19-1196; Rev 0; 2/97 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface ______________________________Features ♦ 12-Bit DAC with Configurable Output Amplifier 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 MAX5352/MAX5353 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 SPI™/QSPI™ and 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. ♦ Available in 8-Pin µMAX ________________________Applications Industrial Process Controls Automatic Test Equipment Digital Offset and Gain Adjustment ♦ +5V Single-Supply Operation (MAX5352) +3.3V Single-Supply Operation (MAX5353) ♦ Low Supply Current: 0.28mA Normal Operation 2µA Shutdown Mode ♦ Power-On Reset Clears DAC Output to Zero ♦ SPI/QSPI and Microwire Compatible ♦ Schmitt-Trigger Digital Inputs for Direct Optocoupler Interface ♦ +3.3V MAX5353 Directly Interfaces with +5V Logic _________________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 MAX5352ACUA 0°C to +70°C 8 µMAX ±1/2 MAX5352BCUA 0°C to +70°C 8 µMAX ±1 PART* TEMP. RANGE MAX5352ACPA MAX5352BCPA Ordering Information continued at end of data sheet. *Contact factory for availability of 8-pin SO package. 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 MAX5352 MAX5353 SCLK 4 16-BIT SHIFT REGISTER MAX5352 MAX5353 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 MAX5352/MAX5353 __________________General Description The MAX5352/MAX5353 combine a low-power, voltageoutput, 12-bit digital-to-analog converter (DAC) and a precision output amplifier in an 8-pin µMAX or DIP package. The MAX5352 operates from a single +5V supply, and the MAX5353 operates from a single +3.3V supply. Both devices draw less than 280µA of supply current. MAX5352/MAX5353 Low-Power, 12-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 9.09mW/°C above +70°C) .................727mW µMAX (derate 4.10mW/°C above +70°C) ......................330mW CERDIP (derate 8.00mW/°C above +70°C) ...................640mW Operating Temperature Ranges MAX5352_C_A/MAX5353_C_A.............................0°C to +70°C MAX5352_E_A/MAX5353_E_A ..........................-40°C to +85°C MAX5352BMJA/MAX5353BMJA .....................-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: MAX5352 (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 N 12 Bits MAX5352A ±0.5 MAX5352B ±1.0 MAX5352BMJA ±2.0 Integral Nonlinearity (Note 1) INL Differential Nonlinearity DNL Offset Error VOS ±0.3 TCVOS 6 GE -0.3 Offset-Error Tempco Gain Error (Note 1) Guaranteed monotonic ±1.0 Gain-Error Tempco Power-Supply Rejection Ratio ±8 4.5V ≤ VDD ≤ 5.5V LSB mV ppm/°C ±3 1 PSRR LSB LSB ppm/°C 600 µV/V REFERENCE INPUT Reference Input Range VREF Reference Input Resistance RREF 0 Code dependent, minimum at code 1554 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, 12-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 14 µs 0 to VDD V Current into FB 0.001 Start-Up Time 20 µs 5 nV-s CS = VDD, DIN = 100kHz Digital Feedthrough ±0.1 µA POWER SUPPLIES Supply Voltage VDD Supply Current IDD Supply Current in Shutdown 5.5 V (Note 3) 4.5 0.28 0.4 mA (Note 3) 4 20 µA 0.001 ±0.5 µA Reference Current in Shutdown TIMING CHARACTERISTICS (Figure 6) 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 tDS 40 ns DIN Setup Time 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 11 to code 4095 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 MAX5352/MAX5353 ELECTRICAL CHARACTERISTICS: MAX5352 (continued) MAX5352/MAX5353 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface ELECTRICAL CHARACTERISTICS: MAX5353 (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 Integral Nonlinearity (Note 4) Differential Nonlinearity Offset Error Offset-Error Tempco Gain Error (Note 4) N INL DNL 12 ±1 MAX5353B ±2 MAX5353BMJA ±4 Guaranteed monotonic ±1.0 VOS ±0.3 TCVOS 6 GE -0.3 Gain-Error Tempco Power-Supply Rejection Ratio Bits MAX5353A ±8 LSB LSB mV ppm/°C ±3 1 LSB ppm/°C PSRR 600 µV/V REFERENCE INPUT Reference Input Range VREF Reference Input Resistance RREF 0 Code dependent, minimum at code 1554 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 14 µs 0 to VDD V DYNAMIC PERFORMANCE Voltage Output Slew Rate SR Output Settling Time To ±1/2LSB, VSTEP = 1.25V Output Voltage Swing Rail-to-rail (Note 5) Current into FB 0.001 Start-Up Time 20 µs 5 nV-s CS = VDD, DIN = 100kHz Digital Feedthrough ±0.1 µA POWER SUPPLIES Supply Voltage VDD Supply Current IDD Supply Current in Shutdown Reference Current in Shutdown 4 3.15 3.6 V (Note 6) 0.24 0.4 mA (Note 6) 1.6 10 µA 0.001 ±0.5 µA _______________________________________________________________________________________ Low-Power, 12-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 (Figure 6) 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 22 to code 4095 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 MAX5352/MAX5353 ELECTRICAL CHARACTERISTICS: MAX5353 (continued) __________________________________________Typical Operating Characteristics (MAX5352 only, VDD = +5V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.) MAX5352 360 -0.1 -0.2 -0.3 SUPPLY CURRENT (µA) RELATIVE OUTPUT (dB) -8 -12 -0.4 300 280 260 220 200 -60 -20 0.4 1.2 2.0 2.8 3.6 REFERENCE VOLTAGE (V) 4.4 0 2.5M 3M 5 4 3 300 250 200 1 50 -90 4.0 140 OUTPUT FFT PLOT 4.4 -60 -80 5.6 SUPPLY VOLTAGE (V) FREQUENCY (kHz) FULL-SCALE OUTPUT vs. LOAD REFERENCE FEEDTHROUGH AT 1kHz 0.5 1.6 2.7 3.8 FREQUENCY (kHz) 4.9 6.0 MAX5352-08 2.49968 2.49964 2.49956 0.1k 0 REFERENCE INPUT SIGNAL -20 2.49972 -40 -60 OUTPUT FEEDTHROUGH -80 2.49960 -100 100 10 1 6.0 SIGNAL AMPLITUDE (dB) -40 5.2 2.49976 FULL-SCALE OUTPUT (V) -20 4.8 2.49980 MAX5352-07 VREF = 3.6Vp-p CODE = FULL SCALE fIN = 1kHz -75 -85 TEMPERATURE (°C) 0 -70 -80 0 100 -65 150 100 60 140 -60 350 2 20 100 VREF = 2.5VDC + 1Vp-p SINE CODE = FULL SCALE -55 THD + NOISE (dB) SUPPLY CURRENT (µA) 6 60 -50 MAX5352-05 450 7 20 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 400 -20 -20 TEMPERATURE (°C) 500 8 0 -60 2M 1.5M SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX5352-04 9 1M FREQUENCY (Hz) POWER-DOWN SUPPLY CURRENT vs. TEMPERATURE 10 500k MAX5352-06 -0.5 POWER-DOWN SUPPLY CURRENT (µA) 320 240 -16 6 340 MAX5352-09a/09b INL (LSB) 0 RL = ∞ 380 -4 0.1 MAX5352-03 0.2 400 MAX5352-02 0 MAX5352-01 0.3 SUPPLY CURRENT vs. TEMPERATURE REFERENCE VOLTAGE INPUT FREQUENCY RESPONSE INTEGRAL NONLINEARITY vs. REFERENCE VOLTAGE SIGNAL AMPLITUDE (dB) MAX5352/MAX5353 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface -100 1k 10k LOAD (Ω) 100k 1M 0.5 1.6 2.7 3.8 FREQUENCY (kHz) _______________________________________________________________________________________ 4.9 6.0 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface MAX5352 (continued) DIGITAL FEEDTHROUGH (fSCLK = 100kHz) MAX5352-11 MAX5352-10 MAJOR-CARRY TRANSITION CS 5V/div SCLK, 2V/div OUT, AC COUPLED 100mV/div OUT, AC COUPLED 10mV/div CODE = 2048 10µs/div 2µs/div CS = 5V MAX5352-12 DYNAMIC RESPONSE OUT 1V/div GND 10µs/div GAIN = 2, SWITCHING FROM CODE 0 TO 4020 _______________________________________________________________________________________ 7 MAX5352/MAX5353 ____________________________Typical Operating Characteristics (continued) (MAX5352 only, VDD = +5V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.) ____________________________Typical Operating Characteristics (continued) (MAX5353 only, VDD = +3.3V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.) MAX5353 -0.1 -0.2 -0.3 SUPPLY CURRENT (mA) RELATIVE OUTPUT (dB) -8 -12 280 260 240 -0.4 220 -0.5 200 -60 1.2 1.6 2.0 REFERENCE VOLTAGE (V) -20 100k 2.4 500k 2.5M 400 2.5 2.0 1.5 350 300 250 200 60 100 140 3.0 3.1 3.2 OUTPUT FFT PLOT -60 -80 3.5 3.6 3.7 3.8 FREQUENCY (kHz) FULL-SCALE OUTPUT vs. LOAD REFERENCE FEEDTHROUGH AT 1kHz 1.24988 0.5 1.6 2.7 3.8 FREQUENCY (kHz) 4.9 6.0 1.24986 1.24984 1.24982 1.24978 0.1k 0 REFERENCE INPUT SIGNAL -20 -40 -60 OUTPUT FEEDTHROUGH -80 1.24980 -100 100 10 1 MAX5353-20 MAX5353-19 -40 3.4 SIGNAL AMPLITUDE (dB) -20 3.3 1.24990 FULL-SCALE OUTPUT (V) VREF = 1.9Vp-p CODE = FULL SCALE fIN = 1kHz -70 SUPPLY VOLTAGE (V) TEMPERATURE (°C) 0 -65 -80 100 20 -60 -75 150 -20 140 VREF = 1VDC + 0.5Vp-p SINE CODE = FULL SCALE -55 1.0 0.5 100 -50 THD + NOISE (dB) SUPPLY CURRENT (mA) 3.0 60 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 450 3.5 20 TEMPERATURE (°C) 4.0 0 -60 -20 FREQUENCY (Hz) MAX5353-17 4.5 2M 1.5M SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX5353-16 5.0 1M MAX5353-18 0.8 POWER-DOWN SUPPLY CURRENT vs. TEMPERATURE POWER-DOWN SUPPLY CURRENT (mA) 300 -16 0.4 8 320 MAX5353-21 INL (LSB) 0 RL = ∞ 340 -4 0.1 MAX5353-15 0.2 360 MAX5353-14 0 MAX5353-13 0.3 SUPPLY CURRENT vs. TEMPERATURE REFERENCE VOLTAGE INPUT FREQUENCY RESPONSE INTEGRAL NONLINEARITY vs. REFERENCE VOLTAGE SIGNAL AMPLITUDE (dB) MAX5352/MAX5353 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface -100 1k 10k LOAD (Ω) 100k 1M 0.5 1.2 1.9 2.6 FREQUENCY (kHz) _______________________________________________________________________________________ 3.3 4.0 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface MAX5352/MAX5353 _____________________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 R 2R OUT R 2R 2R MSB REF AGND SHOWN FOR ALL 1s ON DAC Figure 1. Simplified DAC Circuit Diagram _______________Detailed Description The MAX5352/MAX5353 contain a voltage-output digital-to-analog converter (DAC) that is easily addressed using a simple 3-wire serial interface. Each IC includes a 16-bit shift register, and has a double-buffered 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 digital input (12 data bits plus one sub-bit) into an equivalent analog output voltage in proportion to the applied reference voltage. Figure 1 shows a simplified circuit diagram of the DAC. Reference Inputs 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 expressed in the following equation: VOUT = (VREF x NB / 4096) x Gain where NB is the numeric value of the DAC’s binary input code (0 to 4095), 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 1554 hex, to a high value exceeding several giga ohms (leakage currents) with an input code of 0000 hex. Because the input impedance at the reference pin is code dependent, load regulation of the reference source is important. In shutdown mode, the MAX5352/MAX5353’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 (at full scale). The MAX873 +2.5V reference is recommended for the MAX5352. Output Amplifier The MAX5352/MAX5353’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 MAX5352/MAX5353 output, the typical settling time to ±1/2LSB is 14µs when loaded with 5kΩ in parallel with 100pF (loads less than 2kΩ degrade performance). The amplifier’s output dynamic responses and settling performances are shown in the Typical Operating Characteristics. Shutdown Mode The MAX5352/MAX5353 feature a software-programmable shutdown that reduces supply current to a typical value of 4µA. Writing 111X XXXX XXXX XXXX as the inputcontrol word puts the device in shutdown mode (Table 1). In shutdown mode, the amplifier’s output 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 MAX5352/MAX5353 _______________________________________________________________________________________ 9 MAX5352/MAX5353 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface 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. SCLK SK DIN SO CS I/O Serial-Interface Configurations The MAX5352/MAX5353’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 12+1 data bits (MSB first), as shown in Figure 4. The 3-bit control code determines the MAX5352/MAX5353’s response outlined in Table 1. The MAX5352/MAX5353’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). The +3.3V MAX5353 can also directly interface with +5V logic. MAX5352 MAX5353 MICROWIRE PORT Figure 2. Connections for Microwire +5V Serial-Interface Description The MAX5352/MAX5353 require 16 bits of serial data. Table 1 lists the serial-interface programming commands. For certain commands, the 12+1 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 12+1 data bits D11...D0, S0 (Figure 4). Set the sub-bit (S0) to zero. 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 MAX5352/MAX5353 input/DAC register on CS’s rising edge. SS DIN MAX5352 MAX5353 MOSI SCLK SCK CS 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 Sub-Bit C0 D11 .....................................D0, S0 3 Control Bits 12+1 Data Bits Figure 4. Serial-Data Format 10 SPI/QSPI PORT ______________________________________________________________________________________ Low-Power, 12-Bit Voltage-Output DACs with Serial Interface 16-BIT SERIAL WORD S0 FUNCTION C2 C1 C0 D11...............D0 MSB LSB S0 X 0 0 12 bits of data 0 Load input register; DAC register immediately updated (also exit shutdown). X 0 1 12 bits of data 0 Load input register; DAC register unchanged. X 1 0 XXXXXXXXXXXX X Update DAC register from input register (also exit shutdown; recall previous state). 1 1 1 XXXXXXXXXXXX X Shutdown 0 1 1 XXXXXXXXXXXX X No operation (NOP) “X” = Don’t care CS COMMAND EXECUTED SCLK 1 DIN 8 C1 C2 C0 D11 D10 D9 D8 D7 9 D6 16 D5 D4 D3 D2 D1 D0 S0 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 MAX5352/MAX5353 Table 1. Serial-Interface Programming Commands MAX5352/MAX5353 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface DIN SCLK CS1 CS2 TO OTHER SERIAL DEVICES CS3 CS CS MAX5352 MAX5353 CS MAX5352 MAX5353 MAX5352 MAX5353 SCLK SCLK SCLK DIN DIN DIN Figure 7. Multiple MAX5352/MAX5353s Sharing Common DIN and SCLK Lines Figure 7 shows a method of connecting several MAX5352/MAX5353s. 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 1111 1111 1111 (0) 4095 +VREF 4096 1000 0000 0001 (0) 2049 +VREF 4096 1000 0000 0000 (0) + VREF 2048 +VREF = 4096 2 0111 1111 1111 (0) 2047 +VREF 4096 0000 0000 0001 (0) 1 +VREF 4096 0000 0000 0000 (0) 0V Unipolar Output For a unipolar output, the output voltage and the reference input have the same polarity. Figure 8 shows the MAX5352/MAX5353 unipolar output circuit, which is also the typical operating circuit. Table 2 lists the unipolar output codes. Figure 9 illustrates a rail-to-rail output. This circuit shows the MAX5352 with the output amplifier configured with a closed-loop gain of +2 to provide a 0V to 5V full-scale range when a 2.5V reference is used. When the MAX5353 is used with a 1.25V reference, this circuit provides a 0V to 2.5V full-scale range. ANALOG OUTPUT Bipolar Output The MAX5352/MAX5353 output can be configured for bipolar operation using Figure 10’s circuit according to the following equation: VOUT = VREF [(2NB / 4096) - 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 NOTE: ( ) are for sub-bit. Using an AC Reference In applications where the reference has AC-signal components, the MAX5352/MAX5353 have multiplying capability within the reference input range specifications. Figure 11 shows a technique for applying a sinewave 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, 12-Bit Voltage-Output DACs with Serial Interface DAC CONTENTS MSB LSB ANALOG OUTPUT 1 1 1 1 1 1 1 1 11 1 1 ( 0 ) 2047 +VREF 2048 1 0 0 0 0 0 0 0 00 0 1 ( 0 ) 1 +VREF 2048 1 0 0 0 0 0 0 0 00 0 0 ( 0 ) 0V 0 1 1 1 1 1 1 1 11 1 1 ( 0 ) 1 -VREF 2048 0 0 0 0 0 0 0 0 00 0 1 ( 0 ) 2047 -VREF 2048 0 0 0 0 0 0 0 0 00 0 0 ( 0 ) The MAX5352’s total harmonic distortion plus noise (THD+N) is typically less than -77dB (full-scale code), and the MAX5353’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 2048 -VREF = - VREF 2048 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. The output current is calculated with the following equation: IOUT = (VREF/R) x (NB/4096) where NB is the numeric value of the DAC’s binary input code and R is the sense resistor shown in Figure 12. NOTE: ( ) are for sub-bit. MAX5352 MAX5353 MAX5352 MAX5353 +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 MAX5352/MAX5353 Table 3. Bipolar Code Table MAX5352/MAX5353 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface +5V/ +3.3V R1 R2 REF AC REFERENCE INPUT +5V/+3.3V VDD +5V/+3.3V 26k MAX495 V+ FB 500mVp-p 10k VDD REF VOUT DAC OUT DAC V- MAX5352 MAX5353 GND OUT R1 = R2 = 10kΩ ±0.1% MAX5352 MAX5353 GND Figure 10. Bipolar Output Circuit Figure 11. AC Reference Input Circuit Grounding and Layout Considerations +5V/ +3.3V REF VDD DAC VL MAX5352 MAX5353 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 MAX5352/MAX5353 performance, REF must 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, 12-Bit Voltage-Output DACs with Serial Interface PART* TEMP. RANGE PIN-PACKAGE INL (LSB) MAX5352AEPA MAX5352BEPA -40°C to +85°C -40°C to +85°C 8 Plastic DIP 8 Plastic DIP ±1/2 ±1 MAX5352AEUA MAX5352BEUA MAX5352BMJA MAX5353ACPA MAX5353BCPA -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 MAX5353ACUA MAX5353BCUA MAX5353AEPA MAX5353BEPA 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 8 µMAX 8 µMAX 8 Plastic DIP 8 Plastic DIP ±1 ±2 ±1 ±2 MAX5353AEUA MAX5353BEUA MAX5353BMJA -40°C to +85°C -40°C to +85°C -55°C to +125°C 8 µMAX 8 µMAX 8 CERDIP** ±1 ±2 ±4 ___________________Chip Information TRANSISTOR COUNT: 1677 *Contact factory for availability of 8-pin SO package. **Contact factory for availability and processing to MIL-STD-883. PDIPN.EPS ________________________________________________________Package Information ______________________________________________________________________________________ 15 MAX5352/MAX5353 _Ordering Information (continued) 8LUMAXD.EPS ___________________________________________Package Information (continued) CDIPS.EPS MAX5352/MAX5353 Low-Power, 12-Bit Voltage-Output DACs with Serial Interface 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 © 1997 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.