AD5421

REG_SEL1 IODVDD DVDD VLOOP REG_SEL0 REG_SEL2 REGOUT REGIN AD5421 FAULT SYNC S CL K SD IN SD O LDAC RANGE 0 RANGE 1 ALARM CURRENT DIRECTION RINT/REXT INPUT REGISTER CONTROL LOGIC LOOP VOLTAGE MONITOR VOLTAGE REGULATOR DRIVE 24k 16 GAIN / OFFSET ADJUSTMENT REGISTERS / 1 6-B IT DAC RSET 11.5k 52 TEMP SENSOR VREF LOOP - DGND REF OUT2 REFOUT1 REF IN CIN REXT1 REXT2 COM SCLK 1 8 9 24 1 8 9 24 SDIN DB23 DB16 DB15 DB0 DB23 DB16 DB15 DB0 INPUT WORD SPECIFIES REGISTER TO BE READ SDO UNDEFINED DATA NOP OR REGISTER ADDRESS D15 D0 SPECIFIED REGISTER DATA CLOCKED OUT SYNC IODVDD 1 SDO 2 SCLK 3 SYNC 4 SDIN 5 28 REGOUT 27 REGIN 26 DRIVE 25 VLOOP AD5421 TOP VIEW (Not to Scale) 24 LOOP23 REXT2 22 REXT1 LDAC 6 FAULT 7 DVDD 8 ALARM CURRENT DIRECTION 9 21 CIN 20 REFOUT1 19 REFOUT2 18 17 16 15 RINT/REXT 10 RANGE 0 11 REFIN RANGE 1 12 COM 13 REG_SEL0 REG_SEL1 REG_SEL2 COM 14 I LOOP 17.2mA 2N D 3.8mA I LOOP 16 mA 2N I LOOP D 4 mA 20.8mA 2N D 3.2mA DAC Re gisterData 65536 DAC Re gisterData 65536 DAC Re gisterData 65536 DAC Re gisterData 65536 DAC Re gisterData 65536 65534 32769 32768 32767 1 U PDATE ON SY N C H IGH SYN C SCLK MSB D23 D IN LS B D0 24- B IT DATA 24-B IT DATA T RA N S FE R - N O E R ROR C H E CK ING U P DAT E A FTE R SY N C H IGH ONLY IF E R RO R CHE C K PA S SE D S YN C SC L K M SB D31 SDIN 24 BIT DATA LS B D8 D7 D0 8 -B I T F C S FAULT FA U LT PIN GO ES HIGH IF ER RO R CH ECK FA ILS 32-B IT DATA TRA NS FE R W ITH E RROR CHE C KING REGIN VLOOP 19M VLOOP 1M RL AD5421 LOOP COM RDAC * CSLEW CSLEW T 5 * RDAC CSLEW 5ms 5 *15220 10 ms 5 *15220 66 nF CSLEW 130 nF Loop Current vs. Time for a 4mA to 20mA Step 6 Voltage across 250Ohm Load Rload = 250Ohm 5 4 CIN = 68nF 3 2 1 0 -0.002 CIN = 133nF 0 0.002 0.004 0.006 0.008 0.01 0.012 Time(s) RDAC V to I Circuit ry LOOP- CIN CSLEW 200k REGIN DRIVE VLOOP RL AD5421 LOOP CIN CSLEW CHART HART MODE M HART_OUT COM HART_IN 4.5 CHART CSLEW CHART Optional Mosfet DN2540 BS P129 T1 2.5V 0.1µF 0.1µF 200k 2µF IODVDD DVDD RANGE 0 RANGE 1 ALARM CURRENT DIRECTION RINT/REXT ADuC7060 REGOUT REGIN DRIVE VLOOP RL 19M VLOOP SENSOR 24-Bit S-D ADC MCU SYNC S CL K SD IN SD O 1M AD5421 LOOP - REG_SEL0 REG_SEL1 DGND REG_SEL2 FAULT LDAC REF OUT2 REFOUT1 REF IN 0.1µF 0.1µF REXT1 R1 REXT2 CIN COM Optional Resist or Sets Regulator Voltage 4.7nF 16nF HART MODE M VCC TXD RXD RTS HART_IN GND HART_OUT CD 4.5 Power Dissipation (W) 4 3.5 3 2.5 2 1.5 1 0.5 0 25 35 45 55 65 75 85 Am bient Tem perature (°C) 53 52 Supply Voltage (V) 51 50 49 48 47 46 25 35 45 55 65 75 85 Am bient Tem perature (°C) TJ max TA JA 125 105 32 JA 625 mW TJ max 125 87 C PD (52 0.0228 ) 32 125 105 0.0228 32 TJ max TA I LOOP JA 27 V