19-1846; Rev 1; 6/01 +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs Features ♦ Ultra-Small 3mm x 5mm 8-Pin µMAX Package ♦ Low 120µA Supply Current ♦ Fast 1µs Settling Time ♦ 25MHz SPI/QSPI/MICROWIRE-Compatible Serial Interface ♦ VREF Range Extends to VDD ♦ +5V (MAX5441/MAX5442) or +3V (MAX5443/MAX5444) Single-Supply Operation ♦ Full 16-Bit Performance Without Adjustments ♦ Unbuffered Voltage Output Directly Drives 60kΩ Loads ♦ Power-On Reset Circuit Clears DAC Output to Code 0 (MAX5441/MAX5443) or Code 32768 (MAX5442/MAX5444) ♦ Schmitt-Trigger Inputs for Direct Optocoupler Interface ♦ Asynchronous CLR Pin Configurations TOP VIEW CS Applications 2 SCLK 3 DIN High-Resolution Offset and Gain Adjustment 8 GND REF 1 Industrial Process Control MAX5441 MAX5443 4 7 VDD 5 CLR 9 VDD MAX5442 MAX5444 8 RFB DIN 4 7 INV CLR 5 6 OUT µMAX-10 µMAX-8 Automated Test Equipment CS 2 SCLK 3 6 OUT 10 GND REF 1 Functional Diagrams appear at end of data sheet. Data-Acquisition Systems Ordering Information PART TEMP RANGE PIN-PACKAGE INL (LSB) SUPPLY (V) MAX5441ACUA 0°C to +70°C 8 µMAX ±2 5 MAX5441AEUA -40°C to +85°C 8 µMAX ±2 5 MAX5441BCUA 0°C to +70°C 8 µMAX ±4 5 MAX5441BEUA -40°C to +85°C 8 µMAX ±4 5 MAX5442ACUB 0°C to +70°C 10 µMAX ±2 5 MAX5442AEUB -40°C to +85°C 10 µMAX ±2 5 MAX5442BCUB 0°C to +70°C 10 µMAX ±4 5 MAX5442BEUB -40°C to +85°C 10 µMAX ±4 5 SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp. Ordering Information continued at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX5441–MAX5444 General Description The MAX5441–MAX5444 are serial-input, voltage-output, 16-bit digital-to-analog converters (DACs) in tiny µMAX packages, 50% smaller than comparable DACs in 8-pin SOs. They operate from low +3V (MAX5443/ MAX5444) or +5V (MAX5441/MAX5442) single supplies. They provide 16-bit performance (±2LSB INL and ±1LSB DNL) over temperature without any adjustments. Unbuffered DAC outputs result in a low supply current of 120µA and a low offset error of 2LSB. The DAC output ranges from 0 to VREF. For bipolar operation, matched scaling resistors are provided in the MAX5442/MAX5444 for use with an external precision op amp (such as the MAX400), generating a ±VREF output swing. A 16-bit serial word is used to load data into the DAC latch. The 25MHz, 3-wire serial interface is compatible with SPI™/QSPI™/MICROWIRE™, and can interface directly with optocouplers for applications requiring isolation. A power-on reset circuit clears the DAC output to code 0 (MAX5441/MAX5443) or code 32768 (MAX5442 /MAX5444) when power is initially applied. A logic low on CLR asynchronously clears the DAC output to code 0 (MAX5441/MAX5443) or code 32768 (MAX5442/MAX5444) independent of the serial interface. The MAX5441/MAX5443 are available in 8-pin µMAX packages. The MAX5442/MAX5444 are available in 10pin µMAX packages. MAX5441–MAX5444 +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs ABSOLUTE MAXIMUM RATINGS VDD to GND ..............................................................-0.3V to +6V CS, SCLK, DIN, CLR to GND ...................................-0.3V to +6V REF to GND ................................................-0.3V to (VDD + 0.3V) OUT, INV to GND .....................................................-0.3V to VDD RFB to INV ...................................................................-6V to +6V RFB to GND.................................................................-6V to +6V Maximum Current Into Any Pin ...........................................50mA Continuous Power Dissipation (TA = +70°C) 8-Pin µMAX (derate 4.5mW/°C above +70°C)...............362mW 10-Pin µMAX (derate 5.6mW/°C above +70°C) ..............444mW Operating Temperature Ranges MAX544 _ _CU_ ...................................................0°C to +70°C MAX544 _ _EU_.................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Maximum Die Temperature..............................................+150°C Lead Temperature (soldering, 10s) .................................+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 (VDD = +3V (MAX5443/MAX5444) or +5V (MAX5441/MAX5442), VREF = +2.5V, CL = 10pF, GND = 0, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TYP MAX UNITS Guaranteed monotonic ±0.5 ±1 LSB MAX544_A ±0.5 ±2 MAX544_B ±0.5 ±4 STATIC PERFORMANCE—ANALOG SECTION Resolution N Differential Nonlinearity DNL Integral Nonlinearity INL Zero-Code Offset Error ZSE Zero-Code Tempco ZSTC MIN 16 Bits ±2 ±0.05 Gain Error (Note 1) DAC Output Resistance ROUT Bipolar Resistor Matching ppm/°C (Note 2) 6.2 kΩ RFB/RINV 1 Ratio error ±0.015 ±20 BZSTC Power-Supply Rejection PSR REFERENCE INPUT Reference Input Range VREF Reference Input Resistance (Note 4) RREF LSB ±0.1 Bipolar Zero Offset Error Bipolar Zero Tempco LSB ppm/°C ±10 Gain-Error Tempco LSB ±0.5 ±1 +4.5V ≤ VDD ≤ +5.5V (MAX5441/MAX5442) ±1 2.0 Unipolar mode 10 Bipolar mode 6 DYNAMIC PERFORMANCE—ANALOG SECTION Voltage-Output Slew Rate SR (Note 5) LSB ppm/°C +2.7V ≤ VDD ≤ +3.3V (MAX5443/MAX5444) (Note 3) % VDD LSB V kΩ 15 V/µs To ± /2LSB of FS 1 µs DAC Glitch Impulse Major-carry transition 7 nV-s Digital Feedthrough Code = 0000 hex; CS = VDD; SCLK, DIN = 0 to VDD levels 0.2 nV-s Output Settling Time 2 1 _______________________________________________________________________________________ +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs (VDD = +3V (MAX5443/MAX5444) or +5V (MAX5441/MAX5442), VREF = +2.5V, CL = 10pF, GND = 0, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DYNAMIC PERFORMANCE—REFERENCE SECTION Reference -3dB Bandwidth BW Reference Feedthrough Signal-to-Noise Ratio Reference Input Capacitance Code = FFFF hex Code = 0000 hex, VREF = 1VP-P at 100kHz SNR CINREF 1 MHz 1 mVP-P 92 dB Code = 0000 hex 70 Code = FFFF hex 170 pF STATIC PERFORMANCE—DIGITAL INPUTS Input High Voltage VIH Input Low Voltage VIL Input Current IIN Input Capacitance CIN Hysteresis Voltage VH 2.4 (Note 6) V 3 0.8 V ±1 µA 10 pF 0.15 V POWER SUPPLY MAX5443/MAX5444 2.7 3.6 MAX5441/MAX5442 4.5 5.5 Positive Supply Range (Note 7) VDD Positive Supply Current IDD All digital inputs at VDD or GND PD All digital inputs at VDD or GND Power Dissipation 0.12 MAX5443/MAX5444 0.36 MAX5441/MAX5442 0.60 V 0.20 mA mW TIMING CHARACTERISTICS (VDD = +2.7V to +3.3V (MA5443/MAX5444) , VDD = +4.5V to +5.5V (MAX5441/MAX5442), VREF = +2.5V, GND = 0, CMOS inputs, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Figure 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 25 MHz SCLK Frequency fCLK SCLK Pulse Width High tCH 20 ns SCLK Pulse Width Low tCL 20 ns tCSS0 15 ns 15 ns 35 ns CS Low to SCLK High Setup CS High to SCLK High Setup tCSS1 SCLK High to CS Low Hold tCSH0 SCLK High to CS High Hold tCSH1 20 ns DIN to SCLK High Setup tDS 15 ns DIN to SCLK High Hold tDH 0 ns tCLW 20 ns CLR Pulse Width Low VDD High to CS Low (power-up delay) (Note 6) 20 µs Note 1: Gain error tested at VREF = +2.0V, +2.5V, and +3.0V (MAX5443/MAX5444) or VREF = +2.0V, +2.5V, +3.0V, and +5.5V (MAX5441/ MAX5442). Note 2: ROUT tolerance is typically ±20%. Note 3: Min/max range guaranteed by gain-error test. Operation outside min/max limits will result in degraded performance. Note 4: Reference input resistance is code-dependent, minimum at 8555hex in unipolar mode, 4555hex in bipolar mode. Note 5: Slew-rate value is measured from 10% to 90%. Note 6: Guaranteed by design. Not production tested. Note 7: Guaranteed by power-supply rejection test and Timing Characteristics. _______________________________________________________________________________________ 3 MAX5441–MAX5444 ELECTRICAL CHARACTERISTICS (continued) __________________________________________Typical Operating Characteristics (VDD = +3V (MAX5443/MAX5444) or +5V (MAX5441/MAX5442), VREF = +2.5V, GND = 0, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) VDD = +3V 0.075 0.050 0.10 0.09 0.08 0.07 0.025 MAX5441/44 toc03 0.11 0.12 0.11 SUPPLY CURRENT (mA) 0.100 MAX5441/44 toc02 VDD = +5V 0.12 SUPPLY CURRENT (mA) SUUPLY CURRENT (mA) 0.125 MAX5441/44 toc01 0.150 SUPPLY CURRENT vs. REFERENCE VOLTAGE SUPPLY CURRENT vs. REFERENCE VOLTAGE SUPPLY CURRENT vs. TEMPERATURE 0.10 0.09 0.08 0.07 0.06 0.06 VDD = +5V 10 35 60 0 85 ZERO-CODE OFFSET ERROR vs. TEMPERATURE INTEGRAL NONLINEARITY vs. TEMPERATURE 0.6 +INL 0.1 0.2 -0.1 -DNL -0.3 -0.2 -0.4 -0.4 -0.2 -15 10 35 60 -40 85 -15 35 60 GAIN ERROR vs. TEMPERATURE 0.20 0.15 -0.15 -0.25 10 35 TEMPERATURE (°C) 60 85 85 0.075 0.050 0.05 0.025 0 0 -0.025 -0.10 -0.050 -0.15 -0.075 -0.20 -0.100 -0.125 -0.25 -0.30 60 0.100 0.10 -0.05 -0.20 35 DIFFERENTIAL NONLINEARITY DNL (LSB) INL (LSB) -0.10 10 0.125 MAX5441/44 toc08 0.25 MAX5441/44 toc07 -0.05 -15 -15 TEMPERATURE (°C) INTEGRAL NONLINEARITY vs. CODE 0 -40 -40 85 TEMPERATURE (°C) TEMPERATURE (°C) 4 10 MAX5441/44 toc09 -40 3.0 +DNL -INL -0.1 2.5 -0.2 0 0 2.0 0 DNL (LSB) INL (LSB) 0.1 1.5 0.2 0.4 0.2 1.0 DIFFERENTIAL NONLINEARITY vs. TEMPERATURE 0.8 MAX5441/44 toc04 0.3 0.5 REFERENCE VOLTAGE (V) REFERENCE VOLTAGE (V) 0.4 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 TEMPERATURE (°C) MAX5441/44 toc06 -15 MAX5441/44 toc05 -40 OFFSET ERROR (LSB) VDD = +3V 0.05 0.05 0 GAIN ERROR (LSB) MAX5441–MAX5444 +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs 0 5k 15k 25k 35k 45k 55k 66k 0 5k 15k 25k CODE _______________________________________________________________________________________ 35k CODE 45k 55k 66k +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs FULL-SCALE STEP RESPONSE (FALLING) REFERENCE CURRENT vs. DIGITAL INPUT CODE MAX5441/44 toc11 120 MAX5441/44 toc12 MAX5441/44 toc10 140 100 CS 2V/div CS 2V/div AOUT 1V/div AOUT 1V/div 80 60 40 20 CL = 20pF CL = 20pF 0 400ns/div 10000 20000 30000 40000 50000 60000 70000 400ns/div CODE MAJOR-CARRY GLITCH (RISING) MAX5441/44 toc14 MAX5441/44 toc13 MAJOR-CARRY GLITCH (FALLING) CS 1V/div CS 1V/div AOUT 20mV/div AOUT 20mV/div CL = 20pF CL = 20pF 200ns/div 200ns/div INTEGRAL NONLINEARITY vs. REFERENCE VOLTAGE MAX5441/44 toc16 0.70 0.65 DIN 2V/div UNIPOLAR POWER-ON GLITCH (REF = VDD) 0.60 VDD 2V/div 0.55 0.50 AOUT 10mV/div MAX5441/44 toc17 DIGITAL FEEDTHROUGH INL (LSB) 0 MAX5441/44 toc15 REFERENCE CURRENT (µA) FULL-SCALE STEP RESPONSE (RISING) VOUT 10mV/div 0.45 CL = 112pF 0.40 50ns/div 2.0 2.5 3.0 3.5 4.0 4.5 5.0 50ms/div REFERENCE VOLTAGE (V) _______________________________________________________________________________________ 5 MAX5441–MAX5444 Typical Operating Characteristics (continued) (VDD = +3V (MAX5443/MAX5444) or +5V (MAX5441/MAX5442), VREF = +2.5V, GND = 0, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) MAX5441–MAX5444 +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs Pin Description PIN MAX5441 MAX5443 1 MAX5442 MAX5444 1 NAME FUNCTION REF Voltage Reference Input 2 2 CS Chip-Select Input 3 3 SCLK 4 4 DIN Serial Data Input 5 5 CLR Clear Input. Logic low asynchronously clears the DAC to code 0 (MAX5441/MAX5443) or code 32768 (MAX5442/MAX5444). 6 6 OUT DAC Output Voltage — 7 INV Junction of Internal Scaling Resistors. Connect to external op amp’s inverting input in bipolar mode. Serial Clock Input. Duty cycle must be between 40% and 60%. — 8 RFB Feedback Resistor. Connect to external op amp’s output in bipolar mode. 7 9 VDD Supply Voltage. Use +3V for MAX5443/MAX5444 and +5V for MAX5441/MAX5442. 8 10 GND Ground ;;;;;;;;; ;; ;;;;;; tCSH1 tLDACS CS tCSHO tCSSO tCH tCSS1 tCL SCLK tDH tDS DIN D15 D14 D0 Figure 1. Timing Diagram 6 _______________________________________________________________________________________ +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs MAX5441–MAX5444 +2.5V MAX6166 +3V/+5V 1µF 0.1µF 0.1µF (GND) REF VDD MC68XXXX PCS0 CS MOSI DIN SCLK SCLK IC1 CLR UNIPOLAR OUT MAX495 MAX5441 MAX5442 MAX5443 MAX5444 OUT EXTERNAL OP AMP GND Figure 2a. Typical Operating Circuit—Unipolar Output MAX6166 +3V/+5V +2.5V 1µF 0.1µF 0.1µF +5V MC68XXXX RFB VDD PCS0 CS MOSI DIN SCLK SCLK IC1 CLR RINV RFB INV MAX400 OUT MAX5442 MAX5444 BIPOLAR OUT EXTERNAL OP AMP -5V (GND) GND Figure 2b. Typical Operating Circuit—Bipolar Output Detailed Description The MAX5441–MAX5444 voltage-output, 16-bit digitalto-analog converters (DACs) offer full 16-bit performance with less than 2LSB integral linearity error and less than 1LSB differential linearity error, thus ensuring monotonic performance. Serial data transfer minimizes the number of package pins required. The MAX5441–MAX5444 are composed of two matched DAC sections, with a 12-bit inverted R-2R DAC forming the 12 LSBs and the four MSBs derived from 15 identically matched resistors. This architecture allows the lowest glitch energy to be transferred to the DAC output on major-carry transitions. It also lowers the DAC output impedance by a factor of eight compared _______________________________________________________________________________________ 7 MAX5441–MAX5444 +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs to a standard R-2R ladder, allowing unbuffered operation in medium-load applications. The MAX5442/MAX5444 provide matched bipolar offset resistors, which connect to an external op amp for bipolar output swings (Figure 2b). Digital Interface The MAX5441–MAX5444 digital interface is a standard 3-wire connection compatible with SPI/QSPI/ MICROWIRE interfaces. The chip-select input (CS) frames the serial data loading at the data-input pin (DIN). Immediately following CS’s high-to-low transition, the data is shifted synchronously and latched into the input register on the rising edge of the serial clock input (SCLK). After 16 data bits have been loaded into the serial input register, it transfers its contents to the DAC latch on CS’s low-to-high transition (Figure 3). Note that if CS is not kept low during the entire 16 SCLK cycles, data will be corrupted. In this case, reload the DAC latch with a new 16-bit word. Clearing the DAC A 20ns (min) logic-low pulse on CLR asynchronously clears the DAC buffer to code 0 in the MAX5441/ MAX5443 and to code 32768 in the MAX5442/ MAX5444. External Reference The MAX5441–MAX5444 operate with external voltage references from 2V to V DD . The reference voltage determines the DAC’s full-scale output voltage. Power-On Reset The power-on reset circuit sets the output of the MAX5441/MAX5443 to code 0 and the output of the MAX5442/MAX5444 to code 32768 when VDD is first applied. This ensures that unwanted DAC output voltages will not occur immediately following a system power-up, such as after a loss of power. Applications Information Reference and Ground Inputs The MAX5441–MAX5444 operate with external voltage references from 2V to VDD, and maintain 16-bit performance if certain guidelines are followed when selecting and applying the reference. Ideally, the reference’s temperature coefficient should be less than 0.1ppm/°C to maintain 16-bit accuracy to within 1LSB over the -40°C to +85°C extended temperature range. Since this converter is designed as an inverted R-2R voltage-mode DAC, the input resistance seen by the voltage reference is code-dependent. In unipolar mode, the worst-case input-resistance variation is from 11.5kΩ (at code 8555hex) to 200kΩ (at code 0000hex). The maximum change in load current for a 2.5V reference is 2.5V / 11.5k Ω = 217µA; therefore, the required load regulation is 7ppm/mA for a maximum error of 0.1LSB. This implies a reference output impedance of less than 18mΩ. In addition, the impedance of the signal path from the voltage reference to the reference input must be kept low because it contributes directly to the load-regulation error. The requirement for a low-impedance voltage reference is met with capacitor bypassing at the reference inputs and ground. A 0.1µF ceramic capacitor with short leads between REF and GND provides high-frequency bypassing. A surface-mount ceramic chip capacitor is preferred because it has the lowest inductance. An ; ; ;; CS DAC UPDATED SCLK SUB-BITS DIN D15 D14 D13 D12 D11 D10 D9 D8 MSB D7 D6 D5 D4 D3 D2 D1 D0 LSB Figure 3. MAX5441–MAX5444 3-Wire Interface Timing Diagram 8 _______________________________________________________________________________________ +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs Unbuffered Operation Unbuffered operation reduces power consumption as well as offset error contributed by the external output buffer. The R-2R DAC output is available directly at OUT, allowing 16-bit performance from +VREF to GND without degradation at zero-scale. The DAC’s output impedance is also low enough to drive medium loads (RL > 60kΩ) without degradation of INL or DNL; only the gain error is increased by externally loading the DAC output. External Output Buffer Amplifier The requirements on the external output buffer amplifier change whether the DAC is used in the unipolar or bipolar mode of operation. In unipolar mode, the output amplifier is used in a voltage-follower connection. In bipolar mode (MAX5442/MAX5444 only), the amplifier operates with the internal scaling resistors (Figure 2b). In each mode, the DAC’s output resistance is constant and is independent of input code; however, the output amplifier’s input impedance should still be as high as possible to minimize gain errors. The DAC’s output capacitance is also independent of input code, thus simplifying stability requirements on the external amplifier. In bipolar mode, a precision amplifier operating with dual power supplies (such as the MAX400) provides the ±VREF output range. In single-supply applications, precision amplifiers with input common-mode ranges including GND are available; however, their output swings do not normally include the negative rail (GND) without significant degradation of performance. A single-supply op amp, such as the MAX495, is suitable if the application does not use codes near zero. Since the LSBs for a 16-bit DAC are extremely small (38.15µV for VREF = 2.5V), pay close attention to the external amplifier’s input specification. The input offset voltage can degrade the zero-scale error and might require an output offset trim to maintain full accuracy if the offset voltage is greater than 1/2LSB. Similarly, the input bias current multiplied by the DAC output resistance (typically 6.25kΩ) contributes to the zero-scale error. Temperature effects also must be taken into consideration. Over the -40°C to +85°C extended temperature range, the offset voltage temperature coefficient (referenced to +25°C) must be less than 0.24µV/°C to add less than 1/2LSB of zero-scale error. The external amplifier’s input resistance forms a resistive divider with the DAC output resistance, which results in a gain error. To contribute less than 1/2LSB of gain error, the input resistance typically must be greater than: 6.25kΩ × 217 = 819MΩ The settling time is affected by the buffer input capacitance, the DAC’s output capacitance, and PC board capacitance. The typical DAC output voltage settling time is 1µs for a full-scale step. Settling time can be significantly less for smaller step changes. Assuming a single time-constant exponential settling response, a full-scale step takes 12 time constants to settle to within 1/2LSB of the final output voltage. The time constant is equal to the DAC output resistance multiplied by the total output capacitance. The DAC output capacitance is typically 10pF. Any additional output capacitance will increase the settling time. The external buffer amplifier’s gain-bandwidth product is important because it increases the settling time by adding another time constant to the output response. The effective time constant of two cascaded systems, each with a single time-constant response, is approximately the root square sum of the two time constants. The DAC output’s time constant is 1µs / 12 = 83ns, ignoring the effect of additional capacitance. If the time constant of an external amplifier with 1MHz bandwidth is 1 / 2π (1MHz) = 159ns, then the effective time constant of the combined system is: 83ns 2 + 159ns 2 = 180ns ) ( ) ( This suggests that the settling time to within 1/2LSB of the final output voltage, including the external buffer amplifier, will be approximately 12 ✕ 180ns = 2.15µs. Digital Inputs and Interface Logic The digital interface for the 16-bit DAC is based on a 3-wire standard that is compatible with SPI, QSPI, and MICROWIRE interfaces. The three digital inputs (CS, DIN, and SCLK) load the digital input data serially into the DAC. A 20ns (min) logic-low pulse on CLR clears the data in the DAC buffer. All of the digital inputs include Schmitt-trigger buffers to accept slow-transition interfaces. This means that optocouplers can interface directly to the MAX5441– MAX5444 without additional external logic. The digital inputs are compatible with TTL/CMOS-logic levels. _______________________________________________________________________________________ 9 MAX5441–MAX5444 additional 1µF between REF and GND provides low-frequency bypassing. A low-ESR tantalum, film, or organic semiconductor capacitor works well. Leaded capacitors are acceptable because impedance is not as critical at lower frequencies. The circuit can benefit from even larger bypassing capacitors, depending on the stability of the external reference with capacitive loading. MAX5441–MAX5444 +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs Unipolar Configuration Figure 2a shows the MAX5441–MAX5444 configured for unipolar operation with an external op amp. The op amp is set for unity gain, and Table 1 lists the codes for this circuit. The bipolar MAX5442/MAX5444 can also be used in unipolar configuration by connecting RFB and INV to REF. This allows the DAC to power-up to midscale. Bipolar Configuration Figure 2b shows the MAX5442/MAX5444 configured for bipolar operation with an external op amp. The op amp is set for unity gain with an offset of -1/2VREF. Table 2 lists the offset binary codes for this circuit. Power-Supply Bypassing and Ground Management Bypass VDD with a 0.1µF ceramic capacitor connected between VDD and GND. Mount the capacitor with short leads close to the device (less than 0.25 inches). 10 Table 1. Unipolar Code Table DAC LATCH CONTENTS MSB ANALOG OUTPUT, VOUT LSB 1111 1111 1111 1111 VREF ✕ (65,535 / 65,536) 1000 0000 0000 0000 VREF ✕ (32,768 / 65,536) = 1/2VREF 0000 0000 0000 0001 VREF ✕ (1 / 65,536) 0000 0000 0000 0000 0 Table 2. Bipolar Code Table DAC LATCH CONTENTS MSB ANALOG OUTPUT, VOUT LSB 1111 1111 1111 1111 +VREF ✕ (32,767 / 32,768) 1000 0000 0000 0001 +VREF ✕ (1 / 32,768) 1000 0000 0000 0000 0 0111 1111 1111 1111 -VREF ✕ (1 / 32,768) 0000 0000 0000 0000 -VREF ✕ (32,768 / 32,768) = -VREF ______________________________________________________________________________________ +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs VDD VDD REF REF OUT 16-BIT DAC CS SCLK DIN RFB INV MAX5442 MAX5444 MAX5441 MAX5443 CS 16-BIT DATA LATCH SCLK DIN CONTROL LOGIC SERIAL INPUT REGISTER CLR OUT 16-BIT DAC 16-BIT DATA LATCH CONTROL LOGIC SERIAL INPUT REGISTER CLR GND GND Ordering Information (continued) PART TEMP RANGE PIN-PACKAGE INL (LSB) SUPPLY (V) 3 MAX5443ACUA 0°C to +70°C 8 µMAX ±2 MAX5443AEUA -40°C to +85°C 8 µMAX ±2 3 MAX5443BCUA 0°C to +70°C 8 µMAX ±4 3 MAX5443BEUA -40°C to +85°C 8 µMAX ±4 3 MAX5444ACUB 0°C to +70°C 10 µMAX ±2 3 MAX5444AEUB -40°C to +85°C 10 µMAX ±2 3 MAX5444BCUB 0°C to +70°C 10 µMAX ±4 3 MAX5444BEUB -40°C to +85°C 10 µMAX ±4 3 _____________________Chip Information TRANSISTOR COUNT: 2800 PROCESS: BiCMOS ______________________________________________________________________________________ 11 MAX5441–MAX5444 Functional Diagrams 8LUMAXD.EPS ________________________________________________________Package Information 10LUMAX.EPS MAX5441–MAX5444 +3V/+5V, Serial-Input, Voltage-Output, 16-Bit DACs 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. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.