LTC2630-HZ8

FEATURES ■ LTC2630 Single 12-/10-/8-Bit Rail-toRail DACs with Integrated Reference in SC70 DESCRIPTION The LTC®2630 is a family of 12-, 10-, and 8-bit voltageoutput DACs with an integrated, high-accuracy, low-drift reference in a 6-lead SC70 package. It has a rail-to-rail output buffer and is guaranteed monotonic. The LTC2630-L has a full-scale output of 2.5V, and operates from a single 2.7V to 5.5V supply. The LTC2630-H has a full-scale output of 4.096V, and operates from a 4.5V to 5.5V supply. Each DAC can also operate in supply as reference mode, which sets the full-scale output to the supply voltage. The parts use a simple SPI/MICROWIRE™ compatible 3-wire serial interface which operates at clock rates up to 50MHz. The LTC2630 incorporates a power-on reset circuit. Options are available for reset to zero or reset to midscale after power-up. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5396245, 5859606, 6891433 and 6937178. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Integrated Precision Reference 2.5V Full Scale 10ppm/°C (LTC2630-L) 4.096V Full Scale 10ppm/°C (LTC2630-H) Maximum INL Error: 1 LSB (LTC2630A-12) Low Noise: 0.7mVP-P, 0.1Hz to 200kHz Guaranteed Monotonic over Temperature Selectable Internal Reference or Supply as Reference 2.7V to 5.5V Supply Range (LTC2630-L) Low Power Operation: 180µA at 3V Power Down to 1.5µA Maximum (C and I Grades) Power-on Reset to Zero or Midscale Options SPI Serial Interface Double-Buffered Data Latches Tiny 6-Lead SC70 Package APPLICATIONS ■ ■ ■ ■ ■ Mobile Communications Process Control and Industrial Automation Automatic Test Equipment Portable Equipment Automotive TYPICAL APPLICATION VCC INTERNAL REFERENCE SDI CONTROL DECODE LOGIC SCK 24-BIT SHIFT REGISTER DACREF CS/LD –0.5 INPUT REGISTER DAC REGISTER DAC VOUT RESISTOR DIVIDER INL (LSB) 0.5 Integral Nonlinearity (LTC2630A-LZ12) 1.0 VCC = 3V VFS = 2.5V 0 –1.0 GND 2630 BD 0 1024 2048 CODE 3072 4095 2630 TA03 2630f 1 LTC2630 ABSOLUTE MAXIMUM RATINGS (Note 1) PIN CONFIGURATION TOP VIEW CS/LD 1 SCK 2 SDI 3 6 VOUT 5 GND 4 VCC Supply Voltage (VCC) ................................... –0.3V to 6V ⎯C⎯S/LD, SCK, SDI .......................................... –0.3V to 6V VOUT .................................. –0.3V to min(VCC + 0.3V, 6V) Operating Temperature Range LTC2630C ................................................ 0°C to 70°C LTC2630I ............................................. –40°C to 85°C LTC2630H .......................................... –40°C to 125°C Maximum Junction Temperature .......................... 150°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) .................. 300°C SC6 PACKAGE 6-LEAD PLASTIC SC70 TJMAX = 150°C (Note 4), θJA = 300°C/W ORDER INFORMATION LTC2630 A C SC6 –L M 12 #TRM PBF LEAD FREE DESIGNATOR TAPE AND REEL TR = Tape and Reel TRM = 500-Piece Tape and Reel RESOLUTION 12 = 12-Bit 10 = 10-Bit 8 = 8-Bit POWER-ON RESET M = Reset to Mid-Scale Z = Reset to Zero-Scale FULL-SCALE VOLTAGE, INTERNAL REFERENCE MODE L = 2.5V H = 4.096V PACKAGE TYPE SC6 = 6-Lead SC70 TEMPERATURE GRADE C = Commercial Temperature Range (0°C to 70°C) I = Industrial Temperature Range (–40°C to 85°C) H = Automotive Temperature Range (–40°C to 125°C) ELECTRICAL GRADE (OPTIONAL) A = ±1 LSB Maximum INL (12-Bit) PRODUCT PART NUMBER Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 2630f 2 LTC2630 PRODUCT SELECTION GUIDE PART NUMBER LTC2630A-LM12 LTC2630A-LZ12 LTC2630A-HM12 LTC2630A-HZ12 LTC2630-LM12 LTC2630-LM10 LTC2630-LM8 LTC2630-LZ12 LTC2630-LZ10 LTC2630-LZ8 LTC2630-HM12 LTC2630-HM10 LTC2630-HM8 LTC2630-HZ12 LTC2630-HZ10 LTC2630-HZ8 VFS WITH INTERNAL REFERENCE 2.5V • (4095/4096) 2.5V • (4095/4096) 4.096V • (4095/4096) 4.096V • (4095/4096) 2.5V • (4095/4096) 2.5V • (1023/1024) 2.5V • (255/256) 2.5V • (4095/4096) 2.5V • (1023/1024) 2.5V • (255/256) 4.096V • (4095/4096) 4.096V • (1023/1024) 4.096V • (255/256) 4.096V • (4095/4096) 4.096V • (1023/1024) 4.096V • (255/256) POWER-ON RESET TO CODE Mid-Scale Zero Mid-Scale Zero Mid-Scale Mid-Scale Mid-Scale Zero Zero Zero Mid-Scale Mid-Scale Mid-Scale Zero Zero Zero RESOLUTION 12-Bit 12-Bit 12-Bit 12-Bit 12-Bit 10-Bit 8-Bit 12-Bit 10-Bit 8-Bit 12-Bit 10-Bit 8-Bit 12-Bit 10-Bit 8-Bit VCC 2.7V–5.5V 2.7V–5.5V 4.5V–5.5V 4.5V–5.5V 2.7V–5.5V 2.7V–5.5V 2.7V–5.5V 2.7V–5.5V 2.7V–5.5V 2.7V–5.5V 4.5V–5.5V 4.5V–5.5V 4.5V–5.5V 4.5V–5.5V 4.5V–5.5V 4.5V–5.5V MAXIMUM INL ±1LSB ±1LSB ±1LSB ±1LSB ±2LSB ±1LSB ±0.5LSB ±2LSB ±1LSB ±0.5LSB ±2LSB ±1LSB ±0.5LSB ±2LSB ±1LSB ±0.5LSB 2630f 3 LTC2630 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VOUT unloaded unless otherwise specified. LTC2630-LM12/-LM10/-LM8/-LZ12/-LZ10/-LZ8, LTC2630A-LM12/-LZ12 (VFS = 2.5V) LTC2630-8 SYMBOL PARAMETER DC Performance Resolution Monotonicity DNL INL ZSE VOS VOSTC FSE VFSTC VCC = 3V, Internal Ref. (Note 2) ● ● LTC2630-10 LTC2630-12 LTC2630A-12 MAX UNITS Bits Bits ±1 ±0.5 0.5 ±0.5 ±10 ±0.2 ±10 ±10 ±10 0.13 0.256 ±0.8 ±1 5 ±5 LSB LSB mV mV μV/°C %FSR ppm/°C ppm/°C ppm/°C LSB/ mA Ω CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP 8 8 ±0.5 ±0.05 ±0.5 0.5 ±0.5 ±10 ● 10 10 ±0.5 ±0.2 0.5 ±0.5 ±10 ±0.2 ±0.8 ±10 ±10 ±10 0.03 0.064 ±1 5 ±5 12 12 ±1 ±1 0.5 ±0.5 ±10 ±0.2 ±0.8 ±10 ±10 ±10 0.13 0.256 ±2 5 ±5 12 12 Differential Nonlinearity VCC = 3V, Internal Ref. (Note 2) ● Integral Nonlinearity VCC = 3V, Internal Ref. (Note 2) ● Zero Scale Error Offset Error VOS Temperature Coefficient Full Scale Error Full Scale Voltage Temperature Coefficient Load Regulation VCC = 3V, Internal Ref., Code = 0 ● VCC = 3V, Internal Ref. (Note 3) ● VCC = 3V, Internal Ref. (Note 3) VCC = 3V, Internal Ref. VCC = 3V, Internal Ref. (Note 8) C-Grade I-Grade H-Grade VCC = 3V ±10% or 5V ±10%, Internal Ref., Midscale, –5mA ≤ IOUT ≤ 5mA ● 5 ±5 ±0.2 ±0.8 ±10 ±10 ±10 0.008 0.016 ROUT DC Output Impedance VCC = 3V ±10% or 5V ±10%, Internal Ref., Midscale, –5mA ≤ IOUT ≤ 5mA ● 0.08 0.156 0.08 0.156 0.08 0.156 0.08 0.156 SYMBOL PARAMETER VOUT PSR ISC DAC Output Span Power Supply Rejection Short Circuit Output Current (Note 4) Sinking Sourcing Power Supply Voltage Supply Current (Note 5) CONDITIONS Supply as Reference Internal Reference VCC = 3V ±10% or 5V ±10% VFS = VCC = 5.5V Zero Scale; VOUT Shorted to VCC Full Scale; VOUT Shorted to GND For Specified Performance Midscale VCC = 3V, Supply as Reference VCC = 3V, Internal Reference VCC = 5V, Supply as Reference VCC = 5V, Internal Reference ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● MIN TYP 0V to VCC 0V to 2.5 –80 27 –28 MAX UNITS V V dB 50 –50 5.5 mA mA V μA μA μA μA μA μA V V Power Supply VCC ICC 2.7 160 180 180 190 0.36 0.36 2.4 2.0 0.8 0.6 ±1 2.5 220 240 250 260 1.5 3 ISD Supply Current in Shutdown Mode (Note 5) VCC = 5V, C-Grade, I-Grade VCC = 5V, H-Grade Digital Input High Voltage Digital Input Low Voltage Digital Input Leakage Digital Input Capacitance VCC = 3.6V to 5.5V VCC = 2.7V to 3.6V VCC = 4.5V to 5.5V VCC = 2.7V to 4.5V VIN = GND to VCC (Note 6) Digital I/O VIH VIL ILK CIN V V μA pF 2630f 4 LTC2630 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER AC Performance tS Settling Time VCC = 3V (Note 7) ±0.39% (±1LSB at 8 Bits) ±0.098% (±1LSB at 10 Bits) ±0.024% (±1LSB at 12 Bits) 3.2 3.9 4.4 1.0 500 At Midscale Transition At f = 1kHz, Supply as Reference At f = 10kHz, Supply as Reference At f = 1kHz, Internal Reference At f = 10kHz, Internal Reference 0.1Hz to 10Hz, Supply as Reference 0.1Hz to 10Hz, Internal Reference 0.1Hz to 200kHz, Supply as Reference 0.1Hz to 200kHz, Internal Reference 2 140 130 160 150 20 20 650 700 μs μs μs V/μs pF nV•s nV/√Hz nV/√Hz nV/√Hz nV/√Hz μVP-P μVP-P μVP-P μVP-P The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VOUT unloaded unless otherwise specified. LTC2630-LM12/-LM10/-LM8/-LZ12/-LZ10/-LZ8, LTC2630A-LM12/-LZ12 (VFS = 2.5V) CONDITIONS MIN TYP MAX UNITS Voltage Output Slew Rate Capacitive Load Driving Glitch Impulse en Output Voltage Noise Density Output Voltage Noise TIMING CHARACTERISTICS SYMBOL t1 t2 t3 t4 t5 t6 t7 t10 PARAMETER SDI Valid to SCK Setup SDI Valid to SCK Hold SCK High Time SCK Low Time ⎯C⎯S/LD Pulse width SCK High to ⎯C⎯S/LD High ⎯C⎯S/LD Low to SCK High ⎯C⎯S/LD High to SCK Positive Edge SCK Frequency The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V. (See Figure 1) (Note 6). LTC2630-LM12/-LM10/-LM8/-LZ12/-LZ10/-LZ8, LTC2630A-LM12/-LZ12 (VFS = 2.5V) CONDITIONS ● ● ● ● ● ● ● ● MIN 4 4 9 9 10 7 7 7 TYP MAX UNITS ns ns ns ns ns ns ns ns 50% Duty Cycle ● 50 MHz 2630f 5 LTC2630 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 4.5V to 5.5V, VOUT unloaded unless otherwise specified. LTC2630-HM12/-HM10/-HM8/-HZ12/-HZ10/-HZ8, LTC2630A-HM12/-HZ12 (VFS = 4.096V) LTC2630-8 SYMBOL PARAMETER DC Performance Resolution Monotonicity DNL INL ZSE VOS VOSTC FSE VFSTC ● LTC2630-10 LTC2630-12 LTC2630A-12 MAX UNITS Bits Bits ±1 ±0.5 0.5 ±0.5 ±10 ±0.2 ±10 ±10 ±10 0.10 0.1 0.16 0.156 ±0.8 ±1 5 ±5 LSB LSB mV mV μV/°C %FSR ppm/°C ppm/°C ppm/°C LSB/ mA Ω CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP 8 8 ±0.5 ±0.05 ±0.5 0.5 ±0.5 ±10 ● 10 10 ±0.5 ±0.2 0.5 ±0.5 ±10 ±0.2 ±0.8 ±10 ±10 ±10 0.025 0.04 0.1 0.156 ±1 5 ±5 12 12 ±1 ±1 0.5 ±0.5 ±10 ±0.2 ±0.8 ±10 ±10 ±10 0.10 0.16 0.1 0.156 ±2 5 ±5 12 12 VCC = 5V, Internal Ref. (Note 2) ● Differential Nonlinearity VCC = 5V, Internal Ref. (Note 2) ● Integral Nonlinearity VCC = 5V, Internal Ref. (Note 2) ● Zero Scale Error Offset Error VOS Temperature Coefficient Full Scale Error Full Scale Voltage Temperature Coefficient Load Regulation VCC = 5V, Internal Ref., Code = 0 ● VCC = 5V, Internal Ref. (Note 3) ● VCC = 5V, Internal Ref. (Note 3) VCC = 5V, Internal Ref. VCC = 5V, Internal Ref. (Note 8) C-Grade I-Grade H-Grade ● VCC = 5V ±10%, Internal Ref., Midscale, –10mA ≤ IOUT ≤ 10mA 5 ±5 ±0.2 ±0.8 ±10 ±10 ±10 0.006 0.01 0.1 0.156 ROUT ● DC Output Impedance VCC = 5V ±10%, Internal Ref., Midscale, –10mA ≤ IOUT ≤ 10mA SYMBOL PARAMETER VOUT PSR ISC DAC Output Span Power Supply Rejection Short Circuit Output Current (Note 4) Sinking Sourcing Power Supply Voltage Supply Current (Note 5) CONDITIONS Supply as Reference Internal Reference VCC = 5V ±10% VFS = VCC = 5.5V Zero Scale; VOUT Shorted to VCC Full Scale; VOUT Shorted to GND For Specified Performance Midscale VCC = 5V, Supply as Reference VCC = 5V, Internal Reference ● ● ● ● ● ● ● ● ● MIN TYP 0V to VCC 0V to 4.096 –80 27 –28 MAX UNITS V V dB 50 –50 5.5 mA mA V μA μA μA μA V Power Supply VCC ICC 4.5 180 200 0.36 0.36 2.4 0.8 ±1 2.5 260 280 1.5 3 ISD Supply Current in Shutdown Mode (Note 5) VCC = 5V, C-Grade, I-Grade VCC = 5V, H-Grade Digital Input High Voltage Digital Input Low Voltage Digital Input Leakage Digital Input Capacitance VIN = GND to VCC (Note 6) Digital I/O VIH VIL ILK CIN V μA pF ● ● 2630f 6 LTC2630 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER AC Performance tS Settling Time VCC = 5V (Note 7) ±0.39% (±1LSB at 8 Bits) ±0.098% (±1LSB at 10 Bits) ±0.024% (±1LSB at 12 Bits) 3.7 4.4 4.8 1.0 500 At Midscale Transition At f = 1kHz, Supply as Reference At f = 10kHz, Supply as Reference At f = 1kHz, Internal Reference At f = 10kHz, Internal Reference 0.1Hz to 10Hz, Supply as Reference 0.1Hz to 10Hz, Internal Reference 0.1Hz to 200kHz, Supply as Reference 0.1Hz to 200kHz, Internal Reference 2.4 140 130 210 200 20 20 650 750 μs μs μs V/μs pF nV•s nV/√Hz nV/√Hz nV/√Hz nV/√Hz μVP-P μVP-P μVP-P μVP-P The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 4.5V to 5.5V, VOUT unloaded unless otherwise specified. LTC2630-HM12/-HM10/-HM8/-HZ12/-HZ10/-HZ8, LTC2630A-HM12/-HZ12 (VFS = 4.096V) CONDITIONS MIN TYP MAX UNITS Voltage Output Slew Rate Capacitive Load Driving Glitch Impulse en Output Voltage Noise Density Output Voltage Noise The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 4.5V to 5.5V. (See Figure 1) (Note 6). LTC2630-HM12/-HM10/-HM8/-HZ12/-HZ10/-HZ8, LTC2630A-HM12/-HZ12 (VFS = 4.096V) SYMBOL PARAMETER t1 t2 t3 t4 t5 t6 t7 t10 SDI Valid to SCK Setup SDI Valid to SCK Hold SCK High Time SCK Low Time ⎯CS/LD Pulse width ⎯ SCK High to ⎯C⎯S/LD High ⎯CS/LD Low to SCK High ⎯ ⎯C⎯S/LD High to SCK Positive Edge SCK Frequency 50% Duty Cycle CONDITIONS ● ● ● ● ● ● ● ● ● TIMING CHARACTERISTICS MIN 4 4 9 9 10 7 7 7 TYP MAX UNITS ns ns ns ns ns ns ns ns 50 MHz Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Linearity and monotonicity are defined from code kL to code 2N–1, where N is the resolution and kL is given by kL = 0.016 • (2N/ VFS), rounded to the nearest whole code. For VFS = 2.5V and N = 12, kL = 26 and linearity is defined from code 26 to code 4,095. For VFS = 4.096V and N = 12, kL = 16 and linearity is defined from code 16 to code 4,095. Note 3: Inferred from measurement at code 16 (LTC2630-12), code 4 (LTC2630-10) or code 1 (LTC2630-8). Note 4: This IC includes current limiting that is intended to protect the device during momentary overload conditions. Junction temperature can exceed the rated maximum during current limiting. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 5: Digital inputs at 0V or VCC. Note 6: Guaranteed by design and not production tested. Note 7: Internal Reference mode. DAC is stepped 1/4 scale to 3/4 scale and 3/4 scale to 1/4 scale. Load is 2kΩ in parallel with 100pF to GND. Note 8: Temperature coefficient is calculated by dividing the maximum change in output voltage by the specified temperature range. 2630f 7 LTC2630 TYPICAL PERFORMANCE CHARACTERISTICS LTC2630-LM12/-LZ12 (VFS = 2.5V) Integral Nonlinearity (INL) 1.0 VCC = 3V 0.5 DNL (LSB) INL (LSB) 1.0 VCC = 3V 0.5 Differential Nonlinearity (DNL) 0 0 –0.5 –0.5 –1.0 0 1024 2048 CODE 3072 4095 2630 G01 –1.0 0 1024 2048 CODE 3072 4095 2630 G02 INL vs Temperature 1.0 VCC = 3V 0.5 INL (POS) DNL (LSB) INL (LSB) 0.5 1.0 DNL vs Temperature 2.52 VCC = 3V FS OUTPUT VOLTAGE (V) 2.51 Full-Scale Output Voltage vs Temperature VCC = 3V DNL (POS) 0 DNL (NEG) –0.5 0 INL (NEG) –0.5 2.50 2.49 –1.0 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2630 G03 –1.0 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2630 G04 2.48 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2630 G05 Settling to ±1LSB Settling to ±1LSB 3/4 SCALE TO 1/4 SCALE STEP VCC = 3V, VFS = 2.5V RL = 2k, CL = 100pF AVERAGE OF 256 EVENTS CS/LD 2V/DIV VOUT 1LSB/DIV 4.4µs 3.6µs VOUT 1LSB/DIV 1/4 SCALE TO 3/4 SCALE STEP VCC = 3V, VFS = 2.5V RL = 2k, CL = 100pF AVERAGE OF 256 EVENTS 2µs/DIV 2630 G06 CS/LD 2V/DIV 2µs/DIV 2630 G07 2630f 8 LTC2630 TYPICAL PERFORMANCE CHARACTERISTICS LTC2630-HM12/-HZ12 (VFS = 4.096V) Integral Nonlinearity (INL) 1.0 VCC = 5V 0.5 DNL (LSB) INL (LSB) 0.5 1.0 VCC = 5V Differential Nonlinearity (DNL) 0 0 –0.5 –0.5 –1.0 0 1024 2048 CODE 3072 4095 2630 G08 –1.0 0 1024 2048 CODE 3072 4095 2630 G09 INL vs Temperature 1.0 VCC = 5V 0.5 INL (POS) DNL (LSB) INL (LSB) 0.5 1.0 DNL vs Temperature 4.115 VCC = 5V FS OUTPUT VOLTAGE (V) 4.105 Full-Scale Output Voltage vs Temperature VCC = 5V DNL (POS) 0 DNL (NEG) –0.5 0 INL (NEG) –0.5 4.095 4.085 –1.0 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2630 G10 –1.0 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2630 G11 4.075 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2630 G12 Settling to ±1LSB Settling to ±1LSB CS/LD 2V/DIV VOUT 1LSB/DIV 4.8µs VOUT 1LSB/DIV 4.0µs 1/4 SCALE TO 3/4 SCALE STEP VCC = 5V, VFS = 4.096V RL = 2k, CL = 100pF AVERAGE OF 256 EVENTS 2µs/DIV 2630 G13 CS/LD 2V/DIV 1/4 SCALE TO 3/4 SCALE STEP VCC = 5V, VFS = 4.096V RL = 2k, CL = 100pF AVERAGE OF 256 EVENTS 2µs/DIV 2630 G14 2630f 9 LTC2630 TYPICAL PERFORMANCE CHARACTERISTICS LTC2630-10 Integral Nonlinearity (INL) 1.0 VCC = 5V VFS = 4.096V 0.5 DNL (LSB) INL (LSB) 0.5 1.0 VCC = 5V VFS = 4.096V Differential Nonlinearity (DNL) 0 0 –0.5 –0.5 –1.0 0 256 512 CODE 768 1023 2630 G15 –1.0 0 256 512 CODE 768 1023 2630 G16 LTC2630-8 Integral Nonlinearity (INL) 1.0 VCC = 3V VFS = 2.5V 0.5 DNL (LSB) INL (LSB) 0.25 0.50 VCC = 3V VFS = 2.5V Differential Nonlinearity (DNL) 0 0 –0.5 –0.25 –1.0 0 64 128 CODE 192 255 2630 G17 –0.50 0 64 128 CODE 192 255 2630 G18 LTC2630 Load Regulation 10 8 6 4 ∆VOUT (mV) VOUT (V) 2 0 –2 –4 –6 –8 –10 –30 –20 –10 INTERNAL REF. CODE = MIDSCALE 0 10 IOUT (mA) 20 30 2630 G19 Current Limiting 0.20 0.15 0.10 0.05 0 VCC = 5V (LTC2630-H) VCC = 5V (LTC2630-L) VCC = 3V (LTC2630-L) OFFSET ERROR (mV) 3 2 1 0 –1 –2 Offset Error vs Temperature VCC = 5V (LTC2630-H) VCC = 5V (LTC2630-L) VCC = 3V (LTC2630-L) –0.05 –0.10 –0.15 –0.20 –30 –20 –10 INTERNAL REF. CODE = MIDSCALE 0 10 IOUT (mA) 20 30 2630 G20 –3 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2630 G21 2630f 10 LTC2630 TYPICAL PERFORMANCE CHARACTERISTICS LTC2630 Large-Signal Response Midscale-Glitch Impulse INTERNAL REF Power-On Reset Glitch LTC2630-L CS/LD 5V/DIV 0.5V/DIV VOUT 5mV/DIV VFS = VCC = 5V 1/4 SCALE TO 3/4 SCALE 2µs/DIV 2630 G22 VCC 2V/DIV LTC2630-H12, VCC = 5V: 2.4nV-s TYP ZERO-SCALE LTC2630-L12, VCC = 3V: 2.0nV-s TYP 2µs/DIV 2630 G23 VOUT 2mV/DIV 200µs/DIV 2630 G24 Headroom at Rails vs Output Current 5.0 4.5 4.0 3.5 VOUT (V) 3.0 2.5 2.0 1.5 1.0 0.5 0 0 3V (LTC2630-L) SINKING 1 2 3 4 5 IOUT (mA) 6 7 8 5V SINKING 3V (LTC2630-L) SOURCING 5V SOURCING 500 Noise Voltage vs Frequency CODE = MIDSCALE 0.1Hz to 10Hz Voltage Noise VCC = 4V, VFS = 2.5V CODE = MIDSCALE NOISE VOLTAGE (nV/√Hz) 400 300 LTC2630-H (VCC = 5V) 10µV/DIV 200 100 LTC2630-L (VCC = 4V) 0 100 1k 10k FREQUENCY (Hz) 100k 1M 2630 G26 1s/DIV 2630 G27 2630 G25 Exiting Power-Down to Midscale 1.0 Supply Current vs Logic Voltage SWEEP SCK, SDI, CS/LD BETWEEN 0V AND VCC CS/LD 2V/DIV ICC (mA) 0.8 0.6 VCC = 5V VOUT 0.5V/DIV 0.4 VCC = 3V (LTC2630-L) 0.2 LTC2630-H 4µs/DIV 2630 G28 0 0 1 2 3 LOGIC VOLTAGE (V) 4 5 2630 G29 2630f 11 LTC2630 PIN FUNCTIONS ⎯C⎯S/LD (Pin 1): Serial Interface Chip Select/Load Input. When ⎯C⎯S/LD is low, SCK is enabled for shifting data on SDI into the register. When ⎯C⎯S/LD is taken high, SCK is disabled and the specified command (see Table 1) is executed. SCK (Pin 2): Serial Interface Clock Input. CMOS and TTL compatible. SDI (Pin 3): Serial Interface Data Input. Data on SDI is clocked into the DAC on the rising edge of SCK. The LTC2630 accepts input word lengths of either 24 or 32 bits. VCC (Pin 4): Supply Voltage Input. 2.7V ≤ VCC ≤ 5.5V (LTC2630-L) or 4.5V ≤ VCC ≤ 5.5V (LTC2630-H). Also used as the reference input when the part is programmed to operate in supply as reference mode. Bypass to GND with a 0.1μF capacitor. GND (Pin 5): Ground. VOUT (Pin 6): DAC Analog Voltage Output. BLOCK DIAGRAM VCC INTERNAL REFERENCE SDI CONTROL DECODE LOGIC SCK 24-BIT SHIFT REGISTER DACREF CS/LD INPUT REGISTER DAC REGISTER DAC VOUT RESISTOR DIVIDER GND 2630 BD 2630f 12 LTC2630 TIMING DIAGRAM t1 t2 SCK 1 t3 2 t4 3 23 t6 24 t10 SDI t5 CS/LD 2630 F01 t7 Figure 1. Serial Interface Timing OPERATION The LTC2630 is a family of single voltage output DACs in 6-lead SC70 packages. Each DAC can operate rail-to-rail referenced to the input supply, or with its full-scale voltage set by an integrated reference. Twelve combinations of accuracy (12-, 10-, and 8-bit), power-on reset value (zero or midscale), and full-scale voltage (2.5V or 4.096V) are available. The LTC2630 is controlled using a 3-wire SPI/MICROWIRE compatible interface. Power-On Reset The LTC2630-HZ/-LZ clear the output to zero scale when power is first applied, making system initialization consistent and repeatable. For some applications, downstream circuits are active during DAC power-up, and may be sensitive to nonzero outputs from the DAC during this time. The LTC2630 contains circuitry to reduce the power-on glitch: the analog output typically rises less than 5mV above zero scale during power on if the power supply is ramped to 5V in 1ms or more. In general, the glitch amplitude decreases as the power supply ramp time is increased. See “Power-On Reset Glitch” in the Typical Performance Characteristics section. The LTC2630-HM/-LM provide an alternative reset, setting the output to midscale when power is first applied. Transfer Function The digital-to-analog transfer function is ⎛k⎞ VOUT(IDEAL) = ⎜ N ⎟ VREF ⎝2 ⎠ where k is the decimal equivalent of the binary DAC input code, N is the resolution, and VREF is either 2.5V (LTC2630-L) or 4.096V (LTC2630-H) in internal reference mode, and VCC in Supply as reference mode. Table 1. Command Codes Command* C3 C2 C1 C0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 1 0 1 1 0 1 1 0 0 1 Write to Input Register Update (Power up) DAC Register Write to and Update (Power up) DAC Register Power down Select Internal Reference (Power-on Reset Default) Select Supply as Reference (VREF = VCC ) *Command codes not shown are reserved and should not be used. 2630f 13 LTC2630 OPERATION INPUT WORD (LTC2630-12) COMMAND C3 C2 C1 C0 4 DON'T-CARE BITS X X X X D11 D10 MSB INPUT WORD (LTC2630-10) COMMAND C3 C2 C1 C0 4 DON'T-CARE BITS X X X X D9 MSB INPUT WORD (LTC2630-8) COMMAND C3 C2 C1 C0 4 DON'T-CARE BITS X X X X D7 MSB D6 D5 D4 D3 DATA (8 BITS + 8 DON'T-CARE BITS) D2 D1 D0 LSB X X X X X X X X 2630 F02 DATA (12 BITS + 4 DON'T-CARE BITS) D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 LSB X X X X DATA (10 BITS + 6 DON'T-CARE BITS) D8 D7 D6 D5 D4 D3 D2 D1 D0 LSB X X X X X X Figure 2. Command and Data Input Format Serial Interface The ⎯C⎯S/LD input is level triggered. When this input is taken low, it acts as a chip-select signal, enabling the SDI and SCK buffers and the input shift register. Data (SDI input) is transferred at the next 24 rising SCK edges. The 4-bit command, C3-C0, is loaded first; then 4 don’t-care bits; and finally the 16-bit data word. The data word comprises the 12-, 10- or 8-bit input code, ordered MSB-to-LSB, followed by 4, 6 or 8 don’t-care bits (LTC2630-12, -10 and -8 respectively; see Figure 2). Data can only be transferred to the device when the ⎯C⎯S/LD signal is low, beginning on the first rising edge of SCK. SCK may be high or low at the falling edge of ⎯C⎯S/LD. The rising edge of ⎯C⎯S/LD ends the data transfer and causes the device to execute the command specified in the 24-bit input sequence. The complete sequence is shown in Figure 3a. The command (C3-C0) assignments are shown in Table 1. The first three commands in the table consist of write and update operations. A Write operation loads a 16-bit data word from the 24-bit shift register into the input register. In an Update operation, the input register is copied to the DAC register and converted to an analog voltage at the DAC output. Write to and Update combines the first two commands. The Update operation also powers up the DAC if it had been in power-down mode. The data path and registers are shown in the Block Diagram. While the minimum input sequence is 24 bits, it may optionally be extended to 32 bits to accommodate microprocessors that have a minimum word width of 16 bits (2 bytes). To use the 32-bit width, 8 don’t-care bits are transferred to the device first, followed by the 24-bit sequence described. Figure 3b shows the 32-bit sequence. The 16-bit data word is ignored for all commands that do not include a Write operation. Power-Down Mode For power-constrained applications, power-down mode can be used to reduce the supply current whenever the DAC output is not needed. When in power-down, the buffer amplifier, bias circuit, and reference circuit are disabled and draw essentially zero current. The DAC output is put into a high-impedance state, and the output pin is passively pulled to ground through a 200kΩ resistor. Input and DAC register contents are not disturbed during power-down. The DAC can be put into power-down mode by using command 0100. The supply current is reduced to 1.5µA maximum when the DAC is powered down. Normal operation resumes after executing any command that includes a DAC update, as shown in Table 1. The DAC is powered up and its voltage output is updated. Normal settling is delayed while the bias, reference, and amplifier circuits are re-enabled. The power up delay time is 18μs for settling to 12 bits. 2630f 14 LTC2630 OPERATION Reference Modes For applications where an accurate external reference is not available, the LTC2630 has a user-selectable, integrated reference. The LTC2630-LM and LTC2630-LZ provide a full-scale output of 2.5V. The LTC2630-HM and LTC2630HZ provide a full-scale output of 4.096V. The internal reference can be useful in applications where the supply voltage is poorly regulated. Internal Reference mode can be selected by using command 0110, and is the power-on default. The DAC can also operate in supply as reference mode using command 0111. In this mode, VCC supplies the DAC’s reference voltage and the supply current is reduced. Voltage Output The LTC2630’s integrated rail-to-rail amplifier has guaranteed load regulation when sourcing or sinking up to 10mA at 5V, and 5mA at 3V. Load regulation is a measure of the amplifier’s ability to maintain the rated voltage accuracy over a wide range of load current. The measured change in output voltage per change in forced load current is expressed in LSB/mA. DC output impedance is equivalent to load regulation, and may be derived from it by simply calculating a change in units from LSB/mA to ohms. The amplifier’s DC output impedance is 0.1Ω when driving a load well away from the rails. When drawing a load current from either rail, the output voltage headroom with respect to that rail is limited by the 50Ω typical channel resistance of the output devices (e.g., when sinking 1mA, the minimum output voltage is 50Ω • 1mA, or 50mV). See the graph “Headroom at Rails vs. Output Current” in the Typical Performance Characteristics section. The amplifier is stable driving capacitive loads of up to 500pF. Rail-to-Rail Output Considerations In any rail-to-rail voltage output device, the output is limited to voltages within the supply range. Since the analog output of the DAC cannot go below ground, it may limit for the lowest codes as shown in Figure 4b. Similarly, limiting can occur near full scale when using the supply as reference. If VFS = VCC and the DAC full-scale error (FSE) is positive, the output for the highest codes limits at VCC, as shown in Figure 4. No full-scale limiting can occur if VFS is less than VCC–FSE. Offset and linearity are defined and tested over the region of the DAC transfer function where no output limiting can occur. Board Layout The PC board should have separate areas for the analog and digital sections of the circuit. A single, solid ground plane should be used, with analog and digital signals carefully routed over separate areas of the plane. This keeps digital signals away from sensitive analog signals and minimizes the interaction between digital ground currents and the analog section of the ground plane. The resistance from the LTC2630 GND pin to the ground plane should be as low as possible. Resistance here will add directly to the effective DC output impedance of the device (typically 0.1Ω). Note that the LTC2630 is no more susceptible to this effect than any other parts of this type; on the contrary, it allows layout-based performance improvements to shine rather than limiting attainable performance with excessive internal resistance. Another technique for minimizing errors is to use a separate power ground return trace on another board layer. The trace should run between the point where the power supply is connected to the board and the DAC ground pin. Thus the DAC ground pin becomes the common point for analog ground, digital ground, and power ground. When the LTC2630 is sinking large currents, this current flows out the ground pin and directly to the power ground trace without affecting the analog ground plane voltage. It is sometimes necessary to interrupt the ground plane to confine digital ground currents to the digital portion of the plane. When doing this, make the gap in the plane only as long as it needs to be to serve its purpose and ensure that no traces cross over the gap. 2630f 15 LTC2630 OPERATION Optoisolated 4mA to 20mA Process Controller Figure 5 shows how to use an LTC2630HZ to make an optoisolated, digitally-controlled 4mA to 20mA transmitter. The transmitter circuitry, including optoisolation, is powered by the loop voltage which has a wide range of 5.4V to 80V. The 5V output of the LT®3010-5 is used to set the 4mA offset current and VOUT is used to digitally control the 0mA to 16mA signal current. The supply current for the regulator, DAC, and op amp is well below the 4mA budget at zero scale. RS senses the total loop current, which includes the quiescent supply current and additional current through Q1. Note that at the maximum loop voltage of 80V, Q1 will dissipate 1.6W when IOUT = 20mA and must have an appropriate heat sink. ROFFSET and RGAIN are the closest 0.1% values to ideal for controlling a 4mA to 20mA output as the digital input varies from zero scale to full scale. Alternatively, ROFFSET can be a 365k, 1% resistor in series with a 20k trim pot and RGAIN can be a 75.0k, 1% resistor in series with a 5k trim pot. The optoisolators shown will limit the speed of the serial bus; the 6N139 is an alternative that will allow higher data rates. CS/LD SCK SDI 1 C3 C2 2 3 C1 4 C0 X 5 X 6 X 7 X 8 9 D11 10 D10 11 D9 12 D8 13 D7 14 D6 15 D5 16 D4 17 D3 18 D2 19 D1 20 D0 X 21 22 X 23 X 24 X 2630 F03a COMMAND WORD 4 DON’T-CARE BITS DATA WORD 24-BIT INPUT WORD Figure 3a. 24-Bit Load Sequence (Minimum Input Word) LTC2630-12 SDI Data Word: 12-Bit Input Code + 4 Don’t-Care Bits (Shown); LTC2630-10 SDI Data Word: 10-Bit Input Code + 6 Don’t-Care Bits; LTC2630-8 SDI Data Word: 8-Bit Input Code + 8 Don’t-Care Bits CS/LD SCK SDI X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 9 C3 10 C2 11 C1 12 C0 13 X 14 X 15 X 16 X 17 D11 18 D10 19 D9 20 D8 21 D7 22 D6 23 D5 24 D4 25 D3 26 D2 27 D1 28 D0 29 X 30 X 31 X 32 X 8 DON’T-CARE BITS COMMAND WORD 4 DON’T-CARE BITS DATA WORD 2630 F03b 32-BIT INPUT WORD Figure 3b. 32-Bit Load Sequence LTC2630-12 SDI Data Word: 12-Bit Input Code + 4 Don’t-Care Bits (Shown); LTC2630-10 SDI Data Word: 10-Bit Input Code + 6 Don’t-Care Bits; LTC2630-8 SDI Data Word: 8-Bit Input Code + 8 Don’t-Care Bits 2630f 16 OPERATION POSITIVE FSE VREF = VCC VREF = VCC OUTPUT VOLTAGE OUTPUT VOLTAGE INPUT CODE (c) 0V 0 2,048 INPUT CODE (a) 4,095 2630 F04 OUTPUT VOLTAGE 0V NEGATIVE OFFSET INPUT CODE (b) Figure 4. Effects of Rail-to-Rail Operation on a DAC Transfer Curve (Shown for 12 Bits). (a) Overall Transfer Function (b) Effect of Negative Offset for Codes Near Zero (c) Effect of Positive Full-Scale Error for Codes Near Full Scale LTC2630 17 2630f LTC2630 TYPICAL APPLICATION 12-Bit, 2.7V to 5.5V Single Supply, Voltage Output DAC 2.7V TO 5.5V 0.1µF SDI µP SCK CS/LD GND 2630 TA01 VCC LTC2630-LZ12 V OUT OUTPUT 0V TO 2.5V OR 0V TO VCC 2630f 18 LTC2630 PACKAGE DESCRIPTION SC6 Package 6-Lead Plastic SC70 (Reference LTC DWG # 05-08-1638 Rev B) 0.47 MAX 0.65 REF 1.80 – 2.20 (NOTE 4) 1.00 REF 2.8 BSC 1.8 REF 1.80 – 2.40 1.15 – 1.35 (NOTE 4) INDEX AREA (NOTE 6) PIN 1 RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.10 – 0.40 0.65 BSC 0.15 – 0.30 6 PLCS (NOTE 3) 0.80 – 1.00 0.00 – 0.10 REF 1.00 MAX GAUGE PLANE 0.15 BSC 0.26 – 0.46 NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. DETAILS OF THE PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE INDEX AREA 7. EIAJ PACKAGE REFERENCE IS EIAJ SC-70 8. JEDEC PACKAGE REFERENCE IS MO-203 VARIATION AB 0.10 – 0.18 (NOTE 3) SC6 SC70 1205 REV B 2630f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 19 LTC2630 TYPICAL APPLICATION VLOOP 5.4V TO 80V ROFFSET 374k 0.1% LT3010-5 IN OUT SHDN SENSE 1µF GND FROM OPTOISOLATED INPUTS SDI SCK CS/LD VCC LTC2630-HZ VOUT 3.01k + 1µF RGAIN 76.8k 0.1% + LTC2054 1k Q1 2N3440 – 1000PF 10k 5V OPTO-ISOLATORS 10k SDI SCK CS/LD RS 10Ω IOUT 2630 F05 SDI SCK CS/LD 500Ω 4N28 Figure 5. An Optoisolated 4mA to 20mA Process Controller RELATED PARTS PART NUMBER LTC1660/LTC1665 LTC1663 LTC1664 LTC1669 LTC1821 LTC2600/LTC2610/LTC2620 LTC2601/LTC2611/LTC2621 LTC2602/LTC2612/LTC2622 LTC2604/LTC2614/LTC2624 LTC2605/LTC2615/LTC2625 LTC2606/LTC2616/LTC2626 LTC2609/LTC2619/LTC2629 DESCRIPTION Octal 10-/8-Bit VOUT DACs in 16-Pin Narrow SSOP Single 10-Bit VOUT DAC in SOT-23 Quad 10-Bit VOUT DAC in 16-Pin Narrow SSOP Single 10-Bit VOUT DAC in SOT-23 Parallel 16-Bit Voltage Output DAC Octal 16-/14-/12-Bit VOUT DACs in 16-Lead SSOP Single 16-/14-/12-Bit VOUT DACs in 10-Lead DFN Dual 16-/14-/12-Bit VOUT DACs in 8-Lead MSOP Quad 16-/14-/12-Bit VOUT DACs in 16-Lead SSOP Octal 16-/14-/12-Bit VOUT DACs with I2C Interface COMMENTS VCC = 2.7V to 5.5V, Micropower, Rail-to-Rail Output VCC = 2.7V to 5.5V, 60μA, Internal reference, SMBus Interface VCC = 2.7V to 5.5V, Micropower, Rail-to-Rail Output VCC = 2.7V to 5.5V, 60μA, Internal reference, I2C Interface Precision 16-Bit Settling in 2μs for 10V Step 250μA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output, SPI Serial Interface 300μA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output, SPI Serial Interface 300μA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output, SPI Serial Interface 250μA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output, SPI Serial Interface 250μA per DAC, 2.7V to 5.5V Supply Range, Rail-to-Rail Output, I2C Interface Single 16-/14-/12-Bit VOUT DACs with I2C Interface 270μA per DAC, 2.7V to 5.5V Supply Range, Rail-to-Rail Output, I2C Interface Quad 16-/14-/12-Bit VOUT DACs with I2C Interface 250μA per DAC, 2.7V to 5.5V Supply Range, Rail-to-Rail Output with Separate VREF Pins for Each DAC 2630f 20 Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● LT 0407 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007