AD5751ACPZ [ADI]

Industrial I/V Output Driver, Single-Supply, 55 V Maximum Supply, Programmable Ranges;
AD5751ACPZ
型号: AD5751ACPZ
厂家: ADI    ADI
描述:

Industrial I/V Output Driver, Single-Supply, 55 V Maximum Supply, Programmable Ranges

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Industrial I/V Output Driver, Single-Supply,  
55 V Maximum Supply, Programmable Ranges  
Data Sheet  
AD5751  
FEATURES  
GENERAL DESCRIPTION  
Current output ranges: 0 mA to 20 mA, 0 mA to 24 mA,  
or 4 mA to 20 mA  
±0.03ꢀ FSR typical total unadjusted error (TUE)  
±± ppm/°C typical output drift  
The AD5751 is a single-channel, low cost, precision, voltage/  
current output driver with hardware or software programmable  
output ranges. The software ranges are configured via an SPI-/  
MICROWIRE™-compatible serial interface. The AD5751 targets  
applications in PLC and industrial process control. The analog  
input to the AD5751 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.  
2ꢀ overrange  
Voltage output ranges: 0 V to ± V, 0 V to 10 V, 0 V to 40 V  
±0.02ꢀ FSR typical total unadjusted error (TUE)  
±3 ppm/°C typical output drift  
Overrange capability on all ranges  
Flexible serial digital interface  
On-chip output fault detection  
The output current range is programmable across three current  
ranges: 0 mA to 20 mA, 0 mA to 24 mA, or 4 mA to 20 mA.  
Voltage output is provided from a separate pin that can be  
configured to provide 0 V to 5 V, 0 V to 10 V, and 0 V to 40 V  
output ranges. An overrange is available on the voltage ranges.  
PEC error checking  
Asynchronous CLEAR function  
Power supply range  
AVDD: 12 V (± 10ꢀ) to ±± V (maximum)  
Output loop compliance to AVDD − 2.7± V  
Temperature range: −40°C to +10±°C  
32-lead ± mm × ± mm LFCSP package  
Analog outputs are short-circuit and open-circuit protected and  
can drive capacitive loads of 1 μF and 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 AVDD − 2.75 V.  
APPLICATIONS  
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.  
Process control  
Actuator control  
PLCs  
The device also includes a power-on reset function ensuring  
that the device powers up in a known state (0 V or tristate)  
and an asynchronous CLEAR pin that sets the outputs to zero-  
scale/midscale voltage output or 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 Device  
Part Number  
Description  
AD5422  
Single-channel, 16-bit, serial input current  
source and voltage output DAC  
Rev. D  
Document Feedback  
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other  
rights of third parties that may result from its use. Specifications subject to change without notice. No  
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.  
Trademarks and registeredtrademarks arethe property of their respective owners.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781.329.4700 ©2009–2018 Analog Devices, Inc. All rights reserved.  
Technical Support  
www.analog.com  
 
 
 
AD5751  
Data Sheet  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
OUTEN........................................................................................ 24  
Software Control ........................................................................ 24  
Hardware Control ...................................................................... 26  
Transfer Function....................................................................... 26  
Detailed Description of Features.................................................. 27  
Output Fault Alert—Software Mode ....................................... 27  
Output Fault Alert—Hardware Mode ..................................... 27  
Voltage Output Short-Circuit Protection................................ 27  
Asynchronous Clear (CLEAR)................................................. 27  
External Current Setting Resistor ............................................ 27  
Programmable Overrange Modes............................................ 28  
Packet Error Checking............................................................... 28  
Applications Information .............................................................. 29  
Transient Voltage Protection .................................................... 29  
Thermal Considerations............................................................ 29  
Layout Guidelines....................................................................... 30  
Galvanically Isolated Interface ................................................. 30  
Microprocessor Interfacing....................................................... 30  
Outline Dimensions....................................................................... 31  
Ordering Guide .......................................................................... 31  
Applications....................................................................................... 1  
General Description......................................................................... 1  
Revision History ............................................................................... 2  
Functional Block Diagram .............................................................. 3  
Specifications..................................................................................... 4  
Timing Characteristics ................................................................ 7  
Absolute Maximum Ratings............................................................ 9  
ESD Caution.................................................................................. 9  
Pin Configuration and Function Descriptions........................... 10  
Typical Performance Characteristics ........................................... 12  
Current Output........................................................................... 15  
Terminology .................................................................................... 20  
Theory of Operation ...................................................................... 21  
Software Mode ............................................................................ 21  
Currrent Output Architecture .................................................. 23  
Driving Inductive Loads............................................................ 23  
Power-On State of the AD5751 ................................................ 23  
Default Registers at Power-On ................................................. 24  
Reset Function ............................................................................ 24  
REVISION HISTORY  
10/2013—Rev. A to Rev. B  
1/2018—Rev. C to Rev. D  
Changed Thermal Impedance from 28°C/W to 42°C/W  
(Throughout) .....................................................................................9  
Added Endnote 1 to Table 4.............................................................9  
Changes to Table 12 Calculations................................................. 29  
Updated Outline Dimensions....................................................... 31  
Changed CP-32-7 to CP-32-2 ...................................... Throughout  
Changes to Figure 4........................................................................ 10  
Updated Outline Dimensions....................................................... 31  
Changes to Ordering Guide .......................................................... 31  
3/2017—Rev. B to Rev. C  
5/2010—Rev. 0 to Rev. A  
Changes to Table 2, Power Requirements......................................6  
Changed CP-32-2 to CP-32-7 ...................................... Throughout  
Changes to Figure 4........................................................................ 10  
Updated Outline Dimensions....................................................... 31  
Changes to Ordering Guide .......................................................... 31  
10/2009—Revision 0: Initial Version  
Rev. D | Page 2 of 32  
 
Data Sheet  
AD5751  
FUNCTIONAL BLOCK DIAGRAM  
DVCC GND  
AVDD GND COMP1 COMP2  
CLEAR  
CLRSEL  
VSENSE+  
VOUT  
INPUT SHIFT  
REGISTER  
AND  
CONTROL  
LOGIC  
SCLK/OUTEN*  
SDIN/R0*  
VOUT RANGE  
SCALING  
SYNC/RSET*  
SDO/VFAULT*  
VOUT  
SHORT FAULT  
STATUS  
REGISTER  
HW SELECT  
AVDD  
VIN  
R3  
R2  
VREF  
RESET  
IOUT RANGE  
SCALING  
IOUT  
OVERTEMP  
REXT1  
REXT2  
VOUT SHORT FAULT  
IOUT OPEN FAULT  
FAULT/TEMP*  
NC/IFAULT*  
R
SET  
POWER-  
ON RESET  
IOUT  
OPEN FAULT  
AD5751  
AD2/R1*  
AD1/R2*  
AD0/R3*  
*
DENOTES SHARED PIN. SOFTWARE MODE DENOTED BY REGULAR TEXT, HARDWARE MODE  
DENOTED BY ITALIC TEXT. FOR EXAMPLE, FOR FAULT/TEMP PIN, IN SOFTWARE MODE, THIS  
PIN TAKES ON FAULT FUNCTION. IN HARDWARE MODE, THIS PIN TAKES ON TEMP FUNCTION.  
Figure 1. Functional Block Diagram  
Rev. D | Page 3 of 32  
 
 
AD5751  
Data Sheet  
SPECIFICATIONS  
AVDD = 12 V ( 10%) to 55 V (maximum), DVCC = 2.7 V to 5.5 V, GND = 0 V. IOUT: RLOAD = 300 Ω. All specifications TMIN to TMAX  
,
unless otherwise noted.  
Table 2.  
Parameter1  
Min  
Typ  
Max  
Unit  
Test Conditions/Comments  
INPUT VOLTAGE RANGE  
Output unloaded  
0 to 4.096  
V
Input Leakage Current  
REFERENCE INPUT  
−1  
+1  
µA  
Reference Input Voltage  
4.096  
V
External reference must be exactly as stated;  
otherwise, accuracy errors show up as error  
in output  
Input Leakage Current  
VOLTAGE OUTPUT  
−1  
+1  
µA  
Output Voltage Ranges  
0
0
5
10  
V
V
AVDD must have minimum 1.3 V headroom  
or >11.3 V  
0
0
40  
6
V
V
Output Voltage Overranges2  
Programmable overranges; see Detailed  
Description of Features section  
0
0
12  
44  
V
V
Accuracy  
Total Unadjusted Error (TUE)  
B Version3  
−0.1  
−0.05  
−0.3  
−0.1  
−0.02  
−14  
+0.1  
+0.05  
+0.3  
+0.1  
+0.02  
+14  
% FSR  
% FSR  
% FSR  
% FSR  
% FSR  
mV  
0.02  
TA = 25°C  
TA = 25°C  
A Version3  
0.05  
0.005  
8
Relative Accuracy (INL)  
Dead Band on Output, RTI  
Offset Error  
Referred to 4.096 V input range  
0 V to 10 V range  
−5  
+5  
mV  
−4  
−3  
0.5  
+4  
+3  
mV  
mV  
TA = 25°C, 0 V to 10 V range  
0 V to 5 V range  
−2.2  
−20  
0.3  
+2.2  
+20  
mV  
mV  
TA = 25°C, 0 V to 5 V range  
0 V to 40 V range  
−17  
0.5  
+17  
mV  
TA = 25°C, 0 V to 40 V range  
0 V to 5 V, 0 V to 10 V range  
TA = 25°C  
0 V to 40 V range  
TA = 25°C  
Gain Error  
−0.05  
−0.04  
−0.09  
−0.05  
+0.05  
+0.04  
+0.09  
+0.05  
% FSR  
% FSR  
% FSR  
% FSR  
0.015  
0.02  
0.5  
Gain Error TC4  
Full-Scale Error  
ppm FSR/°C All ranges  
−0.05  
−0.04  
−0.09  
−0.05  
+0.05  
+0.04  
+0.09  
+0.05  
% FSR  
% FSR  
% FSR  
% FSR  
0 V to 5 V, 0 V to 10 V range  
TA = 25°C  
0 V to 40 V range  
TA = 25°C  
0.015  
0.02  
1.5  
Full-Scale Error TC4  
OUTPUT CHARACTERISTICS4  
Headroom  
ppm FSR/°C All ranges  
1.3  
V
Output unloaded  
Short-Circuit Current  
15  
mA  
Load  
1
5
kΩ  
kΩ  
For specified performance, 0 V to 5 V and 0 V  
to 10 V ranges  
For specified performance, 0 V to 40 V range  
Rev. D | Page 4 of 32  
 
Data Sheet  
AD5751  
Parameter1  
Min  
Typ  
Max  
Unit  
Test Conditions/Comments  
Capacitive Load Stability  
RLOAD = ∞  
RLOAD = 1 kΩ  
TA = 25°C  
1
1
2
nF  
nF  
µF  
RLOAD = ∞  
External compensation capacitor required;  
see Driving Large Capacitive Loads section  
DC Output Impedance  
Settling Time  
0.12  
0 V to 5 V Range, ¼ to ¾ Step  
0 V to 5 V Range, 40 mV Input Step  
0 V to 40 V Range, ¼ to ¾ Step  
Slew Rate  
7
µs  
µs  
µs  
V/µs  
µV rms  
µV rms  
Specified with 2 kΩ || 220 pF, 0.05%  
Specified with 2 kΩ || 220 pF, 0.05%  
Specified with 5 kΩ || 220 pF, 0.05%  
Specified with 1 kΩ || 220 pF  
0.1 Hz to 10 Hz bandwidth  
100 kHz bandwidth; specified with 2 kΩ ||  
220 pF  
4.5  
15.8  
2
3.5  
45.5  
Output Noise  
Output Noise Spectral Density  
AC PSRR  
165  
65  
nV/√Hz  
dB  
Measured at 10 kHz; specified with 2 kΩ ||  
220 pF  
200 mV, 50 Hz/60 Hz sine wave  
superimposed on power supply voltage  
DC PSRR  
10  
µV/V  
CURRENT OUTPUT  
Output Current Ranges  
0
0
3.92  
0
0
24  
20  
20  
24.5  
20.4  
20.4  
mA  
mA  
mA  
mA  
mA  
mA  
Output Current Overranges2  
See Detailed Description of Features section  
See Detailed Description of Features section  
See Detailed Description of Features section  
3.92  
ACCURACY (INTERNAL RSET  
)
Total Unadjusted Error (TUE)  
B Version3  
−0.2  
−0.08  
−0.5  
−0.3  
−0.02  
−16  
+0.2  
+0.08  
+0.5  
+0.3  
+0.02  
+16  
% FSR  
% FSR  
% FSR  
% FSR  
% FSR  
µa  
0.03  
TA = 25°C  
TA = 25°C  
A Version3  
0.15  
0.01  
Relative Accuracy (INL)  
Offset Error  
−10  
+5  
3
8
+10  
µa  
TA = 25°C  
Offset Error TC4  
Dead Band on Output, RTI  
Gain Error  
ppm FSR/°C  
mV  
+14  
+0.2  
+0.125  
Referred to 4.096 V input range  
TA = 25°C  
−0.2  
−0.125  
% FSR  
% FSR  
ppm FSR/°C  
% FSR  
% FSR  
ppm FSR/°C  
0.02  
10  
Gain TC4  
Full-Scale Error  
−0.2  
−0.125  
+0.2  
+0.125  
0.02  
4
TA = 25°C  
Full-Scale TC4  
ACCURACY (EXTERNAL RSET  
)
Total Unadjusted Error (TUE)  
B Version3  
−0.1  
−0.08  
−0.3  
−0.1  
−0.02  
−14  
+0.1  
+0.08  
+0.3  
+0.1  
+0.02  
+14  
% FSR  
% FSR  
% FSR  
% FSR  
% FSR  
µA  
0.03  
TA = 25°C  
TA = 25°C  
A Version3  
0.02  
0.01  
Relative Accuracy (INL)  
Offset Error  
−11  
+5  
2
8
+11  
TA = 25°C  
Offset Error TC4  
Dead Band on Output, RTI  
Gain Error  
ppm FSR/°C  
mV  
% FSR  
+14  
+0.08  
+0.07  
Referred to 4.096 V input range  
TA = 25°C  
−0.08  
−0.07  
0.02  
% FSR  
Rev. D | Page 5 of 32  
AD5751  
Data Sheet  
Parameter1  
Gain TC4  
Min  
Typ  
Max  
Unit  
Test Conditions/Comments  
1
ppm FSR/°C  
% FSR  
Full-Scale Error  
−0.1  
+0.1  
−0.07  
0.02  
2
+0.07  
% FSR  
ppm FSR/°C  
TA = 25°C  
Full-Scale TC4  
OUTPUT CHARACTERISTICS4  
Current Loop Compliance Voltage  
Resistive Load  
0
AVDD − 2.75  
V
Chosen such that compliance is not  
exceeded  
Inductive Load  
See test conditions/comments column  
H
Needs appropriate capacitor at higher  
inductance values; see Driving Inductive  
Loads section  
Settling Time  
4 mA to 20 mA, Full-Scale Step  
120 µA Step, 4 mA to 20 mA Range  
DC PSRR  
Output Impedance  
DIGITAL INPUTS4  
8.5  
1.2  
1
µs  
µs  
µA/V  
MΩ  
250 Ω load  
250 Ω load  
130  
JEDEC compliant  
Input High Voltage, VIH  
Input Low Voltage, VIL  
Input Current  
2
V
V
µA  
pF  
0.8  
+1  
−1  
Per pin  
Per pin  
Pin Capacitance  
5
DIGITAL OUTPUTS4  
FAULT, IFAULT, TEMP, VFAULT  
VOL, Output Low Voltage  
0.4  
V
V
V
10 kΩ pull-up resistor to DVCC  
At 2.5 mA  
10 kΩ pull-up resistor to DVCC  
0.6  
VOH, Output High Voltage  
SDO  
3.6  
VOL, Output Low Voltage  
VOH, Output High Voltage  
High Impedance Output  
Capacitance  
0.5  
DVCC − 0.5  
0.5  
DVCC − 0.5  
3
V
V
pF  
Sinking 200 µA  
Sourcing 200 µA  
High Impedance Leakage Current  
−1  
+1  
55  
µA  
V
POWER REQUIREMENTS  
AVDD  
DVCC  
Input Voltage  
AIDD  
10.8  
2.7  
5.5  
5.6  
6.2  
6.2  
1
V
4.4  
5.2  
5.2  
0.3  
108  
mA  
mA  
mA  
mA  
mW  
Output unloaded, output disabled  
Current output enabled  
Voltage output enabled  
VIH = DVCC, VIL = GND  
AVDD = 24 V, outputs unloaded  
DICC  
Power Dissipation  
1 Temperature range: −40°C to +105°C; typical at +25°C.  
2 Overranges are nominal; gain and offset are not trimmed as per nominal ranges.  
3 Specification includes gain and offset errors, over temperature, and drift after 1000 hours, TA = 125°C.  
4 Guaranteed by characterization, but not production tested.  
Rev. D | Page 6 of 32  
Data Sheet  
AD5751  
TIMING CHARACTERISTICS  
AVDD = 12 V ( 10%) to 55 V (maximum), DVCC = 2.7 V to 5.5 V, GND = 0 V. VOUT: RLOAD = 2 kΩ (5 kΩ for 0 V to 40 V range),  
CL = 200 pF, IOUT: RLOAD = 300 Ω. All specifications TMIN to TMAX, unless otherwise noted.  
Table 3.  
Parameter1, 2  
Limit at TMIN, TMAX  
Unit  
Description  
t1  
t2  
t3  
t4  
20  
8
8
ns min  
ns min  
ns min  
ns min  
ns min  
ns min  
ns min  
ns min  
µs max  
ns min  
SCLK cycle time  
SCLK high time  
SCLK low time  
5
SYNC falling edge to SCLK falling edge setup time  
16th SCLK falling edge to SYNC rising edge (on 24th SCLK falling edge if using PEC)  
Minimum SYNC high time (write mode)  
Data setup time  
Data hold time  
CLEAR pulse low/high activation time  
Minimum SYNC high time (read mode)  
t5  
10  
5
t6  
t7  
t8  
t9, t10  
t11  
t12  
t13  
5
5
1.5  
5
40  
10  
ns max SCLK rising edge to SDO valid (SDO CL = 15 pF)  
ns min  
RESET pulse low time  
1 Guaranteed by characterization, but not production tested.  
2 All input signals are specified with tR = tF = 5 ns (10% to 90% of DVCC) and timed from a voltage level of 1.2 V.  
Timing Diagrams  
t1  
SCLK  
1
2
16  
t3  
t2  
t6  
t4  
t5  
SYNC  
t8  
t7  
D15  
SDIN  
CLEAR  
VOUT  
D0  
t10  
t9  
RESET  
t13  
Figure 2. Write Mode Timing Diagram  
Rev. D | Page 7 of 32  
 
 
AD5751  
Data Sheet  
SCLK  
t11  
SYNC  
SDIN  
SDO  
A2  
A1  
A0  
R = 1  
0
X
X
X
X
X
X
X
X
X
X
X
t12  
PEC  
ERROR  
OVER  
TEMP  
IOUT  
FAULT  
VOUT  
FAULT  
X
X
X
X
X
R3  
R2  
R1  
R0  
CLRSEL OUTEN RSET  
Figure 3. Readback Mode Timing Diagram  
Rev. D | Page 8 of 32  
Data Sheet  
AD5751  
ABSOLUTE MAXIMUM RATINGS  
TA = 25°C, unless otherwise noted. Transient currents of up to  
100 mA do not cause SCR latch-up.  
Stresses at or above those listed under Absolute Maximum  
Ratings may cause permanent damage to the product. This is a  
stress rating only; functional operation of the product at these  
or any other conditions above those indicated in the operational  
section of this specification is not implied. Operation beyond  
the maximum operating conditions for extended periods may  
affect product reliability.  
Table 4.  
Parameter  
Rating  
AVDD to GND  
DVCC to GND  
−0.3 V to +58 V  
−0.3 V to +7 V  
Digital Inputs to GND  
−0.3 V to DVCC + 0.3 V, or 7 V  
(whichever is less)  
ESD CAUTION  
Digital Outputs to GND  
−0.3 V to DVCC + 0.3 V, or 7 V  
(whichever is less)  
VREF to GND  
VSENSE+ to GND  
VIN to GND  
−0.3 V to +7 V  
−0.3 V to AVDD  
−0.3 V to +7 V  
−0.3 V to AVDD  
VOUT, IOUT to GND  
Operating Temperature Range  
Industrial  
Storage Temperature Range  
Junction Temperature (TJ max)  
32-Lead LFCSP Package  
θJA Thermal Impedance1  
Lead Temperature  
Soldering  
−40°C to +105°C  
−65°C to +150°C  
125°C  
42°C/W  
JEDEC industry standard  
J-STD-020  
1 Simulated data based on a JEDEC 2s2p test board with thermal vias.  
Rev. D | Page 9 of 32  
 
 
AD5751  
Data Sheet  
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS  
SDO/VFAULT 1  
CLRSEL 2  
CLEAR 3  
DVCC 4  
GND 5  
SYNC/RSET 6  
SCLK/OUTEN 7  
SDIN/R0 8  
24 VSENSE+  
23 VOUT  
22 GND  
AD5751  
TOP VIEW  
(Not to Scale)  
21 GND  
20 COMP1  
19 COMP2  
18 IOUT  
17 AVDD  
NOTES  
1. NC = NO CONNECT. CAN BE TIED TO GND.  
2. THE EXPOSED PADDLE IS TIED TO GND.  
Figure 4. Pin Configuration  
Table 5. Pin Function Descriptions  
Pin No.  
Mnemonic  
Description  
1
SDO/VFAULT  
Serial Data Output (SDO). In software mode, this pin is used to clock data from the input shift register in  
readback mode. Data is clocked out on the rising edge of SCLK and is valid on the falling edge of SCLK.  
This pin is a CMOS output.  
Short-Circuit Fault Alert (VFAULT). In hardware mode, this pin acts as a short-circuit fault alert pin and is  
asserted low when a short-circuit error is detected. This pin is an open-drain output and must be  
connected to a pull-up resistor.  
2
3
CLRSEL  
CLEAR  
In hardware or software mode, this pin selects the clear value, either zero-scale or midscale code. In  
software mode, this pin is implemented as a logic OR with the internal CLRSEL bit.  
Active High Input. Asserting this pin sets the output current/voltage to zero-scale code or midscale code  
of range selected (user-selectable). CLEAR is a logic OR with the internal clear bit. See the Asynchronous  
Clear (CLEAR) section for more details.  
In software mode, during power-up, the CLEAR pin level determines the power-on condition of the  
voltage channel, which can be active 0 V or tristate.  
4
5
6
DVCC  
GND  
SYNC/RSET  
Digital Power Supply.  
Ground Connection.  
Positive Edge-Sensitive Latch (SYNC). In software mode, a rising edge parallel loads the input shift  
register data into the AD5751, also updating the output.  
Resistor Select (RSET). In hardware mode, this pin selects whether the internal or the external current  
sense resistor is used.  
If RSET = 0, the external sense resistor is chosen.  
If RSET = 1, the internal sense resistor is chosen.  
7
8
9
SCLK/OUTEN  
SDIN/R0  
Serial Clock Input (SCLK). In software mode, data is clocked into the input shift register on the falling  
edge of SCLK. This pin operates at clock speeds up to 50 MHz.  
Output Enable (OUTEN). In hardware mode, this pin acts as an output enable pin.  
Serial Data Input (SDIN). In software mode, data must be valid on the falling edge of SCLK.  
Range Decode Bit (R0). In hardware mode, this pin, in conjunction with R1, R2, and R3, selects the output  
current/voltage range setting on the part.  
AD2/R1  
Device Addressing Bit (AD2). In software mode, this pin, in conjunction with AD0 and AD1, allows up to  
eight devices to be addressed on one bus.  
Range Decode Bit (R1). In hardware mode, this pin, in conjunction with R0, R2, and R3, selects the output  
current/voltage range setting on the part.  
Rev. D | Page 10 of 32  
 
Data Sheet  
AD5751  
Pin No.  
Mnemonic  
Description  
10  
AD1/R2  
Device Addressing Bit (AD1). In software mode, this pin, in conjunction with AD0 and AD2, allows up to  
eight devices to be addressed on one bus.  
Range Decode Bit (R2). In hardware mode, this pin, in conjunction with R0, R1, and R3, selects the output  
current/voltage range setting on the part.  
11  
AD0/R3  
Device Addressing Bit (AD0). In software mode, this pin, in conjunction with AD1 and AD2, allows up to  
eight devices to be addressed on one bus.  
Range Decode Bit (R3). In hardware mode, this pin, in conjunction with R0, R1, and R2, selects the output  
current/voltage range setting on the part.  
12, 13  
REXT2, REXT1  
A 15 kΩ external current setting resistor can be connected between the REXT1 and REXT2 pins to  
improve the IOUT temperature drift performance.  
14  
15  
16  
17  
VREF  
VIN  
GND  
AVDD  
IOUT  
Buffered Reference Input.  
Buffered Analog Input (0 V to 4.096 V).  
Ground Connection.  
Positive Analog Supply.  
Current Output.  
18  
19, 20  
COMP2, COMP1 Optional Compensation Capacitor Connections for the Voltage Output Buffer. These are used to drive  
higher capacitive loads on the output. These pins also reduce overshoot on the output. Care should be  
taken when choosing the value of the capacitor connected between the COMP1 and COMP2 pins  
because it has a direct influence on the settling time of the output. See the Driving Large Capacitive  
Loads section for further details.  
21  
22  
23  
24  
GND  
GND  
VOUT  
VSENSE+  
Ground Connection.  
Ground Connection.  
Buffered Analog Output Voltage.  
Sense Connection for the Positive Voltage Output Load Connection.  
No Connect. Can be tied to GND.  
25, 26, 27, 28 NC  
29  
30  
31  
HW SELECT  
This part is used to configure the part to hardware or software mode.  
HW SELECT = 0 selects software control.  
HW SELECT = 1 selects hardware control.  
In software mode, this pin resets the part to its power-on state. Active low.  
In hardware mode, there is no reset. If using the part in hardware mode, the RESET pin should be tied  
high.  
Fault Alert (FAULT). In software mode, this pin acts as a general fault alert pin. It is asserted low when an  
open-circuit, short-circuit, overtemperature error, or PEC interface error is detected. This pin is an open-  
drain output and must be connected to a pull-up resistor.  
RESET  
FAULT/TEMP  
Overtemperature Fault (TEMP). In hardware mode, this pin acts as an overtemperature fault pin. It is  
asserted low when an overtemperature error is detected. This pin is an open-drain output and must be  
connected to a pull-up resistor.  
32  
NC/IFAULT  
No Connect (NC). In software mode, this pin is a no connect. Instead, tie this pin to GND.  
Open-Circuit Fault Alert (IFAULT). In hardware mode, this pin acts as an open-circuit fault alert pin. It is  
asserted low when an open-circuit error is detected. This pin is an open-drain output and must be  
connected to a pull-up resistor.  
33 (EPAD)  
Exposed paddle The exposed paddle is tied to GND.  
Rev. D | Page 11 of 32  
AD5751  
Data Sheet  
TYPICAL PERFORMANCE CHARACTERISTICS  
0.010  
0.10  
0.08  
0.06  
0.04  
0.02  
0V TO 5V  
0V TO 5V POSITIVE TUE  
0.008  
0.006  
0V TO 10V  
0V TO 40V  
0V TO 10V POSITIVE TUE  
0V TO 40V POSITIVE TUE  
0V TO 5V NEGATIVE TUE  
0V TO 10V NEGATIVE TUE  
0V TO 40V NEGATIVE TUE  
0.004  
0.002  
0
0
–0.002  
–0.02  
–0.04  
–0.06  
–0.08  
–0.10  
–0.004  
–0.006  
–0.008  
–0.010  
–40  
25  
TEMPERATURE (°C)  
105  
V
(V)  
IN  
Figure 5. Integral Nonlinearity Error vs. VIN  
Figure 8. Total Unadjusted Error vs. Temperature  
0.010  
0.008  
0.006  
0.004  
0.002  
0.05  
0.04  
0.03  
0.02  
0.01  
0
0V TO 5V RANGE  
0V TO 10V RANGE  
0V TO 40V RANGE  
0V TO 5V RANGE  
0V TO 10V RANGE  
0V TO 40V RANGE  
0
–0.002  
–0.01  
–0.02  
–0.004  
–0.006  
–0.008  
–0.010  
–0.03  
–0.04  
–40  
25  
105  
–40  
25  
105  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 9. Full-Scale Error vs. Temperature  
Figure 6. Integral Nonlinearity Error vs. Temperature  
0.04  
0.03  
0.02  
0.01  
0
0.010  
0.008  
0.006  
0.004  
0.002  
0
0V TO 5V RANGE  
0V TO 10V RANGE  
0V TO 40V RANGE  
0V TO 5V  
0V TO 10V  
0V TO 40V  
–0.01  
–0.02  
–0.03  
–0.002  
–0.004  
–0.006  
–0.008  
–0.010  
–0.04  
–40  
25  
105  
TEMPERATURE (°C)  
V
(V)  
IN  
Figure 10. Gain Error vs. Temperature  
Figure 7. Total Unadjusted Error vs. VIN  
Rev. D | Page 12 of 32  
 
 
 
Data Sheet  
AD5751  
1.00  
0.95  
0.90  
0.85  
4.0  
0V TO 5V RANGE  
0V TO 10V RANGE  
0V TO 40V RANGE  
V
HEADROOM, LOAD OFF  
DD  
3.  
5
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0.80  
0.75  
0.70  
0
–0.5  
–1.0  
–1.5  
–40  
25  
TEMPERATURE (°C)  
105  
–40  
25  
105  
TEMPERATURE (°C)  
Figure 14. AVDD Headroom, 0 V to 10 V Range, Output Set to 10 V, Load Off  
Figure 11. Offset Error vs. Temperature  
0.007  
0.010  
5V LINEARITY, NO LOAD  
10V LINEARITY, NO LOAD  
40V LINEARITY, NO LOAD  
5V RANGE  
0.006  
0.008  
0.006  
0.005  
0.004  
0.003  
0.002  
0.004  
0.002  
0
–0.002  
–0.004  
–0.006  
–0.008  
–0.010  
0.001  
0
–0.001  
–0.002  
24  
48  
55  
–15 –13 –11 –9 –7 –5 –3 –1  
1
3
5
7
9
11 13 15  
SUPPLY VOLTAGE (V)  
SOURCE/SINK CURRENT (mA)  
Figure 15. Source and Sink Capability of Output Amplifier  
Figure 12. INL Error vs. Supply Voltage  
12  
0.010  
0.008  
0.006  
0.004  
0.002  
0
10  
8
0V TO 5V POSITIVE TUE  
0V TO 10V POSITIVE TUE  
0V TO 40V POSITIVE TUE  
6
0V TO 5V NEGATIVE TUE  
0V TO 10V NEGATIVE TUE  
0V TO 40V NEGATIVE TUE  
–0.002  
–0.004  
–0.006  
–0.008  
–0.010  
4
2
0
–8  
–3  
2
7
12  
17  
22  
27  
24  
48  
55  
SUPPLY VOLTAGE (V)  
TIME (µs)  
Figure 13. Total Unadjusted Error vs. Supply Voltage  
Figure 16. Full-Scale Positive Step, 10 V Range  
Rev. D | Page 13 of 32  
 
AD5751  
Data Sheet  
12  
10  
8
6
4
2
5µV/DIV  
1s/DIV  
0
–8  
–3  
2
7
12  
17  
22  
27  
TIME (µs)  
Figure 20. Peak-to-Peak Noise (0.1 Hz to 10 Hz Bandwidth)  
Figure 17. Full-Scale Negative Step, 10 V Range  
40  
35  
30  
25  
20  
15  
10  
5
0
100µV/DIV  
1s/DIV  
–5  
–1.0  
–0.5  
0
0.5  
1.0  
1.5  
2.0  
2.5  
TIME (ms)  
Figure 18. VOUT vs. Time on Power-Up, Load = 2 kΩ || 200 pF  
Figure 21. Peak-to-Peak Noise (100 kHz Bandwidth)  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
1.0  
0.8  
0.6  
0.4  
0.2  
0
1
V
DD  
V
OUT  
2
–0.2  
–1.5  
–1.0  
–0.5  
0
0.5  
1.0  
1.5  
2.0  
B
TIME (ms)  
CH1 5.00V CH2 20.0mV  
M1.0µs  
A
CH1  
3.00V  
W
Figure 19. VOUT Enable Glitch, Load = 2 kΩ || 1 nF  
Figure 22. VDD and VOUT vs. Time on Power-Up  
Rev. D | Page 14 of 32  
Data Sheet  
AD5751  
CURRENT OUTPUT  
0.005  
0.010  
0.008  
0.006  
0.004  
0.002  
0
4mA TO 20mA EXTERNAL R  
RESISTOR  
RESISTOR  
RESISTOR  
SET  
SET  
SET  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
LINEARITY  
LINEARITY  
LINEARITY  
SET  
SET  
SET  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
0.004  
0.003  
0.002  
0.001  
0
–0.001  
–0.002  
–0.003  
–0.004  
–0.005  
–0.002  
–0.004  
–0.006  
–0.008  
–0.010  
24V  
48V  
SUPPLY VOLTAGE (AVDD)  
55V  
V
(V)  
IN  
Figure 26. Integral Nonlinearity Current Mode, Internal RSET Sense Resistor  
Figure 23. Integral Nonlinearity Error vs. VIN, External RSET Resistor  
0.05  
0.005  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
TUE  
TUE  
TUE  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
RESISTOR  
RESISTOR  
RESISTOR  
SET  
SET  
SET  
SET  
SET  
SET  
0.04  
0.03  
0.02  
0.01  
0
0.004  
0.003  
0.002  
0.001  
0
–0.01  
–0.02  
–0.03  
–0.04  
–0.05  
–0.001  
–0.002  
–0.003  
–0.004  
–0.005  
V
(V)  
V
(V)  
IN  
IN  
Figure 27. Total Unadjusted Error vs. VIN, External RSET Resistor  
Figure 24. Integral Nonlinearity Error vs. VIN, Internal RSET Resistor  
0.05  
0.010  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
TUE  
TUE  
TUE  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
LINEARITY  
LINEARITY  
LINEARITY  
SET  
SET  
SET  
SET  
SET  
SET  
0.04  
0.03  
0.02  
0.01  
0
0.008  
0.006  
0.004  
0.002  
0
–0.01  
–0.02  
–0.03  
–0.04  
–0.05  
–0.002  
–0.004  
–0.006  
–0.008  
–0.010  
24V  
48V  
SUPPLY VOLTAGE (AVDD)  
55V  
V
(V)  
IN  
Figure 28. Total Unadjusted Error vs. VIN, Internal RSET Resistor  
Figure 25. Integral Nonlinearity Current Mode, External RSET Sense Resistor  
Rev. D | Page 15 of 32  
 
AD5751  
Data Sheet  
0.020  
0.005  
0.004  
0.003  
0.002  
0.001  
0
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
POSITIVE TUE  
POSITIVE TUE  
POSITIVE TUE  
SET  
SET  
SET  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
LINEARITY  
LINEARITY  
LINEARITY  
SET  
SET  
SET  
0.015  
0.010  
0.005  
0
–0.005  
–0.010  
–0.015  
–0.020  
–0.001  
–0.002  
–0.003  
–0.004  
–0.005  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
NEGATIVE TUE  
NEGATIVE TUE  
NEGATIVE TUE  
SET  
SET  
SET  
24V  
48V  
55V  
–40  
25  
TEMPERATURE (°C)  
105  
SUPPLY VOLTAGE (AVDD)  
Figure 29. Total Unadjusted Error Current Mode, External RSET Sense Resistor  
Figure 32. Integral Nonlinearity Error vs. Temperature,  
External RSET Sense Resistor  
0.010  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
NEGATIVE TUE  
NEGATIVE TUE  
SET  
SET  
0.10  
0.08  
0.06  
0.04  
0.02  
0
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
POSITIVE TUE  
POSITIVE TUE  
POSITIVE TUE  
NEGATIVE TUE  
NEGATIVE TUE  
NEGATIVE TUE  
SET  
SET  
SET  
SET  
SET  
SET  
0.005  
0
0mA TO 24mA INTERNAL  
NEGATIVE TUE  
R
SET  
4mA TO 20mA INTERNAL  
–0.005  
–0.010  
–0.015  
–0.020  
–0.025  
R
POSITIVE TUE  
SET  
–0.02  
–0.04  
–0.06  
–0.08  
–0.10  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
POSITIVE TUE  
POSITIVE TUE  
SET  
SET  
24V  
48V  
SUPPLY VOLTAGE (AVDD)  
55V  
–40  
25  
TEMPERATURE (°C)  
105  
Figure 30. Total Unadjusted Error Current Mode, Internal RSET Sense Resistor  
Figure 33. Total Unadjusted Error vs. Temperature, Internal RSET Sense Resistor  
0.10  
0.08  
0.06  
0.04  
0.02  
0
0.005  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
LINEARITY  
LINEARITY  
LINEARITY  
SET  
SET  
SET  
0.004  
0.003  
0.002  
0.001  
0
–0.02  
–0.001  
–0.002  
–0.003  
–0.004  
–0.005  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
POSITIVE TUE  
POSITIVE TUE  
POSITIVE TUE  
NEGATIVE TUE  
NEGATIVE TUE  
NEGATIVE TUE  
SET  
SET  
SET  
SET  
SET  
SET  
–0.04  
–0.06  
–0.08  
–0.10  
–40  
25  
TEMPERATURE (°C)  
105  
–40  
25  
TEMPERATURE (°C)  
105  
Figure 31. Integral Nonlinearity Error vs. Temperature,  
Internal RSET Sense Resistor  
Figure 34. Total Unadjusted Error vs. Temperature, External RSET Sense Resistor  
Rev. D | Page 16 of 32  
Data Sheet  
AD5751  
50  
45  
40  
35  
30  
25  
20  
15  
10  
5
4
3
2
1
0
–1  
–2  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
SET  
SET  
SET  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
SET  
SET  
SET  
0
–3  
–40  
25  
105  
–40  
25  
TEMPERATURE (°C)  
105  
TEMPERATURE (°C)  
Figure 35. Zero-Scale Error vs. Temperature, External RSET Sense Resistor  
Figure 38. Offset Error vs. Temperature, External RSET Sense Resistor  
40  
35  
30  
25  
20  
0.05  
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
SET  
SET  
SET  
0.04  
0.03  
0.02  
0.01  
0
–0.01  
–0.02  
–0.03  
–0.04  
–0.05  
15  
10  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
SET  
SET  
SET  
5
0
–40  
25  
TEMPERATURE (°C)  
105  
–40  
25  
105  
TEMPERATURE (°C)  
Figure 36. Zero-Scale Error vs. Temperature, Internal RSET Sense Resistor  
Figure 39. Full-Scale Error vs. Temperature, External RSET Sense Resistor  
0.10  
3
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
SET  
SET  
SET  
0.08  
0.06  
0.04  
0.02  
0
2
1
0
–0.02  
–0.04  
–0.06  
–0.08  
–0.10  
–1  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
SET  
SET  
SET  
–2  
–3  
–40  
25  
105  
–40  
25  
TEMPERATURE (°C)  
105  
TEMPERATURE (°C)  
Figure 40. Full-Scale Error vs. Temperature, Internal RSET Sense Resistor  
Figure 37. Offset Error vs. Temperature, Internal RSET Sense Resistor  
Rev. D | Page 17 of 32  
AD5751  
Data Sheet  
0.10  
0.08  
0.06  
0.04  
0.02  
0
12  
10  
8
0.000010  
0.000008  
0.000006  
0.000004  
0.000002  
0
4mA TO 20mA EXTERNAL R  
0mA TO 20mA EXTERNAL R  
0mA TO 24mA EXTERNAL R  
SET  
SET  
SET  
6
I
OUT  
4
–0.000002  
–0.000004  
–0.000006  
–0.000008  
–0.000010  
–0.02  
–0.04  
–0.06  
–0.08  
–0.10  
2
0
V
DD  
–2  
–10  
–8  
–6  
–4  
–2  
0
2
4
6
8
10  
–40  
25  
105  
TIME (ms)  
TEMPERATURE (°C)  
Figure 41. Gain Error vs. Temperature, External RSET Sense Resistor  
Figure 44. Output Current vs. Time on VDD Power-Up  
0
–2  
–4  
–6  
–8  
0.10  
4mA TO 20mA INTERNAL R  
0mA TO 20mA INTERNAL R  
0mA TO 24mA INTERNAL R  
SET  
SET  
SET  
0.08  
0.06  
0.04  
0.02  
0
–10  
–12  
–14  
–16  
–18  
–0.02  
–0.04  
–0.06  
–0.08  
–0.10  
–2  
–1  
0
1
2
3
4
5
6
7
8
–40  
25  
105  
TEMPERATURE (°C)  
TIME (µs)  
Figure 45. Output Current vs. Time on Output Enable, 0 mA to 20 mA Range  
Figure 42. Gain Error vs. Temperature, Internal RSET Sense Resistor  
2.10  
2.05  
2.00  
0.025  
0.020  
0.015  
0.010  
0.005  
0
1.95  
1.90  
1.85  
1.80  
1.75  
AV  
COMPLIANCE VOLTAGE  
DD  
1.70  
1.65  
–40  
25 105  
–12 –6  
1
8
14 21 28 34 41 48 54 61 68  
TIME (µs)  
TEMPERATURE (°C)  
Figure 43. Output Compliance vs. Temperature  
Tested When IOUT = 10.8 mA, 0 mA to 24 mA Range Selected  
Figure 46. 4 mA to 20 mA Output Current Step  
Rev. D | Page 18 of 32  
Data Sheet  
AD5751  
3000  
2500  
2000  
1500  
1000  
500  
4.10  
4.05  
4.00  
3.95  
3.90  
3.85  
DV  
= 5V  
CC  
3.80  
DV  
= 3V  
CC  
0
3.75  
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0  
LOGIC LEVEL (V)  
24  
48  
AV (V)  
55  
DD  
Figure 47. DICC vs. Logic Input Voltage  
Figure 49. AIDD vs. AVDD, IOUT = 0 mA  
4.10  
4.05  
4.00  
3.95  
3.90  
3.85  
3.80  
3.75  
24  
48  
DD  
55  
AV  
(V)  
Figure 48. AIDD vs. AVDD, VOUT = 0 V  
Rev. D | Page 19 of 32  
AD5751  
Data Sheet  
TERMINOLOGY  
Total Unadjusted Error (TUE)  
Zero-Scale TC  
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).  
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.  
Offset Error  
Relative Accuracy or Integral Nonlinearity (INL)  
INL is a measure of the maximum deviation, in % FSR, from a  
straight line passing through the endpoints of the output driver  
transfer function. A typical INL vs. input voltage plot is shown  
in Figure 5.  
Offset error is a measurement of the difference between the  
actual VOUT and the ideal VOUT expressed in millivolts (mV)  
in the linear region of the transfer function. It can be negative  
or positive.  
Output Voltage Settling Time  
Full-Scale Error  
Output voltage settling time is the amount of time it takes for  
the output to settle to a specified level for a half-scale input change.  
Full-scale error is the deviation of the actual full-scale analog  
output from the ideal full-scale output. Full-scale error is  
expressed as a percentage of full-scale range (% FSR).  
Slew Rate  
The slew rate of a device is a limitation in the rate of change of  
the output voltage. The output slewing speed is usually limited  
by the slew rate of the amplifier used at its output. Slew rate is  
measured from 10% to 90% of the output signal and is  
expressed in V/μs.  
Full-Scale TC  
Full-scale TC is a measure of the change in the full-scale error  
with a change in temperature. It is expressed in ppm FSR/°C.  
Gain Error  
Gain error is a measure of the span error of the output. It is the  
deviation in slope of the output transfer characteristic from the  
ideal expressed in % FSR. A plot of gain error vs. temperature is  
shown in Figure 10.  
Current Loop Voltage Compliance  
Current loop voltage compliance is the maximum voltage at the  
IOUT pin for which the output current is equal to the  
programmed value.  
Gain Error TC  
Power-On Glitch Energy  
Gain error TC is a measure of the change in gain error with  
changes in temperature. Gain error TC is expressed in ppm  
FSR/°C.  
Power-on glitch energy is the impulse injected into the analog  
output when the AD5751 is powered on. It is specified as the  
area of the glitch in nV-sec.  
Zero-Scale Error  
Power Supply Rejection Ratio (PSRR)  
PSRR indicates how the output is affected by changes in the  
power supply voltage.  
Zero-scale error is the deviation of the actual zero-scale analog  
output from the ideal zero-scale output. Zero-scale error is  
expressed in millivolts (mV).  
Rev. D | Page 20 of 32  
 
Data Sheet  
AD5751  
THEORY OF OPERATION  
The AD5751 is a single-channel, low cost, precision, voltage/  
current output driver with hardware or software programmable  
output ranges. The software ranges are configured via an SPI-/  
MICROWIRE-compatible serial interface. The hardware ranges  
are programmed using the range pins (R0 to R3). The analog  
input to the AD5751 is provided from a low voltage, single-supply  
DAC (0 V to 4.096 V), which is internally conditioned to provide  
the desired output current/voltage range.  
one time. The output range is selected by programming the R3  
to R0 bits in the control register (see Table 7 and Table 8).  
Figure 50 and Figure 51 show a typical configuration of AD5751 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 AD5751 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. The supply and reference for the DAC,  
as well as the reference for the AD5751, can be supplied from a  
reference such as the ADR392. The AD5751 can operate with a  
single supply up to 55 V.  
The output current range is programmable across three ranges:  
0 mA to 20 mA, 0 mA to 24 mA, or 4 mA to 20 mA. The voltage  
output is provided from a separate pin that can be configured to  
provide 0 V to 5 V, 0 V to 10 V, and 0 V to 40 V output ranges.  
An overrange of 20% is available on the 5 V and 10 V output  
voltage ranges, and of 10% on the 0 V to 40 V range. The VOUT  
and IOUT pins can be connected together. An overrange of 2%  
is available on the 0 mA to 20 mA, 0 mA to 24 mA, and 4 mA to  
20 mA current ranges. The current and voltage outputs are  
available on separate pins. Only one output can be enabled at  
SOFTWARE MODE  
In current mode, software-selectable output ranges include 0 mA  
to 20 mA, 0 mA to 24 mA, or 4 mA to 20 mA.  
In voltage mode, software-selectable output ranges include 0 V  
to 5 V, 0 V to 10 V, 0 V to 40 V.  
AVDD  
AGND  
ADP1720  
AVDD  
GND  
AD5751  
VSENSE+  
ADR392  
VDD REFIN  
VREF  
VOUT  
RANGE  
SCALE  
SCLK  
SDI/DIN  
SDO  
VOUT  
0V TO 5V, 0V TO 10V,  
0V TO 40V  
VIN  
AD506x  
AD566x  
MCU  
IOUT  
RANGE  
SCALE  
SYNC1  
IOUT  
0mA TO 20mA,  
0mA TO 24mA,  
4mA TO 20mA  
SCLK  
SDIN  
SDO  
VOUT SHORT FAULT  
IOUT OPEN FAULT  
OVERTEMP FAULT  
SERIAL  
INTERFACE  
SYNC  
STATUS REGISTER  
HW SELECT  
FAULT  
Figure 50. Typical System Configuration in Software Mode (Pull-Up Resistors Not Shown for Open-Drain Outputs)  
Rev. D | Page 21 of 32  
 
 
 
AD5751  
Data Sheet  
AVDD AGND  
AVDD GND  
ADP1720  
AD5751  
VSENSE+  
VREF  
ADR392  
VDD  
REFIN  
VOUT  
RANGE  
SCALE  
SCLK  
SDI/DIN  
SDO  
VOUT  
0V TO 5V, 0V TO 10V,  
0V TO 40V  
VIN  
AD506x  
AD566x  
MCU  
SYNC1  
IOUT  
RANGE  
SCALE  
IOUT  
0mA TO 20mA,  
0mA TO 24mA,  
4mA TO 20mA  
DVCC  
HW SELECT  
OUTEN  
R3  
R2  
R1  
OUTPUT RANGE  
SELECT PINS  
TEMP  
VFAULT  
IFAULT  
R0  
Figure 51. Typical System Configuration in Hardware Mode Using Internal DAC Reference (Pull-Up Resistors Not Shown for Open-Drain Outputs)  
Table 6. Suggested Parts for Use with the AD5751  
DAC  
Reference Power  
Resolution/Accuracy Description  
AD5660  
AD5664R  
AD5668  
AD5060  
AD5064/AD5066 ADR434  
AD5662  
AD5664  
Internal  
Internal  
Internal  
ADR434  
ADP17201  
N/A  
N/A  
ADP1720  
N/A  
ADR3922  
16-bit/12-bit  
16-bit/12-bit  
16-bit/12-bit  
16-bit/16-bit  
16-bit/16-bit  
16-bit/12-bit  
16-bit/12-bit  
Mid end system, single channel, internal reference  
Mid end system, quad channel, internal reference  
Mid end system, octal channel, internal reference  
High end system, single channel, external reference  
High end system, quad channel, external reference  
Mid end system, single channel, external reference  
Mid end system, quad channel, external reference  
ADR3922  
ADR3922  
N/A  
1 ADP1720 input range up to 28 V.  
2 ADR392 input range up to 15 V.  
Rev. D | Page 22 of 32  
 
Data Sheet  
AD5751  
Driving Large Capacitive Loads  
CURRRENT OUTPUT ARCHITECTURE  
The voltage input from the analog input VIN core (0 V to 4.096 V)  
is either converted to a current (see Figure 52), 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, or it is buffered and scaled to output a software-selectable  
unipolar voltage range (see Figure 53). The reference is used to  
provide internal offsets for range and gain scaling. The selecta-  
ble output range is programmable through the digital interface  
(software mode) or via the range pins (R0 to R3) (hardware mode).  
AVDD  
The voltage output amplifier is capable of driving capacitive loads  
of up to 1 µF with the addition of a nonpolarized compensation  
capacitor between the COMP1 and COMP2 pins.  
Without the compensation capacitor, up to 20 nF capacitive loads  
can be driven. Care should be taken to choose an appropriate  
value for the CCOMP capacitor. This capacitor, while allowing the  
AD5751 to drive higher capacitive loads and reduce overshoot,  
increases the settling time of the part and therefore affects the  
bandwidth of the system. Considered values of this capacitor  
should be in the range of 0 nF to 4 nF depending on the trade-off  
required between settling time, overshoot, and bandwidth.  
R2  
R3  
RANGE DECODE  
POWER-ON STATE OF THE AD5751  
FROM INTERFACE  
T2  
On power-up, the AD5751 senses whether hardware or software  
mode is loaded and sets the power-up conditions accordingly.  
A2  
T1  
VIN  
IOUT  
VOUT RANGE  
SCALING  
A1  
In software SPI mode, the power-up state of the output is  
dependent on the state of the CLEAR pin. If the CLEAR pin is  
pulled high, the part powers up, driving an active 0 V on the  
output. If the CLEAR pin is pulled low, the part powers up with  
the voltage output channel in tristate mode. In both cases, the  
current output channel powers up in the tristate condition (0  
mA). This allows the voltage and current outputs to be  
connected together if desired.  
VREF  
R1  
Figure 52. Current Output Configuration  
RANGE DECODE  
FROM INTERFACE  
VSENSE+  
VOUT  
To put the part into normal operation, the user must set the  
OUTEN bit in the control register to enable the output and, in  
the same write, set the output range configuration using the R3  
to R0 range bits. If the CLEAR pin is still high (active) during  
this write, the part automatically clears to its normal clear state  
as defined by the programmed range and by the CLRSEL pin or  
the CLRSEL bit (see the Asynchronous Clear (CLEAR) section  
for more details). The CLEAR pin must be taken low to operate  
the part in normal mode.  
VIN  
VOUT RANGE  
SCALING  
(0V TO 4.096V)  
VREF  
VOUT SHORT FAULT  
GND  
Figure 53. Voltage Output  
DRIVING INDUCTIVE LOADS  
When driving inductive or poorly defined loads, connect a 0.01 µF  
capacitor between IOUT and GND. This ensures stability with  
loads beyond 50 mH. There is no maximum capacitance limit.  
The capacitive component of the load may cause slower settling.  
The CLEAR pin is typically driven directly from a microcontroller.  
In cases where the power supply for the AD5751 supply is  
independent of the microcontroller power supply, the user can  
connect a weak pull-up resistor to DVCC or a pull-down resistor  
to ground to ensure that the correct power-up condition is  
achieved independent of the microcontroller. A 10 kΩ pull-up/  
pull-down resistor on the CLEAR pin should be sufficient for  
most applications.  
Voltage Output Amplifier  
The voltage output amplifier is capable of driving a load of 1 kΩ  
(for 0 V to 5 V and 0 V to 10 V ranges) and a load of 5 kΩ (for  
0 V to 40 V range) and capacitive loads up to 2 µF (with an  
external compensation capacitor on the COMP1 and COMP2  
pins). The source and sink capabilities of the output amplifier  
can be seen in Figure 15. The slew rate is 2 V/µs.  
If hardware mode is selected, the part powers up to the conditions  
defined by the R3 to R0 range bits and the status of the OUTEN  
or CLEAR pin. It is recommended to keep the output disabled  
when powering up the part in hardware mode.  
Internal to the device, there is a 2.5 MΩ resistor connected  
between VOUT and VSENSE+. If a fault condition occurs,  
these resistors act to protect the AD5751 by ensuring that the  
amplifier loop is closed so that the part does not enter into an  
open-loop condition.  
The current and voltage are output on separate pins and cannot  
be output simultaneously. This allows the user to tie both the  
current and voltage output pins together and configure the end  
system as a single-channel output.  
Rev. D | Page 23 of 32  
 
 
 
 
 
 
AD5751  
Data Sheet  
disabled, both the current and voltage channels go into tristate.  
The user must set the OUTEN bit to enable the output and  
simultaneously set the output range configuration.  
DEFAULT REGISTERS AT POWER-ON  
The AD5751 power-on-reset circuit ensures that all registers are  
loaded with zero code.  
In hardware mode, the output can be enabled or disabled using  
the OUTEN pin. When the output is disabled, both the current  
and voltage channels go into tristate. The user must write to the  
OUTEN pin to enable the output. It is recommended that the  
output be disabled when changing the ranges.  
In software SPI mode, the part powers up with all outputs  
disabled (OUTEN bit = 0). The user must set the OUTEN bit in  
the control register to enable the output and, in the same write,  
set the output range configuration using the R3 to R0 bits.  
If hardware mode is selected, the part powers up to the  
conditions defined by the R3 to R0 bits and the status of the  
OUTEN pin. It is recommended to keep the output disabled  
when powering up the part in hardware mode.  
SOFTWARE CONTROL  
Software control is enabled by connecting the HW SELECT pin  
to ground. In software mode, the AD5751 is controlled over a  
versatile 3-wire serial interface that operates at clock rates up to  
50 MHz. It is compatible with SPI, QSPI™, MICROWIRE, and  
DSP standards.  
RESET FUNCTION  
RESET  
In software mode, the part can be reset using the  
pin  
(active low) or the reset bit (reset = 1). A reset disables both the  
current and voltage outputs to their power-on condition. The  
user must write to the OUTEN bit to enable the output and, in  
Input Shift Register  
The input shift register is 16 bits wide. Data is loaded into the  
device MSB first as a 16-bit word under the control of a serial  
clock input, SCLK. Data is clocked in on the falling edge of SCLK.  
The input shift register consists of 16 control bits, as shown in  
Table 7. The timing diagram for this write operation is shown in  
Figure 2. The first three bits of the input shift register are used to set  
the hardware address of the AD5751 device on the printed circuit  
board (PCB). Up to eight devices can be addressed per board.  
RESET  
the same write, set the output range configuration. The  
pin is a level sensitive input; the part stays in reset mode as long  
RESET  
as the  
pin is low. The reset bit clears to 0 following a  
reset command to the control register.  
In hardware mode, there is no reset. If using the part in  
RESET  
hardware mode, the  
pin should be tied high.  
OUTEN  
Bit D11, Bit D1, and Bit D0 must always be set to 0 during any  
write sequence.  
In software mode, the output can be enabled or disabled using  
the OUTEN bit in the control register. When the output is  
Table 7. Input Shift Register Contents for a Write Operation—Control Register  
MSB  
LSB  
D0  
0
D15  
D14  
D13  
D12  
D11  
D10  
D9  
D8  
D7  
D6  
D5  
D4  
D3  
D2  
D1  
A2  
A1  
A0  
R/W  
0
R3  
R2  
R1  
R0  
CLRSEL  
OUTEN  
Clear  
RSET  
Reset  
0
Table 8. Input Shift Register Descriptions for Control Register  
Bit  
Description  
A2, A1, A0  
Used in association with the AD2, AD1, and AD0 external pins to determine which part is being addressed by the system  
controller.  
A2  
0
0
0
0
1
1
1
1
A1  
0
0
1
1
0
0
1
1
A0  
0
1
0
1
0
1
0
1
Function  
Addresses part with Pin AD2 = 0, Pin AD1 = 0, Pin AD0 = 0.  
Addresses part with Pin AD2 = 0, Pin AD1 = 0, Pin AD0 = 1.  
Addresses part with Pin AD2 = 0, Pin AD1 = 1, Pin AD0 = 0.  
Addresses part with Pin AD2 = 0, Pin AD1 = 1, Pin AD0 = 1.  
Addresses part with Pin AD2 = 1, Pin AD1 = 0, Pin AD0 = 0.  
Addresses part with Pin AD2 = 1, Pin AD1 = 0, Pin AD0 = 1.  
Addresses part with Pin AD2 = 1, Pin AD1 = 1, Pin AD0 = 0.  
Addresses part with Pin AD2 = 1, Pin AD1 = 1, Pin AD0 = 1.  
R/W  
Indicates a read from or a write to the addressed register.  
Rev. D | Page 24 of 32  
 
 
 
 
 
 
Data Sheet  
AD5751  
Bit  
Description  
R3, R2, R1, R0  
Selects the output configuration in conjunction with RSET.  
RSET  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
R3  
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
R2  
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
R1  
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
R0  
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Output Configuration  
4 mA to 20 mA (external 15 kΩ current sense resistor).  
0 mA to 20 mA (external 15 kΩ current sense resistor).  
0 mA to 24 mA (external 15 kΩ current sense resistor).  
Unused command. Do not program.  
Unused command. Do not program.  
0 V to 5 V.  
0 V to 10 V.  
Unused command. Do not program.  
Unused command. Do not program.  
0 V to 6.0 V (20% overrange).  
0 V to 12.0 V (20% overrange).  
Unused command. Do not program.  
Unused command. Do not program.  
Unused command. Do not program.  
0 V to 40 V.  
0 V to 44 V.  
4 mA to 20 mA (internal current sense resistor).  
0 mA to 20 mA (internal current sense resistor).  
0 mA to 24 mA (internal current sense resistor).  
Unused command. Do not program.  
Unused command. Do not program.  
0 V to 5 V.  
0 V to 10 V.  
Unused command. Do not program.  
Unused command. Do not program.  
0 V to 6.0 V (20% overrange).  
0 V to 12.0 V (20% overrange).  
Unused command. Do not program.  
Unused command. Do not program.  
3.92 mA to 20.4 mA (internal current sense resistor).  
0 mA to 20.4 mA (internal current sense resistor).  
0 mA to 24.5 mA (internal current sense resistor).  
CLRSEL  
Sets clear mode to zero scale or midscale. See the Asynchronous Clear (CLEAR) section.  
CLRSEL  
Function  
0
1
Clear to 0 V.  
Clear to midscale in unipolar mode; clear to zero scale in bipolar mode.  
OUTEN  
Clear  
Output enable bit. This bit must be set to 1 to enable the outputs.  
Software clear bit; active high.  
RSET  
Select internal/external current sense resistor.  
RSET  
Function  
1
0
Select internal current sense resistor; used with R3 to R0 bits to select range.  
Select external current sense resistor; used with R3 to R0 bits to select range.  
Reset  
Resets the part to its power-on state.  
Rev. D | Page 25 of 32  
AD5751  
Data Sheet  
Readback Operation  
HARDWARE CONTROL  
Readback mode is activated by selecting the correct device address  
Hardware control is enabled by connecting the HW SELECT  
pin to DVCC. In this mode, the R3, R2, R1, and R0 pins, in  
conjunction with the RSET pin, are used to configure the  
output range, as per Table 8.  
W
(A2, A1, A0) and then setting the R/ bit to 1. By default, the  
SDO pin is disabled. After having addressed the AD5751 for a  
W
read operation, setting R/ to 1 enables the SDO pin and SDO  
data is clocked out on the 5th rising edge of SCLK. After the data  
In hardware mode, there is no status register. The fault condi-  
tions (open circuit, short circuit, and overtemperature) are  
available on Pin IFAULT, Pin VFAULT, and Pin TEMP. If any  
one of these fault conditions is set, a low is asserted on the  
specific fault pin. IFAULT, VFAULT, and TEMP are open-drain  
outputs and, therefore, can be connected together to allow the  
user to generate one interrupt to the system controller to  
communicate a fault. If hardwired in this way, it is not possible  
to isolate which fault occurred in the system.  
SYNC  
has been clocked out on SDO, a rising edge on  
disables  
(tristate) the SDO pin again. Status register data (see Table 9)  
and control register data are both available during the same  
read cycle.  
The status bits comprise four read-only bits. They are used to  
notify the user of specific fault conditions that occur, such as an  
open circuit or short circuit on the output, overtemperature  
error, or an interface error. If any of these fault conditions occur,  
a hardware FAULT is also asserted low, which can be used as a  
hardware interrupt to the controller.  
TRANSFER FUNCTION  
The AD5751 consists of an internal signal conditioning block  
that maps the analog input voltage to a programmed output  
range. The available analog input range is 0 V to 4.096 V.  
See the Detailed Description of Features section for a full  
explanation of fault conditions.  
For all ranges, both current and voltage, the AD5751 imple-  
ments a straight linear mapping function, where 0 V maps to  
the lower end of the selected range and 4.096 V maps to the  
upper end of the selected range.  
Table 9. Input Shift Register Contents for a Read Operation—Status Register  
MSB  
LSB  
D15  
D14 D13 D12 D11 D10 D9 D8 D7 D6  
D5  
D4  
D3  
D2  
D1  
D0  
A2  
A1 A0 R3 R2 R1 R0 CLRSEL OUTEN RSET PEC error OVER TEMP IOUT fault  
1
0
VOUT fault  
Table 10. Status Bit Options  
Bit  
Description  
PEC Error  
OVER TEMP  
IOUT Fault  
VOUT Fault  
This bit is set if there is an interface error detected by CRC-8 error checking. See the Detailed Description of Features section.  
This bit is set if the AD5751 core temperature exceeds approximately 150°C.  
This bit is set if there is an open circuit on the IOUT pin.  
This bit is set if there is a short circuit on the VOUT pin.  
Rev. D | Page 26 of 32  
 
 
 
Data Sheet  
AD5751  
DETAILED DESCRIPTION OF FEATURES  
A short is detected on the voltage output pin. The short-  
circuit current is limited to 15 mA. If this fault is detected,  
the VFAULT pin is forced low.  
The core temperature of the AD5751 exceeds approx-  
imately 150°C. If this fault is detected, the TEMP pin is  
forced low.  
OUTPUT FAULT ALERT—SOFTWARE MODE  
In software mode, the AD5751 is equipped with one FAULT  
pin; this is an open-drain output allowing several AD5751  
devices to be connected together to one pull-up resistor for  
global fault detection. In software mode, the FAULT pin is  
forced active low by any one of the following fault scenarios:  
VOLTAGE OUTPUT SHORT-CIRCUIT PROTECTION  
The voltage at IOUT attempts to rise above the compliance  
range due to an open-loop circuit or insufficient power  
supply voltage. The internal circuitry that develops the  
fault output avoids using a comparator with window limits  
because this requires an actual output error before the fault  
output becomes active. Instead, the signal is generated  
when the internal amplifier in the output stage has less  
than approximately 1 V of remaining drive capability.  
Thus, the fault output activates slightly before the com-  
pliance limit is reached. Because the comparison is made  
within the feedback loop of the output amplifier, the output  
accuracy is maintained by its open-loop gain, and an  
output error does not occur before the fault output  
becomes active.  
Under normal operation the voltage output sinks and sources  
up to 12 mA and maintains specified operation. The maximum  
current that the voltage output delivers is 15 mA; this is the  
short-circuit current.  
ASYNCHRONOUS CLEAR (CLEAR)  
CLEAR is an active high clear that allows the voltage output to  
be cleared to either zero-scale code or midscale code, and is  
user-selectable via the CLRSEL pin or the CLRSEL bit of the  
input shift register, as described in Table 8. (The clear select  
feature is a logical OR function of the CLRSEL pin and the  
CLRSEL bit). The current loop output clears to the bottom of its  
programmed range. When the CLEAR signal is returned low,  
the output returns to its programmed value or to a new  
programmed value. A clear operation can also be performed via  
the clear command in the control register.  
A short is detected on the voltage output pin (VOUT). The  
short-circuit current is limited to 15 mA.  
An interface error is detected due to the packet error  
checking failure (PEC). See the Packet Error Checking  
section.  
Table 11. CLRSEL Options  
Output Clear Value  
The core temperature of the AD5751 exceeds  
approximately 150°C.  
Unipolar Output  
Voltage Range  
CLRSEL  
Unipolar Current Output Range  
0
0 V  
Zero-scale; for example:  
4 mA on the 4 mA to 20 mA range  
OUTPUT FAULT ALERT—HARDWARE MODE  
0 mA on the 0 mA to 20 mA  
Midscale; for example:  
12 mA on the 4 mA to 20 mA range  
10 mA on the 0 mA to 20 mA range  
In hardware mode, the AD5751 is equipped with three fault pins:  
VFAULT, IFAULT, and TEMP. These are open-drain outputs  
allowing several AD5751 devices to be connected together to  
one pull-up resistor for global fault detection. In hardware  
control mode, these fault pins are forced active by any one of  
the following fault scenarios:  
1
Midscale  
EXTERNAL CURRENT SETTING RESISTOR  
Referring to Figure 1, RSET is an internal sense resistor and is  
part of the voltage-to-current conversion circuitry. The nominal  
value of the internal current sense resistor is 15 kΩ. To allow for  
overrange capability in current mode, the user can also select  
the internal current sense resistor to be 14.7 kΩ, giving a nominal  
2% overrange capability. This feature is available in the 0 mA to  
20 mA, 0 mA to 24 mA, and 4 mA to 20 mA current ranges.  
An open-circuit is detected. The voltage at IOUT attempts  
to rise above the compliance range, due to an open-loop  
circuit or insufficient power supply voltage. The internal  
circuitry that develops the fault output avoids using a  
comparator with window limits because this requires an  
actual output error before the fault output becomes active.  
Instead, the signal is generated when the internal amplifier  
in the output stage has less than approximately 1 V of  
remaining drive capability. Thus, the fault output activates  
slightly before the compliance limit is reached. Because the  
comparison is made within the feedback loop of the output  
amplifier, the output accuracy is maintained by its open-  
loop gain, and an output error does not occur before the  
fault output becomes active. If this fault is detected, the  
IFAULT pin is forced low.  
The stability of the output current value over temperature is  
dependent on the stability of the value of RSET. As a method of  
improving the stability of the output current over temperature,  
an external low drift resistor can be connected to the REXT1  
and REXT2 pins of the AD5751, which can be used instead of  
the internal resistor. The external resistor is selected via the  
input shift register. If the external resistor option is not used, the  
REXT1 and REXT2 pins should be left floating.  
Rev. D | Page 27 of 32  
 
 
 
 
 
 
AD5751  
Data Sheet  
PROGRAMMABLE OVERRANGE MODES  
PACKET ERROR CHECKING  
The AD5751 contains an overrange mode for most of the  
available ranges. The overranges are selected by configuring the  
R3, R1, R1, and R0 bits (or pins) accordingly.  
To verify that data has been received correctly in noisy  
environments, the AD5751 offers the option of error checking  
based on an 8-bit (CRC-8) cyclic redundancy check. The device  
controlling the AD5751 should generate an 8-bit frame check  
sequence using the following polynomial:  
In voltage mode, depending on selected range, the overranges  
are 10% or 20%, providing programmable output ranges of 0 V  
to 6 V, 0 V to 12 V, and 0 V to 44 V. The 0 V to 4.096 V analog  
input remains the same.  
C(x) = x8 + x2 + x1 + 1  
This is added to the end of the data-word, and 24 data bits are  
In current mode, the overranges are typically 2%. In current  
mode, the overrange capability is only available on three ranges,  
0 mA to 20 mA, 0 mA to 24 mA, and 4 mA to 20 mA. For these  
ranges, the analog input also remains the same (0 V to 4.096 V).  
SYNC  
sent to the AD5751 before taking  
receives a 24-bit data frame, it performs the error check when  
SYNC  
high. If the AD5751  
goes high. If the check is valid, then the data is written to  
the selected register. If the error check fails, the FAULT pin goes  
low and Bit D3 of the status register is set. After reading this  
register, this error flag is cleared automatically and the FAULT  
pin goes high again.  
UPDATE ON SYNC HIGH  
SYNC  
SCLK  
D15  
(MSB)  
D0  
(LSB)  
16-BIT DATA  
SDIN  
16-BIT DATA TRANSER—NO ERROR CHECKING  
UPDATE AFTER SYNC HIGH  
ONLY IF ERROR CHECK PASSED  
SYNC  
SCLK  
SDIN  
D23  
(MSB)  
D8  
(LSB)  
D7  
D0  
8-BIT FCS  
16-BIT DATA  
FAULT GOES LOW IF  
ERROR CHECK FAILS  
FAULT  
16-BIT DATA TRANSER WITH ERROR CHECKING  
Figure 54. PEC Error Checking Timing  
Rev. D | Page 28 of 32  
 
 
Data Sheet  
AD5751  
APPLICATIONS INFORMATION  
TRANSIENT VOLTAGE PROTECTION  
THERMAL CONSIDERATIONS  
It is important to understand the effects of power dissipation  
on the package and how it affects junction temperature. The  
internal junction temperature should not exceed 125°C. The  
AD5751 is packaged in a 32-lead, 5 mm × 5 mm LFCSP pack-  
age. The thermal impedance, θJA, is 42 °C /W. It is important that  
the devices not be operated under conditions that cause the  
junction temperature to exceed its limit. Worst-case conditions  
occur when the AD5751 are operated from the maximum AVDD  
(55 V) and driving the maximum current (24 mA) directly to  
ground. The quiescent current of the AD5751 should also be  
taken into account, nominally ~4 mA. The following calculations  
estimate maximum power dissipation under these worst-case  
conditions, and determine maximum ambient temperature based  
on this. These figures assume that proper layout and grounding  
techniques are followed to minimize power dissipation, as  
outlined in the Layout Guidelines section.  
The AD5751 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 AD5751 from excessively high voltage transients, external  
power diodes and a surge current limiting resistor may be  
required, as shown in Figure 55. The constraint on the resistor  
value is that during normal operation the output level at IOUT  
must remain within its voltage compliance limit of AVDD  
2.75 V and the two protection diodes and resistor must have  
appropriate power ratings. Further protection can be added  
with transient voltage suppressors if needed.  
AV  
DD  
AV  
DD  
AD5751  
R
P
I
OUT  
R
LOAD  
Figure 55. Output Transient Voltage Protection  
Table 12. Thermal and Supply Considerations  
Considerations  
32-Lead LFCSP Package  
Maximum allowed power dissipation when operating at an ambient  
temperature of 85°C  
TJMAX TA  
12585  
=
= 0.95 W  
θJA  
42  
Maximum allowed ambient temperature when operating from a supply of  
55 V and driving 24 mA directly to ground (include 4 mA for internal AD5751  
current)  
T
JMAX − (PD × θJA) = 125 − ((55 × 0.028) × 42) = 60.3°C  
Maximum allowed supply voltage when operating at an ambient  
temperature of 85°C and driving 24 mA directly to ground  
TJMAX TA  
AIDD ×θJA  
12585  
0.028×42  
)
=
= 34 V  
(
Rev. D | Page 29 of 32  
 
 
 
 
AD5751  
Data Sheet  
corresponding thermal land paddle on the PCB (GND).  
Thermal vias should be designed into the PCB land paddle area  
to further improve heat dissipation.  
LAYOUT GUIDELINES  
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 AD5751 is  
mounted should be designed so that the AD5751 lies on the  
analog plane.  
GALVANICALLY ISOLATED INTERFACE  
In many process control applications, it is necessary to provide  
an isolation barrier between the controller and the unit being  
controlled to protect and isolate the controlling circuitry from  
any hazardous common-mode voltages that may occur. The  
iCoupler® family of products from Analog Devices, Inc., provides  
voltage isolation in excess of 5.0 kV. The serial loading structure  
of the AD5751 makes it ideal for isolated interfaces because the  
number of interface lines is kept to a minimum. Figure 57 shows a  
4-channel isolated interface to the AD5751 using an ADuM1400.  
For further information, visit http://www.analog.com/icouplers.  
The AD5751 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 0.1 µF capaci-  
tor should have low effective series resistance (ESR) and low  
effective series inductance (ESI) such as the common ceramic  
types, which provide a low impedance path to ground at high  
frequencies to handle transient currents due to internal logic  
switching.  
CONTROLLER  
ADuM14001  
In systems where there are many devices on one board, it is often  
useful to provide some heat sinking capability to allow the power  
to dissipate easily.  
V
V
V
V
V
OA  
OB  
OC  
OD  
IA  
IB  
IC  
ID  
TO  
SERIAL  
ENCODE  
ENCODE  
ENCODE  
ENCODE  
DECODE  
DECODE  
DECODE  
DECODE  
SCLK  
CLOCK OUT  
V
V
V
TO  
SDIN  
SERIAL  
DATA OUT  
AD5751  
TO  
SYNC  
SYNC OUT  
TO  
CLEAR  
CONTROL OUT  
1
ADDITIONAL PINS OMITTED FOR CLARITY.  
GND  
PLANE  
Figure 57. Isolated Interface  
MICROPROCESSOR INTERFACING  
BOARD  
Microprocessor interfacing to the AD5751 is via a serial bus that  
uses a protocol compatible with microcontrollers and DSP proces-  
sors. The communication channel is a 3-wire (minimum)  
Figure 56. Paddle Connection to Board  
SYNC  
interface consisting of a clock signal, a data signal, and a  
The AD5751 has an exposed paddle beneath the device.  
Connect this paddle to the GND of the AD5751. For optimum  
performance, special considerations should be used to design  
the motherboard and to mount the package. For enhanced  
thermal, electrical, and board level performance, the exposed  
paddle on the bottom of the package should be soldered to the  
signal. The AD5751 requires a 16-bit data-word with data valid  
on the falling edge of SCLK.  
Rev. D | Page 30 of 32  
 
 
 
 
Data Sheet  
AD5751  
OUTLINE DIMENSIONS  
5.10  
5.00 SQ  
4.90  
0.60 MAX  
0.60 MAX  
PIN 1  
INDICATOR  
0.50  
BSC  
PIN 1  
INDICATOR  
4.75  
BSC SQ  
3.25  
3.10 SQ  
2.95  
0.50  
0.40  
0.30  
0.20 MIN  
TOP VIEW  
BOTTOM VIEW  
3.50 REF  
0.80 MAX  
0.65 TYP  
12° MAX  
1.00  
0.85  
0.80  
FOR PROPER CONNECTION OF  
THE EXPOSED PAD, REFER TO  
THE PIN CONFIGURATION AND  
FUNCTION DESCRIPTIONS  
0.05 MAX  
0.02 NOM  
COPLANARITY  
0.08  
0.30  
0.25  
0.18  
SECTION OF THIS DATA SHEET.  
SEATING  
PLANE  
0.20 REF  
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2  
Figure 58. 32-Lead Lead Frame Chip Scale Package [LFCSP]  
5 mm × 5 mm Body and 0.85 mm Package Height  
(CP-32-2)  
Dimensions shown in millimeters  
ORDERING GUIDE  
Model1  
Temperature Range  
−40°C to +105°C  
−40°C to +105°C  
−40°C to +105°C  
Package Description  
32-Lead LFCSP  
32-Lead LFCSP  
Package Option  
CP-32-2  
CP-32-2  
AD5751ACPZ  
AD5751ACPZ-REEL7  
AD5751BCPZ  
32-Lead LFCSP  
CP-32-2  
1 Z = RoHS Compliant Part.  
Rev. D | Page 31 of 32  
 
 
AD5751  
NOTES  
Data Sheet  
©2009–2018 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D07269-0-1/18(D)  
Rev. D | Page 32 of 32  

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