19-2462; Rev 1; 7/02 KIT ATION EVALU E L B A IL AVA One-Time Programmable, Linear-Taper Digital Potentiometers Features Wiper Position Stored After One-Time Fuse Programming User-Defined Power-On Reset Position 35ppm/C End-to-End Temperature Coefficient and 5ppm/C Ratiometric Temperature Coefficient 32 Tap Positions Tiny 8-Pin Thin QFN and MAX Packages Ultra-Low 1.5A (max) Static Supply Current 2.7V to 5.5V Single-Supply Operation Wiper Position Programmed Through Simple 2-Wire Serial Interface 10k, 50k, and 100k End-to-End Resistances Ordering Information Applications PART TEMP RANGE PIN-PACKAGE Mechanical Potentiometer Replacement MAX5427EUA -40C to +85C 8 MAX 100 Products Using One-Time Factory Calibration MAX5427ETA -40C to +85C 8 Thin QFN-EP* 100 MAX5428EUA -40C to +85C 8 MAX 50 MAX5428ETA -40C to +85C 8 Thin QFN-EP* 50 Pin Configurations TOP VIEW R (k) MAX5429EUA -40C to +85C 8 MAX 10 MAX5429ETA -40C to +85C 8 Thin QFN-EP* 10 *EP = Exposed paddle. W 1 8 H CS 2 7 L VDD 3 GND 4 MAX5427 MAX5428 MAX5429 Functional Block Diagram H 8 6 U/D 5 VPP VDD GND 3 4 MAX S32 MAX5427 MAX5428 MAX5429 R31 S31 R30 * W 1 CS 2 VDD 3 GND 4 8 H 7 L MAX5427 MAX5428 MAX5429 CS U/D 2 6 UP/DOWN COUNTER 5 ONE-TIME PROGRAM BLOCK RW 1 W S3 R2 6 U/D 5 VPP S30 32POSITION DECODER VPP S2 R1 * S1 QFN 7 *EXPOSED PADDLE. CONNECTED TO GND. L ________________________________________________________________ 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 MAX5427/MAX5428/MAX5429 General Description The MAX5427/MAX5428/MAX5429 linear-taper digital potentiometers function as mechanical potentiometers, but replace the mechanics with a simple 2-wire digital interface. These digital potentiometers are unique in that they have an optional one-time programmable feature that either sets the wiper's power-on reset (POR) position to a user-defined value, or the wiper can be set and the interface disabled to prevent further adjustment. The MAX5427 has an end-to-end resistance of 100k, the MAX5428 a resistance of 50k, and the MAX5429 a resistance of 10k. All these devices have 32 wiper positions, operate from a single 2.7V to 5.5V supply, and use less than 1.5A (max) static supply current. The MAX5427/MAX5428/MAX5429 are available in 8-pin thin QFN and MAX packages. Each device is guaranteed over the extended temperature range of -40C to +85C. MAX5427/MAX5428/MAX5429 One-Time Programmable, Linear-Taper Digital Potentiometers ABSOLUTE MAXIMUM RATINGS VDD to GND ...........................................................-0.3V to +6.0V VPP to GND..........................................................-0.3V to +12.0V All Other Pins to GND.................................-0.3V to (VDD + 0.3V) Input and Output Latchup Immunity...............................200mA Maximum Continuous Current into H, L, and W MAX5427 .................................................................1.5mA MAX5428 .................................................................1.5mA MAX5429 .................................................................2.0mA Continuous Power Dissipation (TA = +70C) 8-Pin MAX (derate 4.5mW/C above +70C) .............362mW 8-Pin QFN-EP (derate 24.4mW/C above +70C)......1951mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C 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 = 2.7V to 5.5V, VPP = GND, VH = VDD, VL = GND, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = 5.0V, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC PERFORMANCE Resolution 32 End-to-End Resistance End-to-End Resistance Tempco 75 100 125 MAX5428 37.5 50 62.5 MAX5429 7.5 10 12.5 TCR Ratiometric Resistance Tempco Taps MAX5427 35 MAX5427/MAX5428 5 MAX5429 10 k ppm/C ppm/C Integral Nonlinearity INL Potentiometer configuration, no load, Figure 1 1 LSB Differential Nonlinearity DNL Potentiometer configuration, no load, Figure 1 1 LSB Full-Scale Error Potentiometer configuration, no load, Figure 1 -0.5 LSB Zero-Scale Error Potentiometer configuration, no load, Figure 1 +0.5 LSB 240 Wiper Resistance RW MAX5427 IW = 20A; MAX5428 IW = 40A; MAX5429 IW = 200A 100 DIGITAL INPUTS (CS, U/D) Input High Voltage VIH Input Low Voltage VIL 0.7 x VDD V 0.3 x VDD Input Current IIN 0.1 Input Capacitance CIN 5 1 V A pF TIMING CHARACTERISTICS (Note 2) U/D Mode to CS Setup 2 tCU Figures 2, 3 50 ns CS Hold to U/D Mode tCI Figures 2, 3 50 ns U/D Step Hold to CS tIC Figures 2, 3 0 ns U/D Step Low Time tIL Figures 2, 3 100 ns _______________________________________________________________________________________ One-Time Programmable, Linear-Taper Digital Potentiometers (VDD = 2.7V to 5.5V, VPP = GND, VH = VDD, VL = GND, TA = -40C to +85C, unless otherwise noted. Typical values are at VDD = 5.0V, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS U/D Step High Time tIH Figures 2, 3 Wiper Switching Time tIW CL = 0pF, Figures 2, 3 VPP Rising Edge to CS Falling Edge tPC Figure 4 1 ms CS Falling Edge to VPP Falling Edge tCP Figure 4 5 ms CS Step Low Time tCL Figure 4 5 ms CS Step High Time tCH Figure 4 5 ms VPP Falling Edge to CS Rising Edge tPH Figure 4 1 ms U/D Frequency fU/DMAX Power-Up Time tUP Output Settling Time tSETTLE 100 ns 100 (Note 3) 100k variable resistor configuration, CL = 10pF, Figure 1 ns 5 MHz 1 ms 1 s 100k potentiometer configuration, CL = 10pF, Figure 1 0.25 POWER SUPPLY Supply Voltage VDD Static Supply Current IDD Programming Voltage VPP Programming Current IPP Note 1: Note 2: Note 3: Note 4: 2.7 5.5 V 1.5 A TA < +50C 10.45 11.55 TA +50C 11 11.55 (Note 4) VPP = 11V 5 V mA All devices are production tested at TA = +25C and are guaranteed by design for TA = -40C to +85C. Digital timing is guaranteed by design, not production tested. Power-up time is the period of time from when the power supply is applied until the serial interface is ready for writing. Digital inputs CS and U/D are connected to GND or VDD. POTENTIOMETER CONFIGURATION VARIABLE-RESISTOR CONFIGURATION H H W L L Figure 1. Potentiometer/Variable-Resistor Configuration _______________________________________________________________________________________ 3 MAX5427/MAX5428/MAX5429 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VDD = 5.0V, TA = +25C, unless otherwise noted.) END-TO-END RESISTANCE PERCENT CHANGE vs. TEMPERATURE VDD = 3.3V 120 100 VDD = 5.0V 80 MAX5429 0 -0.1 MAX5427 90 2 3 4 80 70 MAX5427 60 MAX5428 50 40 30 20 MAX5428 -0.2 MAX5427-29 toc03 MAX5427-29 toc02 0.1 100 MAX5429 10 0 -0.3 1 0 5 -40 -15 10 35 0 85 60 5 10 15 20 25 TEMPERATURE (C) TAP POSITION SUPPLY CURRENT vs. TEMPERATURE TAP-TO-TAP SWITCHING TRANSIENT WIPER TRANSIENT AT POWER-ON MAX5427-29 toc04 0.25 U/D 2V/div 30 MAX5427-29 toc06 WIPER VOLTAGE (V) 0.30 SUPPLY CURRENT (A) 0.2 MAX5427-29 toc05 WIPER RESISTANCE () 140 0.3 END-TO-END RESISTANCE CHANGE (%) MAX5427 toc01 160 W-TO-L RESISTANCE vs. TAP POSITION W-TO-L RESISTANCE (k) WIPER RESISTANCE vs. WIPER VOLTAGE VDD 2V/div VDD = 5.0V 0.20 0.15 0.10 OUTPUT W 100mV/div VDD = 3.3V OUTPUT W 1V/div 0.05 CL = 10pF 0 -40 -15 10 35 60 100ns/div 2s/div R-INL ERROR vs. INPUT CODE (MAX5427) R-DNL ERROR vs. INPUT CODE (MAX5428) 85 TEMPERATURE (C) 0.010 0.020 MAX5427-29 toc08 0.015 0.08 0.06 0.015 0.010 R-INL (LSB) 0 -0.005 R-DNL (LSB) 0.04 0.005 0.02 0 -0.02 -0.04 -0.010 -0.015 -0.08 -0.020 -0.10 5 10 15 20 INPUT CODE (DECIMAL) 25 30 0.005 0 -0.005 -0.010 -0.06 0 4 0.10 MAX5427-29 toc07 0.020 MAX5427-29 toc09 R-DNL ERROR vs. INPUT CODE (MAX5427) R-DNL (LSB) MAX5427/MAX5428/MAX5429 One-Time Programmable, Linear-Taper Digital Potentiometers -0.015 -0.020 0 5 10 15 20 INPUT CODE (DECIMAL) 25 30 0 5 10 15 20 INPUT CODE (DECIMAL) _______________________________________________________________________________________ 25 30 One-Time Programmable, Linear-Taper Digital Potentiometers R-DNL ERROR vs. INPUT CODE (MAX5429) 0.08 0.06 0.020 0.015 0.08 0.06 0.02 0 -0.02 0.04 R-INL (LSB) 0.010 R-DNL (LSB) R-INL (LSB) 0.04 0.10 MAX5427-29 toc11 0.025 MAX5427-29 toc10 0.10 R-INL ERROR vs. INPUT CODE (MAX5429) 0.005 0 -0.005 0.02 0 -0.02 -0.04 -0.010 -0.04 -0.06 -0.015 -0.06 -0.08 -0.020 -0.08 -0.10 -0.025 0 5 10 15 20 25 30 MAX5427-29 toc12 R-INL ERROR vs. INPUT CODE (MAX5428) -0.10 0 INPUT CODE (DECIMAL) 5 10 15 20 25 30 INPUT CODE (DECIMAL) 0 5 10 15 20 25 30 INPUT CODE (DECIMAL) Pin Description PIN 1 NAME W FUNCTION 2 CS Chip-Select Input. A high-to-low CS transition determines the mode: increment if U/D is high, or decrement if U/D is low. CS is also used for one-time programming (see the One-Time Programming section). 3 VDD Power-Supply Voltage 4 GND Ground 5 VPP Programming Voltage for One-Time Programming. Connect VPP to 10V supply when one-time programming the device. For normal operation, connect to ground or let float. 6 U/D Up/Down Control Input. With CS low, a low-to-high transition increments or decrements the wiper position. Wiper Connection 7 L Low Terminal of Resistor 8 H High Terminal of Resistor Detailed Description The MAX5427/MAX5428/MAX5429 are 100k/50k/ 10k (end-to-end resistance) digitally controlled potentiometers. They have 32 tap positions that are accessible to the wiper along the resistor array between H and L. The wiper (W) position is adjusted sequentially through the tap positions using a simple 2-wire interface. These digital potentiometers have an optional one-time programmable feature that sets the POR position of the wiper. The 2-wire interface can then be disabled, permanently preventing unwanted adjustment. Digital Interface Operation The MAX5427/MAX5428/MAX5429 have two modes of operation when the serial interface is active: increment mode and decrement mode. The serial interface is only active when CS is low. The CS and U/D inputs control the position of the wiper along the resistor array. When CS transitions from high to low, the part goes into increment mode if U/D is high (Figure 2), and into decrement mode if U/D is low (Figure 3). Once the mode is set, the device remains in that mode until CS goes high. A low-to-high transition at the U/D increments or decrements the wiper position depending on the current mode. When the CS input transitions to high (when serial interface is inactive) and U/D is low, the wiper increments or decrements one position. If U/D is high when CS transitions to high, the wiper remains in the same position. _______________________________________________________________________________________ 5 MAX5427/MAX5428/MAX5429 Typical Operating Characteristics (continued) (VDD = 5.0V, TA = +25C, unless otherwise noted.) MAX5427/MAX5428/MAX5429 One-Time Programmable, Linear-Taper Digital Potentiometers VDD tUP CS tCU tCI tIL tIH tIC U/D tIW VW Figure 2. Increment Mode Serial Interface Timing Diagram VDD tUP CS tCU tCI tIH tIL tIC U/D tIW VW Figure 3. Decrement Mode Serial Interface Timing Diagram The value of the counter is then stored and the wiper position is maintained. The wiper performs a make-before-break transition, ensuring that there is never an open circuit during a transition from one resistor tap to another. When the wiper is at either end (max/min) of the resistor array, additional transitions in the direction of the endpoint do not change the counter value (the counter does not wrap around). One-Time Programming The factory-set default position of the wiper on powerup is tap 16. However, the power-up position can be changed once using the one-time programming feature. After the wiper is moved to the desired position, the programming sequence is initiated by setting U/D high, applying 11V to VPP, and then taking CS low. Five pulses on CS (consisting of CS starting from low and going high for tCH and then low for tCL) program the device (Figure 4). The programming voltage should then be taken to zero. After the device is programmed, VPP can be set to zero or be allowed to float. The wiper position is still adjustable, but always returns to this programmed position on power-up. 6 If the intent is to program the device to a specific wiper position and not to allow further adjustments, then six programming pulses are required (as opposed to five), as shown in Figure 4. The sixth pulse locks the wiper position and disables the serial interface. This also allows U/D and CS to float without any increase in supply current. Once the lockout bit is set, no further adjustment to the potentiometer is possible, effectively changing the potentiometer into a fixed resistor-divider (Table 1). Table 1. One-Time Programming Options POWER-ON RESET WIPER POSITION ADJUSTABLE WIPER Tap 16 Yes Programmed (5 Programming Pulses) Programmed position Yes Lock-Bit Set (6 Programming Pulses) Programmed position No MODE Factory Default (Unprogrammed) _______________________________________________________________________________________ One-Time Programmable, Linear-Taper Digital Potentiometers MAX5427/MAX5428/MAX5429 U/D 11V VPP 0V tCH tCL tCP tPH CS tPC OPTIONAL LOCKOUT BIT 5 BITS RECORD WIPER POSITION Figure 4. One-Time Program Mode Serial Interface Timing Diagram It is recommended that the user either use six CS pulses (convert to a fixed voltage-divider) or five pulses (program the initial power-up value of the device, but still be able to adjust the wiper). If the device is programmed with five pulses and later it is desired to disable the interface (convert to a fixed voltage-divider), then care must be taken to ensure that the wiper is in the same position as it was originally set to (when programmed with five pulses). The full six programming pulses must be applied. If the wiper is not in its original programmed position prior to disabling the interface, the final locked-out position is correct. Note that once the six-pulse program occurs, no further programming is possible. The VPP power supply must be able to source at least 5mA and have a good transient response. The VPP power supply should be decoupled with 22F and have no more than 250H of inductance and/or 40 of parasitic resistance between the capacitors and the device (Figure 5). The device does not require decoupling capacitors near VPP, provided the above guidelines are met. TRACE PARASITICS VPP = 11V 22F LPARASITIC RPARASITIC < 250H < 40 VPP MAX5427 MAX5428 MAX5429 Figure 5. VPP Power-Supply Connection Chip Information TRANSISTOR COUNT: 2270 PROCESS: BiCMOS _______________________________________________________________________________________ 7 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) 6, 8, &10L, QFN THIN.EPS MAX5427/MAX5428/MAX5429 One-Time Programmable, Linear-Taper Digital Potentiometers PACKAGE OUTLINE, 6, 8 & 10L, QFN THIN (DUAL), EXPOSED PAD, 3x3x0.80 mm 21-0137 8 _______________________________________________________________________________________ C One-Time Programmable, Linear-Taper Digital Potentiometers COMMON DIMENSIONS SYMBOL A MIN. 0.70 MAX. 0.80 D 2.90 3.10 E 2.90 3.10 A1 0.00 0.05 L k 0.20 0.40 0.25 MIN A2 0.20 REF. PACKAGE VARIATIONS PKG. CODE N D2 E2 e JEDEC SPEC b T633-1 6 1.500.10 2.300.10 0.95 BSC MO229 / WEEA 0.400.05 1.90 REF T833-1 8 1.500.10 2.300.10 0.65 BSC MO229 / WEEC 0.300.05 1.95 REF T1033-1 10 1.500.10 2.300.10 0.50 BSC MO229 / WEED-3 0.250.05 2.00 REF [(N/2)-1] x e PACKAGE OUTLINE, 6, 8 & 10L, QFN THIN (DUAL), EXPOSED PAD, 3x3x0.80 mm 21-0137 C _______________________________________________________________________________________ 9 MAX5427/MAX5428/MAX5429 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) 4X S 8 E y 0.500.1 8 INCHES DIM A A1 A2 b H c D e E H 0.60.1 1 L 1 0.60.1 S BOTTOM VIEW D MIN 0.002 0.030 MAX 0.043 0.006 0.037 0.014 0.010 0.007 0.005 0.120 0.116 0.0256 BSC 0.120 0.116 0.198 0.188 0.026 0.016 6 0 0.0207 BSC 8LUMAXD.EPS MAX5427/MAX5428/MAX5429 One-Time Programmable, Linear-Taper Digital Potentiometers MILLIMETERS MAX MIN 0.05 0.75 1.10 0.15 0.95 0.25 0.36 0.13 0.18 2.95 3.05 0.65 BSC 2.95 3.05 4.78 5.03 0.41 0.66 0 6 0.5250 BSC TOP VIEW A1 A2 e A c b L SIDE VIEW FRONT VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 8L uMAX/uSOP APPROVAL DOCUMENT CONTROL NO. 21-0036 REV. J 1 1 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. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.