Datasheet AD7294 (Analog Devices) - 29

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Data Sheet AD7294 ADC Channel Allocation Table 14. TSENSE Register (First Read)
The three channel address bits indicate which channel the result
MSB LSB
in the result register represents. Table 13 details the channel ID bits
D15 D14 D13 D12 D11 D10 D9 D8
(S.E. indicates single-ended and DIFF indicates differential). Alert_Flag CHID2 CHID1 CHID0 B11 B10 B9 B8
Table 13. ADC Channel Allocation Table 15. Register (Second Read) Channel ID MSB LSB Function CHID2 CHID1 CHID0 D7 D6 D5 D4 D3 D2 D1 D0
VIN0 (S.E.) or 0 0 0 B7 B6 B5 B4 B3 B2 B1 B0 VIN0 − VIN1 (DIFF)
TSENSEINT RESULT REGISTER (0X04)
VIN1 (S.E.) or 0 0 1 VIN1 − VIN0 (DIFF) The TSENSEINT register is a 16-bit read-only register used to VIN2 (S.E.) or 0 1 0 store the ADC data generated from the internal temperature VIN2 − VIN3 (DIFF) sensor. Similar to the TSENSE1 and TSENSE2 result registers, this VIN3 (S.E.) or 0 1 1 register stores the temperature readings from the ADC in an 11- VIN3 − VIN2 (DIFF) bit twos complement format, D10 to D0, and uses the MSB as a ISENSE1 1 0 0 general alert flag. Bits[D14:D11] are not used and are set to ISENSE2 1 0 1 zero. Conversions take place approximately every 5 ms. The TSENSE1 1 1 0 temperature data format in Table 16 also applies to the internal TSENSE2 1 1 1 temperature sensor data.
TSENSE1, TSENSE2 RESULT REGISTERS (0X02 AND Temperature Value Format 0X03)
The temperature reading from the ADC is stored in an 11-bit Register TSENSE1 and Register TSENSE2 are 16-bit read only registers. twos complement format, D10 to D0, to accommodate both The MSB, D15 is the alert_flag bit whereas Bit D14 to Bit D12 positive and negative temperature measurements. The temper- contain the three ADC channel allocation bits. D11 is reserved ature data format is provided in Table 16. for flagging diode open circuits. The temperature reading from the ADC is stored in an 11-bit twos complement format, D10 to D0 (see Table 14 and Table 15). Conversions take place approx- imately every 5 ms.
Table 16. TSENSE Data Format Input D10 (MSB) D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 (LSB) Value (°C)
−256 +128 +64 +32 +16 +8 +4 +2 +1 +0.5 +0.25 Rev. I | Page 29 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