MAXIM MAX5422, MAX5423, MAX5424 User Manual

General Description

The MAX5422/MAX5423/MAX5424 nonvolatile, lineartaper, digital potentiometers perform the function of a mechanical potentiometer, but replace the mechanics with a simple 3-wire SPI™-compatible digital interface. Each device performs the same function as a discrete potentiometer or variable resistor and has 256 tap points.

The devices feature an internal, nonvolatile EEPROM used to store the wiper position for initialization during power-up. The 3-wire SPI-compatible serial interface allows communication at data rates up to 5MHz, minimizing board space and reducing interconnection complexity in many applications.

The MAX5422/MAX5423/MAX5424 provide three nominal resistance values: 50kΩ (MAX5422), 100kΩ (MAX5423), or 200kΩ (MAX5424). The nominal resistor temperature coefficient is 35ppm/°C end-to-end and only 5ppm/°C ratiometric. This makes the devices ideal for applications requiring a low-temperature-coefficient variable resistor, such as low-drift, programmable gainamplifier circuit configurations.

The MAX5422/MAX5423/MAX5424 are available in a 3mm x 3mm 8-pin TDFN package, and are specified over the extended -40°C to +85°C temperature range.

Applications

Mechanical Potentiometer Replacement

Low-Drift Programmable Gain Amplifiers

Audio Volume Control

Liquid-Crystal Display (LCD) Contrast Control

Low-Drift Programmable Filters

Features

♦ Wiper Position Stored in Nonvolatile Memory

(EEPROM) and Recalled Upon Power-Up or Interface Command

♦ 3mm x 3mm x 0.8mm TDFN Package

♦ 35ppm/°C End-to-End Resistance Temperature

Coefficient

♦ 5ppm/°C Ratiometric Temperature Coefficient

♦ 50kΩ, 100kΩ, and 200kΩ Resistor Values

♦ 5MHz SPI-Compatible Serial Interface

♦ 500nA (typ) Static Supply Current

♦ Single-Supply Operation: +2.7V to +5.25V

♦ 256 Tap Positions

♦ ±0.5 LSB DNL in Voltage-Divider Mode

♦ ±0.5 LSB INL in Voltage-Divider Mode

MAX5422/MAX5423/MAX5424

256-Tap, Nonvolatile, SPI-Interface,

Digital Potentiometers

________________________________________________________________ Maxim Integrated Products 1

Ordering Information/Selector Guide

19-3371; Rev 0; 7/04

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

Pin Configuration

SPI

INTERFACE

256POSITION DECODER

GND

SCLK

8-BIT

MEMORY

8-BIT

LATCH

8-BIT

SHIFT

POR

256

DIN

MAX5422 MAX5423 MAX5424

Functional Diagram

SPI is a trademark of Motorola, Inc.

*EP = Exposed pad.

TOP VIEW

SCLK

DIN

MAX5422 MAX5423 MAX5424

GND

TDFN (3mm x 3mm)

PART TEMP RANGE

MAX5422ETA -40°C to +85°C50

MAX5423ETA -40°C to +85°C 100

MAX5424ETA -40°C to +85°C 200

END-TO-END

RESISTANCE (kΩ)

PIN-PACKAGE TOP MARK

8 TDFN-EP*

AIJ

AII

AIH

MAX5422/MAX5423/MAX5424

256-Tap, Nonvolatile, SPI-Interface, Digital Potentiometers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +2.7V to +5.25V, H = VDD, L = GND, TA= -40°C to +85°C. Typical values are at VDD= +5.0V, TA= +25°C, unless otherwise noted.)

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.

VDDto GND...........................................................-0.3V to +6.0V

All Other Pins to GND.................................-0.3V to (V

+ 0.3V)

Maximum Continuous Current into H, L, and W

MAX5422......................................................................±1.3mA

MAX5423......................................................................±0.6mA

MAX5424......................................................................±0.3mA

Continuous Power Dissipation (T

= +70°C)

8-Pin TDFN (derate 24.4mW/°C above +70°C) .........1951mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-60°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DC PERFORMANCE (VOLTAGE-DIVIDER MODE)

Resolution N 256 Taps

Integral Nonlinearity INL (Note 1) ±0.5 LSB

Differential Nonlinearity DNL (Note 1) ±0.5 LSB

End-to-End Resistance Temperature Coefficient

Ratiometric Resistance Temperature Coefficient

Zero-Scale Error

DC PERFORMANCE (VARIABLE-RESISTOR MODE)

Integral Nonlinearity (Note 2)

Differential Nonlinearity (Note 2)

DC PERFORMANCE (RESISTOR CHARACTERISTICS)

Wiper Resistance R

Wiper Capacitance C

INL

DNL

MAX5422 -0.6

MAX5423 -0.3Full-Scale Error

MAX5424 -0.15

MAX5422 0.7

MAX5423 0.35

MAX5424 0.18

VDD = 3V ±3.0

= 5V ±1.5

VDD = 3V, MAX5422, -40°C ≤ TA ≤ +85°C, guaranteed monotonic

VDD = 3V, MAX5422, 0°C ≤ TA ≤ +85°C, guaranteed monotonic

VDD = 3V, MAX5423 ±1.0

VDD = 3V, MAX5424 ±1.0

= 5V ±1.0

VDD = 3V to 5.25V (Note 3) 325 675 Ω

MAX5422 37.5 50 62.5

MAX5423 75 100 125End-to-End Resistance

MAX5424 150 200 250

35 ppm/°C

5 ppm/°C

-1.0 +2.0

-1.0 +1.2

10 pF

LSB

kΩ

MAX5422/MAX5423/MAX5424

256-Tap, Nonvolatile, SPI-Interface,

Digital Potentiometers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +2.7V to +5.25V, H = VDD, L = GND, TA= -40°C to +85°C. Typical values are at VDD= +5.0V, TA= +25°C, unless otherwise noted.)

TIMING CHARACTERISTICS

(VDD= +2.7V to +5.25V, H = VDD, L = GND, TA= -40°C to +85°C. Typical values are at VDD= +5.0V, TA= +25°C, unless otherwise noted. See Figure 1.) (Note 7)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DIGITAL INPUTS (CS, DIN, SCLK)

VDD = 3.4V to 5.25V 2.4

Input High Voltage (Note 4) V

Input Low Voltage V

Input Leakage Current I

Input Capacitance C

DYNAMIC CHARACTERISTICS

Wiper -3dB Bandwidth (Note 5)

NONVOLATILE MEMORY RELIABILITY

Data Retention TA = +85°C 50 Years

Endurance

POWER SUPPLY

Supply Voltage V

Standby Current I

Programming Current I

VDD < 3.4V

VDD = 2.7V to 5.25V (Note 4) 0.8 V

MAX5422 100

MAX5423 50

MAX5424 25

TA = +25°C 200,000

= +85°C 50,000

Digital inputs = VDD or GND, TA = +25°C 0.5 1 µA

During nonvolatile write to memory; digital inputs = V

or GND (Note 6)

0.7 x V

±0.1 ±1 µA

5pF

2.70 5.25 V

200 400 µA

kHz

Stores

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

ANALOG SECTION

MAX5422 400

DIGITAL SECTION

SCLK Frequency f

SCLK Clock Period t

SCLK Pulse-Width High t

SCLK Pulse-Width Low t CS Fall to SCLK Rise Setup t SCLK Rise to CS Rise Hold t

DIN to SCLK Setup t

SCLK

CSS

CSH

MAX5423 600Wiper Settling Time (Note 8) t

MAX5424 1000

5MHz

200 ns

80 ns

0ns

50 ns

DNL vs. TAP POSITION

MAX5422 toc01

TAP POSITION

DNL (LSB)

224192128 16064 9632

-0.20

-0.15

-0.10

-0.05

0.05

0.10

0.15

0.20

0.25

-0.25 0256

VOLTAGE-DIVIDER MODE

INL vs. TAP POSITION

MAX5422 toc02

TAP POSITION

INL (LSB)

224192128 16064 9632

-0.20

-0.15

-0.10

-0.05

0.05

0.10

0.15

0.20

0.25

-0.25 0256

VOLTAGE-DIVIDER MODE

RESISTANCE (Ω)

100

200

300

400

500

600

700

WIPER RESISTANCE vs. TAP POSITION

MAX5422 toc03

TAP POSITION

224192128 16064 96320 256

VDD = 2.7V I

SRC

= 50μA

Typical Operating Characteristics

(VDD= 5.0V, TA= +25°C, unless otherwise noted.)

MAX5422/MAX5423/MAX5424

256-Tap, Nonvolatile, SPI-Interface, Digital Potentiometers

4 _______________________________________________________________________________________

TIMING CHARACTERISTICS (continued)

(VDD= +2.7V to +5.25V, H = VDD, L = GND, TA= -40°C to +85°C. Typical values are at VDD= +5.0V, TA= +25°C, unless otherwise noted. See Figure 1.) (Note 7)

Note 1: The DNL and INL are measured with the potentiometer configured as a voltage-divider with H = VDDand L = GND. The

wiper terminal is unloaded and measured with a high-input-impedance voltmeter.

Note 2: The DNL and INL are measured with the potentiometer configured as a variable resistor. H is unconnected and L = GND.

For the 5V condition, the wiper terminal is driven with a source current of 80µA for the 50kΩ configuration, 40µA for the 100kΩ configuration, and 20µA for the 200kΩ configuration. For the 3V condition, the wiper terminal is driven with a source current of 40µA for the 50kΩ configuration, 20µA for the 100kΩ, and 10µA for the 200kΩ configuration.

Note 3: The wiper resistance is measured using the source currents given in Note 2. For operation to V

= 2.7V, see Maximum

Wiper Resistance vs. Temperature in the Typical Operating Characteristics.

Note 4: The device draws higher supply current when the digital inputs are driven with voltages between (V

- 0.5V) and (GND +

0.5V). See Supply Current vs. Digital Input Voltage in the Typical Operating Characteristics.

Note 5: Wiper at midscale with a 10pF load (DC measurement). L = GND; an AC source is applied to H; and the W output is mea-

sured. A 3dB bandwidth occurs when the AC W/H value is 3dB lower than the DC W/H value.

Note 6: The programming current operates only during power-up and NV writes. Note 7: Digital timing is guaranteed by design and characterization, and is not production tested. Note 8: Wiper-settling time is the worst-case 0% to 50% rise-time measured between consecutive wiper positions. H = V

, L =

GND, and the wiper terminal is unloaded and measured with a 10pF oscilloscope probe.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DIN Hold after SCLK t SCLK Rise to CS Fall Delay t

CS Rise to SCLK Rise Hold t CS Pulse-Width High t

Write NV Register Busy Time t

CS0

CS1

CSW

BUSY

0ns

20 ns

80 ns

200 ns

12 ms

+ 7 hidden pages

MAXIM MAX5422, MAX5423, MAX5424 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual