGISTER A (0x05), REGISTER B (0x06), AND REGISTER C (0x07) CHANNEL SEQUENCE REGISTER (0x08) CONFIGURATION REGISTER (0x09) Sample Delay and Bit Trial Delay POWER-DOWN REGISTER (0x0A) DATAHIGH/DATALOW REGISTERS: 0x0B, 0x0C (VIN0); 0x0E, 0x0F (VIN1); 0x11, 0x12 (VIN2); 0x14, 0x15 (VIN3) HYSTERESIS REGISTERS: 0X0D (VIN0), 0X10 (VIN1), 0X13 (VIN2), 0X16 (VIN3) TSENSE OFFSET REGISTERS (0x26 AND 0x27) I2C INTERFACE GENERAL I2C TIMING SERIAL BUS ADDRESS BYTE INTERFACE PROTOCOL Writing a Single Byte of Data to an 8-Bit Register Writing Two Bytes of Data to a 16-Bit Register Writing to Multiple Registers Reading Data from an 8-Bit Register Reading Two Bytes of Data from a 16-Bit Register MODES OF OPERATION COMMAND MODE AUTOCYCLE MODE ALERTS AND LIMITS THEORY ALERT_FLAG BIT ALERT STATUS REGISTERS DATAHIGH AND DATALOW MONITORING FEATURES HYSTERESIS Using the Limit Registers to Store Minimum/Maximum Conversion Results APPLICATIONS INFORMATION BASE STATION POWER AMPLIFIER MONITOR AND CONTROL GAIN CONTROL OF POWER AMPLIFIER LAYOUT AND CONFIGURATION POWER SUPPLY BYPASSING AND GROUNDING Layout Considerations for External Temperature Sensors OUTLINE DIMENSIONS ORDERING GUIDE