19-1124; Rev 1; 12/96 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface ______________________________Features The MAX535/MAX5351 combine a low-power, voltageoutput, 13-bit digital-to-analog converter (DAC) and a precision output amplifier in an 8-pin µMAX or DIP package. The MAX535 operates from a single +5V supply and the MAX5351 operates from a single +3.3V supply. Both devices draw only 280µA of supply current. The output amplifier’s inverting input is available to the user, allowing specific gain configurations, remote sensing, and high output current capability. This makes the MAX535/MAX5351 ideal for a wide range of applications, including industrial process control. Other features include a software shutdown and power-on reset. The serial interface is compatible with either SPI™/ QSPI™ or Microwire™. The DAC has a double-buffered input, organized as an input register followed by a DAC register. A 16-bit serial word loads data into the input register. The DAC register can be updated independently or simultaneously with the input register. All logic inputs are TTL/CMOS-logic compatible and buffered with Schmitt triggers to allow direct interfacing to optocouplers. ♦ 13-Bit DAC with Configurable Output Amplifier ________________________Applications ♦ +5V Single-Supply Operation (MAX535) +3.3V Single-Supply Operation (MAX5351) ♦ Low Supply Current: 0.24mA Normal Operation 2µA Shutdown Mode ♦ Available in 8-Pin µMAX ♦ Power-On Reset Clears DAC Output to 0V ♦ SPI/QSPI and Microwire Compatible ♦ Schmitt-Trigger Digital Inputs for Direct Optocoupler Interface _________________Ordering Information PIN-PACKAGE INL (LSB) 0°C to +70°C 8 Plastic DIP ±1/2 0°C to +70°C 8 Plastic DIP ±1 ±1/2 PART TEMP. RANGE MAX535ACPA MAX535BCPA MAX535ACUA 0°C to +70°C 8 µMAX† Industrial Process Controls MAX535BCUA 0°C to +70°C 8 µMAX ±1 Automatic Test Equipment MAX535BC/D 0°C to +70°C Dice* ±1 Ordering Information continued at end of data sheet. †Contact factory for availability. *Dice are tested at TA = +25°C, DC parameters only. Digital Offset and Gain Adjustment Motion Control Remote Industrial Controls Microprocessor-Controlled Systems ____________________Functional Diagram VDD GND REF _______________________Pin Configuration TOP VIEW FB DAC REGISTER OUT DAC CONTROL CS 2 INPUT REGISTER CS DIN SCLK OUT 1 DIN 3 MAX535 MAX5351 SCLK 4 16-BIT SHIFT REGISTER MAX535 MAX5351 8 VDD 7 GND 6 REF 5 FB DIP/µMAX SPI and QSPI are registered trademarks of Motorola, Inc. Microwire is a registered trademark of National Semiconductor Corp. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 MAX535/MAX5351 __________________General Description MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface ABSOLUTE MAXIMUM RATINGS VDD to GND .................................................................-0.3V, +6V REF, OUT, FB to GND ................................-0.3V to (VDD + 0.3V) Digital Inputs to GND ...............................................-0.3V to +6V Continuous Current into Any Pin.......................................±20mA Continuous Power Dissipation (TA = +70°C) Plastic DIP (derate 6.90mW/°C above +70°C) .................552mW µMAX (derate 4.00mW/°C above +70°C) ......................330mW CERDIP (derate 8.00mW/°C above +70°C) ...................640mW Operating Temperature Ranges MAX535_C_A/MAX5351_C_A...............................0°C to +70°C MAX535_E_A/MAX5351_E_A ............................-40°C to +85°C MAX535BMJA/MAX5351BMJA .......................-55°C to +125°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10sec) .............................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS: MAX535 (VDD = +5V ±10%, REF = 2.5V, GND = 0V, RL = 5kΩ, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. Output buffer connected in unity-gain configuration (Figure 8).) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS STATIC PERFORMANCE—ANALOG SECTION Resolution Integral Nonlinearity (Note 1) N INL Differential Nonlinearity DNL Offset Error VOS Offset-Error Tempco Gain Error (Note 1) 13 MAX535A ±0.5 MAX535B ±1.0 MAX535MJA ±2.0 Guaranteed monotonic ±0.3 TCVOS 6 GE -0.5 Gain-Error Tempco Power-Supply Rejection Ratio Bits ±1.0 LSB ±8 mV ppm/°C ±6 1 PSRR 4.5V ≤ VDD ≤ 5.5V LSB LSB ppm/°C 600 µV/V REFERENCE INPUT Reference Input Range VREF Reference Input Resistance RREF 0 Code dependent, minimum at code 1555 hex 14 VDD - 1.4 V 20 kΩ MULTIPLYING-MODE PERFORMANCE Reference -3dB Bandwidth VREF = 0.67Vp-p 650 kHz Reference Feedthrough Input code = all 0s, VREF = 3.6Vp-p at 1kHz -84 dB VREF = 1Vp-p at 25kHz, code = full scale 77 dB Signal-to-Noise Plus Distortion Ratio SINAD DIGITAL INPUTS 2 Input High Voltage VIH Input Low Voltage VIL Input Leakage Current IIN Input Capacitance CIN 2.4 VIN = 0V or VDD V 0.001 8 _______________________________________________________________________________________ 0.8 V ±0.5 µA pF Low-Power, 13-Bit Voltage-Output DACs with Serial Interface (VDD = +5V ±10%, REF = 2.5V, GND = 0V, RL = 5kΩ, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. Output buffer connected in unity-gain configuration (Figure 8).) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DIGITAL INPUTS DYNAMIC PERFORMANCE Voltage Output Slew Rate SR Output Settling Time To ±1/2LSB, VSTEP = 2.5V Output Voltage Swing Rail-to-rail (Note 2) 0.6 V/µs 16 µs 0 to VDD Current into FB 0.001 Time to Valid Operation on Start-Up CS = VDD, DIN = 100kHz Digital Feedthrough V ±0.1 µA 20 µs 5 nV-s POWER SUPPLIES Supply Voltage VDD Supply Current IDD Supply Current in Shutdown 4.5 (Note 3) 5.5 V 0.4 mA 4 20 µA 0.001 ±0.5 µA 0.28 (Note 3) Reference Current in Shutdown TIMING CHARACTERISTICS SCLK Clock Period tCP 100 ns SCLK Pulse Width High tCH 40 ns SCLK Pulse Width Low tCL 40 ns CS Fall to SCLK Rise Setup Time tCSS 40 ns SCLK Rise to CS Rise Hold Time tCSH 0 ns DIN Setup Time tDS 40 ns DIN Hold Time tDH 0 ns SCLK Rise to CS Fall Delay tCS0 40 ns CS Rise to SCLK Rise Hold Time tCS1 40 ns CS Pulse Width High tCSW 100 ns Note 1: Guaranteed from code 22 to code 8191 in unity-gain configuration. Note 2: Accuracy is better than 1LSB for VOUT = 8mV to VDD - 100mV, guaranteed by a power-supply rejection test at the end points. Note 3: RL = ∞, digital inputs at GND or VDD. _______________________________________________________________________________________ 3 MAX535/MAX5351 ELECTRICAL CHARACTERISTICS: MAX535 (continued) MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface ELECTRICAL CHARACTERISTICS: MAX5351 (VDD = +3.15V to +3.6V, REF = 1.25V, GND = 0V, RL = 5kΩ, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. Output buffer connected in unity-gain configuration (Figure 8).) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS STATIC PERFORMANCE—ANALOG SECTION Resolution N Integral Nonlinearity (Note 4) INL Differential Nonlinearity DNL Offset Error VOS 13 Bits MAX5351A ±1 MAX5351B ±2 MAX5351MJA Offset-Error Tempco Gain Error (Note 4) ±4 Guaranteed monotonic ±0.3 TCVOS 6 GE -0.5 Gain-Error Tempco Power-Supply Rejection Ratio LSB ±1.0 LSB ±8 mV ppm/°C ±6 1 LSB ppm/°C PSRR 600 µV/V REFERENCE INPUT Reference Input Range VREF Reference Input Resistance RREF 0 Code dependent, minimum at code 1555 hex 14 VDD - 1.4 V 20 kΩ MULTIPLYING-MODE PERFORMANCE (VDD = +3.3V) Reference -3dB Bandwidth VREF = 0.67Vp-p 650 kHz Reference Feedthrough Input code = all 0s, VREF = 1.9Vp-p at 1kHz -84 dB VREF = 1Vp-p at 25kHz, code = full scale 72 dB Signal-to-Noise Plus Distortion Ratio SINAD DIGITAL INPUTS Input High Voltage VIH Input Low Voltage VIL Input Leakage Current IIN Input Capacitance CIN 2.4 VIN = 0V or VDD V 0.001 0.6 V ±0.5 µA 8 pF 0.6 V/µs 16 µs DYNAMIC PERFORMANCE Voltage Output Slew Rate SR Output Settling Time To ±1/2LSB, VSTEP = 1.25V Output Voltage Swing Rail-to-rail (Note 5) 0 to VDD Current into FB 0.001 Time to Valid Operation on Start-Up CS = VDD, DIN = 100kHz Digital Feedthrough V ±0.1 µA 20 µs 5 nV-s POWER SUPPLIES Supply Voltage VDD Supply Current IDD Supply Current in Shutdown Reference Current in Shutdown 4 3.15 (Note 6) (Note 6) 3.6 V 0.4 mA 1.6 10 µA 0.001 ±0.5 µA 0.24 _______________________________________________________________________________________ Low-Power, 13-Bit Voltage-Output DACs with Serial Interface (VDD = +3.15V to +3.6V, REF = 1.25V, GND = 0V, RL = 5kΩ, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. Output buffer connected in unity-gain configuration (Figure 8).) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS TIMING CHARACTERISTICS SCLK Clock Period tCP 100 ns SCLK Pulse Width High tCH 40 ns SCLK Pulse Width Low tCL 40 ns CS Fall to SCLK Rise Setup Time tCSS 40 ns SCLK Rise to CS Rise Hold Time tCSH 0 ns DIN Setup Time tDS 40 ns DIN Hold Time tDH 0 ns SCLK Rise to CS Fall Delay tCS0 40 ns CS Rise to SCLK Rise Hold Time tCS1 40 ns CS Pulse Width High tCSW 100 ns Note 4: Guaranteed from code 44 to code 8191 in unity-gain configuration. Note 5: Accuracy is better than 1LSB for VOUT = 8mV to VDD - 150mV, guaranteed by a power-supply rejection test at the end points. Note 6: RL = ∞, digital inputs at GND or VDD. _______________________________________________________________________________________ 5 MAX535/MAX5351 ELECTRICAL CHARACTERISTICS: MAX5351 (continued) __________________________________________Typical Operating Characteristics (MAX535 only, VDD = +5V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.) MAX535 360 -0.1 -0.2 -0.3 SUPPLY CURRENT (µA) RELATIVE OUTPUT (dB) 0 -8 -12 -16 -0.4 340 320 300 280 260 240 220 200 -60 -20 0 1M 1.5M 2M 2.5M 3M 6 5 4 3 300 250 200 20 60 100 -70 -75 -80 -85 -90 0 4.0 140 4.4 4.8 5.2 5.6 100 10 1 6.0 TEMPERATURE (°C) SUPPLY VOLTAGE (V) FREQUENCY (kHz) OUTPUT FFT PLOT FULL-SCALE OUTPUT vs. LOAD REFERENCE FEEDTHROUGH AT 1kHz 2.499 -40 -60 -80 0 2.498 REFERENCE INPUT SIGNAL SIGNAL AMPLITUDE (dB) -20 2.500 MAX535-08 VREF = 3.6Vp-p CODE = FULL SCALE fIN = 1kHz MAX535-07 0 FULL-SCALE OUTPUT (V) -20 -65 150 50 1 140 -60 350 100 2 VREF = 2.5VDC + 1Vp-p SINE CODE = FULL SCALE -55 400 THD + NOISE (dB) 7 100 -50 MAX535-05 450 SUPPLY CURRENT (µA) 8 60 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 500 MAX535-04 9 20 TEMPERATURE (°C) SUPPLY CURRENT vs. SUPPLY VOLTAGE 10 -20 FREQUENCY (Hz) POWER-DOWN SUPPLY CURRENT vs. TEMPERATURE 0 -60 500k MAX535-06 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.4 REFERENCE VOLTAGE (V) 2.497 2.496 2.495 2.494 2.493 -20 MAX535-09a/09b -0.5 POWER-DOWN SUPPLY CURRENT (µA) RL = ∞ 380 -4 0.1 MAX535-03 0.2 400 MAX535-02 0 MAX535-01 0.3 INL (LSB) SUPPLY CURRENT vs. TEMPERATURE REFERENCE VOLTAGE INPUT FREQUENCY RESPONSE INTEGRAL NONLINEARITY vs. REFERENCE VOLTAGE SIGNAL AMPLITUDE (dB) MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface -40 -60 OUTPUT FEEDTHROUGH -80 2.492 2.491 -100 0.5 2.490 1.6 2.7 3.8 FREQUENCY (kHz) 6 4.9 6.0 0.01k 0.1k 1k 10k 100k LOAD (Ω) 1M 10M -100 0.5 1.6 2.7 3.8 FREQUENCY (kHz) _______________________________________________________________________________________ 4.9 6.0 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface MAX535 (continued) DIGITAL FEEDTHROUGH (fSCLK = 100kHz) MAX535-11 MAX535-10 MAJOR-CARRY TRANSITION CS 5V/div SCLK, 2V/div OUT, AC COUPLED 100mV/div OUT, AC COUPLED 10mV/div CODE = 4096 10µs/div 2µs/div CS = 5V MAX535-12 DYNAMIC RESPONSE OUT 1V/div GND 10µs/div GAIN = 2, SWITCHING FROM CODE 0 TO 8040 _______________________________________________________________________________________ 7 MAX535/MAX5351 ____________________________Typical Operating Characteristics (continued) (MAX535 only, VDD = +5V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.) ____________________________Typical Operating Characteristics (continued) (MAX5351 only, VDD = +3.3V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.) MAX5351 -0.2 -0.4 -0.6 SUPPLY CURRENT (µA) RELATIVE OUTPUT (dB) 0 -8 -12 320 300 280 260 240 -16 -0.8 220 0.8 1.2 1.6 2.0 REFERENCE VOLTAGE (V) 2.4 500k 2.5M 3.0 2.5 2.0 1.5 MAX535-17 400 350 300 250 200 60 100 140 3.0 3.1 3.2 -65 -70 3.3 3.4 3.5 3.7 3.6 3.8 FREQUENCY (kHz) FULL-SCALE OUTPUT vs. LOAD OUTPUT FFT PLOT -60 -80 0 1.24930 1.24928 REFERENCE INPUT SIGNAL SIGNAL AMPLITUDE (dB) -40 REFERENCE FEEDTHROUGH AT 1kHz MAX535-20 1.24932 MAX535-19 VREF = 1.9Vp-p CODE = FULL SCALE fIN = 1kHz FULL-SCALE OUTPUT (V) 0 100 10 1 SUPPLY VOLTAGE (V) TEMPERATURE (°C) -20 -60 -80 100 20 140 -75 150 -20 100 VREF = 1VDC + 0.5Vp-p SINE CODE = FULL SCALE -55 1.0 0.5 60 -50 THD + NOISE (dB) 3.5 20 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 450 SUPPLY CURRENT (µA) 4.0 0 -60 -20 TEMPERATURE (°C) SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX535-16 4.5 2M 1.5M FREQUENCY (Hz) POWER-DOWN SUPPLY CURRENT vs. TEMPERATURE 5.0 1M 1.24926 1.24924 1.24922 1.24920 1.24918 MAX535-21 0.4 200 -60 MAX535-18 -20 100k -1.0 POWER-DOWN SUPPLY CURRENT (µA) RL = ∞ 340 -4 0.2 MAX535-15 360 MAX535-14 0.4 INL (LSB) 0 MAX535-13 0.6 SUPPLY CURRENT vs. TEMPERATURE REFERENCE VOLTAGE INPUT FREQUENCY RESPONSE INTEGRAL NONLINEARITY vs. REFERENCE VOLTAGE SIGNAL AMPLITUDE (dB) MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface -20 -40 -60 OUTPUT FEEDTHROUGH -80 1.24916 -100 0.5 1.24914 1.6 2.7 3.8 FREQUENCY (kHz) 8 4.9 6.0 100 1k 10k 100k LOAD (Ω) 1M 10M -100 0.5 1.2 1.9 2.6 FREQUENCY (kHz) _______________________________________________________________________________________ 3.3 4.0 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface MAX535/MAX5351 _____________________Pin Description FB PIN NAME FUNCTION 1 OUT 2 CS Chip-Select Input. Active low. 3 DIN Serial-Data Input 4 SCLK Serial-Clock Input 5 FB 6 REF Reference Voltage Input 7 GND Ground 8 VDD Positive Power Supply R DAC Output Voltage 2R DAC Output Amplifier Feedback 2R D0 R 2R D10 OUT R 2R 2R D11 D12 REF AGND SHOWN FOR ALL 1s ON DAC Figure 1. Simplified DAC Circuit Diagram _______________Detailed Description The MAX535/MAX5351 contain a 13-bit, voltage-output digital-to-analog converter (DAC) that is easily addressed using a simple 3-wire serial interface. It includes a 16-bit shift register, and has a doubledbuffered input composed of an input register and a DAC register (see Functional Diagram). In addition to the voltage output, the amplifier’s negative input is available to the user. The DAC is an inverted R-2R ladder network that converts a 13-bit digital input into an equivalent analog output voltage in proportion to the applied reference voltage input. Figure 1 shows a simplified circuit diagram of the DAC. code of 0000 hex. Because the input impedance at the reference pin is code dependent, load regulation of the reference source is important. The REF reference input has a 14kΩ guaranteed minimum input impedance. A voltage reference with a load regulation of 6ppm/mA, such as the MAX873, would typically deviate by 0.0062LSB (0.009LSB worst case) when driving the MAX535 reference input at 2.5V. In shutdown mode, the MAX535/MAX5351’s REF input enters a high-impedance state with a typical input leakage current of 0.001µA. The reference input capacitance is also code dependent and typically ranges from 15pF (with an input code of all 0s) to 50pF (with an input code of all 1s). Reference Inputs Output Amplifier The reference input accepts positive DC and AC signals. The voltage at the reference input sets the fullscale output voltage for the DAC. The reference input voltage range is 0V to (VDD - 1.4V). The output voltage (VOUT) is represented by a digitally programmable voltage source as: The MAX535/MAX5351’s DAC output is internally buffered by a precision amplifier with a typical slew rate of 0.6V/µs. Access to the output amplifier’s inverting input provides the user greater flexibility in output gain setting/signal conditioning (see the Applications Information section). With a full-scale transition at the MAX535/MAX5351 output, the typical settling time to ±1/2LSB is 16µs when loaded with 5kΩ in parallel with 100pF (loads less than 2kΩ degrade performance). The MAX535 output amplifier’s output dynamic responses and settling performances are shown in the Typical Operating Characteristics. VOUT = (VREF x NB / 8192 ) x Gain where NB is the numeric value of the DAC’s binary input code (0 to 8191), VREF is the reference voltage, and Gain is the externally set voltage gain. The impedance at the reference input is code dependent, ranging from a low value of 14kΩ when the DAC has an input code of 1555 hex, to a high value exceeding several giga ohms (leakage currents) with an input _______________________________________________________________________________________ 9 MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface Shutdown Mode The MAX535/MAX5351 feature a software-programmable shutdown that reduces supply current to a typical value of 4µA. Writing 111XXXXXXXXXXXXX as the input-control word puts the MAX535/MAX5351 in shutdown mode (Table 1). In shutdown mode, the MAX535/MAX5351 output amplifier and the reference input enter a high-impedance state. The serial interface remains active. Data in the input registers is retained in shutdown, allowing the MAX535/MAX5351 to recall the output state prior to entering shutdown. Exit shutdown mode by either recalling the previous configuration or by updating the DAC with new data. When powering up the device or bringing it out of shutdown, allow 20µs for the output to stabilize. Serial-Interface Configurations The MAX535/MAX5351’s 3-wire serial interface is compatible with both Microwire™ (Figure 2) and SPI™/QSPI™ (Figure 3). The serial input word consists of three control bits followed by 13 data bits (MSB first), as shown in Figure 4. The 3-bit control code determines the MAX535/MAX5351’s response outlined in Table 1. The MAX535/MAX5351’s digital inputs are double buffered. Depending on the command issued through the serial interface, the input register can be loaded without affecting the DAC register, the DAC register can be loaded directly, or the DAC register can be updated from the input register (Table 1). 10 SK DIN SO CS I/O MAX535 MAX5351 MICROWIRE PORT Figure 2. Connections for Microwire +5V SS DIN MAX535 MAX5351 Serial-Interface Description The MAX535/MAX5351 require 16 bits of serial data. Table 1 lists the serial-interface programming commands. For certain commands, the 13 data bits are “don’t cares.” Data is sent MSB first and can be sent in two 8-bit packets or one 16-bit word (CS must remain low until 16 bits are transferred). The serial data is composed of three control bits (C2, C1, C0), followed by the 13 data bits D12...D0 (Figure 4). The 3-bit control code determines: • The register to be updated • The configuration when exiting shutdown Figure 5 shows the serial-interface timing requirements. The chip-select pin (CS) must be low to enable the DAC’s serial interface. When CS is high, the interface control circuitry is disabled. CS must go low at least tCSS before the rising serial clock (SCLK) edge to properly clock in the first bit. When CS is low, data is clocked into the internal shift register via the serial-data input pin (DIN) on SCLK’s rising edge. The maximum guaranteed clock frequency is 10MHz. Data is latched into the MAX535/MAX5351 input/DAC register on CS’s rising edge. SCLK MOSI SCLK SCK CS SPI/QSPI PORT I/O CPOL = 0, CPHA = 0 Figure 3. Connections for SPI/QSPI MSB ..................................................................................LSB 16 Bits of Serial Data Control Bits C2 C1 Data Bits MSB.............................................LSB C0 D12................................................D0 3 Control Bits 13 Data Bits Figure 4. Serial-Data Format ______________________________________________________________________________________ Low-Power, 13-Bit Voltage-Output DACs with Serial Interface 16-BIT SERIAL WORD C1 C0 D12............................D0 MSB LSB FUNCTION C2 X 0 0 13 bits of data Load input register; DAC register immediately updated (also exit shutdown). X 0 1 13 bits of data Load input register; DAC register unchanged. X 1 0 XXXXXXXXXXXXX Update DAC register from input register (also exit shutdown; recall previous state). 1 1 1 XXXXXXXXXXXXX Shutdown 0 1 1 XXXXXXXXXXXXX No operation (NOP) “X” = Don’t care CS COMMAND EXECUTED SCLK 1 DIN 8 C1 C2 C0 D12 D11 D10 D9 D8 9 D7 16 D6 D5 D4 D3 D2 D1 D0 Figure 5. Serial-Interface Timing Diagram tCSW CS tCSO tCSS tCL tCH tCP tCSH tCS1 SCLK tDS tDH DIN Figure 6. Detailed Serial-Interface Timing Diagram ______________________________________________________________________________________ 11 MAX535/MAX5351 Table 1. Serial-Interface Programming Commands MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface DIN SCLK CS1 CS2 TO OTHER SERIAL DEVICES CS3 CS CS MAX535 MAX5351 CS MAX535 MAX5351 MAX535 MAX5351 SCLK SCLK SCLK DIN DIN DIN Figure 7. Multiple MAX535/MAX5351s Sharing Common DIN and SCLK Lines Figure 7 shows a method of connecting several MAX535/MAX5351s. In this configuration, the clock and the data bus are common to all devices and separate chip-select lines are used for each IC. __________Applications Information Table 2. Unipolar Code Table DAC CONTENTS MSB LSB 11111 1111 1111 8191 +VREF 8192 10000 0000 0001 4097 +VREF 8192 10000 0000 0000 4096 + VREF +VREF = 2 8192 01111 1111 1111 4095 +VREF 8192 00000 0000 0001 1 +VREF 8192 00000 0000 0000 0V Unipolar Output For a unipolar output, the output voltage and the reference input have the same polarity. Figure 8 shows the MAX535/MAX5351 unipolar output circuit, which is also the typical operating circuit. Table 2 lists the unipolar output codes. For rail-to-rail output, see Figure 9. This circuit shows the MAX535/MAX5351 with the output amplifier configured with a closed-loop gain of +2 to provide 0V to 5V full-scale range when a 2.5V reference is used. When using the MAX5351 with a 1.25V reference, this circuit provides a 0V to 2.5V full-scale range. Bipolar Output The MAX535/MAX5351 output can be configured for bipolar operation using Figure 10’s circuit. VOUT = VREF [(2NB / 8192) - 1] where NB is the numeric value of the DAC’s binary input code. Table 3 shows digital codes (offset binary) and the corresponding output voltage for Figure 10’s circuit. 12 ANALOG OUTPUT Using an AC Reference In applications where the reference has AC-signal components, the MAX535/MAX5351 have multiplying capability within the reference input range specifications. Figure 11 shows a technique for applying a sine-wave signal to the reference input where the AC signal is offset before being applied to REF. The reference voltage must never be more negative than GND. ______________________________________________________________________________________ Low-Power, 13-Bit Voltage-Output DACs with Serial Interface DAC CONTENTS MSB LSB ANALOG OUTPUT 11111 1111 1111 4095 +VREF 4096 10000 0000 0001 1 +VREF 4096 10000 0000 0000 0V 01111 1111 1111 1 -VREF 4096 00000 0000 0001 4095 -VREF 4096 00000 0000 0000 4096 -VREF = - VREF 4096 MAX535 MAX5351 The MAX535’s total harmonic distortion plus noise (THD + N) is typically less than -77dB (full-scale code), and the MAX5351’s THD + N is typically less than -72dB (full-scale code), given a 1Vp-p signal swing and input frequencies up to 25kHz. The typical -3dB frequency is 650kHz for both devices, as shown in the Typical Operating Characteristics graphs. Digitally Programmable Current Source The circuit of Figure 12 places an NPN transistor (2N3904 or similar) within the op-amp feedback loop to implement a digitally programmable, unidirectional current source. This circuit can be used to drive 4–20mA current loops, which are commonly used in industrialcontrol applications. The output current is calculated with the following equation: IOUT = (VREF / R) x (NB / 8192) where NB is the numeric value of the DAC’s binary input code and R is the sense resistor shown in Figure 12. MAX535 MAX5351 +5V/+3.3V REF +5V/+3.3V REF VDD VDD FB 10k FB 10k DAC OUT GND Figure 8. Unipolar Output Circuit DAC OUT GND Figure 9. Unipolar Rail-to-Rail Output Circuit ______________________________________________________________________________________ 13 MAX535/MAX5351 Table 3. Bipolar Code Table MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface +5V/ +3.3V R1 R2 +5V/+3.3V REF AC REFERENCE INPUT +5V/+3.3V VDD 26k MAX495 +V FB 500mVp-p 10k VDD REF VOUT DAC OUT DAC V- MAX535 MAX5351 GND OUT R1 = R2 = 10kΩ ±0.1% MAX535 MAX5351 GND Figure 10. Bipolar Output Circuit Figure 11. AC Reference Input Circuit Grounding and Layout Considerations +5V/ +3.3V REF VDD VL DAC MAX535 MAX5351 IOUT OUT 2N3904 Digital or AC transient signals on GND can create noise at the analog output. Tie GND to the highest-quality ground available. Good printed circuit board ground layout minimizes crosstalk between the DAC output, reference input, and digital input. Reduce crosstalk by keeping analog lines away from digital lines. Wire-wrapped boards are not recommended. FB GND R Figure 12. Digitally Programmable Current Source Power-Supply Considerations On power-up, the input and DAC registers are cleared (set to zero code). For rated MAX535/MAX5351 performance, REF should be at least 1.4V below VDD. Bypass VDD with a 4.7µF capacitor in parallel with a 0.1µF capacitor to GND. Use short lead lengths and place the bypass capacitors as close to the supply pins as possible. 14 ______________________________________________________________________________________ Low-Power, 13-Bit Voltage-Output DACs with Serial Interface PART INL (LSB) TEMP. RANGE PIN-PACKAGE MAX535AEPA MAX535BEPA -40°C to +85°C -40°C to +85°C 8 Plastic DIP 8 Plastic DIP ±1/2 ±1 MAX535AEUA MAX535BEUA MAX535BMJA MAX5351ACPA MAX5351BCPA -40°C to +85°C -40°C to +85°C -55°C to +125°C 0°C to +70°C 0°C to +70°C 8 µMAX† 8 µMAX 8 CERDIP** 8 Plastic DIP 8 Plastic DIP ±1/2 ±1 ±2 ±1 ±2 MAX5351ACUA MAX5351BCUA MAX5351BC/D MAX5351AEPA MAX5351BEPA 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 8 µMAX† 8 µMAX Dice* 8 Plastic DIP 8 Plastic DIP ±1 ±2 ±2 ±1 ±2 MAX5351AEUA MAX5351BEUA MAX5351BMJA -40°C to +85°C 8 µMAX† -40°C to +85°C 8 µMAX -55°C to +125°C 8 CERDIP** ___________________Chip Information TRANSISTOR COUNT: 1677 ±1 ±2 ±4 † Contact factory for availability. * Dice are tested at +25°C, DC parameters only. ** Contact factory for availability and processing to MIL-STD-883. ________________________________________________________Package Information D E DIM E1 A A1 A2 A3 B B1 C D1 E E1 e eA eB L A3 A A2 L A1 0° - 15° C e B1 B eA eB D1 Plastic DIP PLASTIC DUAL-IN-LINE PACKAGE (0.300 in.) INCHES MAX MIN 0.200 – – 0.015 0.175 0.125 0.080 0.055 0.022 0.016 0.065 0.045 0.012 0.008 0.080 0.005 0.325 0.300 0.310 0.240 – 0.100 – 0.300 0.400 – 0.150 0.115 PKG. DIM PINS P P P P P N D D D D D D 8 14 16 18 20 24 INCHES MIN MAX 0.348 0.390 0.735 0.765 0.745 0.765 0.885 0.915 1.015 1.045 1.14 1.265 MILLIMETERS MIN MAX – 5.08 0.38 – 3.18 4.45 1.40 2.03 0.41 0.56 1.14 1.65 0.20 0.30 0.13 2.03 7.62 8.26 6.10 7.87 2.54 – 7.62 – – 10.16 2.92 3.81 MILLIMETERS MIN MAX 8.84 9.91 18.67 19.43 18.92 19.43 22.48 23.24 25.78 26.54 28.96 32.13 21-0043A ______________________________________________________________________________________ 15 MAX535/MAX5351 _Ordering Information (continued) MAX535/MAX5351 Low-Power, 13-Bit Voltage-Output DACs with Serial Interface ___________________________________________Package Information (continued) DIM C α A 0.101mm 0.004 in e B A1 L A A1 B C D E e H L α INCHES MAX MIN 0.044 0.036 0.008 0.004 0.014 0.010 0.007 0.005 0.120 0.116 0.120 0.116 0.0256 0.198 0.188 0.026 0.016 6° 0° MILLIMETERS MIN MAX 0.91 1.11 0.10 0.20 0.25 0.36 0.13 0.18 2.95 3.05 2.95 3.05 0.65 4.78 5.03 0.41 0.66 0° 6° 21-0036D E H 8-PIN µMAX MICROMAX SMALL-OUTLINE PACKAGE D DIM E1 E D A 0°-15° Q L L1 e C B1 B S1 S CERDIP CERAMIC DUAL-IN-LINE PACKAGE (0.300 in.) A B B1 C E E1 e L L1 Q S S1 INCHES MIN MAX – 0.200 0.014 0.023 0.038 0.065 0.008 0.015 0.220 0.310 0.290 0.320 0.100 0.125 0.200 0.150 – 0.015 0.070 – 0.098 0.005 – DIM PINS D D D D D D 8 14 16 18 20 24 MILLIMETERS MIN MAX – 5.08 0.36 0.58 0.97 1.65 0.20 0.38 5.59 7.87 7.37 8.13 2.54 3.18 5.08 3.81 – 0.38 1.78 – 2.49 0.13 – INCHES MILLIMETERS MIN MAX MIN MAX – 0.405 – 10.29 – 0.785 – 19.94 – 0.840 – 21.34 – 0.960 – 24.38 – 1.060 – 26.92 – 1.280 – 32.51 21-0045A Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.