16-Channel, 16/14-Bit, Serial Input, Voltage-Output DAC AD5360/AD5361 Preliminary Technical Data SPI compatible serial interface 2.5 V to 5.5 V digital interface Power-on reset Digital reset (RESET) Clear function to user-defined SIGGND (CLR pin) Simultaneous update of DAC outputs (LDAC pin) FEATURES 16-channel DAC in 52-LQFP and 56-LFCSP Guaranteed monotonic to 16/14 bits Nominal output voltage range of -10 V to +10 V Multiple output spans available Temperature Monitoring Function Channel Monitoring Multiplexer GPIO Function System calibration function allowing user-programmable offset and gain Channel grouping and addressing features Data error checking feature APPLICATIONS Instrumentation Industrial control systems Level setting in automatic test equipment (ATE) Variable optical attenuators (VOA) Optical Line Cards FUNCTIONAL BLOCK DIAGRAM DVCC TEMP_OUT PEC VDD TEMP SENSOR 8 CONTROL REGISTER MON_IN0 n 6 MUX n n n MON_OUT 2 GPIO GPIO REGISTER BIN/2SCOMP n SYNC n n SDI SCLK SERIAL INTERFACE AGND DNGD LDAC VREF0 AD5360, n = 16 AD5361, n = 14 8 VOUT0 VOUT15 MON_IN1 VSS n A/B SELECT REGISTER 14 8 X1A REGISTER TO MUX 2's MUX 1 X1B REGISTER n X2A REGISTER X2B REGISTER n · · · · · · n C REGISTER ·· ·· · · ·· ·· · · X1A REGISTER MUX 1 X1B REGISTER n ·· · · · · ·· · ·· · n X2A REGISTER X2B REGISTER n M REGISTER GROUP 0 BUFFER OFFSET DAC 0 BUFFER n M REGISTER 14 OFS0 REGISTER MUX n 2 · · · · · · MUX n 2 DAC 0 REGISTER · · · · · · DAC 7 REGISTER OUTPUT BUFFER AND POWER DOWN CONTROL VOUT0 DAC 0 · · · · · · · · · · · · VOUT2 VOUT7 DAC 7 OUTPUT BUFFER AND POWER DOWN CONTROL n n BUSY RESET n CLR n n STATE MACHINE n n POWER-ON RESET AD5360/ AD5361 n n n n X1A REGISTER X1B REGISTER 8 TO MUX 2's MUX 1 n · · · · ·· X1A REGISTER MUX 1 M REGISTER X2A REGISTER X2B REGISTER n n · · ·· ·· · · · · · · X2A REGISTER MUX 2 · ·· ·· · n X2B REGISTER n MUX n 2 · · · · · · n · ·· ·· · X1B REGISTER VOUT5 VOUT6 SIGGND0 OFS1 REGISTER 14 VREF1 OFFSET DAC 1 BUFFER n M REGISTER C REGISTER VOUT4 GROUP 1 14 A/B SELECT REGISTER VOUT3 n C REGISTER SDO 8 VOUT1 n n DAC 0 REGISTER · · · · · · n DAC 7 REGISTER OUTPUT BUFFER AND POWER DOWN CONTROL VOUT8 · · · · · · · · · · · · VOUT10 DAC 7 OUTPUT BUFFER AND POWER DOWN CONTROL DAC 0 VOUT9 VOUT11 VOUT12 VOUT13 VOUT14 VOUT15 SIGGND1 5360-0001 n C REGISTER Figure 1. AD5360/AD5361—Protected by U.S. Patent No. 5,969,657; other patents pending Rev. PrF 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 companies. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. www.analog.com Tel: 781.329.4700 Fax: 781.326.8703 © 2006 Analog Devices, Inc. All rights reserved. AD5360/AD5361 Preliminary Technical Data TABLE OF CONTENTS General Description ......................................................................... 3 Clear Function ............................................................................ 16 Specifications..................................................................................... 4 BUSY and LDAC Functions...................................................... 16 AC Characteristics........................................................................ 5 Monitor Function....................................................................... 17 Timing Characteristics ................................................................ 6 GPIO Pin ..................................................................................... 17 Absolute Maximum Ratings............................................................ 8 Power-Down Mode.................................................................... 17 ESD Caution.................................................................................. 8 Thermal Monitoring Function ................................................. 17 Pin Configuration and Function Descriptions............................. 9 Toggle Mode................................................................................ 17 Terminology .................................................................................... 11 Serial Interface ................................................................................ 18 Functional Description .................................................................. 12 SPI Write Mode .......................................................................... 18 DAC Architecture—General..................................................... 12 Register Update Rates ................................................................ 18 Channel Groups.......................................................................... 12 SPI Readback Mode ................................................................... 19 A/ B Registers Gain/Offset Adjustment .................................. 13 Channel Addressing And Special Modes................................ 19 Offset DACS................................................................................ 13 Special Function Mode.............................................................. 20 Output Amplifier........................................................................ 14 Power Supply Decoupling ......................................................... 22 Transfer Function ....................................................................... 14 Power Supply Sequencing ......................................................... 22 Reference Selection .................................................................... 14 Interfacing Examples ................................................................. 23 Calibration................................................................................... 15 Outline Dimensions ....................................................................... 24 AD5360 Calibration Example................................................... 15 Ordering Guide .......................................................................... 24 Reset Function ............................................................................ 15 REVISION HISTORY Pr B2. Modified SPI Timing Diagrams Added Reference Selection and Calibration text Pr F rewrote calibration section Changed SPI read diagram Rev. PrF | Page 2 of 25 Preliminary Technical Data AD5360/AD5361 GENERAL DESCRIPTION The AD5360/AD5361 contains 16, 16/14-bit DACs in a single, 56-lead, LFCSP or 52-lead LQFP package. It provides buffered voltage outputs with a span 4 times the reference voltage. The gain and offset of each DAC can be independently trimmed to remove errors. For even greater flexibility, the device is divided into two groups of 8 DACs, and the output range of each group can be independently adjusted by an offset DAC. The AD5360/AD5361 offers guaranteed operation over a wide supply range with VSS from -4.5 V to -16.5 V and VDD from +8 V to +16.5 V. The output amplifier headroom requirement is 1.4 V operating with a load current of 1 mA. The AD5360/AD5361 has a high-speed 4-wire serial interface, which is compatible with SPI®, QSPI™, MICROWIRE™, and DSP interface standards and can handle clock speeds of up to 50 MHz. All the outputs can be updated simultaneously by taking the LDAC input low. Each channel has a programmable gain and an offset adjust register. Each DAC output is amplified and buffered on-chip with respect to an external SIGGND input. The DAC outputs can also be switched to SIGGND via the CLR pin. Table 1. High Channel Count Bipolar DACs Model Resolution Nominal Output Span Output Channels Linearity Error (LSB) Package Description Package Option AD5360BCPZ AD5360BSTZ AD5361BCPZ AD5361BSTZ AD5362BCPZ AD5362BSTZ AD5363BCPZ AD5363BSTZ AD5370BCPZ AD5370BSTZ AD5371BCPZ AD5371BSTZ AD5372BCPZ AD5372BSTZ AD5373BCPZ AD5373BSTZ 16 Bits 16 Bits 14 Bits 14 Bits 16 Bits 16 Bits 14 Bits 14 Bits 16 Bits 16 Bits 14 Bits 14 Bits 16 Bits 16 Bits 14 Bits 14 Bits 4 × VREF (20 V) 4 × VREF (20 V) 4 × VREF (20 V) 4 × VREF (20 V) 4 × VREF (20 V) 4 × VREF (20 V) 4 × VREF (20 V) 4 × VREF (20 V) 4 × VREF (12 V) 4 × VREF (12 V) 4 × VREF (12 V) 4 × VREF (12 V) 4 × VREF (12 V) 4 × VREF (12 V) 4 × VREF (12 V) 4 × VREF (12 V) 16 16 16 16 8 8 8 8 40 40 40 40 32 32 32 32 ±4 ±4 ±1 ±1 ±4 ±4 ±1 ±1 ±4 ±4 ±2 ±2 ±4 ±4 ±2 ±2 56-Lead LFCSP 52-Lead LQFP 56-Lead LFCSP 52-Lead LQFP 56-Lead LFCSP 52-Lead LQFP 56-Lead LFCSP 52-Lead LQFP 64-Lead LFCSP 64-Lead LQFP 100-Ball CSPBGA 80-Lead LQFP 56-Lead LFCSP 64-Lead LQFP 56-Lead LFCSP 64-Lead LQFP CP-56 ST-52 CP-56 ST-52 CP-56 ST-52 CP-56 ST-52 CP-64 ST-64 BC-100-2 ST-80 CP-56 ST-64 CP-56 ST-64 Rev. PrF | Page 3 of 25 AD5360/AD5361 Preliminary Technical Data SPECIFICATIONS DVCC = 2.3 V to 5.5 V; VDD = 11.4 V to 16.5 V; VSS = −11.4 V to −16.5 V; VREF = 5 V; AGND = DGND = SIGGND = 0 V; RL = Open Circuit; Gain (m), Offset(c) and DAC Offset registers at default value; all specifications TMIN to TMAX, unless otherwise noted.; Table 2. Performance Specifications B Version1 Unit Test Conditions/Comments1 Differential Nonlinearity Offset Error Gain Error Offset Error2 Gain Error2 Gain Error of Offset DAC 16 14 ±4 ±1 ±1 ±20 ±20 100 100 ±35 Bits Bits LSB max LSB max LSB max mV max mV max µV max µV max mV max VOUT Temperature Coefficient DC Crosstalk1 5 0.5 ppm FSR/°C typ mV max AD5360 AD5361 AD5360 AD5361 Guaranteed monotonic by design over temperature. Prior to calibration Prior to calibration After calibration After calibration Positive or Negative Full Scale. See Offset DACS section for details Includes linearity, offset, and gain drift. Typically 100 µV. Measured channel at mid-scale, fullscale change on any other channel 1 60 2/5 MΩ min nA max V min/max Typically 100 MΩ. Per input. Typically ±30 nA. ±2% for specified operation. 55 ±0.5 kΩ min V min/max Typically 60 kΩ. VSS + 1.4 VDD − 1.4 −10 to +10 10 ±1 2200 0.5 V min V max V mA max mA max pF max Ω max ILOAD = 1 mA. ILOAD = 1 mA. 500 100 2 Ω typ nA typ mA max 1.7 2.0 0.8 0.7 ±1 10 V min V min V max V µA max pF max 0.5 DVCC − 0.5 ±5 10 V max V min µA max pF typ Parameter ACCURACY Resolution Relative Accuracy REFERENCE INPUTS (VREF0, VREF1)1 VREF DC Input Impedance VREF Input Current VREF Range4 SIGGND INPUT (SIGGND0, TO SIGGND1)1 DC Input Impedance Input Range OUTPUT CHARACTERISTICS1 Output Voltage Range Nominal Output Voltage Range Short Circuit Current Load Current Capacitive Load DC Output Impedance MONITOR PIN (MON_OUT) Output Impedance Three State Leakage Current Continuous Current Limit DIGITAL INPUTS Input High Voltage Input Low Voltage Input Current Input Capacitance1 DIGITAL OUTPUTS (SDO, BUSY, GPIO, PEC) Output Low Voltage Output High Voltage (SDO) High Impedance Leakage Current High Impedance Output Capacitance Rev. PrF | Page 4 of 25 JEDEC compliant. DVCC = 2.3 V to 3.6 V. DVCC = 3.6 V to 5.5 V. DVCC = 2.5 V to 5.5 V. DVCC = 2.3 V to 2.7 V. All other digital input pins. Sinking 200 µA. Sourcing 200 µA. SDO only. Preliminary Technical Data Parameter TEMPERATURE SENSOR (TMP_OUT) Accuracy Output Voltage at 25 °C Output Voltage Scale Factor Output Voltage Range Output Load Current Power On Time POWER REQUIREMENTS DVCC VDD VSS Power Supply Sensitivity1 ∆ Full Scale/∆ VDD ∆ Full Scale/∆ VSS ∆ Full Scale/∆ VCC DICC IDD ISS Power Dissipation Power Dissipation Unloaded (P) Junction Temperature AD5360/AD5361 B Version1 Unit Test Conditions/Comments1 ±1 ±5 1.5 5 0/3 200 10 °C °C max V typ mV/°C typ V min/max µA max ms typ @25 °C -40 °C < T < +85°C 2.3/5.5 8/16.5 −4.5/−16.5 V min/max V min/max V min/max −75 −75 −90 2 7 7 dB typ dB typ dB typ mA max mA max mA max VCC = 5.5 V, VIH = VCC, VIL = GND. Outputs unloaded. Outputs unloaded. 173 130 mW °C max VSS = -12 V, VDD = +12 V, DVCC = 2.5 V TJ = TA + PTOTAL × θJ3 Current source only. To within ±5 °C 1 Temperature range for B Version: -40°C to +85°C. Typical specifications are at 25°C. Guaranteed by design and characterization, not production tested. 3 Where θJ represents the package thermal impedance. 4 . Specifications are guaranteed for a 5V reference only. 2 AC CHARACTERISTICS DVCC = 2.5 V; VDD = 15 V; VSS = −15 V; VREF = 5 V; AGND = DGND = SIGGND = 0 V; RL = 10 kΩ to GND; CL = 200 pF to GND; Gain (m), Offset(c) and DAC Offset registers at default values; all specifications TMIN to TMAX, unless otherwise noted. Table 3. AC Characteristics Parameter DYNAMIC PERFORMANCE Output Voltage Settling Time Slew Rate Digital-to-Analog Glitch Energy Glitch Impulse Peak Amplitude Channel-to-Channel Isolation DAC-to-DAC Crosstalk Digital Crosstalk Digital Feedthrough Output Noise Spectral Density @ 10 kHz 1 2 B Version1,2 Unit Test Conditions/Comments TBD 30 1 20 10 100 40 10 0.1 1 250 µs typ µs max V/µs typ nV-s typ mV max dB typ nV-s typ nV-s typ nV-s typ nV-s typ nV/(Hz)1/2 typ Full-scale change DAC latch contents alternately loaded with all 0s and all 1s. Between DACs inside a group. Between DACs from different groups. Effect of input bus activity on DAC output under test. VREF = 0 V. Temperature range for B Version: -40°C to +85°C. Typical specifications are at 25°C. Guaranteed by design and characterization, not production tested. Rev. PrF | Page 5 of 25 AD5360/AD5361 Preliminary Technical Data TIMING CHARACTERISTICS DVCC = 2.3 V to 5.5 V; VDD = 8 V to 16.5 V; VSS = −4.5 V to −16.5 V; VREF = 5 V; AGND = DGND = SIGGND = 0 V;RL = Open Circuit; Gain (m), Offset(c) and DAC Offset registers at default value; all specifications TMIN to TMAX, unless otherwise noted. SPI INTERFACE (Figure 4 and Figure 5) Parameter1, 2, 3 t1 t2 t3 t4 t5 t6 t7 t8 t93 Limit at TMIN, TMAX 20 8 8 11 20 10 5 5 t10 42 Unit ns min ns min ns min ns min ns min ns min ns min ns min ns max Description SCLK Cycle Time. SCLK High Time. SCLK Low Time. SYNC Falling Edge to SCLK Falling Edge Setup Time. Minimum SYNC High Time. 24th SCLK Falling Edge to SYNC Rising Edge. Data Setup Time. Data Hold Time. SYNC Rising Edge to BUSY Falling Edge. 1.25 µs max t11 t12 t13 t14 500 20 10 3 ns max ns min ns min BUSY Pulse Width Low (Single-Channel Update.) See Table 7. Single-Channel Update Cycle Time 24th SCLK Falling Edge to LDAC Falling Edge. LDAC Pulse Width Low. BUSY Rising Edge to DAC Output Response Time. t15 t16 0 3 µs max t17 t18 t19 t20 20/30 125 30 400 µs typ/max ns max ns min µs max t21 t225 270 25 ns min ns max µs max ns min BUSY Rising Edge to LDAC Falling Edge. LDAC Falling Edge to DAC Output Response Time. DAC Output Settling Time. CLR/RESET Pulse Activation Time. RESET Pulse Width Low. RESET Time Indicated by BUSY Low. Minimum SYNC High Time in Readback Mode. SCLK Rising Edge to SDO Valid. 1 Guaranteed by design and characterization, not production tested. All input signals are specified with tr = tf = 2 ns (10% to 90% of VCC) and timed from a voltage level of 1.2 V. 3 See Figure 4 and Figure 5. 4 This is measured with the load circuit of Figure 2. 5 This is measured with the load circuit of Figure 3. 2 V CC 200µA RL TO OUTPUT PIN 2.2kΩ TO OUTPUT PIN CL IOL V OH (min) - V OL (max) 2 50pF V OL CL 50pF 200µA Figure 2. Load Circuit for BUSY Timing Diagram IOL Figure 3. Load Circuit for SDO Timing Diagram Rev. PrF | Page 6 of 25 Preliminary Technical Data AD5360/AD5361 t1 SCLK 1 24 2 t3 24 t11 t4 SYNC 1 t2 t6 t5 t7 t8 SDI DB0 DB23 t9 t10 BUSY t12 t13 LDAC1 t17 t14 VOUT1 t15 t13 LDAC2 t17 VOUT2 t16 CLR t18 VOUT t19 RESET VOUT t18 t20 05814-004A BUSY 1LDAC ACTIVE DURING BUSY. 2LDAC ACTIVE AFTER BUSY. Figure 4. SPI Write Timing t22 SCLK 48 24 t21 SYNC SDI DB23 DB0 INPUT WORD SPECIFIES REGISTER TO BE READ NOP CONDITION DB0 SDO DB0 DB23 DB23 DB0 5371-0005D LSB FROM PREVIOUS WRITE Figure 5. SPI Read Timing Rev. PrF | Page 7 of 25 SELECTED REGISTER DATA CLOCKED OUT AD5360/AD5361 Preliminary Technical Data ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Transient currents of up to 100 mA do not cause SCR latch-up. Table 4. Absolute Maximum Ratings Parameter VDD to AGND VSS to AGND DVCC to DGND Digital Inputs to DGND Digital Outputs to DGND VREF0, VREF1 to AGND VOUT0–VOUT15 to AGND SIGGND to AGND AGND to DGND Operating Temperature Range (TA) Industrial (B Version) Storage Temperature Range Junction Temperature (TJ max) Reflow Soldering Peak Temperature Time at Peak Temperature Rating −0.3 V to +17 V −17 V to +0.3 V −0.3 V to +7 V −0.3 V to VCC + 0.3 V −0.3 V to VCC + 0.3 V −0.3 V to +5.5 V VSS − 0.3 V to VDD + 0.3 V ±1 V −0.3 V to +0.3 V Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only, and functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. -40°C to +85°C −65°C to +150°C 150°C 230°C 10 s to 40 s ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Rev. PrF | Page 8 of 25 Preliminary Technical Data AD5360/AD5361 VOUT5 VOUT7 VOUT6 DVCC DGND SCLK SYNC PEC SDI DVCC 39 38 PIN 1 INDICATOR VOUT4 SIGGND0 RESET 3 BIN/2SCOMP 4 BUSY GPIO 5 MON_OUT 7 MON_IN0 8 NC NC 10 30 VDD 11 29 VSS 12 28 VSS VDD VREF1 13 27 NC NC = NO CONNECT 37 36 35 AD5360/ AD5361 TOP VIEW (Not to scale) 6 9 34 33 32 31 VOUT3 VOUT2 VOUT1 VOUT0 TEMP_OUT MON_IN1 VREF0 NC Figure 6. 56 Lead LFCSP Pin Configuration NC NC NC VOUT14 VOUT15 VOUT12 VOUT13 NC = NO CONNECT NC NC 15 NC 16 VOUT8 17 VOUT9 18 VOUT10 19 VOUT11 20 SIGGND1 21 VOUT12 22 VOUT13 23 VOUT14 24 VOUT15 25 NC 26 NC 27 NC 28 2 VOUT11 VOUT5 VOUT4 SIGGND0 VOUT3 VOUT2 VOUT1 VOUT0 TEMP_OUT MON_IN1 VREF0 NC NC VSS VDD CLR SIGGND1 AD5360/ AD5361 TOP VIEW (Not to scale) 42 41 40 39 38 37 36 35 34 33 32 31 30 29 1 VOUT10 PIN 1 INDICATOR 52 51 50 49 48 47 46 45 44 43 42 41 40 LDAC VOUT8 VOUT9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 SDO AGND 56 CLR 55 LDAC 54 AGND 53 DGND 52 DVCC 51 SDO 50 PEC 49 SDI 48 SCLK 47 SYNC 46 DVCC 45 DGND 44 VOUT7 43 VOUT6 RESET BIN/2SCOMP BUSY GPIO MON_OUT MON_IN0 NC NC NC NC NC VDD VSS VREF1 DGND PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 7. 52 Lead LQFP Pin Configuration Table 5. Pin Function Descriptions Pin Name DVCC VSS VDD AGND DGND SIGGND0 SIGGND1 VREF0 VREF1 VOUT0 to VOUT15 SYNC SCLK SDI SDO LDAC BUSY Function Logic Power Supply; 2.3 V to 5.5 V. These pins should be decoupled with 0.1 µF ceramic capacitors and 10 µF capacitors. Negative Analog Power Supply; −11.4 V to −16.5 V for specified performance. These pins should be decoupled with 0.1 µF ceramic capacitors and 10 µF capacitors. Positive Analog Power Supply; +11.4 V to +16.5 V for specified performance. These pins should be decoupled with 0.1 µF ceramic capacitors and 10 µF capacitors. Ground for All Analog Circuitry. All AGND pins should be connected to the AGND plane. Ground for All Digital Circuitry. All DGND pins should be connected to the DGND plane. Reference Ground for DACs 0 to 7. VOUT0 to VOUT7 are referenced to this voltage. Reference Ground for DACs 8 to 15. VOUT8 to VOUT15 are referenced to this voltage. Reference Input for DACs 0 to 7. This voltage is referred to AGND. Reference Input for DACs 8 to 15. This voltage is referred to AGND. DAC Outputs. Buffered analog outputs for each of the 16 DAC channels. Each analog output is capable of driving an output load of 10 kΩ to ground. Typical output impedance of these amplifiers is 0.5 Ω. Active Low or SYNC Input for SPI Interface. This is the frame synchronization signal for the SPI serial interface. See SPI timing diagrams and descriptions for more details. Serial Clock Input for SPI Interface. See SPI timing diagrams and descriptions for more details. Serial Data Input for SPI Interface. See SPI timing diagrams and descriptions for more details. Serial Data Output for SPI Interface. See SPI timing diagrams and descriptions for more details. Load DAC Logic Input (Active Low). See the BUSY AND LDAC FUNCTIONS section for more information. RESET Digital Input/Open-Drain Output. BUSY is open-drain when an output. See the BUSY AND LDAC FUNCTIONS section for more information Asynchronous Digital Reset Input CLR Asynchronous clear input (level sensitive, active low). See the Clear Function section for more information PEC Packet Error Check output. This is an open-drain output with a 50 kΩ pullup, that goes low if the packet error check fails. Provides an output voltage proportional to chip temperature. This is typically 1.5 V at 25 C with an output variation of 5 mV/C. Analog multiplexer output. Any DAC output or the MON_IN0 or the MON_IN1 input can be switched to this output. Analog multiplexer inputs, which can be switched to MON_OUT. TEMP_OUT MON_OUT MON_IN0, MON_IN1 Rev. PrF | Page 9 of 25 AD5360/AD5361 Pin Name GPIO BIN/2SCOMP EXPOSED PADDLE Preliminary Technical Data Function Digital I/O pin. This pin can be configured as an input or output that can be read or programmed high or low via the serial interface. When configured as an input it has a weak pulldown. Digital input, sets the DAC coding. 0 = offset binary, 1 = 2’s complement. This input has a weak pulldown. The Lead Free Chip Scale Package (LFCSP) has an exposed paddle on the underside. This should be connected to VSS Rev. PrF | Page 10 of 25 Preliminary Technical Data AD5360/AD5361 TERMINOLOGY Relative Accuracy Relative accuracy, or endpoint linearity, is a measure of the maximum deviation from a straight line passing through the endpoints of the DAC transfer function. It is measured after adjusting for zero-scale error and full-scale error and is expressed in least significant bits (LSB). Differential Nonlinearity Differential nonlinearity is the difference between the measured change and the ideal 1 LSB change between any two adjacent codes. A specified differential nonlinearity of 1 LSB maximum ensures monotonicity. Zero-Scale Error Zero-scale error is the error in the DAC output voltage when all 0s are loaded into the DAC register. Zero-scale error is a measure of the difference between VOUT (actual) and VOUT (ideal) expressed in mV. Zero-scale error is mainly due to offsets in the output amplifier. Full-Scale Error Full-scale error is the error in DAC output voltage when all 1s are loaded into the DAC register. Full-scale error is a measure of the difference between VOUT (actual) and VOUT (ideal) expressed in mV. It does not include zero-scale error. Gain Error Gain error is the difference between full-scale error and zero-scale error. It is expressed in mV. Gain Error = Full-Scale Error − Zero-Scale Error VOUT Temperature Coefficient This includes output error contributions from linearity, offset, and gain drift. DC Output Impedance DC output impedance is the effective output source resistance. It is dominated by package lead resistance. DC Crosstalk The DAC outputs are buffered by op amps that share common VDD and VSS power supplies. If the dc load current changes in one channel (due to an update), this can result in a further dc change in one or more channel outputs. This effect is more significant at high load currents and reduces as the load currents are reduced. With high impedance loads, the effect is virtually immeasurable. Multiple VDD and VSS terminals are provided to minimize dc crosstalk. Output Voltage Settling Time The amount of time it takes for the output of a DAC to settle to a specified level for a full-scale input change. Digital-to-Analog Glitch Energy The amount of energy injected into the analog output at the major code transition. It is specified as the area of the glitch in nV-s. It is measured by toggling the DAC register data between 0x1FFF and 0x2000. Channel-to-Channel Isolation Channel-to-channel isolation refers to the proportion of input signal from one DAC’s reference input that appears at the output of another DAC operating from another reference. It is expressed in dB and measured at midscale. DAC-to-DAC Crosstalk DAC-to-DAC crosstalk is the glitch impulse that appears at the output of one converter due to both the digital change and subsequent analog output change at another converter. It is specified in nV-s. Digital Crosstalk The glitch impulse transferred to the output of one converter due to a change in the DAC register code of another converter is defined as the digital crosstalk and is specified in nV-s. Digital Feedthrough When the device is not selected, high frequency logic activity on the device’s digital inputs can be capacitively coupled both across and through the device to show up as noise on the VOUT pins. It can also be coupled along the supply and ground lines. This noise is digital feedthrough. Output Noise Spectral Density Output noise spectral density is a measure of internally generated random noise. Random noise is characterized as a spectral density (voltage per √Hz). It is measured by loading all DACs to midscale and measuring noise at the output. It is 1/2 measured in nV/(Hz) . Rev. PrF | Page 11 of 25 AD5360/AD5361 Preliminary Technical Data FUNCTIONAL DESCRIPTION DAC ARCHITECTURE—GENERAL The AD5360/AD5361 contains 16 DAC channels and 16 output amplifiers in a single package. The architecture of a single DAC channel consists of a 16-bit resistor-string DAC in the case of the AD5360 and a 14-bit DAC in the case of the AD5361, followed by an output buffer amplifier. The resistor-string section is simply a string of resistors, each of value R, from VREF to AGND. This type of architecture guarantees DAC monotonicity. The 16(14)-bit binary digital code loaded to the DAC register determines at which node on the string the voltage is tapped off before being fed into the output amplifier. The output amplifier multiplies the DAC out voltage by 4. The output span is 12 V with a 3 V reference and 20 V with a 5 V reference. CHANNEL GROUPS The 16 DAC channels of the AD5360/AD5361 are arranged into two groups of 8 channels. The eight DACs of Group 0 derive their reference voltage from VREF0, and those of Group 1 from VREF1. Table 6. AD5360(AD5361) Registers Register Name Word Length (Bits) Description X1A (group)(channel) 16(14) Input data register A, one for each DAC channel. X1B (group) (channel) 16(14) Input data register B, one for each DAC channel. M (group) (channel) 16(14) Gain trim registers, one for each DAC channel. C (group) (channel) 16(14) Offset trim registers, one for each DAC channel. X2A (group)(channel) 16(14) Output data register A, one for each DAC channel. These registers store the final, calibrated DAC data after gain and offset trimming. They are not readable, nor directly writable. X2B (group) (channel) 16(14) Output data register B, one for each DAC channel. These registers store the final, calibrated DAC data after gain and offset trimming. They are not readable, nor directly writable. DAC (group) (channel) OFS0 Data registers from which the DACs take their final input data. The DAC registers are updated from the X2A or X2B registers. They are not readable, nor directly writable. 14 Offset DAC 0 data register, sets offset for Group 0. OFS1 14 Offset DAC 1 data register, sets offset for Group 1. Control 8 Bit 4 = Overtemperature indicator. 1 = chip temperature > 130 °C. Bit 3 = PEC error flag. 1 = PEC error. Cleared on reading control register. Bit 2 = A/B. 0 = global selection of X1A input data registers. 1 = X1B registers. Bit 1 = Enable Temp Shutdown. 0 = disable temp shutdown. 1 = enable. Bit 0 = Soft Power Down. 0 = soft power up. 1 = soft power down. Monitor 6 GPIO 2 Bit 5 = Monitor enable. 0 = off. 1 = on. Bit 4 = 0, DAC selected by bits 3 to 0. Bits 3 – 0 = DAC channel 0000 = 0 to 1111 = 15. Bit 4 = 1, MON_IN pin selected by bit 0. Bit 0 = MON_IN select. 0 = MON_IN0. 1 = MON_IN1. Bit 1 = GPIO configuration. 0 = input. 1 = output. Bit 0 = GPIO data. Stores state of GPIO pin when input. Drives GPIO pin when output. Rev. PrF | Page 12 of 25 Preliminary Technical Data AD5360/AD5361 X1A REGISTER X2A REGISTER MUX MUX X1B REGISTER X2B REGISTER DAC REGISTER DAC M REGISTER C REGISTER Figure 8 Data Registers Associated With Each DAC Channel Each DAC channel also has a gain (M) and offset (C) register, which allow trimming out of the gain and offset errors of the entire signal chain. Data from the X1A register is operated on by a digital multiplier and adder controlled by the contents of the M and C registers. The calibrated DAC data is then stored in the X2A register. Similarly, data from the X1B register is operated on by the multiplier and adder and stored in the X2B register. Although a multiplier and adder symbol are shown for each channel, there is only one multiplier and one adder in the device, which are shared between all channels. This has implications for the update speed when several channels are updated at once, as described later. Each time data is written to the X1A register, or to the M or C register with the A/B control bit set to 0, the X2A data is recalculated and the X2A register is automatically updated. Similarly, X2B is updated each time data is written to X1B, or to M or C with A/B set to 1. The X2A and X2B registers are not readable, nor directly writable by the user. OFFSET DACS In addition to the gain and offset trim for each DAC, there are two 14-bit Offset DACs, one for Group 0, and one for Group 1. These allow the output range of all DACs connected to them to be offset within a defined range. Thus, subject to the limitations of headroom, it is possible to set the output range of Group 0, and/or Group 1 to be unipolar positive, unipolar negative, or bipolar, either symmetrical or asymmetrical about zero volts. The DACs in the AD5360/AD5361 are factory trimmed with the Offset DACs set at their default values. This gives the best offset and gain performance for the default output range and span. When the output range is adjusted by changing the value of the Offset DAC an extra offset is introduced due to the gain error of the Offset DAC. The amount of offset is dependent on the magnitude of the reference and how much the Offset DAC moves from its default value. This offset is quoted on the specification page. The worst case offset occurs when the Offset DAC is at positive or negative full-scale. This value can be added to the offset present in the main DAC of a channel to give an indication of the overall offset for that channel. In most cases the offset can be removed by programming the channels C register with an appropriate value. The extra offset cause by the Offset DACs only needs to be taken into account when the Offset DAC is changed from its default value. Figure 9 shows the allowable code range which may be loaded to the Offset DAC and this is dependant on the reference value used. Thus, for a 5V reference, the Offset DAC should not be programmed with a value greater than 8192 (0x2000). Data output from the X2A and X2B registers is routed to the final DAC register by a multiplexer. Whether each individual DAC takes its data from the X2A or X2B register is controlled by an 8-bit A/B Select Register associated with each group of 8 DACs. If a bit in this register is 0, the DAC takes its data from the X2A register; if 1 the DAC takes its data from the X2B register (bit 0 controls DAC 0 through bit 7 controls DAC 7). Note that, since there are 16 bits in 2 registers, it is possible to set up, on a per-channel basis, whether each DAC takes its data from the X2A or X2B register. A global command is also provided that sets all bits in the A/B Select Registers to 0 or to 1. Rev. PrF | Page 13 of 25 5 RESERVED 4 3 2 1 0 0 5370-0200 Each DAC channel has seven data registers. The actual DAC data word can be written to either the X1A or X1B input register, depending on the setting of the A/B bit in the Control Register. If the A/B bit is 0, data will be written to the X1A register. If the A/B bit is 1, data will be written to the X1B register. Note that this single bit is a global control and affects every DAC channel in the device. It is not possible to set up the device on a per-channel basis so that some writes are to X1A registers and some writes are to X1B registers. All DACs in the AD5360/AD5361 can be updated simultaneously by taking LDAC low, when each DAC register will be updated from either its X2A or X2B register, depending on the setting of the A/B select registers. The DAC register is not readable, nor directly writable by the user. VREF (V) A/ B REGISTERS GAIN/OFFSET ADJUSTMENT 4096 8192 12288 OFFSET DAC CODE Figure 9. Offset DAC Code Range 16383 AD5360/AD5361 Preliminary Technical Data OUTPUT AMPLIFIER As the output amplifiers can swing to 1.4 V below the positive supply and 1.4 V above the negative supply, this limits how much the output can be offset for a given reference voltage. For example, it is not possible to have a unipolar output range of 20V, since the maximum supply voltage is ±16.5 V. S1 DAC CHANNEL DAC_CODE = INPUT_CODE × (m+1)/214 + c - 213 DAC output voltage:- R6 10kΩ CLR VOUT = 4 × VREF × (DAC_CODE – OFFSET_CODE )/214 +VSIGGND R5 R1 CLR CLR S3 R4 R3 R2 SIGGND SIGGND OFFSET DAC 2049-0008 CHECK VALUE OF R1 &R5 R1,R2,R3 = 20kΩ R4,R5 = 60kΩ R6 = 10kΩ Figure 10. Output Amplifier and Offset DAC Figure 10 shows details of a DAC output amplifier and its connections to the Offset DAC. On power up, S1 is open, disconnecting the amplifier from the output. S3 is closed, so the output is pulled to SIGGND. S2 is also closed to prevent the output amplifier being open-loop. If CLR is low at power-up, the output will remain in this condition until CLR is taken high. The DAC registers can be programmed, and the outputs will assume the programmed values when CLR is taken high. Even if CLR is high at power-up, the output will remain in the above condition until VDD > 6 V and VSS < -4 V and the initialization sequence has finished. The outputs will then go to their poweron default value. TRANSFER FUNCTION From the foregoing, it can be seen that the output voltage of a DAC in the AD5360/AD5361 depends on the value in the input register, the value of the M and C registers, and the offset from the Offset DAC. The transfer function is given by: AD5360 Code applied to DAC from X1A or X1B register:DAC_CODE = INPUT_CODE × (m+1)/216 + c - 215 DAC output voltage:- AD5361 Code applied to DAC from X1A or X1B register:- OUTPUT S2 OFFSET_CODE is the 14-bit code written to the offset DAC register. As this DAC is a 14 bit device, the code is multiplied by 4 to make the transfer function correct, since the X, M and C registers are 16-bit. The default value for the Offset DAC is 8192 (0x2000) Notes DAC_CODE should be within the range of 0 to 16383 For 12 V span VREF = 3.0 V. For 20 V span VREF = 5.0 V. X1A, X1B default code = 8192 m = code in gain register; default m code = 214 – 1. c = code in offset register; default m code = 213. OFFSET_CODE is the code loaded to the offset DAC. The default value for the Offset DAC is 8192 (0x2000) REFERENCE SELECTION The AD5360/AD5361 has two reference input pins. The voltage applied to the reference pins determines the output voltage span on VOUT0 to VOUT15. VREF0 determines the voltage span for VOUT0 to VOUT7 and VREF1 determines the voltage span for VOUT8 to VOUT15. The reference voltage applied to each VREF pin can be different, if required, allowing each group of 8 channels to have a different voltage span. The output voltage range can be adjusted further by programming the offset and gain registers for each channel as well as programming the offset DAC. If the offset and gain features are not used (i.e. the m and c registers are left at their default values) the required reference levels can be calculated as follows: VREF = (VOUTmax – VOUTmin)/4 If the offset and gain features of the AD5360/AD5361 are used, then the required output range is slightly different. The chosen output range should take into account the system offset and gain errors that need to be trimmed out. Therefore, the chosen output range should be larger than the actual, required range. The required reference levels can be calculated as follows: VOUT = 4 × VREF × (DAC_CODE – OFFSET_CODE × 4 )/216 +VSIGGND Notes DAC_CODE should be within the range of 0 to 65535 For 12 V span VREF = 3.0 V. For 20 V span VREF = 5.0 V. X1A, X1B default code = 32768 m = code in gain register; default m code = 216 – 1. c = code in offset register; default m code = 215. Rev. PrF | Page 14 of 25 1. Identify the nominal output range on VOUT. 2. Identify the maximum offset span and the maximum gain required on the full output signal range. 3. Calculate the new maximum output range on VOUT including the expected maximum offset and gain errors. 4. Choose the new required VOUTmax and VOUTmin, keeping the VOUT limits centered on the nominal Preliminary Technical Data AD5360/AD5361 values. Note that VDD and VSS must provide sufficient headroom. 5. Calculate the value of VREF as follows: VREF = (VOUTMAX – VOUTMIN)/4 the C register. Note that only negative zero-scale error can be reduced. Full-scale error can be reduced as follows: 1. Measure the zero-scale error. Nominal Output Range = 20V (-10V to +10V) Offset Error = ±100mV Gain Error = ±3% SIGGND = AGND = 0V 2. Set the output to the highest possible value. 3. Measure the actual output voltage and compare it with the required value. Add this error to the zero-scale error. This is the full-scale error. 1) Gain Error = ±3% => Maximum Positive Gain Error = +3% => Output Range incl. Gain Error = 20 + 0.03(20)=20.6V 4. 2) Offset Error = ±100mV => Maximum Offset Error Span = 2(100mV)=0.2V => Output Range including Gain Error and Offset Error = 20.6V + 0.2V = 20.8V Calculate the number of LSBs equivalent to the full-scale error and subtract it from the default value of the M register. Note that only positive full-scale error can be reduced. 5. The M and C registers should not be programmed until both zero-scale and full-scale errors have been calculated. Reference Selection Example 3) VREF Calculation Actual Output Range = 20.6V, that is -10.3V to +10.3V (centered); VREF = (10.3V + 10.3V)/4 = 5.15V AD5360 CALIBRATION EXAMPLE This example assumes that a −10 V to +10 V output is required. The DAC output is set to −10 V but measured at −10.03 V. This gives an zero-scale error of −30 mV. If the solution yields an inconvenient reference level, the user can adopt one of the following approaches: 1. Use a resistor divider to divide down a convenient, higher reference level to the required level. 2. Select a convenient reference level above VREF and modify the Gain and Offset registers to digitally downsize the reference. In this way the user can use almost any convenient reference level but may reduce the performance by overcompaction of the transfer function. 3. 1. 1 LSB = 20 V/65536 = 305.176 µV 2. 30 mV = 98 LSB 3. 98 LSB should be added to the default C register value: (32768 + 98) = 32866 4. 32866 should be programmed to the C register The full-scale error can now be removed. The output is set to +10 V and a value of +10.02 V is measured. The full-scale error is +20 mV – (–30 mV) = +50 mV This is a full-scale error of +50 mV. 1. 50 mV = 164 LSBs 2. 164 LSB should be subtracted from the default M register value: (65535 − 164) = 65371 3. 65371 should be programmed to the M register Use a combination of these two approaches CALIBRATION The user can perform a system calibration on the AD5360 and AD5361 to reduce gain and offset errors to below 1 LSB. This is achieved by calculating new values for the M and C registers and reprogramming them. Reducing Zero-scale and Full-scale Error Zero-scale error can be reduced as follows: 1. Set the output to the lowest possible value. 2. Measure the actual output voltage and compare it with the required value. This gives the zero-scale error. 3. Calculate the number of LSBs equivalent to the error and subtract this from the default value of RESET FUNCTION When the RESET pin is taken low, the DAC buffers are disconnected and the DAC outputs VOUT0 to VOUT15 are tied to their associated SIGGND signals via a 10 kΩ resistor. On the rising edge of RESET the AD5360/AD5361 state machine initiates a reset sequence to reset the X, M and C registers to their default values. This sequence typically takes 300µs and the user should not write to the part during this time. When the reset sequence is complete, and provided that CLR is high, the Rev. PrF | Page 15 of 25 AD5360/AD5361 Preliminary Technical Data DAC output will be at a potential specified by the default register settings which will be equivalent to SIGGGND. The DAC outputs will remain at SIGGND until the X, M or C registers are updated and LDAC is taken low. CLEAR FUNCTION CLR is an active low input which should be high for normal operation. The CLR pin has in internal 500kΩ pull-down resistor. When CLR is low, the input to each of the DAC output buffer stages, VOUT0 to VOUT15, is switched to the externally set potential on the relevant SIGGND pin. While CLR is low, all LDAC pulses are ignored. When CLR is taken high again, the DAC outputs remain cleared until LDAC is taken low. The contents of input registers and DAC registers 0 to 15 are not affected by taking CLR low. To prevent glitches appearing on the outputs CLR should be brought low whenever the output span is adjusted by writing to the offset DAC. BUSY AND LDAC FUNCTIONS The value of an X2 (A or B) register is calculated each time the user writes new data to the corresponding X1, C, or M registers. During the calculation of X2, the BUSY output goes low. While BUSY is low, the user can new data to the X1, M, or C registers, provided the first stage of the calculation is complete (see the Register Update Rates section for more details). The BUSY pin is bidirectional and has a 50 kΩ internal pullup resistor. Where multiple AD5360 or AD5361 devices may be used in one system the BUSY pins can be tied together. This is useful where it is required that no DAC in any device is updated until all other DACs are ready. When each device has finished updating the X2 (A or B) registers it will release the BUSY pin. If another device hasn’t finished updating its X2 registers it will hold BUSY low, thus delaying the effect of LDAC going low. The DAC outputs are updated by taking the LDAC input low. If LDAC goes low while BUSY is active, the LDAC event is stored and the DAC outputs update immediately after BUSY goes high. A user can also hold the LDAC input permanently low. In this case, the DAC outputs update immediately after BUSY goes high. BUSY also goes low, for approximately 500ns, whenever the A/B Select Registers are written to. Table 7. BUSY Pulse Widths Action Loading X1A, X1B, C, or M to 1 channel Loading X1A, X1B, C, or M to 2 channels Loading X1A, X1B, C, or M to 8 channels Loading X1A, X1B, C, or M to 16 channels BUSY Pulse Width (µs max) 1.25 1.75 4.75 8.75 BUSY Pulse Width = ((Number of Channels +1) × 500ns) +250ns The AD5360/AD5361 contains an extra feature whereby a DAC register is not updated unless its X2A or X2B register has been written to since the last time LDAC was brought low. Normally, when LDAC is brought low, the DAC registers are filled with the contents of the X2A or X2B registers, depending on the setting of the A/B Select Registers. However the AD5360/AD5361 updates the DAC register only if the X2 data has changed, thereby removing unnecessary digital crosstalk. BIN/2SCOMP PIN The BIN/2SCOMP pin determines if the input data is interpreted as offset binary or 2’s complement. If this pin is low, then the data is binary. If it is 1, the data is interpreted as 2’s complement. This affects only the X, C, and Offset DAC registers. The M register data and all control and command data is interpreted as straight binary. TEMPERATURE SENSOR The on-chip temperature sensor provides a voltage output at the TEMP_OUT pin that is linearly proportional to the Centigrade temperature scale. The typical accuracy of the temperature sensor is ±1°C at +25°C and ±5°C over the −40°C to +85°C range. Its nominal output voltage is 1.5V at +25°C, varying at 5 mV/°C, giving a typical output range of 1.175V to 1.9 V over the full temperature range. Its low output impedance, low self heating, and linear output simplify interfacing to temperature control circuitry and A/D converters. As described later, the AD5360/AD5361 has flexible addressing that allows writing of data to a single channel, all channels in a group, or all channels in the device. This means that several register values may need to be calculated and updated. As there is only one multiplier shared between 16 channels, this task must be done sequentially, so the length of the BUSY pulse will vary according to the number of channels being updated. Rev. PrF | Page 16 of 25 Preliminary Technical Data AD5360/AD5361 MONITOR FUNCTION POWER-DOWN MODE The AD5360/AD5361 contains a channel monitor function that consists of an analog multiplexer addressed via the serial interface, allowing any channel output to be routed to this pin for monitoring using an external ADC. In addition, two monitor inputs, MON_IN0 and MON_IN1 are provided, which can also be routed to MON_OUT. The monitor function is controlled by the Monitor Register, which allows the monitor output to be enabled or disabled, and selection of a DAC channel or one of the monitor pins. When disabled, the monitor output is high impedance, so several monitor outputs may be connected in parallel and only one enabled at a time. Table 8 shows the control register settings relevant to the monitor function. The AD5360/AD5361 can be powered down by setting Bit 0 in the control register. This will turn off the DACs thus reducing the current consumption. The DAC outputs will be connected to their respective SIGGND potentials. The power-down mode doesn’t change the contents of the registers and the DACs will return to their previous voltage when the power-down bit is cleared. Table 8. Control Register Monitor Functions F5 0 1 1 1 1 1 1 F4 X X 0 0 0 1 1 F3 X X 0 0 1 0 0 F2 X X 0 0 1 0 0 F1 X X 0 0 1 0 0 F0 X X X 1 1 0 1 MON_OUT Disabled MON_OUT Enabled MON_OUT = VOUT0 MON_OUT = VOUT1 MON_OUT = VOUT15 MON_OUT = MON_IN0 MON_OUT = MON_IN1 The multiplexer is implemented as a series of analog switches. Since this could conceivably cause a large amount of current to flow from the input of the multiplexer, i.e. VOUTx or MON_INx to the output of the multiplexer, MON_OUT, care should taken to ensure that whatever is connected to the MON_OUT pin is of high enough impedance to prevent the Continuous Current Limit specification from being exceeded. GPIO PIN The AD5360/AD5361 has a general-purpose I/O pin, GPIO. This can be configured as an input or an output and read back or programmed (when configured as an output) via the serial interface. Typical applications for this pin include monitoring the status of a logic signal, limit switch, or controlling an external multiplexer. The GPIO pin is configured by writing to the GPIO register, which has the special function code of 0b001101 (see Table 13 and Table 14 ). When Bit F1 is set the GPIO pin will be an output and F0 will determine whether the pin is high or low. The GPIO pin can be set as an input by writing 0 to both F1 and F0. The status of the GPIO pin can be determined by initiating a read operation using the appropriate bits in Table 15. The status of the pin will be indicated by the LSB of the register read. THERMAL MONITORING FUNCTION The AD5360/AD5361 can be programmed to power down the DACs if the temperature on the die exceeds 130°C. Setting Bit 1 in the control register (see Table 14) will enable this function. If the die temperature exceeds 130°C the AD5360/AD5361 will enter a temperature power-down mode, which is equivalent to setting the power-down bit in the control register. To indicate that the AD5360/AD5361 has entered temperature shutdown mode Bit 4 of the control register is set. The AD5360/AD5361 will remain in temperature shutdown mode, even if the die temperature falls, until Bit 1 in the control register is cleared. TOGGLE MODE The AD5360/AD5361 has two X2 registers per channel, X2A and X2B, which can be used to switch the DAC output between two levels with ease. This approach greatly reduces the overhead required by a micro-processor which would otherwise have to write to each channel individually. When the user writes to either the X1A, X2A, M or C registers the calculation engine will take a certain amount of time to calculate the appropriate X2A or X2B values. If the application only requires that the DAC output switch between two levels, such as a data generator, any method which reduces the amount of calculation time encountered is advantageous. For the data generator example the user need only set the high and low levels for each channel once, by writing to the X1A and X1B registers. The values of X2A and X2B will be calculated and stored in their respective registers. The calculation delay therefore only happens during the setup phase, i.e. when programming the initial values. To toggle a DAC output between the two levels it is only required to write to the relevant A/B Select Register to set the MUX2 register bit. Furthermore, since there are 8 MUX2 control bits per register it is possible to update eight channels with a single write. Table 16 shows the bits that correspond to each DAC output. Rev. PrF | Page 17 of 25 AD5360/AD5361 Preliminary Technical Data SERIAL INTERFACE REGISTER UPDATE RATES Serial data input pin. As mentioned previously the value of the X2 (A or B) register is calculated each time the user writes new data to the corresponding X1, C or M registers. The calculation is performed by a three stage process. The first two stages take 500ns each and the third stage takes 250ns. When the write to one of the X1, C or M registers is complete the calculation process begins. If the write operation involves the update of a single DAC channel the user is free to write to another register provided that the write operation doesn’t finish until the first stage calculation is complete, i.e. 500ns after the completion of the first write operation. If a group of channels is being updated by a single write operation the first stage calculation will be repeated for each channel, taking 500ns per channel. In this case the user should not complete the next write operation until this time has elapsed. SDO PACKET ERROR CHECKING Serial data output pin To verify that data has been received correctly in noisy environments, the AD5360/AD5361 offers the option of error checking based on an 8-bit (CRC-8) cyclic redundancy check. The device controlling the AD5360/AD5361 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 32 data bits are sent to the AD5360/AD5361 before taking SYNC high. If the AD5360/AD5361 sees a 32-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 Packet Error Check output (PEC) will go low and bit 3 of the Control Register is set. After reading this register, this error flag is cleared automatically and PEC goes high again. The AD5360/AD5361 contains an SPI-compatible interface operating at clock frequencies up to 50MHz (20MHz for read operations). To minimize both the power consumption of the device and on-chip digital noise, the interface powers up fully only when the device is being written to, that is, on the falling edge of SYNC. The serial interface is 2.5 V LVTTL compatible when operating from a 2.3 V to 3.6 V DVCC supply. It is controlled by four pins, as follows. SYNC Frame synchronization input. SCLK Clocks data in and out of the device. SDI SPI WRITE MODE The AD5360/AD5361 allows writing of data via the serial interface to every register directly accessible to the serial interface, which is all registers except the X2A and X2B registers and the DAC registers. The X2A and X2B registers are updated automatically when writing to the X1A, X1B, M and C registers, and the DAC registers are updated by LDAC. The serial word (see Table 9 and Table 10) is 24 bits long. 16(14) of these bits are data bits, five bits are address bits, and two bits are mode bits that determine what is done with the data. The serial interface works with both a continuous and a burst (gated) serial clock. Serial data applied to SDI is clocked into the AD5360/AD5361 by clock pulses applied to SCLK. The first falling edge of SYNC starts the write cycle. At least 24 falling clock edges must be applied to SCLK to clock in 24 bits of data, before SYNC is taken high again. If SYNC is taken high before the 24th falling clock edge, the write operation will be aborted. If a continuous clock is used, and PEC mode isn’t used, SYNC must be taken high before the 25th falling clock edge. This inhibits the clock within the AD5360/AD5361. If more than 24 falling clock edges are applied before SYNC is taken high again, the input data will be corrupted. If an externally gated clock of exactly 24 pulses is used, SYNC may be taken high any time after the 24th falling clock edge. The input register addressed is updated on the rising edge of SYNC. In order for another serial transfer to take place, SYNC must be taken low again. UPDATE ON SYNC HIGH SYNC SCLK MSB D23 DIN LSB D0 24-BIT DATA 24-BIT DATA TRANSFER - NO ERROR CHECKING UPDATE AFTER SYNC HIGH ONLY IF ERROR CHECK PASSED SYNC SCLK MSB D31 LSB D8 24 BIT DATA DIN D0 D7 8-BIT FCS PEC GOES LOW IF ERROR CHECK FAILS PEC 24-BIT DATA TRANSFER WITH ERROR CHECKING 5360-0010 Figure 11. SPI Write With and Without Error Checking Rev. PrF | Page 18 of 25 Preliminary Technical Data AD5360/AD5361 Table 9. AD5360 Serial Word Bit Assignation I23 I22 I21 I20 I19 I18 I17 I16 I15 I14 I13 I12 I11 I10 I9 I8 I7 I6 I5 I4 I3 I2 I1 I0 M1 M0 A5 A4 A3 A2 A1 A0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Table 10. AD5361 Serial Word Bit Assignation I23 I22 I21 I20 I19 I18 I17 I16 I15 I14 I13 I12 I11 I10 I9 I8 I7 I6 I5 I4 I3 I2 I1* I0* M1 M0 A5 A4 A3 A2 A1 A0 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 0 0 M1 and M0 are mode bits. A5 is an unused address bit and must always be written as 0. A4 to A0 are address bits. D15 to D0 are data bits. *In the AD5361, bits I1 and I0 only used in Special Function Mode Table 11. Mode Bits SPI READBACK MODE The AD5360/AD5361 allows data readback via the serial interface from every register directly accessible to the serial interface, which is all registers except the X2A, X2B and DAC registers. In order to read back a register, it is first necessary to tell the AD5360/AD5361 which register is to be read. This is achieved by writing to the device a word whose first two bits are the special function code 00. The remaining bits then determine if the operation is a readback, and the register which is to be read back, or if it is a write to of the special function registers such as the control register. After the special function write has been performed, if it is a readback command then data from the selected register will be clocked out of the SDO pin during the next SPI operation. The SDO pin is normally three-state but becomes driven as soon as a read command has been issued. The pin will remain driven until the registers data has been clocked out. See Figure 5 for the read timing diagram. Note that due to the timing requirements of t5 (25ns) the maximum speed of the SPI interface during a read operation should not exceed 20MHz. M1 1 M0 1 1 0 0 0 1 0 Action Write DAC input data (X1A or X1B) register, depending on Control Register A/B bit. Write DAC offset (C) register Write DAC gain (M) register Special function, used in combination with other bits of word The AD5360/AD5361 has very flexible addressing that allows writing of data to a single channel, all channels in a group, the same channel in groups 0 and 1, or all channels in the device. Table 12 shows all these address modes. CHANNEL ADDRESSING AND SPECIAL MODES If the mode bits are not 00, then the data word D15 to D0 is written to the device. Address bits A4 to A0 determine which channel or channels is/are written to, while the mode bits determine to which register (X1A, X1B, C or M) the data is written, as shown in Table 9 or Table 10. If data is to be written to the X1A or X1B register, the setting of the A/B bit in the Control Register determines which register is used (0 Æ X1A, 1 Æ X1B). Rev. PrF | Page 19 of 25 AD5360/AD5361 Preliminary Technical Data Table 12. Group and Channel Addressing This table shows which group(s) and which channel(s) is/are addressed for every combination of address bits A4 to A0. 000 001 010 011 100 101 110 111 ADDRESS BITS A2 TO A0 ADDRESS BITS A4 TO A3 00 All groups, all channels Group 0, all channels Group 1, all channels Unused Unused Unused Unused Unused 01 Group 0, channel 0 Group 0, channel 1 Group 0, channel 2 Group 0, channel 3 Group 0, channel 4 Group 0, channel 5 Group 0, channel 6 Group 0, channel 7 10 Group 1, channel 0 Group 1, channel 1 Group 1, channel 2 Group 1, channel 3 Group 1, channel 4 Group 1, channel 5 Group 1, channel 6 Group 1, channel 7 11 Unused Unused Unused Unused Unused Unused Unused Unused data required for execution of the special function, for example the channel address for data readback. SPECIAL FUNCTION MODE If the mode bits are 00, then the special function mode is selected, as shown in Table 13. Bits I21 to I16 of the serial data word select the special function, while the remaining bits are The codes for the special functions are shown in Table 14. Table 15 shows the addresses for data readback. Table 13. Special Function Mode I23 I22 I21 I20 I19 I18 I17 I16 I15 I14 I13 I12 I11 I10 I9 I8 I7 I6 I5 I4 I3 I2 I1 I0 0 0 S5 S4 S3 S2 S1 S0 F15 F14 F13 F12 F11 F10 F9 F8 F7 F6 F5 F4 F3 F2 F1 F0 Rev. PrF | Page 20 of 25 Preliminary Technical Data AD5360/AD5361 Table 14. Special Function Codes ACTION SPECIAL FUNCTION CODE DATA S5 S4 S3 S2 S1 S0 F15-F0 0 0 0 0 0 0 0000 0000 0000 0000 0 0 0 0 0 1 XXXX XXXX XXX[F4:F0] NOP Write control register F4 = 1 Æ Overtemperature; F4 = 0 Æ Temp OK (Read-only bit) F3 = 1 Æ PEC error; F3 = 0 Æ PEC OK (Read-only bit) F2 = 1 Æ Select B register for input; F2 = 0 Æ Select A register for input F1 = 1 Æ Enable temperature shutdown; F1 = 0 Æ Disable temperature shutdown F0 = 1 Æ Soft power down; F0 = 0 Æ Soft power up 0 0 0 0 1 0 [F13:F0] Write data in F13:F0 to OFS0 register 0 0 0 0 1 1 [F13:F0] Write data in F13:F0 to OFS1 register 0 0 0 1 0 1 See Table 15 Select register for readback 0 0 0 1 1 0 XXXX XXXX[F7:F0] Write data in F7:F0 to A/B Select Register 0 0 0 0 1 1 1 XXXX XXXX[F7:F0] Write data in F7:F0 to A/B Select Register 1 0 0 1 1 0 0 XXXX XXXX XX[F5:F0] F5 = 1 Æ Monitor enable; F5 = 0 Æ Monitor disable F4 = 1 Æ Monitor input pin selected by I0 (0 = MON_IN0, 1 = MON_IN1) F4 = 0 Æ Monitor DAC channel selected by F3:F0 (0000 = channel 0 Æ 1111 = channel 15) 0 0 1 1 0 1 XXXX XXXX XXXX XX[F1:F0] GPIO configure and write F1 = 1 Æ GPIO is output. Data to output is written to F0 F1 = 0 Æ GPIO is input. Data can be read from F0 on readback Note. When writing to the offset registers, the 14-bit data is right justified (bits F15 and F14 are don’t care). When writing to the X, M or C registers of the AD5361, the 14-bit data is left-justified (bits 1 and 0 of the data word are don’t care). Table 15. Address Codes for Data Readback F15 F14 F13 0 0 0 0 0 1 0 1 0 0 1 1 F12 F11 F10 F9 F8 REGISTER READ1 F7 X1A Register Bits F12 to F7 select channel to be read back, from Channel 0 = 001000 to Channel 15 = 010111 X1B Register C Register M Register 1 0 0 0 0 0 0 0 1 Control Register 1 0 0 0 0 0 0 1 0 OFS0 Data Register 1 0 0 0 0 0 0 1 1 OFS1 Data Register 1 0 0 0 0 0 1 1 0 A/B Select Register 0 1 0 0 0 0 0 1 1 1 A/B Select Register 1 1 0 0 0 0 1 0 1 1 GPIO read (data in F0)2 1 F6 to F0 are don’t care for data readback functions except for GPIO read. F6 to F0 should be 0 for GPIO read 2 Table 16. DACs Select by A/B Select Registers A/B Select Register F7 F6 F5 F4 Bits F3 F2 F1 F0 0 1 VOUT7 VOUT15 VOUT6 VOUT141 VOUT5 VOUT13 VOUT4 VOUT12 VOUT3 VOUT11 VOUT2 VOUT10 VOUT1 VOUT9 VOUT0 VOUT8 Rev. PrF | Page 21 of 25 AD5360/AD5361 Preliminary Technical Data POWER SUPPLY DECOUPLING POWER SUPPLY SEQUENCING 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 AD5360/AD5361 is mounted should be designed so that the analog and digital sections are separated and confined to certain areas of the board. If the AD5360/AD5361 is in a system where multiple devices require an AGND-to-DGND connection, the connection should be made at one point only. The star ground point should be established as close as possible to the device. For supplies with multiple pins (VSS, VDD, VCC), it is recommended to tie these pins together and to decouple each supply once. When the supplies are connected to the AD5360/AD5361 it is important that the AGND and DGND pins are connected to the relevant ground plane before the positive or negative supplies are applied. In most applications this is not an issue as the ground pins for the power supplies will be connected to the ground pins of the AD5360/AD5361 via ground planes. Where the AD5360/AD5361 is to be used in a hot-swap card care should be taken to ensure that the ground pins are connected to the supply grounds before the positive or negative supplies are connected. This is required to prevent currents flowing in directions other than towards an analog or digital ground. The AD5360/AD5361 should have ample supply decoupling 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 effective series inductance (ESI), such as the common ceramic types that provide a low impedance path to ground at high frequencies, to handle transient currents due to internal logic switching. Digital lines running under the device should be avoided, because these couple noise onto the device. The analog ground plane should be allowed to run under the AD5362/AD5363 to avoid noise coupling. The power supply lines of the AD5362/AD5363 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 digital signals 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. It is essential to minimize noise on all VREF lines 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 feedthrough 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. As is the case for all thin packages, care must be taken to avoid flexing the package and to avoid a point load on the surface of this package during the assembly process. Rev. PrF | Page 22 of 25 Preliminary Technical Data AD5360/AD5361 INTERFACING EXAMPLES The SPI interface of the AD5360 and AD5361 are designed to allow the parts to be easily connected to industry standard DSPs and micro-controllers. Figure 12 shows how the AD5360/AD5361 could be connected to the Analog Devices Blackfin® DSP. The Blackfin has an integrated SPI port which can be connected directly to the SPI pins of the AD5360 or AD5361 and programmable I/O pins which can be used to set or read the state of the digital input or output pins associated with the interface. the Receive Frame Synchronization (RFS) pin. Similarly the transmit and receive clocks (TCLK and RCLK) are also connected together. The user can write to the AD5360 or AD5361 by writing to the transmit register. A read operation can be accomplished by first writing to the AD5360/AD5361 to tell the part that a read operation is required. A second write operation with a NOP instruction will cause the data to be read from the AD5360/AD5361. The DSPs receive interrupt can be used to indicate when the read operation is complete. AD536x ADSP-BF531 ADSP-21065L AD536x TFSx RFSx SYNC SCLK SPISELx SYNC TCLKx RCLKx SCK SCLK DTxA SDI MOSI SDI DRxA SDO MISO SDO FLAG0 RESET RESET FLAG1 LDAC LDAC FLAG2 CLR PF8 CLR FLAG3 BUSY PF7 BUSY PF10 PF9 536x-0101 536x-0101 Figure 12. Interfacing to a Blackfin DSP The Analog Devices ADSP-21065L is a floating point DSP with two serial ports (SPORTS). Figure 13 shows how one SPORT can be used to control the AD5360 or AD5361. In this example the Transmit Frame Synchronization (TFS) pin is connected to Rev. PrF | Page 23 of 25 Figure 13. Interfacing to an ADSP-21065L DSP AD5360/AD5361 Preliminary Technical Data OUTLINE DIMENSIONS 8.00 BSC SQ 0.60 MAX 0.60 MAX 0.30 0.23 0.18 43 42 PIN 1 INDICATOR TOP VIEW PIN 1 INDICATOR 56 1 6.25 6.10 SQ 5.95 EXPOSED PAD (BOTTOM VIEW) 7.75 BSC SQ 0.50 0.40 0.30 29 28 15 14 0.25 MIN 1.00 0.85 0.80 6.50 REF 0.80 MAX 0.65 TYP 12° MAX 0.05 MAX 0.02 NOM COPLANARITY 0.08 0.20 REF 0.50 BSC SEATING PLANE COMPLIANT TO JEDEC STANDARDS MO-220-VLLD-2 Figure 14. 56 Lead LFCSP Package Dimensions shown in millimeters 0.75 0.60 0.45 12.00 BSC SQ 1.60 MAX 52 40 39 1 SEATING PLANE PIN 1 TOP VIEW 10.00 BSC SQ (PINS DOWN) 1.45 1.40 1.35 0.15 0.05 10° 6° 2° SEATING PLANE 0.20 0.09 VIEW A 13 7° 3.5° 0° 0.10 MAX COPLANARITY 27 14 26 0.65 BSC 0.38 0.32 0.22 VIEW A ROTATED 90° CCW COMPLIANT TO JEDEC STANDARDS MS-026BCC Figure 15. 52 Lead LQFP Package Dimensions shown in millimeters ORDERING GUIDE Model AD5360BCPZ AD5360BSTZ AD5361BCPZ AD5361BSTZ Temperature Range -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C Package Description 56-Lead Free Chip Scale Package (LFCSP) 52-Lead Quad Flat Pack (LQFP) 56-Lead Free Chip Scale Package (LFCSP) 52-Lead Quad Flat Pack (LQFP) Rev. PrF | Page 24 of 25 Package Option CP-56 ST-52 CP-56 ST-52 Preliminary Technical Data AD5360/AD5361 NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. PR05761-0-10/06(PrF) Rev. PrF | Page 25 of 25