Datasheet

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Industrial Current Out Driver, Single-Supply,

55 V Maximum Supply, Programmable Ranges

Data Sheet

AD5749

Rev. B

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FEATURES

Current output ranges: 0 mA to 24 mA or 4 mA to 20 mA

±0.03% FSR typical total unadjusted error (TUE)

±5 ppm/°C typical output drift

2% overrange

Flexible serial digital interface

On-chip output fault detection

PEC error checking

Asynchronous CLEAR function

Power supply range

: 12 V (± 10%) to 55 V (maximum)

Output loop compliance to AV

− 2.75 V

Temperature range: −40°C to +105°C

32-lead, 5 mm × 5 mm LFCSP package

APPLICATIONS

Process control

Actuator control

PLCs

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The AD5749 is a single channel, low cost, precision, current output

driver with hardware or software programmable output ranges.

The software ranges are configured via an SPI-/MICROWIRE™-

compatible serial interface. The AD5749 targets applications in

PLC and industrial process control. The analog input to the

AD5749 is provided from a low voltage, single-supply digital-to-

analog converter (DAC) and is internally conditioned to provide

the desired output current/voltage range.

The output current range is programmable across two current

ranges: 0 mA to 24 mA, or 4 mA to 20 mA. Current output is

open-circuit protected and can drive inductive loads of 0.1 H.

The device is specified to operate with a power supply range

from 10.8 V to 55 V. Output loop compliance is 0 V to AV

−

2.75 V.

The flexible serial interface is SPI and MICROWIRE compatible

and can be operated in 3-wire mode to minimize the digital

isolation required in isolated applications. The interface also

features an optional PEC error checking feature using CRC-8

error checking, useful in industrial environments where data

communication corruption can occur.

The device also includes a power-on reset function ensuring

that the device powers up in a known state and an asynchron-

ous CLEAR pin that sets the outputs to the low end of the

selected current range.

An HW SELECT pin is used to configure the part for hardware

or software mode on power-up.

Table 1. Related Devices

Part No. Description

AD5750 Industrial current/voltage output (I/V) driver with

programmable ranges

AD5751 Industrial I/V output driver, single-supply, 55 V maximum

supply, programmable ranges

AD5748 Industrial I/V output driver with programmable ranges

AD5410/

AD5420

Single-channel, 12-/16-bit, serial input, current source

output DAC

AD5412/

AD5422

Single-channel, 12-/16-bit, serial input, I/V output DAC

08923-001

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Summary of content (28 pages)

PAGE 1
Industrial Current Out Driver, Single-Supply, 55 V Maximum Supply, Programmable Ranges AD5749 Data Sheet FEATURES FUNCTIONAL BLOCK DIAGRAM APPLICATIONS DVCC GND CLEAR CLRSEL INPUT SHIFT REGISTER AND CONTROL LOGIC SCLK/OUTEN* SDIN/R0* SYNC/RSET* SDO/VFAULT* AD5749 AVDD STATUS REGISTER HW SELECT R3 R2 VIN VREF IOUT RANGE SCALING RESET IOUT FAULT/TEMP* NC/IFAULT* Process control Actuator control PLCs AVDD GND OVERTEMP REXT1 IOUT OPEN FAULT RSET REXT2 IOUT OPEN FAULT POWERON RESET AD2/R
PAGE 2
AD5749 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 OUTEN........................................................................................ 18 Applications ....................................................................................... 1 Software Control ........................................................................ 18 Functional Block Diagram ..............................................
PAGE 3
Data Sheet AD5749 SPECIFICATIONS AVDD = 12 V (± 10%) to 55 V (maximum), DVCC = 2.7 V to 5.5 V, GND = 0 V. RLOAD = 300 Ω. All specifications TMIN to TMAX, unless otherwise noted. Table 2. Parameter 1 INPUT VOLTAGE RANGE Input Leakage Current REFERENCE INPUT Reference Input Voltage Min Input Leakage Current CURRENT OUTPUT Output Current Ranges −1 +1 µA 0 4 0 3.92 24 20 24.5 20.4 mA mA mA mA +0.5 +0.3 +0.
PAGE 4
AD5749 Parameter 1 OUTPUT CHARACTERISTICS2 Current Loop Compliance Voltage Resistive Load Inductive Load Settling Time 4 mA to 20 mA, Full-Scale Step 120 µA Step, 4 mA to 20 mA Range DC PSRR Output Impedance DIGITAL INPUTS2 Input High Voltage, VIH Input Low Voltage, VIL Input Current Pin Capacitance DIGITAL OUTPUTS2 FAULT, IFAULT, TEMP, VFAULT VOL, Output Low Voltage VOH, Output High Voltage SDO VOL, Output Low Voltage VOH, Output High Voltage High Impedance Output Capacitance High Impedance Leakage Current
PAGE 5
Data Sheet AD5749 TIMING CHARACTERISTICS AVDD = 12 V (± 10%) to 55 V (maximum), DVCC = 2.7 V to 5.5 V, GND = 0 V. RLOAD = 300 Ω. All specifications TMIN to TMAX, unless otherwise noted. Table 3. Parameter 1, 2 t1 t2 t3 t4 t5 t6 t7 t8 t9, t10 t11 t12 t13 1 2 Limit at TMIN, TMAX 20 8 8 5 10 5 5 5 1.
PAGE 6
AD5749 Data Sheet Timing Diagrams t1 SCLK 1 16 2 t3 t6 t2 t4 t5 SYNC t8 t7 SDIN D0 D15 CLEAR t10 t9 IOUT 08923-002 RESET t13 Figure 2. Write Mode Timing Diagram SCLK SYNC SDIN t11 A2 A1 A0 R=1 R3 0 R2 R1 R0 CLRSEL OUTEN CLEAR RSET RESET 0 0 X X X X X R3 R2 R1 R0 CLRSEL OUTEN Figure 3. Readback Mode Timing Diagram Rev.
PAGE 7
Data Sheet AD5749 ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Transient currents of up to 100 mA do not cause SCR latch-up. Table 4. Parameter AVDD to GND DVCC to GND Digital Inputs to GND Digital Outputs to GND VREF to GND VIN to GND IOUT to GND Operating Temperature Range Industrial Storage Temperature Range Junction Temperature (TJ max) 32-Lead LFCSP Package θJA Thermal Impedance1 Lead Temperature Soldering 1 Rating −0.3 V to +58 V −0.3 V to +7 V −0.3 V to DVCC + 0.
PAGE 8
AD5749 Data Sheet 32 31 30 29 28 27 26 25 NC/IFAULT FAULT/TEMP RESET HW SELECT NC NC NC NC PIN CONFIGURATION AND FUNCTION DESCRIPTIONS 1 2 3 4 5 6 7 8 PIN 1 INDICATOR AD5749 TOP VIEW (Not to Scale) 24 23 22 21 20 19 18 17 DNC DNC GND GND DNC DNC IOUT AVDD NOTES 1. NC = NO CONNECT. 2. THE EXPOSED PADDLE IS TIED TO GND. 08923-004 AD2/R1 AD1/R2 AD0/R3 REXT2 REXT1 VREF VIN GND 9 10 11 12 13 14 15 16 SDO/VFAULT CLRSEL CLEAR DVCC GND SYNC/RSET SCLK/OUTEN SDIN/R0 Figure 4.
PAGE 9
Data Sheet Pin No. 12, 13 Mnemonic REXT2, REXT1 14 15 16 17 18 19, 20, 23, 24 21, 22 25, 26, 27, 28 29 VREF VIN GND AVDD IOUT DNC GND NC HW SELECT 30 RESET 31 FAULT/TEMP 32 NC/IFAULT 33 (EPAD) EPAD AD5749 Description A 15 kΩ external current setting resistor can be connected between the REXT1 and REXT2 pins to improve the IOUT temperature drift performance. Buffered Reference Input. Buffered Analog Input (0 V to 4.096 V). Ground Connection. Positive Analog Supply. Current Output.
PAGE 10
AD5749 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS 0.003 0.002 0.001 0 –0.001 –0.002 –0.003 0 –0.002 –0.004 –0.006 4.096 55V 0.05 –0.01 –0.02 4.096 VIN (V) 08923-009 3.803 3.511 3.218 2.926 2.633 2.341 4.096 VIN (V) 08923-006 3.803 3.511 3.218 2.926 2.633 2.341 2.048 1.755 1.463 0.878 1.170 0.585 –0.05 Figure 9. Total Unadjusted Error vs. VIN, External RSET Resistor Figure 6. Integral Nonlinearity Error vs. VIN, Internal RSET Resistor 0.
PAGE 11
Data Sheet AD5749 0.005 4mA TO 20mA EXTERNAL RSET POSITIVE TUE 0mA TO 24mA EXTERNAL RSET POSITIVE TUE 0.004 INTEGRAL NONLINEARITY (%FSR) 0.015 0.010 0.005 0 –0.005 –0.010 4mA TO 20mA EXTERNAL RSET NEGATIVE TUE 0mA TO 24mA EXTERNAL RSET NEGATIVE TUE –0.015 24V 48V SUPPLY VOLTAGE (AVDD) 55V 0.010 0.001 0 –0.001 –0.002 –0.003 –40 25 TEMPERATURE (°C) 105 Figure 14. Integral Nonlinearity Error vs. Temperature, External RSET Sense Resistor 0.
PAGE 12
AD5749 Data Sheet 4 50 45 3 OFFSET ERROR (µA) ZERO-SCALE ERROR (µA) 40 35 30 25 20 15 2 1 0 –1 10 –2 0 25 TEMPERATURE (°C) 105 –3 0.05 35 0.04 FULL-SCALE ERROR (%FSR) 40 30 25 20 15 10 25 TEMPERATURE (°C) 105 0.03 0.02 0.01 0 –0.01 –0.02 –0.03 –0.05 –40 Figure 18. Zero-Scale Error vs. Temperature, Internal RSET Sense Resistor 105 0.10 0.08 FULL-SCALE ERROR (%FSR) 2 OFFSET ERROR (µA) 25 TEMPERATURE (°C) Figure 21. Full-Scale Error vs.
PAGE 13
Data Sheet AD5749 12 0.10 0.000010 0.000008 10 0.000006 8 0.02 0 0.000004 0.000002 6 IOUT 0 4 –0.000002 –0.02 –0.000004 2 –0.04 –0.000006 VDD –0.06 0 –0.000008 –0.08 –40 25 TEMPERATURE (°C) 08923-023 –0.10 105 –2 –10 –0.000010 –8 –4 –2 0 2 4 6 8 10 Figure 26. Output Current vs. Time on VDD Power-Up 0 0.10 4mA TO 20mA INTERNAL RSET 0mA TO 24mA INTERNAL RSET –2 0.06 –4 0.04 –6 0.02 IOUT (µA) GAIN ERROR (%FSR) –6 TIME (ms) Figure 23. Gain Error vs.
PAGE 14
AD5749 Data Sheet 3000 4.10 2500 4.05 4.00 AIDD (mA) DVCC = 5V 1500 3.95 3.90 1000 3.85 500 3.80 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 LOGIC LEVEL (V) 4.5 5.0 3.75 24 48 AVDD (V) Figure 30. AIDD vs. AVDD, IOUT = 0 mA Figure 29. DICC vs. Logic Input Voltage Rev.
PAGE 15
Data Sheet AD5749 TERMINOLOGY Zero-Scale TC Zero-scale TC is a measure of the change in zero-scale error with a change in temperature. Zero-scale error TC is expressed in ppm FSR/°C. Total Unadjusted Error (TUE) TUE is a measure of the output error taking all the various errors into account: INL error, offset error, gain error, and output drift over supplies, temperature, and time. TUE is expressed as a percentage of full-scale range (% FSR).
PAGE 16
AD5749 Data Sheet THEORY OF OPERATION Figure 31 and Figure 32 show a typical configuration of AD5749 in software mode and in hardware mode, respectively, in an output module system. The HW SELECT pin chooses whether the part is configured in software or hardware mode. The analog input to the AD5749 is provided from a low voltage, single-supply DAC such as the AD506x or AD566x, which can provide an output range of 0 V to 4.096 V.
PAGE 17
Data Sheet AD5749 AVDD AGND ADP1720 AVDD GND ADR392 VDD SDI/DIN MCU SDO AD5749 VREF REFIN IOUT RANGE SCALE VIN AD506x AD566x SYNC1 DVCC IOUT 0mA TO 20mA, 0mA TO 24mA, 4mA TO 20mA HW SELECT OUTEN R3 R2 R1 TEMP IFAULT R0 OUTPUT RANGE SELECT PINS 08923-033 SCLK Figure 32. Typical System Configuration in Hardware Mode Using Internal DAC Reference (Pull-Up Resistors Not Shown for Open-Drain Outputs) Table 6.
PAGE 18
AD5749 Data Sheet CURRENT OUTPUT ARCHITECTURE DEFAULT REGISTERS AT POWER-ON The voltage input from the analog input VIN core (0 V to 4.096 V) is converted to a current (see Figure 33), which is then mirrored to the supply rail so that the application simply sees a current source output with respect to an internal reference voltage. The reference is used to provide internal offsets for range and gain scaling.
PAGE 19
Data Sheet AD5749 Table 7. Input Shift Register Contents for a Write Operation—Control Register MSB D15 A2 D14 A1 D13 A0 D12 R/W D11 0 D10 R3 D9 R2 D8 R1 D7 R0 D6 CLRSEL D5 OUTEN D4 CLEAR D3 RSET D2 RESET D1 0 LSB D0 0 Table 8. Input Shift Register Descriptions for Control Register Bit A2, A1, A0 R/W R3, R2, R1, R0 Description Used in association with the AD2, AD1, and AD0 external pins to determine which part is being addressed by the system controller.
PAGE 20
AD5749 Bit CLRSEL OUTEN CLEAR RSET RESET Data Sheet Description Sets clear mode to zero scale or midscale. See the Asynchronous Clear (CLEAR) section. CLRSEL Function 0 Clear to zero-scale. 1 Clear to midscale. Output enable bit. This bit must be set to 1 to enable the output. Software clear bit; active high. Select internal/external current sense resistor. RSET Function 1 Select internal current sense resistor; used with R3 to R0 bits to select range.
PAGE 21
Data Sheet AD5749 Status Bit Read Operation HARDWARE CONTROL A read of the status bits can be initiated as part of a normal write operation. The read is activated by selecting the correct device address (A2, A1, A0) and then setting the R/W bit to 1. By default, the SDO pin is disabled. After having addressed the AD5749 and setting R/W to 1 the SDO pin is enabled and data is clocked out on the 5th rising edge of SCLK.
PAGE 22
AD5749 Data Sheet DETAILED DESCRIPTION OF FEATURES OUTPUT FAULT ALERT—SOFTWARE MODE • In software mode, the AD5749 is equipped with one FAULT pin; this is an open-drain output allowing several AD5749 devices to be connected together to one pull-up resistor for global fault detection.
PAGE 23
Data Sheet AD5749 PACKET ERROR CHECKING UPDATE ON SYNC HIGH SYNC To verify that data has been received correctly in noisy environments, the AD5749 offers the option of error checking based on an 8-bit (CRC-8) cyclic redundancy check.
PAGE 24
AD5749 Data Sheet APPLICATIONS INFORMATION TRANSIENT VOLTAGE PROTECTION THERMAL CONSIDERATIONS The AD5749 contains ESD protection diodes that prevent damage from normal handling. The industrial control environment can, however, subject I/O circuits to much higher transients. To protect the AD5749 from excessively high voltage transients, external power diodes and a surge current limiting resistor may be required, as shown in Figure 35.
PAGE 25
Data Sheet AD5749 In any circuit where accuracy is important, careful consideration of the power supply and ground return layout helps to ensure the rated performance. The PCB on which the AD5749 is mounted should be designed so that the AD5749 lies on the analog plane. The AD5749 should have ample supply bypassing of 10 µF in parallel with 0.1 µF on each supply, located as close to the package as possible, ideally right up against the device. The 10 µF capacitors are the tantalum bead type. The 0.
PAGE 26
AD5749 Data Sheet OUTLINE DIMENSIONS 5.10 5.00 SQ 4.90 0.60 MAX 0.60 MAX 25 32 24 0.50 BSC 3.25 3.10 SQ 2.95 EXPOSED PAD 17 TOP VIEW 1.00 0.85 0.80 SEATING PLANE 12° MAX 0.80 MAX 0.65 TYP 0.30 0.25 0.18 0.50 0.40 0.30 0.05 MAX 0.02 NOM COPLANARITY 0.08 0.20 REF PIN 1 INDICATOR 8 16 9 BOTTOM VIEW 0.25 MIN 3.50 REF FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET.
PAGE 27
Data Sheet AD5749 NOTES Rev.