AD AD5751BCPZ Industrial i/v output driver, single supply, 60v compliance, programmable range Datasheet

Industrial I/V Output Driver,
Single Supply, 60v Compliance,
Programmable Ranges
AD5751
Preliminary Technical Data
FEATURES
Current Output Ranges: 4–20mA, 0–20mA or 0–24mA,
0.1% Total Unadjusted Error (TUE)
5ppm/°C Output Drift
60V MAX IOUT Compliance Voltage
Voltage Output Ranges: 0-5V, 0-10V, 0-40v
20% over-range
0.1% Total Unadjusted Error (TUE)
Flexible Serial Digital Interface
On-Chip Output Fault Detection
PEC Error Checking
Asynchronous CLEAR Function
Power Supply Range
AVDD : = +12V to +60V (MAX)
Output Loop Compliance to AVDD – 2.5 V
Temperature Range: -40°C to +105°C
LFCSP Packages
APPLICATIONS
Process Control
Actuator Control
PLC
GENERAL DESCRIPTION
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 and is
internally conditioned to provide the desired output
current/voltage range.
The output current range is programmable across three current
ranges - 4–20mA, 0–20mA or 0–24mA.
Voltage output is provided from a separate pin that can be
configured to provide 0V to 5V, 0V to 10V and 0-40V output
ranges. An over-range of 10% is available on the voltage
ranges.
Analog outputs are short and open circuit protected and can
drive capacitive loads of 1uF and inductive loads of 0.1H.
The device is specified to operate with a power supply range
from 12 V to 60 V. Output loop compliance is 0 V to AVDD –
2.5 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
asynchronous CLEAR pin which sets the outputs to zero-scale /
mid-scale voltage output or the low end of the selected current
range.
A HW SELECT pin is used to configure the part for hardware
or software mode on power up.
The total output error is typically ±0.1% in both current mode
and voltage mode.
Table 1. Related Devices
Part Number
AD5422
Description
Single Channel, 16-Bit, Serial
Input Current Source and
Voltage Output DAC
Rev. PrA
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rights of third parties that may result from its use. Specifications subject to change without notice. No
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Fax: 781.461.3113
©2008 Analog Devices, Inc. All rights reserved.
AD5751
Preliminary Technical Data
TABLE OF CONTENTS
Features .............................................................................................. 1
Software control:......................................................................... 15
Applications ....................................................................................... 1
HARDWARE CONTROL: ........................................................ 17
General Description ......................................................................... 1
Features ............................................................................................ 19
Revision History ............................................................................... 2
output fault alert – SOFTWARE MODE ................................ 19
Functional Block Diagram .............................................................. 3
output fault alert – HARDWARE MODE ............................... 19
Specifications..................................................................................... 4
voltage output short circuit protection .................................... 19
Timing Characteristics ................................................................ 6
Asynchronous Clear (CLEAR) ................................................. 19
Absolute Maximum Ratings............................................................ 9
External current setting resistor ............................................... 20
ESD Caution .................................................................................. 9
Applications Information .............................................................. 21
Pin Configuration and Function Descriptions ........................... 10
Transient voltage protection ..................................................... 21
Typical Performance Characteristics ........................................... 12
Layout Guidelines....................................................................... 21
Terminology ................................. Error! Bookmark not defined.
Galvanically Isolated Interface ................................................. 21
Theory of Operation ................... Error! Bookmark not defined.
Microprocessor Interfacing ....................................................... 21
CURRENT OUTPUT Architecture ......................................... 14
Outline Dimensions ....................................................................... 22
OUTEN ........................................................................................ 14
Ordering Guide .......................................................................... 22
REVISION HISTORY
PrA – Preliminary Version. May 6, 2008
Rev. PrA | Page 2 of 22
Preliminary Technical Data
AD5751
FUNCTIONAL BLOCK DIAGRAM
DVCC GND
AVDD GND
COMP1
COMP2
CLEAR
CLRSEL
SCLK/OUTEN*
SDIN/R0*
SYNC/RSEL*
SDO/VFAULT*
INPUT SHIFT
REGISTER
AND
CONTROL
LOGIC
HW SELECT
STATUS REG
VSENSE+
VOUT RANGE
SCALING
VOUT
VOUT SHORT FAULT
AVDD
VIN
VREF
R2
RESET
R3
IOUT RANGE
SCALING
IOUT
OVERTEMP
FAULT/TEMP*
NC/IFAULT*
VOUT SHORT FAULT
RSET
IOUT OPEN FAULT
OUTPUT RANGE ERROR
POWER
ON
RESET
R1
IOUT OPEN FAULT
AD5751
AD2/R1*
AD1/R2*
AD0/R3*
Figure 1. Functional Block Diagram
* Denotes shared pin. Software mode denoted by regular text, hardware mode denoted by bold
text. E.G. for FAULT/TEMP pin, in software mode this pin will take on FAULT function. In
Hardware mode, this pin will take on TEMP function.
Rev. PrA | Page 3 of 22
AD5751
Preliminary Technical Data
SPECIFICATIONS
AVDD=12V (+/-10%) to +60V (MAX) , DVCC =2.7 V to 5.5 V, GND = 0 V. RL = 2 kΩ, CL = 200 pF, IOUT : RL = 300Ω,
50mH All specifications TMIN to TMAX, unless otherwise noted.
HL =
Table 2.
Parameter
Value1
Unit
INPUT VOLTAGE RANGE
Input Leakage Current
0 to 4.096
1
V
uA max
0 to 5
0 to 10
V
V
0 to 40
V
VOLTAGE OUTPUT
Output Voltage Ranges
ACCURACY
Unipolar Output
Total Unadjusted Error (TUE)
Relative Accuracy (INL)
Offset Error
Zero Scale Error
Zero Scale TC
Gain Error
Gain Error TC
Full Scale Error
Full Scale Error TC
Short-Circuit Current
Load Conditions
Resistance
Resistance
Capacitance Load Stability
RL = ∞
RL = 2 kΩ
RL = ∞
0.1% Settling Time
Slew Rate
Output Noise
Output Noise Spectral Density
DC Output Impedance
DC PSRR
AC PSRR
Power-On Glitch Energy
CURRENT OUTPUT
Output Current Ranges
Test Conditions/Comments
AVDD needs to have minimum 1.1v headroom, or
>11.1v.
Output unloaded
0.1
±0.02
0.015
TBD
TBD
0.005
TBD
0.015
TBD
% FSR max
% FSR max
% FSR max
% FSR max
ppm % FSR max
% FSR max
ppm % FSR max
% FSR max
ppm % FSR max
15
mA max
1
5
K Ohm min
K Ohm min
For Specified Performance, 0-5v, 0-10v ranges.
For Specified Performance, 0-40v ranges.
20
TBD
1
10
nF max
nF max
μF max
us
External compensation capacitor of 4nF connected.
Specified with 200pF load
1
TBD
80
100
0.3
10
TBD
V/μs typ
μV rms max
μV rms max
nV/√Hz typ
Ω typ
μV/V
dB
10
nV-sec typ
0 to 24
0 to 20
mA
mA
Rev. PrA | Page 4 of 22
Over temperature and supplies.
Error at analog input = 100mv (?)
Error at analog input = 0.0v
(Ideal Span – Measured Span)/Ideal Span
Error at analog input = 4.096v (FS)
0.1 Hz to 10 Hz Bandwidth
100 kHz Bandwidth
Measured at 10KHz
200mV 50/60Hz Sinewavesuperimposed on power
supply voltage.
Preliminary Technical Data
Parameter
ACCURACY
Total Unadjusted Error (TUE)
TUE TC
Unipolar Output
Relative Accuracy (INL)
Offset Error
Zero Scale Error
Zero Scale TC
Gain Error
Gain Error TC
Full Scale Error
Full Scale Error TC
Total Unadjusted Error (TUE)
TUE TC
Unipolar Output
Relative Accuracy (INL)
Offset Error
Zero Scale Error
Zero Scale TC
Gain Error
Gain Error TC
Full Scale Error
Full Scale Error TC
Output Current Ranges
(over range)
Relative Accuracy (INL)
OUTPUT CHARACTERISTICS
Current Loop Compliance Voltage
Resistive Load
Inductive Load
0.1% Settling Time
DC PSRR
Output Impedance
REFERENCE INPUT
Reference Input
Reference Input Voltage
Input Leakage Current
DIGITAL INPUTS
VIH, Input High Voltage
AD5751
Value1
4 to 20
Unit
mA
Test Conditions/Comments
±0.1
±5
% FSR max
ppm max
With External Precision Resistor
With External Precision Resistor
±0.02
0.01
0.01
TBD
0.15
TBD
0.01
TBD
% FSR max
% FSR max
% FSR max
ppm % FSR max
% FSR max
ppm % FSR max
% FSR max
ppm % FSR max
±0.3
±20
±50
% FSR max
ppm typ
ppm max
±0.02
0.01
0.01
TBD
0.15
TBD
0.01
TBD
% FSR max
% FSR max
% FSR max
ppm % FSR max
% FSR max
ppm % FSR max
% FSR max
ppm % FSR max
0.1 to 24.5
mA
0.1 to 20.4
3.9 to 20.4
mA
mA
±0.02
% FSR max
AVDD – 2.5
See Comment
0.1
10
V max
kΩ max
H max
us
1
25
μA/V max
MΩ typ
4.096
1
V nom
uA max
2
V min
Error at analog input = 100mv (?)
Error at analog input = 0.0v
(Ideal Span – Measured Span)/Ideal Span
Error at analog input = 4.096v (FS)
With Internal Resistor
With Internal Resistor
Error at analog input = 100mv (?)
Error at analog input = 0.0v
(Ideal Span – Measured Span)/Ideal Span
Error at analog input = 4.096v (FS)
Nominal Over-ranges. See Text Page..
Chosen such that compliance is not exceeded.
±1% for specified performance
DVCC = 2.7 V to 5.5 V, JEDEC compliant
Rev. PrA | Page 5 of 22
AD5751
Preliminary Technical Data
Parameter
VIL, Input Low Voltage
Input Current
Pin Capacitance
DIGITAL OUTPUTS
FAULT, IFAULT, TEMP, VFAULT
VOL, Output Low Voltage
VOL, Output Low Voltage
VOH, Output High Voltage
SDO
VOL, Output Low Voltage
VOH, Output High Voltage
High Impedance Leakage
current
High Impedance Output
Capacitance
POWER REQUIREMENTS
AVDD
DVCC
Input Voltage
AVDD
DICC
Power Dissipation
1
Value1
0.8
±1
10
Unit
V max
μA max
pF typ
Test Conditions/Comments
0.4
0.6
3.6
V max
V typ
V min
10kΩ pull-up resistor to DVCC
@ 2.5 mA
10kΩ pull-up resistor to DVCC
0.5
DVCC-0.5
±TBD
V max
V min
ua max
Sinking 200ua
Sourcing 200ua
20
pF max
12 to 24
V min to V max
+/-10%
2.7 to 5.5
TBD
TBD
TBD
V min to V max
mA
mA max
mW typ
Internal supply disabled
Output unloaded
VIH = DVCC, VIL = GND, TBD mA typ
Per pin
Per pin
Temperature range: -40°C to +105°C; typical at +25°C.
TIMING CHARACTERISTICS
AVDD=12V (+/-10%) to +60V (MAX) , DVCC =2.7 V to 5.5 V, GND = 0 V. RL = 2 kΩ, CL = 200 pF, IOUT : RL = 300Ω,
50mH All specifications TMIN to TMAX, unless otherwise noted.
Table 3.
Parameter1, 2
t1
t2
t3
t4
t5
t6
t7
Limit at TMIN, TMAX
33
13
13
13
13
100
5
Unit
ns min
ns min
ns min
ns min
ns min
ns min
ns min
Description
SCLK cycle time
SCLK high time
SCLK low time
SYNC falling edge to SCLK falling edge setup time
16th SCLK falling edge to SYNC rising edge
Minimum SYNC high time (WRITE MODE)
Data setup time
Rev. PrA | Page 6 of 22
HL =
Preliminary Technical Data
t8
t10 , t9
t11
t12
t13
AD5751
0
1
200
25
1
ns min
μs max
ns min
ns max
us max
Data hold time
CLEAR pulse high/low activation time
Minimum SYNC high time (READ MODE)
SCLK rising edge to SDO valid (SDO CL=20pf )
CLEAR pulse low activation time
1 Guaranteed by characterization. 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.
200µA
TO OUTPUT
PIN
IOL
VOH(min)-VOL(max)
CL
15pF
2
200µA
IOH
SDO Load Timing.
Rev. PrA | Page 7 of 22
AD5751
Preliminary Technical Data
t1
SCLK
1
2
16
t2
t3
t6
t5
t4
SYNC
t8
t7
SDIN
DB15
DB0
CLEAR
t10
VOUT
t9
Figure 2. Write Mode Timing Diagram
16
1
2
A2
A1
SCLK
SYNC
SDIN
t11
A0
R=1
X
0
X
X
X
X
X
X
X
X
X
X
t12
SDO
X
X
X
X
X
R3
R2
R1
R0
CLRSEL OUTEN
Figure 3. Readback Mode Timing Diagram
Rev. PrA | Page 8 of 22
RSEL
PEC
Error
OVER
TEMP
IOUT
Fault
VOUT
Fault
Preliminary Technical Data
AD5751
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
REFIN/REFOUT to GND
+VSENSE to GND
VIN to GND
VOUT to GND
IOUT to GND
Operating Temperature Range
Industrial
Storage Temperature Range
Junction Temperature (TJ max)
32-Lead LFCSP Package
θJA Thermal Impedance
Lead Temperature
Soldering
Rating
−0.3V to 60v
−0.3 V to +7 V
−0.3 V to DVCC + 0.3 V or 7 V
(whichever is less)
−0.3 V to DVCC + 0.3 V or 7V
(whichever is less)
−0.3 V to +5 V
to AVDD
−0.3 V to +5 V
to AVDD
−0.3V to AVDD.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
−40°C to +105°C
−65°C to +150°C
125°C
28°C/W
JEDEC Industry Standard
J-STD-020
Rev. PrA | Page 9 of 22
Preliminary Technical Data
AD5751
TOP VIEW
24
23
22
21
20
19
18
17
VSENSE+
VOUT
GND
GND
COMP1
COMP2
IOUT
AVDD
AD2/R1
AD1/R2
AD0/R3
REXT2
REXT1
VREF
VIN
GND
NC = NO CONNECT
PIN 1
INDICATOR
9
10
11
12
13
14
15
16
SDO/VFAULT 1
CLRSEL 2
CLEAR 3
DVCC 4
GND 5
SYNC/RSEL 6
SCLK/OUTEN 7
SDIN/R0 8
00000-000
32
31
30
29
28
27
26
25
NC/IFAULT
FAULT/TEMP
RESET
HW SELECT
NC
NC
NC
NC
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Figure 4. LFCSP Pin Configuration
Table 5. Pin Function Descriptions
LFCSP Pin No.
1
Mnemonic
SDO/VFAULT
Description
In Software Mode, Serial Data Output. Used to clock data from the serial register in
readback mode. Data is clocked out on the rising edge of SCLK and is valid on the
falling edge of SCLK. Open Drain Output, must be connected to a pull up resistor.
In Hardware mode, acts as a SHORT circuit Fault alert pin. This pin is asserted low when
an SHORT circuit. Error is detected. Open drain output, must be connected to a pull-up
resistor.
2
CLRSEL
3
CLEAR
4
5
6
DVCC
GND
SYNC/RSEL
7
SCLK/OUTEN
8
SDIN/RO
9
10
AD2/R1
AD1/R2
In Hardware or software mode, selects the clear value, either zero-scale or mid-scale
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 mid-scale code of range selected (user-selectable). CLEAR is a LOGIC OR with the
internal CLEAR bit.
Digital Power Supply
Ground Connection.
In Software Mode, Positive edge sensitive latch, a rising edge will parallel load the input
shift register data into the INPUT register, also updating the output.
In Hardware mode, this pin chooses whether internal/external current sense resistor is
used
In Software Mode, Serial Clock Input. Data is clocked into the shift register on the falling
edge of SCLK. This operates at clock speeds up to 30 MHz.
In Hardware mode, this pin acts as an output enable pin.
In Software Mode, Serial Data Input. Data must be valid on the falling edge of SCLK.
In Hardware Mode, R0 is Range Decode Bit. This pin, in conjunction with R2, R3, R1
choose the output current/voltage range setting on the part.
In Software Mode, AD2 is Device Addressing bit. This pin, in conjunction with AD1, AD0
allow up to 8 devices to be addressed on one bus.
In Hardware Mode, R1 is Range Decode Bit. This pin, in conjunction with R2, R3, R0
choose the output current/voltage range setting on the part.
In Software Mode, AD1 is Device Addressing bit. This pin, in conjunction with AD2, AD0
allow up to 8 devices to be addressed on one bus.
Rev. PrA | Page 10 of 22
Preliminary Technical Data
LFCSP Pin No.
Mnemonic
11
AD0/R3
12
13
REXT1
REXT 2
14
15
16
17
18
19
20
21
22
23
24
25,26,27,28
29
VREF
VIN
GND
AVDD
IOUT
COMP1
COMP2
GND
GND
VOUT
+VSENSE
NC
HW SELECT
30
RESET
AD5751
Description
In Hardware Mode, R2 is Range Decode Bit. This pin, in conjunction with R3, R1, R0
choose the output current/voltage range setting on the part.
In Software Mode, AD0 is Device Addressing bit. This pin, in conjunction with AD1, AD2
allow up to 8 devices to be addressed on one bus.
In Hardware Mode, R3 is Range Decode Bit. This pin, in conjunction with R2, R1, R0
choose the output current/voltage range setting on the part.
An external current setting resistor can be connected to this pin to improve the IOUT
temperature drift performance.
When using the Internal RSET resistor these pins must be left floating.
Reference Input
Analog Input (0-4.096v)
Ground Connection.
Positive Analog Supply Pin.
Current Output Pin
Optional compensation capacitor connection for the voltage output buffer
Optional compensation capacitor connection for the voltage output buffer
Ground Connection.
Ground Connection.
Buffered Analog Output Voltage.
Sense connection for the positive voltage output load connection.
No Connect Pin. Can be tied to GND.
This part is used to configure the part to hardware/software mode.
HW SELECT = 0 selects Software Control.
HW SELECT = 1 selects Hardware Control.
In software mode, 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.
31
32
FAULT/TEMP
NC/IFAULT
In Software mode, acts as a general Fault alert pin. This pin is asserted low when an
open circuit, short circuit, over temperature or PEC Interface Error is detected. Open
drain output, must be connected to a pull-up resistor.
In Hardware mode, acts as an over temp FAULT pin. This pin is asserted low when an
over temperature Error is detected. Open drain output, must be connected to a pull-up
resistor.
In Hardware mode, acts as a OPEN circuit Fault alert pin. This pin is asserted low when
an OPEN circuit. Error is detected. Open drain output, must be connected to a pull-up
resistor.
In Software mode, is a NC. Tie to GND.
Rev. PrA | Page 11 of 22
AD5751
Preliminary Technical Data
TYPICAL PERFORMANCE CHARACTERISTICS
Figure 5.
Figure 8.
Figure 6.
Figure 9.
Figure 7.
Figure 10
Rev. PrA | Page 12 of 22
AD5751
Preliminary Technical Data
VDD AGND
LDO
AD5751
ADR392
VDD
MCU
SCLK
SDI
SDO
SYNC1
VSENSE+
VSENSE-
REFIN
VOUT
RANGE
SCALE
REFIN
VOUT
0-5V, 0-10V,
VIN
AD566X
IOUT
0-20ma, 0-24ma,
4-20ma.
IOUT
RANGE
SCALE
DVCC
HW SELECT
R3
R2
R1
OUTEN
TEMP
VFAULT* IFAULT*
R0
OUTPUT
RANGE
SELECT
PINS
Figure 12. Typical System Configuration in Hardware Mode. Pull up resistors not shown for open drain outputs.
Rev. PrA | Page 13 of 22
AD5751
Preliminary Technical Data
POWER ON STATE OF AD5751
CURRENT OUTPUT ARCHITECTURE
The voltage input from the analog input VIN core (0-4.096v) is
either converted to a current (see Figure 11) 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 12). The
Reference is used to provide internal offsets for range and gain
scaling. The selectable output range is programmable through
the digital interface.
R2
In software SPI mode, the part will power up with all outputs
disabled (OUTEN bit=0). In disabled mode, both the current
and voltage outputs are put into tri-state mode. The user will
have to set the OUTEN bit in the control register to enable the
output and in the same write the user will also set the output
range configuration using the range bits.
If hardware mode is selected, the part will power up to the
conditions defined by the range bits and the status of the
OUTEN pin. It is recommended to keep the output disabled
when powering up the part in hardware mode.
AVDD
RANGE DECODE
FROM INTERFACE
On Power-up, the AD5751 will sense whether hardware or
software mode is loaded and set the power up conditions
accordingly.
R3
T2
A2
VIN
VREF
IOUT
RANGE
SCALING
T1
A1
IOUT
The AD5750 contains a reset function.
R1
Figure 11. Current Output Configuration
RANGE DECODE
FROM INTERFACE
+VSENSE
VIN
(0-4.096V)
VOUT RANGE
SCALING
VREF
RESET:
VOUT
VOUT SHORT FAULT
In Software mode, the part can be reset using the RESET pin
(active low) or the RESET bit (RESET=1). A reset will disable
both the current and voltage outputs. The user will have to
write to the OUTEN bit to enable the output and in the same
write the user will also set the output range configuration. The
RESET pin is a level sensitive input - the part will stay in
RESET mode as long as RESET pin is low. The RESET bit
will clear to zero following a RESET command to the control
register.
-VSENSE
In hardware mode, there is no RESET. If using the part in
hardware mode the RESET pin should be tied high.
Figure 12. Voltage Output
Voltage Output Amplifier
The voltage output amplifier is capable of generating both
unipolar and bipolar output voltages. It is capable of driving a
load of 1 kΩ in parallel with 1.2 uF. The source and sink
capabilities of the output amplifier can be seen in Figure TBD.
The slew rate is 1 V/μs with a full-scale settling time of 10
μs.(10V step).
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 configuring the
end system as “one channel” output.
Driving Large Capacitive Loads
The voltage output amplifier is capable of driving capacative
loads of up to 1uF with the addition of a non-polarised 4nF
compensation capacitor between the CCOMP1 and CCOMP2 pins.
Without the compensation capacitor, up to 20nF capacitive
loads can be driven.
OUTEN
In Software mode, the output can be enabled/disabled using the
OUTEN bit in the control register. When the output is disabled,
both the current and voltage channels both go into tri-state. The
user will have to set the OUTEN bit to enable the output and at
this time the user will also set the output range configuration.
In Hardware mode, the output can be enabled/disabled using
the OUTEN pin. When the output is disabled, both the current
and voltage channels both go into tri-state. The user will have
to write to the OUTEN pin to enable the output. It is
recommended that the output be disabled when changing the
ranges.
Rev. PrA | Page 14 of 22
Preliminary Technical Data
AD5751
SOFTWARE CONTROL:
Software control is enabled by connecting the HW SELECT pin to ground. In software mode, the AD5751 is controlled over a versatile 3wire serial interface that operates at clock rates up to 30 MHz. It is compatible with SPI®, QSPI™, MICROWIRE™, and DSP standards 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 register consists of 16 control bits as shown in Table 5. The timing
diagram for this operation is shown in Figure 2. The first 3 bits of the Input Register are used to set the hardware address of the AD5751
device on the PCB board. Up to 8 devices can be addressed per board.
Bits D11, D1, D0 must always be set to 0 during any write or read sequence.
Table 3. Input Shift Register Format
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
RSEL
D2
RESET
D1
0
LSB
D0
0
Table 6. Input Shift Register Decoded
Register
A2, A1, A0
Used in association with External Pins AD2, AD1, AD0 to determine which part is
being addressed by the system controller.
A2
A1
A0
Function
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Addresses Part with pins AD2=0, AD1=0,
Addresses Part with pins AD2=0, AD1=0,
Addresses Part with pins AD2=0, AD1=1,
Addresses Part with pins AD2=0, AD1=1,
Addresses Part with pins AD2=1, AD1=0,
Addresses Part with pins AD2=1, AD1=0,
Addresses Part with pins AD2=1, AD1=1,
Addresses Part with pins AD2=1, AD1=1,
R/W
Indicates a read from or a write to the addressed register.
CLEAR
CLRSEL
Software Clear Bit – Active High.
Sets Clear Mode to zero scale or midscale. See Text.
CLRSEL
0
1
OUTEN
RSEL
Clear to Zero Volts
Clear to Mid Scale in Unipolar Mode, Clear to Zero Scale in Bipolar Mode.
Output Enable Bit. This bit must be set to 1 to enable the outputs.
Select Internal/External Current Sense Resistor.
RSEL
1
Select Internal Current Sense Resistor /*used with Range bits to select Range */
0
R3,R2,R1,R0
AD0=0
AD0=1
AD0=0
AD0=1
AD0=0
AD0=1
AD0=0
AD0=1
Select External Current Sense Resistor /*used with Range bits to select Range */
Selects output Configuration in conjunction with RSEL.
RSEL
R3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
R2
0
0
0
0
1
1
1
1
0
0
R1
0
0
1
1
0
0
1
1
0
0
R0
0
1
0
1
0
1
0
1
0
1
Output Configuration
4-20MA
External Current Sense Resistor 15k ohm.
0-20MA
External Current Sense Resistor 15k ohm.
0-24MA
External Current Sense Resistor 15k ohm.
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-5V
0-10V
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-6.0V (20% over range)
Rev. PrA | Page 15 of 22
AD5751
Preliminary Technical Data
0
1
0
1
0
1
0
1
0
1
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0-12.0V (20% over range)
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-40V
0-48V
4-20MA Internal Current Sense Resistor.
0-20MA Internal Current Sense Resistor.
0-24MA Internal Current Sense Resistor.
N/A. Output will revert to CLEAR condition.
N/A. Output will revert to CLEAR condition.
0-5V
0-10V
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-6.0V (20% over range)
0-12.0V (20% over range)
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
3.92ma – 20.4ma Internal Current Sense Resistor.
0ma – 20.4ma
Internal Current Sense Resistor.
0ma – 24.5ma
Internal Current Sense Resistor.
Resets the part to its Power on State
Reset
Readback Operation
Readback mode is invoked 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 AD5751 for a read operation, setting R/W to 1 will enable the SDO pin and SDO data will be clocked
out on the 5th rising edge of SCLK. After the data has been clocked out on SDO, a rising edge on SYNC will disable (tri- state) the SDO
pin once again. STATUS and CONTROL register data will be both available during the same read cycle. See Table 7 below.
Table 7. Input Shift Register Contents for a read operation
MSB
LSB
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A2
A1
A0
1
0
R3
R2
R1
R0
CLRSEL
OUTEN
RSEL
PEC Error Bit
OVER TEMP
IOUT Fault
Vout Fault
The STATUS bits are 5 read only bits. They are used to notify the user of specific fault conditions that have arisen, such as open or short
circuit on the output, over temperature, interface error or a range error. If any one of these fault conditions are set then a general fault
error bit is set (bit D5). This bit also sets a FAULT pin which can be used as a hardware interrupt to the controller.
Full explanation of fault conditions are given in the Features sections.
Table 9. STATUS Bits Options
Option
PEC ERROR
VOUT FAULT
IOUT FAULT
OVER TEMP
Description
Bit Set if there is an Interface Error detected by CRC-8 Error Checking. See features section.
Bit set if there is a short Circuit on VOUT pin.
Bit set is there is an open circuit on IOUT pin.
This bit will be set if the AD5750 core temperature exceeds approx. 150°C.
Rev. PrA | Page 16 of 22
Preliminary Technical Data
AD5751
HARDWARE CONTROL:
Hardware control is enabled by connecting the HW SELECT pin to DVCC. In this mode, pins R3,R2,R1,R0 along with RSEL pin are used
to configure the output range as per Table.
RSEL
R3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
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
4-20MA
External Current Sense Resistor 15k ohm.
0-20MA
External Current Sense Resistor 15k ohm.
0-24MA
External Current Sense Resistor 15k ohm.
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-5V
0-10V
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-6.0V (20% over range)
0-12.0V (20% over range)
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-40V
0-44V
4-20MA Internal Current Sense Resistor.
0-20MA Internal Current Sense Resistor.
0-24MA Internal Current Sense Resistor.
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-5V
0-10V
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
0-6.0V (20% over range)
0-12.0V (20% over range)
N/A. If selected output will drive 0V.
N/A. If selected output will drive 0V.
3.92ma – 20.4ma Internal Current Sense Resistor.
0ma – 20.4ma
Internal Current Sense Resistor.
0ma – 24.5ma
Internal Current Sense Resistor.
In hardware mode there is no status register. The fault conditions; open circuit, short circuit and over temperature are available on pins
IFAULT, VFAULT and TEMP. If any one of these fault conditions are set then 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 generate one interrupt to the system
controller to communicate a fault. If hardwired in this way, it will not be possible to isolate which fault occurred in the system.
Rev. PrA | Page 17 of 22
AD5751
Preliminary Technical Data
DEFAULT CONFIGURATION:
On initial power-up of the AD5751 the power-on-reset circuit ensures that all registers are loaded with zero-code, as such the default
output is the current output with the 4mA to 20mA range selected, the current output until a value is programmed is 0mA. The voltage
output pin will be in three-state. An alternative current range or a voltage output range may be selected via the CONTROL register.
Rev. PrA | Page 18 of 22
Preliminary Technical Data
AD5751
FEATURES
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.
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 control mode, the FAULT pin
is forced active high by any one of the following fault scenarios;
1)
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” since this would
require 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 one volt of remaining drive
capability. Thus the FAULT output activates slightly
before the compliance limit is reached. Since 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.
2)
A short is detected on the voltage output pin. Short
circuit current limited to 25ma.
3)
An interface error is detected due to the PEC error
checking failure. See PEC error checking section.
4)
A range change is detected without the user writing to
the Interface.
5)
If the core temperature of the AD5751 exceeds approx.
150°C.
OUTPUT FAULT ALERT – HARDWARE MODE
In Hardware mode, the AD5751 is equipped with 3 FAULT
pins, VFAULT, IFAULT, TEMP. These are an 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)
Open Circuit Detect. 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” since this
would require 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 one volt of
remaining drive capability. Thus the FAULT output
activates slightly before the compliance limit is
reached. Since the comparison is made within the
If this fault is detected the IFAULT pin is forced low.
2)
A short is detected on the voltage output pin. Short
circuit current limited to 25ma. If this fault is detected
the VFAULT pin is forced low.
3)
If the core temperature of the AD5751 exceeds approx.
150°C. If this fault is detected the TEMP pin is forced
low.
VOLTAGE OUTPUT SHORT CIRCUIT PROTECTION
Under normal operation the voltage output will sink/source
5mA and maintain specified operation. The maximum current
that the voltage output will deliver is 25mA, 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 mid-scale code, userselectable via the CLRSEL pin or the CLRSEL bit of the INPUT
register as described in Table 6. (The Clear select feature is a
logical OR function of the CLR SELECT pin and the CLRSEL
bit). The Current loop output will clear to the bottom of its
programmed range. It is necessary to maintain CLEAR high for a
minimum amount of time (see Figure 2) to complete the
operation. When the CLEAR signal is returned low, the output
returns to its programmed value or a new value if programmed.
A clear operation can also be performed via the CLEAR
command in the control register.
Table 11. CLEAR SELECT Options
CLR
SELECT
0
1
0
1
Rev. PrA | Page 19 of 22
Output CLR Value
Unipolar Output Voltage
Range
0V
Mid-Scale
Unipolar Current Output
Range
Zero-Scale e.g.
4ma on 4-20ma
0ma on 0-20ma etc...
Mid-Scale e.g.
12ma on 4-20ma
10ma on 0-20ma
AD5751
Preliminary Technical Data
EXTERNAL CURRENT SETTING RESISTOR
Referring to Figure 1, RSET is an internal sense resistor as part
of the voltage to current conversion circuitry. 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 RSET pin of the AD5751
to be used instead of the internal resistor RSET. The external
resistor is selected via the input register in software mode or by
setting the RSEL bit in hardware mode. If the external resistor
option is not used the RSET pin should be left floating.
OVER-RANGE MODES
The AD5751 contains an over range mode for most of the
available ranges. In voltage mode the over-range is typically
20% (10% for 0-40v range) and in current mode the over-range
is typically 2%. The overranges are selected by configuring R3,
R1, R1, R0 bits/pins accordingly.
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 polynomial
C(x) = x8 + x2 + x1 +1.
This is added to the end of the data word, and 24 data
bits are sent to the AD5751 before taking SYNC high.
If the AD5751 sees a 24-bit data frame, it will perform
the error check when SYNC goes high. If the check is valid,
then the data will be written to the selected register. If the error
check fails, the FAULT will go high and bit D4 of the Status
Register is set. After reading this register, this error flag is
cleared automatically and PEC goes high again.
UPDATE ON SYNC HIGH
SYNC
In voltage mode the overranges are typically 20% providing
programmable output ranges of 0-6v, 0-12v, 0-44v The 0-4.096v
analog input remains the same.
SCLK
MSB
D15
In current mode the overranges are typically 2%. In current
mode the overrange capability is only available on 3 ranges, 020ma, 0-24ma, 4-20ma. For these ranges the analog input will
also vary, according to the table below.
LSB
D0
16-BIT DATA
DIN
16-BIT DATA TRANSFER - NO ERROR CHECKING
UPDATE AFTER SYNC HIGH
ONLY IF ERROR CHECK PASSED
SYNC
SCLK
MSB
D23
Over Range
0-20.4ma
3.92-20.4ma
0-24.5ma
Analog Input
0.075v – 4.096v
0.06v-4.096v
0.065-4.096v
DIN
PEC
LSB
D8
16 BIT DATA
D0
D7
8-BIT FCS
PEC GOES LOW IF
ERROR CHECK FAILS
16-BIT DATA TRANSFER WITH ERROR CHECKING
PACKET ERROR CHECKING
Figure 13. PEC Error Checking Timing
To verify that data has been received correctly in noisy
Rev. PrA | Page 20 of 22
Preliminary Technical Data
AD5751
APPLICATIONS INFORMATION
separate ground plane, but separating the lines helps). It is
essential to minimize noise on the REFIN line.
TRANSIENT VOLTAGE PROTECTION
The AD5751 contains ESD protection diodes which prevent
damage from normal handling. The industrial control
environment can, however, subject I/O circuits to much higher
transients. In order 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 15. 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 – 2.0V and the two protection diodes
and resistor must have appropriate power ratings.
AVDD
AVDD
AD5751
IOUT
RP
RLOAD
Figure 15. Output Transient Voltage Protection
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 printed circuit board on which the
AD5751 is mounted should be designed so that the AD5751 lies
on the analog plane.
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 capacitor
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.
The power supply lines of the AD5751 should use as large a
trace as possible to provide low impedance paths and reduce the
effects of glitches on the power supply line. Fast switching
signals such as clocks should be shielded with digital ground to
avoid radiating noise to other parts of the board and should
never be run near the reference inputs. A ground line routed
between the SDIN and SCLK lines helps reduce crosstalk
between them (not required on a multilayer board that has a
Avoid crossover of digital and analog signals. Traces on
opposite sides of the board should run at right angles to each
other. This reduces the effects of feed through the board. A
microstrip technique is by far the best, but not always possible
with a double-sided board. In this technique, the component
side of the board is dedicated to ground plane, while signal
traces are placed on the solder side.
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 might occur. The
iCoupler® family of products from Analog Devices provides
voltage isolation in excess of 2.5 kV. The serial loading structure
of the AD5751 make it ideal for isolated interfaces because the
number of interface lines is kept to a minimum. Figure 16 shows
a 4-channel isolated interface to the AD5751 using an
ADuM1400. For further information, visit
http://www.analog.com/icouplers.
Controller
Serial Clock Out
Serial Data Out
SYNC Out
Control out
ADuM1400 *
VIA
VIB
VIC
VID
ENCODE
ENCODE
ENCODE
ENCODE
DECODE
DECODE
DECODE
DECODE
VOA
VOB
VOC
VOD
To SCLK
To SDIN
To SYNC
To CLEAR
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure16. Isolated Interface
MICROPROCESSOR INTERFACING
Microprocessor interfacing to the AD5751 is via a serial bus that
uses protocol compatible with microcontrollers and DSP
processors. The communications channel is a 3-wire
(minimum) interface consisting of a clock signal, a data signal,
and a sync signal. The AD5751 require a 16-bit data-word with
data valid on the falling edge of SCLK.
Rev. PrA | Page 21 of 22
AD5751
Preliminary Technical Data
OUTLINE DIMENSIONS
0.60 MAX
5.00
BSC SQ
0.60 MAX
PIN 1
INDICATOR
TOP
VIEW
0.50
BSC
4.75
BSC SQ
0.50
0.40
0.30
12° MAX
1.00
0.85
0.80
PIN 1
INDICATOR
25
24
32
1
3.25
3.10 SQ
2.95
EXPOSED
PAD
(BOTTOM VIEW)
17
16
9
8
0.25 MIN
3.50 REF
0.80 MAX
0.65 TYP
0.05 MAX
0.02 NOM
SEATING
PLANE
0.30
0.23
0.18
0.20 REF
COPLANARITY
0.08
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2
Figure 17. 32-Lead Lead Frame Chip Scale Package
(CP-32-2)
Dimensions shown in millimeters
ORDERING GUIDE
Model
AD5751BCPZ
Temperature Range
-40°C to 105°C
Package Description
32 Lead LFCSP
Rev. PrA | Page 22 of 22
Package Option
CP-32-2
PR07269-0-5/08(PrA)
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