19-1956; Rev ; 2/1 32-Tap FleaPoT TM, 2-ire Digital General Description The MAX546/MAX5463/MAX5466//MAX5468 linear-taper digital potentiometers perform the same function as a mechanical potentiometer or a variable resistor. These devices consist of a fixed resistor and a wiper contact with 32 tap points that are digitally controlled through a 2-wire serial interface. Applications LCD Screen Adjustment Volume Control Mechanical Potentiometer Replacement Gain Adjustment Line Impedance Matching FleaPoT is a trademark of Maxim Integrated Products. Functional Diagram appears at end of data sheet. TOP VIE V DD GND 1 5 H 2 3 MAX546 MAX5463 4 MAX5466 SOT23, SC7 V DD GND Features Miniature SC7 and SOT23 Packages.3µA Ultra-Low Supply Current +2.7V to +5.5V Single-Supply Operation Glitchless Switching Between Resistor Taps Power-On Reset to Midscale 2-ire Up/Down Serial Interface 1kΩ, 5kΩ, and 1kΩ Resistance Values 1 6 H 2 3 4 SOT23 PART 5 L GND V DD 1 6 H 2 Ordering Information TEMP. RANGE Pin Configurations MAX5468 3 4 SOT23 The MAX5468 is configured as a potentiometer. The rest of the devices in this family are configured as variable resistors. See Pin Configurations for part functionality. Three resistance values are available: 1kΩ (MAX5466/ /MAX5468), 5kΩ (MAX5463), and 1kΩ (MAX546). The MAX546/MAX5463 (1kΩ and 5kΩ) are available in a space-saving 5-pin SC7 package. The MAX5466//MAX5468 (1kΩ) are available in 5-pin and 6-pin SOT23 packages. PIN- PACKAGE 5 TOP MARK R (kω) MAX546EXK -4 C to +85 C 5 SC7 ACA 1 MAX5463EXK -4 C to +85 C 5 SC7 ACB 5 MAX5466EUK -4 C to +85 C 5 SOT23 ADQQ 1 EUT -4 C to +85 C 6 SOT23 AARH 1 MAX5468EUT -4 C to +85 C 6 SOT23 AARI 1 MAX546/MAX5463/MAX5466//MAX5468 Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim s website at www.maxim-ic.com.
MAX546/MAX5463/MAX5466//MAX5468 ABSOLUTE MAXIMUM RATINGS V DD to GND...-.3V to +6V and to GND (MAX546/63/66/67/68)...-.3V to (V DD +.3)V Input and Output Latch-Up Immunity...±2mA Maximum Continuous Current into H, L, and MAX546 (1kΩ)...±.6mA MAX5463 (5kΩ)...±1.3mA MAX5466//MAX5468 (1kΩ)...±1.3mA Continuous Power Dissipation (T A = +7 C) 5-pin SC7 (derate 3.1m/ C above T A = +7 C)...247m 5-pin SOT23 (derate 7.1m/ C above T A = +7 C)...571m 6-pin SOT23(derate 8.7m/ C above T A = +7 C)...695.7m Operating Temperature Range...-4 C to +85 C Junction Temperature...+15 C Storage Temperature Range...-65 C to +15 C Soldering Temperature (soldering, 1s)...+3 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 CHARACTERISTI (V DD = +2.7V to +5.5V, V H = V DD, V L =, T A = -4 C to +85 C. Typical values are at V DD = +2.7V, T A = +25 C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC PERFORMANCE Resolution 32 Taps End-to-End Resistance MAX546 75 1 125 MAX5463 37.5 5 62.5 MAX5466//MAX5468 7.5 1 12.5 End-to-End Resistance Tempco TC R 35 ppm/ C Ratiometric Resistance Tempco 5 ppm/ C Integral Nonlinearity INL ±.5 ±1 LSB Differential Nonlinearity DNL ±1 LSB Full-Scale Error ±.1 LSB Zero-Scale Error 1 LSB MAX546/MAX5463 6 12 iper Resistance R MAX5466//MAX5468 16 24 DIGITAL INPUTS Input High Voltage V IH.7 x V DD V Input Low Voltage V IL.3 x V DD V TIMING CHARACTERISTI (Figures 1, 2) Mode to Setup t CU 25 ns to Step Setup t CI 5 ns to Step Hold t IC 25 ns Step Low Period t IL 25 ns Step High Period t IH 25 ns Up/Down Toggle Rate (Note 1) f TOGGLE 1 MHz 1kΩ var i ab l e r esi stor confi g ur ati on, C L = 1p F 1 Output Settling time (Note 2) t SETTLE 1kΩ p otenti om eter confi g ur ati on, C L = 1p F.25 kω Ω µs 2
ELECTRICAL CHARACTERISTI (continued) (V DD = +2.7V to +5.5V, V H = V DD, V L =, T A = -4 C to +85 C. Typical values are at V DD = +2.7V, T A = +25 C, unless otherwise noted.) IPER RESISTANCE (Ω) RESISTANCE (kω) 7 6 5 4 3 2 1 12 1 8 6 4 2 PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POER SUPPLIES Supply Voltage V DD 2.7 5.5 V Active Supply Current (Note 3) I DD 25 µa Standby Supply Current (Note 4) I SD V DD = +5V.3 1 µa Note 1: Up/Down Toggle Rate: ftoggle = 1 tsettle Note 2: Typical settling times are dependent on end-to-end resistance. Note 3: Supply current taken while changing wiper tap, f TOGGLE = 1MHz. Note 4: Supply current taken while wiper position is fixed. (T A = +25 C, unless otherwise noted.) IPER RESISTANCE vs. IPER VOLTAGE (MAX546/MAX5463) V DD = +2.7V V DD = +5V.5 1. 1.5 2. 2.5 3. 3.5 4. 4.5 5. IPER VOLTAGE (V) END-TO-END RESISTANCE vs. TAP POSITION 1kΩ 5kΩ 1kΩ 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 TAP POSITION MAX546 toc1 MAX546 toc4 IPER REISTANCE (Ω) CURRENT (µa) 2 18 16 14 12 1 8 6 4 2.5.45.4.35.3.25.2.15.1.5. IPER RESISTANCE vs. IPER VOLTAGE (MAX5466//MAX5468) V DD = +2.7V V DD = +5V.5 1. 1.5 2. 2.5 3. 3.5 4. 4.5 5. IPER VOLTAGE (V) SUPPLY CURRENT vs. TEMPERATURE V DD = +2.7V -4-15 1 35 6 85 TEMPERATURE ( C) Typical Operating Characteristics V DD = +5V MAX546 toc2 MAX546 toc5 END-TO-END RESISTANCE % CHNAGE.1.5 -.5 -.1 -.15 -.2 -.25 2V/div OUTPUT 1mV/div END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE 1kΩ 5kΩ, 1kΩ -4-15 1 35 6 85 TEMPERATURE ( C) TAP-TO-TAP SITCHING TRANSIENT (MAX546) 2ns/div MAX546 toc3 MAX546 toc6 MAX546/MAX5463/MAX5466//MAX5468 3
MAX546/MAX5463/MAX5466//MAX5468 (T A = +25 C, unless otherwise noted.) R-DNL (LSB) R-INL LSB.8.6.4.2 -.2 -.4 -.6 -.5 -.1.2.15.1.5 -.5 -.1 R-DNL ERROR vs. INPUT CODE (1kΩ) 5 1 15 2 25 3 R-INL ERROR vs. INPUT CODE (5kΩ) 5 1 15 2 25 3 MAX546 MAX5463 MAX5466 PIN MAX5468 Typical Operating Characteristics (continued) NAME 1 1 1 V DD Power Supply 2 2 2 GND Ground 3 3 3 4 4 4 MAX546 toc7 MAX546 toc1 R-INL (LSB) R-DNL LSB.1.8.6.4.2 -.2 -.4 -.6 -.8 -.1.15.1.5 -.5 -.1 -.15 -.2 -.25 R-INL ERROR vs. INPUT CODE (1kΩ) 5 1 15 2 25 3 R-DNL ERROR vs. INPUT CODE (1kΩ) 5 1 15 2 25 3 MAX546 toc8 MAX546 toc11 R-DNL (LSB) R-INL (LSB).4.2 -.2 -.4 -.6 -.8 -.1 -.12 -.14.3.25.2.15.1.5 -.5 -.1 -.15 R-DNL ERROR vs. INPUT CODE (5kΩ) 5 1 15 2 25 3 R-INL ERROR vs. INPUT CODE (1kΩ) 5 1 15 2 25 3 FUNCTION Pin Description Up/Down Control Input. ith low, a low-to-high transition increments or decrements the wiper position. Chip Select Input. A high-to-low transition determines the mode: increment if is high, or decrement if is low. MAX546 toc9 MAX546 toc12 5 6 6 H High Terminal of Resistor 2 5 2 L Low Terminal of Resistor 5 6 5 iper Terminal of Resistor 4
Detailed Description The MAX546/MAX5463/MAX5466//MAX5468 consist of a fixed resistor and a wiper contact with 32 tap points that are digitally controlled through a 2-wire serial interface. Three resistance values are available: 1kΩ (MAX5466//MAX5468), 5kΩ (MAX5463), and 1kΩ (MAX546). The MAX5468 is designed to operate as a potentiometer. In this configuration, the low terminal of the resistor array is connected to ground (pin 2). The performs as a variable resistor. In this device, the wiper terminal and high terminal of the resistor array are connected at pin 5. The MAX546/ MAX5463/MAX5466 are similar variable resistors, except the low terminal is connected to ground (pin 2). Digital Interface Operation The MAX546/MAX5463/MAX5466//MAX5468 have two modes of operation when the serial interface is t CU Figure 1. Serial Interface Timing Diagram, Increment Mode t CI t IL t SETTLE active: increment and decrement mode. The serial interface is only active when is low. The and inputs control the position of the wiper along the resistor array. hen transitions from high to low, the part will go into increment mode if is high, and into decrement mode if is low. Once the mode is set, the device will remain in that mode until goes high again. A low-to-high transition at the pin will increment or decrement the wiper position depending on the current mode (Figures 1 and 2). hen the input transitions to high (serial interface inactive), the value of the counter is stored and the wiper position is maintained. Power-On Reset All parts in this family feature power-on reset (POR) circuitry that sets the wiper position to midscale at powerup. By default, the chip is in the increment mode. t IH t IC MAX546/MAX5463/MAX5466//MAX5468 5
MAX546/MAX5463/MAX5466//MAX5468 Applications Information The MAX546/MAX5463/MAX5466//MAX5468 are intended for circuits requiring digitally controlled adjustable resistance, such as LCD contrast control, where voltage biasing adjusts the display contrast. Controlling a Switch-Mode LCD Bias Generator Figure 3 shows an application where the variable resistor is used with a MAX1771 to make an adjustable positive LCD-bias circuit. The output of the MAX1771 is a positive voltage that is digitally controlled through the. Similarly, Figure 4 shows the application of the variable resistor in a digitally controlled negative LCD-bias circuit along with the MAX774/MAX775/ MAX776. t CU t CI t SETTLE Figure 2. Serial Interface Timing Diagram, Decrement Mode t IH Alternative Positive LCD Bias Control Alternatively, use an op amp to provide buffering and gain to the output of the MAX5468. Connect the mechanical potentiometer to the positive input of a noninverting op amp (Figure 5) to select a portion of the input signal by digitally controlling the wiper terminal. Figure 6 shows a similar circuit for the. Adjustable Gain Figure 7 shows how to use the variable resistor to digitally adjust the gain of a noninverting op amp configuration. Connect the in series with a resistor to ground to form the adjustable gain control of a noninverting amplifier. The MAX546/MAX5463/MAX5466/ /MAX5468 have a low 5ppm/ C ratiometric tempco that allows for a very stable adjustable gain configuration over temperature. t IL t IC 6
V IN = 5V C1 68µF C3.1µF 5 4 6 V REF = 1.5V C2.1µF 2 V+ REF SHDN AGND +5V H L MAX1771 GND 7 MAX5468 EXT Figure 5. Positive LCD Bias Control FB 1 8 3 Figure 3. Adjustable Positive LCD Bias L1 22µH D1 1N5817-22 C4 N 3µF MTD2N3HDL R SENSE 4mΩ R1 3V GAIN 6 R VAR R2 C5 V OUT(MAX) R2 = + 1 V REF R1 V OUT(MIN) R2 = V REF ( R1 + R VAR(MAX) V OUT = 12V AT.5A ) + 1 V OUT V IN C1 15µF C2.1µF R2 R1 +5V Figure 6. Positive LCD Bias Control H L 1 3 2 R VAR 4 C3.1µF OUT V+ SHDN FB REF MAX774 MAX775 MAX776 GND 8 EXT 5 6 7 L1 22µH 3V R3.7Ω Q1 Si9435 P 1N5822/ MBR34 C4* * MAX774 = 33µF, 1V MAX775/MAX776 = 12µF, 2V V OUT(MAX) R2 V OUT(MIN) R2 =, = V REF R1 V REF R1 + R VAR V REF - V FB 5µA (FOR 2% GAIN-SETTING ACCURACY) R1 + R VAR Figure 4. Adjustable Negative LCD Bias V OUT V OUT MAX546/MAX5463/MAX5466//MAX5468 7
MAX546/MAX5463/MAX5466//MAX5468 V IN H L V CC a) b) Figure 7. Adjustable Gain Circuit V DD GND MAX546 MAX5463 MAX5466 MAX5468 UP/DN COUNTER V OUT Functional Diagram 32-POSITION DECODER H L L V IN TRANSISTOR COUNT: 792 MAX5468 H V CC V OUT Chip Information 8
Package Information SC7, 5L.EPS SOT5L.EPS MAX546/MAX5463/MAX5466//MAX5468 9
MAX546/MAX5463/MAX5466//MAX5468 Package Information (continued) 6LSOT.EPS 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. 1 Maxim Integrated Products, 12 San Gabriel Drive, Sunnyvale, CA 9486 48-737-76 21 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.