Datasheet

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General Description

The MAX5128 nonvolatile, single, linear-taper, digital

potentiometer performs the function of a mechanical

potentiometer, but replaces the mechanics with a sim-

ple 2-wire digital interface. The MAX5128 performs the

same function as a discrete potentiometer or variable

resistor and features 128 taps and 22kΩ end-to-end

resistance. The MAX5128 also features an ultra-small,

2mm x 2mm µDFN package and low 0.5µA (typ) stand-

by supply current, making this device ideal for portable

applications. The MAX5128 operates from a +2.7V to

+5.25V power supply. An integrated nonvolatile memo-

ry recalls the programmed wiper position of the digital

potentiometer. A simple 2-wire up/down interface pro-

grams the wiper position. The digital potentiometer pro-

vides a low 5ppm/°C ratiometric temperature coefficient

and is specified over the extended -40°C to +85°C tem-

perature range.

Applications

COM

Adjustment for LCD Panels

Backlight Adjustment

LED Bias Adjustment

Power-Supply Modules

Fiber-Module Bias Setting

Bias Setting for Radios

Portable Consumer Electronics

Features

♦ Ultra-Small, 2mm x 2mm, 8-Pin µDFN Package

♦ Power-On Recall of Wiper Position from

Nonvolatile Memory

♦ 22kΩ End-to-End Resistance

♦ 128 Tap Positions

♦ 5ppm/°C Ratiometric Temperature Coefficient

♦ 1.5µA (max) Standby Supply Current

♦ +2.7V to +5.25V Single Supply Operation

♦ 80,000 Wiper Store Cycles

♦ 50-Year Wiper Data Retention

MAX5128

128-Tap, Nonvolatile, Linear-Taper Digital

Potentiometer in 2mm x 2mm µDFN Package

________________________________________________________________ Maxim Integrated Products 1

19-3929; Rev 2; 6/07

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.

EVALUATION KIT

AVAILABLE

Ordering Information

PART

TEMP

RANGE

PIN -

PA C K A G E

TOP

MARK

PKG

CODE

M AX 5128E LA+ -40°C to +85°C 8 µDFN AAF L822-1

SERIAL

INTERFACE

128-POSITION

DECODER

GND

7-BIT NV MEMORY

POR

128

TAPS

MAX5128

Functional Diagram

+Denotes a lead-free package.

Summary of content (14 pages)

PAGE 1
9-3929; Rev 2; 6/07 KIT ATION EVALU LE B A IL A AV 128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package The MAX5128 nonvolatile, single, linear-taper, digital potentiometer performs the function of a mechanical potentiometer, but replaces the mechanics with a simple 2-wire digital interface. The MAX5128 performs the same function as a discrete potentiometer or variable resistor and features 128 taps and 22kΩ end-to-end resistance.
PAGE 2
MAX5128 128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +6.0V UP and DN to GND ....................................-0.3V to (VCC + 0.3V) H, L, and W to GND....................................-0.3V to (VCC + 0.3V) Maximum Continuous Current into H, L, and W ..............±0.5mA Maximum Continuous Current into All Other Pins ............
PAGE 3
128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package (VCC = +2.7V to +5.25V, H = VCC, L = GND, TA = -40°C to +85°C. Typical values are at VCC = +5.0V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS NONVOLATILE MEMORY RELIABILITY Data Retention Endurance TA = +85°C 50 TA = +25°C 80,000 TA = +85°C 50,000 Years Stores POWER SUPPLY Supply Voltage VCC 2.
PAGE 4
MAX5128 128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package TIMING CHARACTERISTICS (continued) (VCC = +2.7V to +5.25V, H = VCC, L = GND, TA = -40°C to +85°C. Typical values are at VCC = +5.0V, TA = +25°C, unless otherwise noted.) (See Figures 1, 2, 3, and 4).
PAGE 5
128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package 0.08 0.06 0.02 INL (LSB) 0.04 0.04 0.02 0.04 0.02 0 0 0 -0.02 -0.02 -0.02 -0.04 -0.04 -0.04 -0.06 -0.06 12 24 36 48 60 72 84 96 108 120 CODE VCC = 2.7V, TA = -40°C 0.006 0.010 0.008 VCC = 2.7V, TA = +25°C 0.006 DIFFERENTIAL NONLINEARITY vs. CODE (VOLTAGE-DIVIDER) 0.010 0.008 0 0.004 DNL (LSB) DNL (LSB) 0.002 0.002 0 -0.002 -0.002 0.002 0 -0.002 -0.004 -0.004 -0.004 -0.006 -0.006 -0.
PAGE 6
Typical Operating Characteristics (continued) (VCC = +5.0V, TA = +25°C, unless otherwise noted.) DIFFERENTIAL NONLINEARITY vs. CODE (VARIABLE RESISTOR) 0.15 0.20 VCC = 2.7V, TA = +25°C 0.15 0.10 0.10 0.05 0.05 0.25 VCC = 2.7V, TA = +85°C 0.20 0.15 0 DNL (LSB) DNL (LSB) 0.10 0 -0.05 -0.05 -0.10 -0.10 -0.15 -0.15 -0.20 -0.20 0.05 0 -0.05 -0.10 -0.15 -0.20 -0.25 0 12 24 36 48 60 72 84 96 108 120 CODE RATIOMETRIC TEMPERATURE COEFFICIENT vs. CODE (VOLTAGE-DIVIDER) VCC = 2.
PAGE 7
128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package VCC = 5V WIPER = MIDSCALE 800 0 VCC = 5V WIPER = MIDSCALE -2 -4 100 MAX5128 toc19 1000 MAX5128 toc18 VCC = 5V MAX5128 toc17 1000 WIPER RESPONSE vs. FREQUENCY WIPER RESISTANCE vs. TEMPERATURE SUPPLY CURRENT vs. DIGITAL INPUT VOLTAGE GAIN (dB) RW (Ω) 10 400 -8 -10 -12 1 -14 200 -16 -18 0 0.1 -40 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -15 10 35 60 0.1 85 1 THD+N vs.
PAGE 8
128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package MAX5128 Pin Description PIN NAME FUNCTION 1 VCC Power Supply. Bypass VCC with a 0.1µF capacitor to GND as close to the device as possible. For proper operation, limit the supply voltage slew rate to ≥ 10µs. 2 H High Terminal. The voltage at H can be higher than or lower than the voltage at L. Current can flow into or out of H. 3 W Wiper Terminal 4 L Low Terminal.
PAGE 9
128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package NVM WRITE t MS2 t PWL MAX5128 t PWH t BUSY UP t WP DN t WS t WH Figure 2. Digital-Interface Timing Diagram with tBUSY tBUSY tBUSY UP DN WIPER INCREMENTS WIPER DECREMENTS NVM WRITE NVM WRITE WIPER INCREMENTS WIPER DECREMENTS Figure 3. Digital-Interface Command Diagram Digital Interface The MAX5128 features a 2-wire interface consisting of two logic inputs (UP and DN).
PAGE 10
MAX5128 128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package tIMMU tIMMU UP DN tIMMU tIMMU PULSES WITH WIDTHS LESS THAN tIMMU ARE IGNORED. Figure 4. Glitch-Immunity Timing Diagram Standby Mode DC-DC Converter Applications The MAX5128 operates in standby mode while the serial interface is inactive. Programming the MAX5128 increases the average operating current to 400µA (max). When in standby mode, the static supply current reduces to less than 0.5µA (typ).
PAGE 11
128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package MAX5128 +3.3V 15kΩ 120kΩ +5V H 0.1μF TIMING-CONTROL-IC OUTPUT SIGNAL MAX5128 W 10kΩ MAX4238 +3.3V 22kΩ L VCOM 51kΩ 27kΩ 36kΩ 0.1μF Figure 5. VCOM Generator Circuit for LCD Panels VOUT = 2V TO 5.25V OUT LX H MAX1722 VIN = 0.8V TO VOUT FB W BATT MAX5128 GND L Figure 6.
PAGE 12
MAX5128 128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package SW VOUT = VCC TO 28V LX H MAX8574 VCC = 2.7V TO 5.5V VCC FB SHDN W MAX5128 L GND Figure 7. DC-DC Converter Using a Floating Potentiometer Pin Configuration CN VIN = 2.7V TO 5.5V IN TOP VIEW CP OUT N.C. UP DN GND 8 7 6 5 MAX1574 LED1 MAX5128 H W MAX5128 LED2 SET LED3 L 1 2 3 4 VCC H W L 2mm x 2mm μDFN GND Figure 8.
PAGE 13
128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package XXXX XXXX XXXX b e N SOLDER MASK COVERAGE E PIN 1 0.10x45∞ L PIN 1 INDEX AREA 6, 8, 10L UDFN.EPS A D L1 1 SAMPLE MARKING A A (N/2 -1) x e) 7 CL b L A A2 A1 CL L e EVEN TERMINAL e ODD TERMINAL PACKAGE OUTLINE, 6, 8, 10L uDFN, 2x2x0.
PAGE 14
MAX5128 128-Tap, Nonvolatile, Linear-Taper Digital Potentiometer in 2mm x 2mm µDFN Package 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.) COMMON DIMENSIONS SYMBOL MIN. NOM. A 0.70 0.75 0.80 A1 0.15 0.20 0.25 0.035 A2 0.020 0.025 D 1.95 2.00 E 1.95 2.00 L 0.30 0.40 L1 MAX. - 2.05 2.05 0.50 0.10 REF. PACKAGE VARIATIONS PKG.