DAC7744 ® DAC 774 4 For most current data sheet and other product information, visit www.burr-brown.com 16-Bit, Quad Voltage Output DIGITAL-TO-ANALOG CONVERTER FEATURES DESCRIPTION ● LOW POWER: 200mW ● UNIPOLAR OR BIPOLAR OPERATION ● SINGLE-SUPPLY OUTPUT RANGE: +10V ● DUAL SUPPLY OUTPUT RANGE: ±10V ● SETTLING TIME: 10µs to 0.003% ● 16-BIT MONOTONICITY: –40°C to +85°C The DAC7744 is a 16-bit, quad voltage output digitalto-analog converter with guaranteed 16-bit monotonic performance over the specified temperature range. It accepts 16-bit parallel input data, has double-buffered DAC input logic (allowing simultaneous update of all DACs), and provides a readback mode of the internal input registers. Programmable asynchronous reset clears all registers to a mid-scale code of 8000H or to a zero-scale of 0000H. The DAC7744 operates from either a single +15V supply or from a +15V, –15V, and +5V supply. Low power and small size per DAC make the DAC7744 ideal for automatic test equipment, DAC-per-pin programmers, data acquisition systems, and closed-loop servo-control. The DAC7744 is available in a 48lead SSOP package, and offers guaranteed specifications over the –40°C to +85°C temperature range. ● PROGRAMMABLE RESET TO MID-SCALE OR ZERO-SCALE ● DATA READBACK ● DOUBLE-BUFFERED DATA INPUTS APPLICATIONS ● PROCESS CONTROL ● ATE PIN ELECTRONICS ● CLOSED-LOOP SERVO-CONTROL ● MOTOR CONTROL ● DATA ACQUISITION SYSTEMS ● DAC-PER-PIN PROGRAMMERS VDD VSS VREFL AB Sense VCC VREFL AB VREFH AB VREFH AB Sense DAC7744 16 DATA I/O I/O Buffer Input Register A DAC Register A Input Register B DAC Register B DAC A VOUTA VOUTA Sense DAC B VOUTB VOUTB Sense A1 A0 CS R/W Control Logic Input Register C DAC Register C Input Register D DAC Register D DAC C VOUTC VOUTC Sense DAC D VOUTD VOUTD Sense AGND DGND RST RSTSEL LOADDACs VREFL CD Sense VREFL CD VREFH CD VREFH CD Sense International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 ® © 1999 Burr-Brown Corporation PDS-1534A 1 Printed in U.S.A. November, 1999 DAC7744 SPECIFICATIONS (Dual Supply) At TA = TMIN to TMAX, VCC = +15V, VDD = +5V, VSS = –15V, VREFH = +10V, and VREFL = –10V, unless otherwise noted. DAC7744E PARAMETER CONDITIONS ACCURACY Linearity Error TMIN to TMAX Linearity Match Differential Linearity Error TMIN to TMAX Monotonicity, TMIN to TMAX Bipolar Zero Error Bipolar Zero Error, TMIN to TMAX Full-Scale Error Full-Scale Error, TMIN to TMAX Bipolar Zero Matching Full-Scale Matching Channel-to-Channel Crosstalk Digital Feedthrough Output Noise Voltage MAX MIN TYP ±3 ±4 DAC7744EC MAX MIN TYP ✻ ✻ MAX UNITS ±2 ±3 ±0.025 ±0.05 ±0.025 ±0.05 ±0.024 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ LSB LSB LSB LSB LSB Bits % of FSR % of FSR % of FSR % of FSR % of FSR Channel-to-Channel Matching ±0.024 ✻ ✻ % of FSR At Full Scale 25 ✻ ✻ ppm/V ✻ V mA pF mA ✻ ✻ V V mA mA ✻ µs ±4 T = 25°C T = 25°C Channel-to-Channel Matching VREFL ±5 VREFH VREFL + 1.25 –10 –0.3 –3.2 To ±0.003%, 20V Output Step See Figure 5 9 0.7 • VDD 0 DIGITAL OUTPUT VOH VOL IOH = –0.8mA IOL = 1.6mA POWER SUPPLY VDD VCC VSS IDD ICC ISS Power 3.6 +4.75 +14.25 –14.25 TEMPERATURE RANGE Specified Performance ✻ ✻ –40 +5.0 +15.0 –15.0 50 6 –5 170 ✻ ✻ ✻ ✻ ✻ ✻ 11 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ VDD 0.3 • VDD ±10 ±10 4.5 0.3 ✻ ✻ ✻ ✻ 0.5 2 60 f = 10kHz ✻ ✻ ✻ ✻ +10 VREFH – 1.25 2.6 –0.3 LSB nV-s nV/√Hz ✻ V V µA µA ✻ ✻ ✻ ✻ ✻ ✻ ✻ 200 +85 ✻ ✻ ✻ ✻ 0.4 +5.25 +15.75 –15.75 ±1 ±1 16 ✻ ✻ 500 ±20 Indefinite To VSS, VDD or GND DIGITAL INPUT VIH VIL IIH IIL ±2 ±2 15 ±0.01 ±2 ✻ ±3 ±3 14 T = 25°C REFERENCE INPUT Ref High Input Voltage Range Ref Low Input Voltage Range Ref High Input Current Ref Low Input Current DYNAMIC PERFORMANCE Settling Time TYP T = 25°C Power Supply Rejection Ratio (PSRR) ANALOG OUTPUT Voltage Output Output Current Maximum Load Capacitance Short-Circuit Current Short-Circuit Duration MIN DAC7744EB ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ V V ✻ ✻ ✻ V V V µA mA mA mW ✻ °C ✻ Specifications same as grade to the left. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® DAC7744 2 SPECIFICATIONS (Single Supply) At TA = TMIN to TMAX, VCC = +15V, VDD = +5V, VSS = GND, VREFH = +10V, and VREFL = +50mV, unless otherwise noted. DAC7744E PARAMETER ACCURACY Linearity Error(1) TMIN to TMAX Linearity Match Differential Linearity Error TMIN to TMAX Monotonicity, TMIN to TMAX Unipolar Zero Unipolar Zero Error, TMIN to TMAX Full-Scale Error Full-Scale Error, TMIN to TMAX Unipolar Zero Matching Full-Scale Matching Power Supply Rejection Ratio (PSRR) ANALOG OUTPUT Voltage Output Output Current Maximum Load Capacitance Short-Circuit Current Short-Circuit Duration CONDITIONS Channel-to-Channel Crosstalk Digital Feedthrough Output Noise Voltage MAX MIN TYP ±3 ±4 DAC7744EC MAX MIN TYP ✻ ✻ MAX UNITS ±2 ±3 ±0.025 ±0.05 ±0.025 ±0.05 ±0.024 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ LSB LSB LSB LSB LSB Bits % of FSR % of FSR % of FSR % of FSR % of FSR Channel-to-Channel Matching ±0.024 ✻ ✻ % of FSR At Full Scale 25 ✻ ✻ ppm/V ✻ V ±4 T = 25°C T = 25°C Channel-to-Channel Matching VREFL = 0V, VSS = 0V R = 10kΩ 0 VREFH ±5 To ±0.003%, 10V Output Step See Figure 6 POWER SUPPLY VDD VCC VSS IDD ICC Power TEMPERATURE RANGE Specified Performance 3.6 +4.75 +14.25 –40 +5.0 +15.0 0 50 3.5 50 ✻ ✻ ✻ ✻ ✻ ✻ V V mA mA ✻ ✻ µs ✻ ✻ ✻ ✻ LSB nV-s nV/√Hz ✻ V V µA µA ✻ ✻ ✻ ✻ 0.4 ✻ ✻ 70 +85 ✻ ✻ ✻ ✻ ✻ ✻ ✻ +5.25 +15.75 mA pF mA ✻ ✻ ✻ ✻ ✻ 10 VDD 0.3 • VDD ±10 ±10 4.5 0.3 ✻ ✻ ✻ 0.5 2 60 0.7 • VDD 0 ✻ ✻ ✻ ✻ +10 VREFH – 1.25 1.0 –0.3 8 f = 10kHz ✻ ✻ VREFL + 1.25 0 –0.3 –1.5 ±1 ±1 16 ✻ 500 ±20 Indefinite To VSS, VCC or GND IOH = –0.8mA IOL = 1.6mA ±2 ±2 15 ±0.01 ±2 ✻ ±3 ±3 14 T = 25°C DIGITAL INPUT VIH VIL IIH IIL DIGITAL OUTPUT VOH VOL TYP T = 25°C REFERENCE INPUT Ref High Input Voltage Range Ref Low Input Voltage Range Ref High Input Current Ref Low Input Current DYNAMIC PERFORMANCE Settling Time MIN DAC7744EB ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ V V ✻ ✻ V V V µA mA mW ✻ °C ✻ Specifications same as grade to the left. NOTE: (1) If VSS = 0V, the specification applies at code 0021H and above, due to possible negative zero scale error. ® 3 DAC7744 ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS(1) VCC to VSS ........................................................................... –0.3V to +32V VCC to AGND ...................................................................... –0.3V to +16V VSS to AGND ...................................................................... +0.3V to –16V AGND to DGND ................................................................. –0.3V to +0.3V VREFH to AGND ..................................................................... –9V to +11V VREFL to AGND ...................................................................... –11V to +9V VDD to GND ........................................................................... –0.3V to +6V VREFH to VREFL ........................................................................ –1V to 22V Digital Input Voltage to GND ................................... –0.3V to VDD + 0.3V Digital Output Voltage to GND ................................. –0.3V to VDD + 0.3V Maximum Junction Temperature ................................................... +150°C Operating Temperature Range ........................................ –40°C to +85°C Storage Temperature Range ......................................... –65°C to +150°C Lead Temperature (soldering, 10s) ............................................... +300°C This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. NOTE: (1) Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. Exposure to absolute maximum conditions for extended periods may affect device reliability. PACKAGE/ORDERING INFORMATION PRODUCT LINEARITY ERROR (LSB) DIFFERENTIAL NONLINEARITY (LSB) DAC7744E PACKAGE PACKAGE DRAWING NUMBER SPECIFICATION TEMPERATURE RANGE ±4 ±3 48-Lead SSOP 333 –40°C to +85°C " " " " " " DAC7744EB ±4 ±2 48-Lead SSOP 333 –40°C to +85°C " " " " " " DAC7744EC ±3 ±1 48-Lead SSOP 333 –40°C to +85°C " " " " " " ORDERING NUMBER(1) TRANSPORT MEDIA DAC7744E DAC7744E/1K Rails Tape and Reel DAC7744EB DAC7744EB/1K Rails Tape and Reel DAC7744EC DAC7744EC/1K Rails Tape and Reel NOTE: (1) Models with a slash (/) are available only in Tape and Reel in the quantities indicated (e.g., /1K indicates 1000 devices per reel). Ordering 1000 pieces of “DAC7744E/1K” will get a single 1000-piece Tape and Reel. ESD PROTECTION CIRCUITS VCC VCC VOUT Sense RefH RefH Sense VOUT AGND RefL Sense RefL VSS VSS 4 1 of 2 1 of 4 VDD VDD Typ of Each Logic Input Pin DGND Typ of Each I/O Pin DGND ® DAC7744 4 PIN DESCRIPTIONS PIN CONFIGURATION Top View SSOP PIN NAME DESCRIPTION 1 DB15 Data Bit 15, MSB 2 DB14 Data Bit 14 3 DB13 Data Bit 13 DB15 (MSB) 1 48 NC 4 DB12 Data Bit 12 DB14 2 47 NC 5 DB11 Data Bit 11 6 DB10 Data Bit 10 7 DB9 Data Bit 9 Data Bit 8 DB13 3 46 NC DB12 4 45 NC 8 DB8 VOUTA Sense 9 DB7 Data Bit 7 10 DB6 Data Bit 6 DB11 5 44 DB10 6 43 VOUTA 11 DB5 Data Bit 5 DB9 7 42 VREFL AB Sense 12 DB4 Data Bit 4 13 DB3 Data Bit 3 14 DB2 Data Bit 2 VREFH AB 15 DB1 Data Bit 1 VREFH AB Sense 16 DB0 17 RSTSEL Reset Select. Determines the action of RST. If HIGH, a RST command will set the DAC registers to mid-scale. If LOW, a RST command will set the DAC registers to zero. 18 RST Reset, Edge-Triggered. Depending on the state of RSTSEL, the DAC Input and Output registers are set to either mid-scale or zero. 19 LOADDACs DAC Output Registers Load Control. Rising edge triggered. 20 R/W Enabled by the CS, controls data read and write from the input register. 21 A1 Enabled by the CS, in combination with A0 selects the Individual DAC Input Registers. A0 Enabled by the CS, in combination with A1 selects the individual DAC input registers. DB8 DB7 DB6 8 41 9 40 10 39 VREFL AB DB5 11 38 VOUTB Sense DB4 12 37 VOUTB DAC7744 DB3 13 36 VOUTC Sense DB2 14 35 VOUTC DB1 15 34 VREFH CD Sense DB0 (LSB) 16 33 VREFH CD RSTSEL 17 32 VREFL CD RST 18 31 VREFL CD Sense LOADDACs 19 30 VOUTD Sense 22 R/W 20 29 VOUTD 23 CS A1 21 28 VSS 24 DGND A0 22 27 AGND Data Bit 0, LSB Chip Select, Active LOW. Digital Ground 25 VDD Positive Power Supply 26 VCC Positive Power Supply CS 23 26 VCC 27 AGND DGND 24 25 VDD 28 VSS Negative Power Supply DAC D Voltage Output 29 VOUTD 30 VOUTD Sense 31 VREFL CD Sense 32 VREFL CD 33 VREFH CD 34 VREFH CD Sense 35 VOUTC 36 VOUTC Sense Analog Ground DAC D’s Output Amplifier Inverting Input. Used to close the feedback loop at the load. DAC C and D Reference Low Sense Input DAC C and D Reference Low Input DAC C and D Reference High Input DAC C and D Reference High Sense Input DAC C Voltage Output DAC C’s Output Amplifier Inverting Input. Used to close the feedback loop at the load. 37 VOUTB 38 VOUTB Sense 39 VREFH AB Sense 40 VREFH AB DAC A and B Reference High Input 41 VREFL AB DAC A and B Reference Low Input 42 VREFL AB Sense 43 VOUTA 44 VOUTA Sense 45 NC No Connection 46 NC No Connection 47 NC No Connection 48 NC No Connection DAC B Voltage Output DAC B’s Output Amplifier Inverting Input. Used to close the feedback loop at the load. DAC A and B Reference High Sense Input DAC A and B Reference Low Sense Input DAC A Voltage Input DAC A’s Output Amplifier Inverting Input. Used to close the feedback loop at the load. ® 5 DAC7744 TYPICAL PERFORMANCE CURVES: VSS = 0V At TA = +25°C, VDD = +5V, VCC = +15V, VSS = 0, VREFH = +10V, and VREFL = 0V, representative unit, unless otherwise specified. +25°C LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 DLE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, +25°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) DLE (LSB) LE (LSB) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, +25°C) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, +85°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, +85°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) +85°C Digital Input Code 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code ® DAC7744 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 6 TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = 0, VREFH = +10V, and VREFL = 0V, representative unit, unless otherwise specified. +85°C (cont.) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, +85°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, +85°C) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, –40°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, –40°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 DLE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, –40°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, –40°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) DLE (LSB) LE (LSB) –40°C Digital Input Code 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code ® 7 DAC7744 TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = 0, VREFH = +10V, and VREFL = 0V, representative unit, unless otherwise specified. ZERO-SCALE ERROR vs TEMPERATURE FULL-SCALE ERROR vs TEMPERATURE 2 Code (FFFFH) Code (0021 (0040H) DAC B Positive Full-Scale Error (mV) Zero-Scale Error (mV) 1.5 2 DAC D 1 0.5 0 –0.5 DAC A DAC C –1 –1.5 –2 0 10 20 30 40 50 60 70 80 DAC D 1 0.5 0 –0.5 DAC A DAC C –1 –1.5 90 –40 –30 –20 –10 0 10 20 30 40 50 60 70 VREFL 0 –0.2 –0.4 –0.6 –0.8 –1.0 –1.2 –1.4 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 90 VREF Current (mA) CURRENT vs CODE All DACS Sent to Indicated Code (DAC C and D) VREFH 80 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 VREF Current (mA) CURRENT vs CODE All DACs Sent to Indicated Code (DAC A and B) VREFH VREF Current (mA) Temperature (°C) VREF Current (mA) Temperature (°C) 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 VREFL 0 –0.2 –0.4 –0.6 –0.8 –1.0 –1.2 –1.4 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code POWER SUPPLY CURRENT vs TEMPERATURE POSITIVE SUPPLY CURRENT vs DIGITAL INPUT CODE 4.0 4.0 Data = FFFFH (all DACs) No Load No Load 3.5 ICC 3.0 3.0 2.5 2.5 ICC (mA) Quiescent Current (mA) DAC B –2 –40 –30 –20 –10 3.5 1.5 2.0 1.5 2.0 1.5 1.0 1.0 0.5 IDD 0 0.5 0 –0.5 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 0 90 4000H 6000H 8000H A000H Digital Input Code Temperature (°C) ® DAC7744 2000H 8 C000H E000H FFFFH TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = 0, VREFH = +10V, and VREFL = 0V, representative unit, unless otherwise specified. OUTPUT VOLTAGE vs SETTLING TIME (+10V to 0V) Large-Signal Settling Time: 5V/div Output Voltage Output Voltage OUTPUT VOLTAGE vs SETTLING TIME (0V to +10V) Small-Signal Settling Time: 3LSB/div Small-Signal Settling Time: 3LSB/div Large-Signal Settling Time: 5V/div +5V LDAC 0 +5V LDAC 0 Time (2µs/div) Time (2µs/div) OUTPUT VOLTAGE MIDSCALE GLITCH PERFORMANCE Output Voltage (50mV/div) Output Voltage (50mV/div) OUTPUT VOLTAGE MIDSCALE GLITCH PERFORMANCE 7FFFH to 8000H 8000H to 7FFFH +5V LDAC 0 +5V LDAC 0 Time (1µs/div) Time (1µs/div) OUTPUT NOISE VOLTAGE vs FREQUENCY BROADBAND NOISE 120 Noise (nV/√Hz) Noise Voltage (20µV/div) 100 80 60 40 20 BW = 10kHz Code = 8000H 0 100 Time (100µs/div) 1k 10k 100k 1M Frequency (Hz) ® 9 DAC7744 TYPICAL PERFORMANCE CURVES: VSS = 0V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = 0, VREFH = +10V, and VREFL = 0V, representative unit, unless otherwise specified. LOGIC SUPPLY CURRENT vs LOGIC INPUT LEVEL FOR DATA BITS OUTPUT VOLTAGE vs RLOAD 16 14 10 12 Source 8 VOUT (V) Logic Supply Current (mA) 12 6 4 10 8 6 4 2 2 Sink 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 0.01 5 0.1 1 Logic Input Level for Data Bits (V) SINGLE-SUPPLY CURRENT LIMIT vs INPUT CODE 100 POWER SUPPLY REJECTION RATIO vs FREQUENCY 0 20 Short to Ground –10 15 –20 10 –30 PSRR (dB) 5 0 –5 +15V –40 –50 –60 +5V –10 –70 –15 –80 Short to VCC –90 –20 0000H 2000H 4000H 6000H 8000H A000H 0000H E000H FFFFH 100 1k 10k Frequency (Hz) Input Code DIGITAL-TO-ANALOG OUTPUT GLITCH Output Voltage (50mV/div) IOUT (mA) 10 RLOAD (kΩ) 2LSB/div +5V CS 0 Time (500ns/div) ® DAC7744 10 100k 1M TYPICAL PERFORMANCE CURVES: VSS = –15V At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, VREFH = +10V, and VREFL = –10V, representative unit, unless otherwise specified. LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, +25°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) +25°C 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, +25°C) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code +85°C LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, +85°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, +85°C) Digital Input Code 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code ® 11 DAC7744 TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, VREFH = +10V, and VREFL = –10V, representative unit, unless otherwise specified. +85°C (cont.) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, +85°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, +85°C) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, –40°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, –40°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 DLE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, –40°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, –40°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) DLE (LSB) LE (LSB) DLE (LSB) LE (LSB) –40°C Digital Input Code 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code ® DAC7744 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 12 TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, VREFH = +10V, and VREFL = –10V, representative unit, unless otherwise specified. CURRENT vs CODE All DACs Sent to Indicated Code (DAC A and B) VREFH VREF Current (mA) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 VREF Current (mA) VREF Current (mA) VREFL 0.5 0 –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH VREFL 0.5 0 –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code BIPOLAR ZERO SCALE ERROR vs TEMPERATURE (Code 8000H) POSITIVE FULL-SCALE ERROR vs TEMPERATURE (Code FFFFH) 2 2 1.5 1.5 1 Positive Full-Scale Error (mV) Bipolar Zero Scale Error (mV) 2.0 1.5 1.0 0.5 0 -0.5 –1.0 –1.5 VREF Current (mA) CURRENT vs CODE All DACs Sent to Indicated Code (DAC C and D) VREFH DAC D DAC B 0.5 0 DAC A –0.5 DAC C –1 –1.5 –2 1.0 DAC B DAC D 0.5 0 DAC A –0.5 DAC C –1.0 –1.5 –2.0 –40 –20 0 20 40 60 80 –40 –30 –20 –10 100 0 NEGATIVE FULL-SCALE ERROR vs TEMPERATURE (Code 0000H) DAC B Quiescent Current (mA) Negative Full-Scale Error (mV) 1.5 DAC D 0.5 0 –0.5 DAC A DAC C –1.0 –1.5 –2.0 –40 –30 –20 –10 0 10 20 30 40 20 30 40 50 60 70 80 90 80 90 POWER SUPPLY CURRENT vs TEMPERTURE 2 1.0 10 Temperature (°C) Temperature (°C) 50 60 70 80 7 6 5 4 3 2 1 0 –1 –2 –3 –4 –5 –6 –7 ICC IDD ISS Data = FFFFH (all DACs) No Load –40 –30 –20 –10 90 0 10 20 30 40 50 60 70 Temperature (°C) Temperature (°C) ® 13 DAC7744 TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, VREFH = +10V, and VREFL = –10V, representative unit, unless otherwise specified. SUPPLY CURRENT vs CODE OUTPUT VOLTAGE vs RLOAD 15 10 Source (mA) VOUT (V) 5 0 –5 Sink –10 –15 0.01 0.1 1 10 7 6 5 4 3 2 1 0 1 2 3 4 5 6 7 ICC IDD ISS 0000H 100 2000H 4000H 6000H 8000H A000H C000H E000H RLOAD (kΩ) Digital Input Code OUTPUT VOLTAGE vs SETTLING TIME (–10V to +10V) OUTPUT VOLTAGE vs SETTLING TIME (+10V to –10V) Small-Signal Settling Time: 3LSB/div Output Voltage Output Voltage Large-Signal Settling Time: 5V/div FFFFH Small-Signal Settling Time: 3LSB/div Large-Signal Settling Time: 5V/div +5V LDAC 0 +5V LDAC 0 Time (2µs/div) Time (2µs/div) DUAL SUPPLY CURRENT LIMIT vs INPUT CODE Short to Ground POWER SUPPLY REJECTION RATIO vs FREQUENCY 20 0 15 –10 –20 10 PSRR (dB) IOUT (mA) –30 5 0 –5 –40 –50 –15V –60 +15V –70 –10 –80 –15 –90 –20 0000H +5V –100 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 100 Digital Input Code 10k Frequency (Hz) ® DAC7744 1k 14 100k 1M TYPICAL PERFORMANCE CURVES: VSS = –15V (Cont.) At TA = +25°C, VDD = +5V, VCC = +15V, VSS = –15V, VREFH = +10V, and VREFL = –10V, representative unit, unless otherwise specified. OUTPUT VOLTAGE MID-SCALE GLITCH PERFORMANCE Output Voltage (50mV/div) Output Voltage (50mV/div) OUTPUT VOLTAGE MID-SCALE GLITCH PERFORMANCE 7FFFH to 8000H 8000H to 7FFFH +5V LDAC 0 +5V LDAC 0 Time (1µs/div) Time (1µs/div) ® 15 DAC7744 THEORY OF OPERATION by the external voltage references (VREFL and VREFH, respectively). The digital input is a 16-bit parallel word and the DAC input registers offer a readback capability. The converters can be powered from either a single +15V supply or a dual ±15V supply. The device offers a reset function which immediately sets all DAC output voltages and DAC registers to mid-scale code 8000H or to zero scale, code 0000H. See Figures 2 and 3 for the basic operation of the DAC7744. The DAC7744 is a quad voltage output, 16-bit digital-toanalog converter (DAC). The architecture is an R-2R ladder configuration with the three MSB’s segmented followed by an operational amplifier that serves as a buffer. Each DAC has its own R-2R ladder network, segmented MSBs and output op amp (see Figure 1). The minimum voltage output (zero scale) and maximum voltage output (full scale) are set RF VOUT Sense VOUT R 2R 2R 2R 2R 2R 2R 2R 2R 2R VREFH VREFH Sense VREFL VREFL Sense FIGURE 1. DAC7744 Architecture. Data Bus 1 DB15 (MSB) NC 48 2 DB14 NC 47 3 DB13 NC 46 4 DB12 NC 45 5 DB11 VOUTA Sense 44 6 DB10 VOUTA 43 7 DB9 VREFL AB Sense 42 8 DB8 VREFL AB 41 9 DB7 VREFH AB 40 10 DB6 VREFH AB Sense 39 11 DB5 VOUTB Sense 38 12 DB4 VOUTB 37 13 DB3 VOUTC Sense 36 14 DB2 VOUTC 35 15 DB1 VREFH CD Sense 34 16 DB0 (LSB) VREFH CD 33 17 RSTSEL VREFL CD 32 VREFL CD Sense 31 VOUTD Sense 30 VOUTD 29 DAC7744 Reset DACs 18 RST Load DAC Registers 19 LOADDACS READ/WRITE 20 R/W 21 A1 VSS 28 22 A0 AGND 27 23 CS VCC 26 24 DGND VDD 25 Address Chip Select 0V to +10V +10.000V 0V to +10V 0V to +10V +10.000V 0V to +10V 0.1µF NC = No Connection 0.1µF FIGURE 2. Basic Single-Supply Operation of the DAC7744. ® DAC7744 16 + + +15V 1µF +5V 1µF Data Bus 1 DB15 (MSB) NC 48 2 DB14 NC 47 3 DB13 NC 46 4 DB12 NC 45 5 DB11 VOUTA Sense 44 6 DB10 VOUTA 43 7 DB9 VREFL AB Sense 42 8 DB8 VREFL AB 41 –10V 9 DB7 VREFH AB 40 +10V 10 DB6 VREFH AB Sense 39 11 DB5 VOUTB Sense 38 12 DB4 VOUTB 37 13 DB3 VOUTC Sense 36 14 DB2 VOUTC 35 15 DB1 VREFH CD Sense 34 DAC7744 –10V to +10V –10V to +10V –10V to +10V 16 DB0 (LSB) VREFH CD 33 +10V +5V 17 RSTSEL VREFL CD 32 –10V Reset DACs 18 RST VREFL CD Sense 31 Load DAC Registers 19 LOADDACS VOUTD Sense 30 READ/WRITE 20 R/W VOUTD 29 21 A1 VSS 28 Address Chip Select A0 AGND 27 23 CS VCC 26 DGND VDD –15V 0.1µF 22 24 –10V to +10V + 1µF +15V + 1µF 0.1µF 25 NC = No Connection +5V + 0.1µF 1µF FIGURE 3. Basic Dual-Supply Operation of the DAC7744. ANALOG OUTPUTS When VSS = –15V (dual supply operation), the output amplifier can swing to within 4V of the supply rails, guaranteed over the –40°C to +85°C temperature range. With VSS = 0V (single-supply operation), and with RLOAD also connected to ground, the output can swing to ground. Care must also be taken when measuring the zero-scale error when VSS = 0V. Since the output voltage cannot swing below ground, the output voltage may not change for the first few digital input codes (0000H, 0001H, 0002H, etc.), if the output amplifier has a negative offset. At the negative limit of –5mV, the first specified output starts at code 0021H. allows the loop around the output amplifier to be closed at the load, thus ensuring an accurate output voltage, as shown in Figure 4. DAC7744 Due to the high accuracy of these D/A converters, system design problems such as grounding and contact resistance become very important. A 16-bit converter with a 10V fullscale range has a 1LSB value of 152µV. With a load current of 1mA, series wiring and connector resistance of only 150mΩ (RW2) will cause a voltage drop of 150µV, as shown in Figure 4. To understand what this means in terms of a system layout, the resistivity of a typical 1 ounce copper-clad printed circuit board is 1/2 mΩ per square. For a 1mA load, a 20 milli-inch wide printed circuit conductor 6 inches long will result in a voltage drop of 150µV. NC 48 NC 47 NC 46 NC 45 VOUTA Sense 44 VOUTA 43 VREFL AB Sense 42 VREFL AB 41 VREFH AB 40 VREFH AB Sense 39 VOUTB Sense 38 VOUTB 37 RW1 RW2 VOUT RLOAD +V +10V RW1 RW2 VOUT RLOAD FIGURE 4. Analog Output Closed-Loop Configuration (1/2 DAC7744). RW represents wiring resistances. The DAC7744 offers a force and sense output configuration for the high open-loop gain output amplifiers. This feature ® 17 DAC7744 REFERENCE INPUTS The reference inputs, VREFL and VREFH, can be any voltage between VSS + 4V and VCC – 4V, provided that VREFH is at least 1.25V greater than VREFL. The minimum output of each DAC is equal to VREFL plus a small offset voltage (essentially, the offset of the output op amp). The maximum output is equal to VREFH plus a similar offset voltage. Note that VSS (the negative power supply) must either be connected to ground or must be in the range of –14.25V to –15.75V. The voltage on VSS sets several bias points within the converter. If VSS is not in one of these two configurations, the bias values may be in error and proper operation of the device is not guaranteed. microamps to approximately 2.0mA. The reference input appears as a varying load to the reference. If the reference can sink or source the required current, a reference buffer is not required. The DAC7744 features a reference drive and sense connection such that the internal errors caused by the changing reference current and the circuit impedances can be minimized. Figures 5 through 12 show different reference configurations and the effect on the linearity and differential linearity. The analog supplies (or the analog supplies and the reference power supplies) have to come up first. If the power supplies for the reference come up first, then the VCC and VSS supplies will be “powered from the reference via the ESD protection diode”, see page 4. The current into the VREFH input and out of VREFL depends on the DAC output voltages and can vary from a few NC 48 NC 47 NC 46 NC 45 VOUTA Sense 44 VOUTA 43 VREFL AB Sense 42 VREFL AB 41 VREFH AB 40 VREFH AB Sense 39 DAC7744 +V OPA2234 VOUT 100Ω 2200pF –10V 1000pF VOUTB Sense 38 VOUTB 37 100Ω –V 1000pF +V 2200pF +10V VOUT FIGURE 5. Dual Supply Configuration-Buffered References, used for Dual Supply Performance Curves (1/2 DAC7744). NC 48 NC 47 NC 46 NC 45 VOUTA Sense 44 VOUTA 43 VREFL AB Sense 42 DAC7744 VREFL AB 41 VREFH AB 40 VREFH AB Sense 39 VOUTB Sense 38 VOUTB 37 +V VOUT 100Ω 2kΩ 2200pF OPA350 1000pF +0.050V 100Ω 99kΩ 1000pF 2200pF +V OPA227 +10V VOUT NOTE: VREFL has been chosen to be 50mV to allow for current sinking voltage drops across the 100Ω resistor and the output stage of the buffer op amp. FIGURE 6. Single-Supply Buffered Reference with a Reference Low of 50mV Used for Single-Supply Performance Curves (1/2 DAC7744). ® DAC7744 18 LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 1.0 0.5 0.5 0 –0.5 0 –0.5 –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, +25°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 1.0 1.0 0.5 0.5 DLE (LSB) LE (LSB) –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 1.0 DLE (LSB) DLE (LSB) LE (LSB) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, +25°C) 0 –0.5 –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 0 –0.5 –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code FIGURE 7. Integral Linearity and Differential Linearity Error Curves for Figure 8. NC 48 NC 47 NC 46 NC 45 VOUTA Sense 44 VOUTA 43 VREFL AB Sense 42 VREFL AB 41 VREFH AB 40 VREFH AB Sense 39 VOUTB Sense 38 VOUTB 37 DAC7744 +V OPA2234 VOUT 100Ω 2200pF –5V 1000pF –V 100Ω 1000pF 2200pF +V +5V VOUT –V FIGURE 8. Dual-Supply Buffered Referenced with VREFL = –5V and VREFH = +5V (1/2 DAC7744). ® 19 DAC7744 NC 48 NC 47 NC 46 NC 45 VOUTA Sense 44 VOUTA 43 VREFL AB Sense 42 VREFL AB 41 VREFH AB 40 VREFH AB Sense 39 DAC7744 +V VOUT 1kΩ 100Ω 2200pF OPA350 1000pF VOUTB Sense 38 VOUTB 37 0.05V 100Ω 99kΩ 1000pF 2200pF +V OPA227 +5V VOUT FIGURE 9. Single-Supply Buffered Reference with a Reference Low of 50mV and Reference High of +5V. LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC B, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 1.0 0.5 0.5 0 –0.5 Digital Input Code Digital Input Code LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC C, +25°C) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC D, +25°C) LE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 1.0 1.0 0.5 0.5 DLE (LSB) LE (LSB) 0 –0.5 –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH DLE (LSB) 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 1.0 DLE (LSB) DLE (LSB) LE (LSB) LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs CODE (DAC A, +25°C) 0 –0.5 –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 0 –0.5 –1.0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Digital Input Code FIGURE 10. Integral Linearity and Differential Linearity Error Curves for Figure 9. ® DAC7744 20 A1 A0 R/W CS RST L L H H L L H H X X X X L H L H L H L H X X X X L L L L H H H H X X X X L L L L L L L L H H X X X X X X X X X X X X ↑ ↑ RSTSEL LOADDACS X X X X X X X X X X L H X X X X X X X X ↑ H X X INPUT REGISTER DAC REGISTER MODE DAC Write Write Write Write Read Read Read Read Hold Hold Hold Hold Hold Hold Hold Hold Hold Hold Write Hold Reset to Zero Reset to Midscale Write Input Write Input Write Input Write Input Read Input Read Input Read Input Read Input Update Hold Reset to Zero Reset to Midscale A B C D A B C D All All All All TABLE I. DAC7744 Logic Truth Table. DIGITALLY-PROGRAMMABLE CURRENT SOURCE The DAC7744 offers a unique set of features that allows a wide range of flexibility in designing applications circuits such as programmable current sources. The DAC7744 offers both a differential reference input as well as an open-loop configuration around the output amplifier. The open-loop configuration around the output amplifier allows transistor to be placed within the loop to implement a digitallyprogrammable, uni-directional current source. The availability of a differential reference also allows programmability for both the full-scale and zero-scale currents. The output current is calculated as: DIGITAL INTERFACE Table I shows the basic control logic for the DAC7744. Note that each DAC register is edge triggered and not level triggered. When the LOADDACS signal is transitioned to HIGH, the digital word currently in the DAC register is latched. The first set of registers (the input registers) are triggered via the A0, A1, R/W, and CS inputs. Only one of these registers is transparent at any given time. The double-buffered architecture is designed mainly so that each DAC input register can be written to at any time and then all DAC voltages updated simultaneously by the rising edge of LOADDACS. It also allows a DAC input register to be written to at any point then the DAC output voltages can be synchronously changed via a trigger signal connected to LOADDACS. V H – VREF L N I OUT = REF • R SENSE 65, 536 DIGITAL TIMING Figure 11 and Table II provide detailed timing for the digital interface of the DAC7744. + (VREF L / R SENSE ) Figure 12 shows a DAC7744 in a 4-to-20mA current output configuration. The output current can be determined by Equation 3: DIGITAL INPUT CODING The DAC7744 input data is in Straight Binary format. The output voltage is given by Equation 1. VOUT = VREF (V H – VREF L) • N L + REF (2) (3) 5V – 1V N 1V • I OUT = + 250Ω 65, 536 250Ω (1) 65, 536 where N is the digital input code. This equation does not include the effects of offset (zero scale) or gain (full scale) errors. At full scale, the output current is 16mA plus the 4mA for the zero current. At zero scale, the output current is the offset current of 4mA (1V/250Ω). ® 21 DAC7744 tWCS CS tRCS CS tRDH tRDS tWS tWH tAS tAH R/W A0/A1 R/W tLS tLH tLWD tAH tAS tLX LOADDACS A0/A1 tDZ ±0.003% of FSR Error Band tDH tDS Data In tS Data Valid Data Out tCSD VOUT Data Read Timing Data Write Timing tSS ±0.003% of FSR Error Band tSH RESET SEL tRSH tRSS RST +FS VOUT,RESET SEL LOW –FS +FS VOUT,RESET SEL HIGH MS –FS DAC7744 Reset Timing FIGURE 11. Digital Input and Output Timing. SYMBOL DESCRIPTION MIN tRCS tRDS tRDH tDZ tCSD tWCS tWS tWH tAS tAH tLS tLH tLX tDS tDH tLWD tSS tSH tRSS tRSH tS CS LOW for Read R/W HIGH to CS LOW R/W HIGH after CS HIGH CS HIGH to Data Bus in High Impedance CS LOW to Data Bus Valid CS LOW for Write R/W LOW to CS LOW R/W LOW after CS HIGH Address Valid to CS LOW Address Valid after CS HIGH CS LOW to LOADDACS HIGH CS LOW after LOADDACS HIGH LOADDACS HIGH Data Valid to CS LOW Data Valid after CS HIGH LOADDACS LOW RSTSEL Valid Before RESET HIGH RSTSEL Valid After RESET HIGH RESET LOW Before RESET HIGH RESET LOW After RESET HIGH Settling Time 100 10 10 10 TABLE II. Timing Specifications (TA = –40°C to +85°C). ® DAC7744 22 TYP 85 MAX 70 130 40 0 10 0 15 40 80 40 0 15 40 0 120 10 10 11 UNITS ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns µs IOUT VPROGRAMMED DAC7744 NC 48 NC 47 NC 46 NC 45 VOUTA Sense 44 VOUTA 43 VREFL AB Sense 42 VREFL AB 41 VREFH AB 40 VREFH AB Sense 39 RSENSE 250Ω +V OPA2350 100Ω 20kΩ 2200pF 1000pF VOUTB Sense 38 VOUTB 37 +1.0V 100Ω 80kΩ 1000pF 2200pF +V IOUT VPROGRAMMED RSENSE 250Ω GND FIGURE 12. 4-to-20mA Digitally-Controlled Current Source (1/2 DAC7744). ® 23 DAC7744