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 Information furnished by Analog Devices is believed to be accurate and reliable. However, no 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 registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com 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)