MAXIM MAX5407 User Manual

General Description

The MAX5407 SOT-PoT™ is a logarithmic taper digital
potentiometer with 32 tap points that has 1dB steps
between taps. This device is ideal for audio applica­tions, such as volume control and fading/balancing
audio signals.

The MAX5407 consists of a resistor string and CMOS
switches that are digitally controlled through a simple 2­wire serial interface. This device performs the same
function as a mechanical potentiometer. The device
has a fixed end-to-end resistance of 20kΩ and features
zero-crossing detection to minimize the audible noise
generated by the wiper transitions.

This device has nominal resistor temperature coefficients
of 35ppm/°C end-to-end and 5ppm/°C ratiometric. The
MAX5407 is available in a space saving 8-pin SOT23
package and is guaranteed from -40°C to +85°C.

Applications

Audio Volume Control

Fading/Balancing Audio Signals

Mechanical Potentiometer Replacement

Features

♦ Miniature 3mm x 3mm 8-Pin SOT23 Package

♦ Logarithmic Taper with 1dB Steps Between Taps

♦ 32 Tap Positions

♦ Low 0.35µA Supply Current

♦ +2.7V to +5.5V Single-Supply Operation

♦ Zero-Crossing Detection to Minimize Audible

Clicks During Wiper Transitions

♦ Simple Up/Down 2-Wire Serial Data Interface

♦ Power-On Reset

Wiper Goes To Maximum Attenuation
(Lowest Tap Position)

♦ 20kΩ End-to-End Resistance

MAX5407

32-Tap Audio Logarithmic Taper

Digital Potentiometer

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration

Ordering Information

UP/DOWN
COUNTER

V

DD

GND

CS

H

L

W

U/D

ZCEN

32-POSITION

DECODER

MAX5407

Functional Diagram

19-2196; Rev 0; 10/01

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.

SOT-PoT is a trademark of Maxim Integrated Products, Inc.

PART TEMP. RANGE

MAX5407EKA -40°C to +85°C 8 SOT23 AAID

PIN-

PACKAGE

TOP MARK

TOP VIEW

1

H

2

GND

3

W

4

ZCEN

8

V

7

MAX5407

SOT23

DD

6

CS

5

U/DL

MAX5407

32-Tap Audio Logarithmic Taper
Digital Potentiometer

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +2.7V to +5.5V, VH= VDD, VL= 0, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VDD= +5V and TA= +25°C.)

(Note 1)

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 +6V

H, W, L, CS, ZCEN, and U/D to GND .........-0.3V to (V

DD

+ 0.3V)

Input and Output Latchup Immunity...............................±200mA

Maximum Continuous Current into H, L, and W ..............±500µA

Continuous Power Dissipation (T

A

= +70°C)

8-Pin SOT23-8 (derate 8.9mW/°C above +70°C) ......714mW

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

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

Storage Temperature Range .............................-65°C to +150°C

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

Number of Resistor Taps 32 Taps

End-to-End Resistance 15 20 25 kΩ

Bandwidth (Note 2) (Notes 3, 4) 500 kHz

Absolute Tolerance (Note 5) (Note 3) ±0.25 ±1 dB

Tap-to-Tap Tolerance (Note 6) (Note 3) ±0.05 ±0.1 dB

Total H ar m oni c D i stor ti on + N oi se THD + N

Power-Supply Rejection Ratio PSRR -80 dB

End-to-End Resistance
Temperature Coefficient
Ratiometric Resistance
Temperature Coefficient

Wiper Resistance R

DIGITAL INPUTS

Input High Voltage V

Input Low Voltage V

Input Leakage Current ±1 µA

Input Capacitance 5pF

TIMING CHARACTERISTICS (Figures 1, 2)

U/D Mode to CS Setup t

CS to U/D Step Setup t

CS to U/D Step Hold

U/D Step Low Period

U/D Step High Period t

Up/Down Toggle Rate f

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

TC

R

W

IH

IL

CU

CI

t

IC

t

IL

IH

TOGGLE

V

= 1V

IN

Tap = -6dB (Notes 3, 4)

VDD = 2.7V 400 1700 Ω

RMS

, f = 1kHz,

2.4 V

0.002 %

35 ppm/°C

5 ppm/°C

0.8 V

25 ns

25 ns

25 ns

25 ns

25 ns

7 MHz

Wiper Switching Time t

Zero-Crossing Timeout 50 ms

IW

Zero-crossing detection disabled (Note 4) 0.1 µs

MAX5407

32-Tap Audio Logarithmic Taper

Digital Potentiometer

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +2.7V to +5.5V, VH= VDD, VL= 0, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VDD= +5V and TA= +25°C.)

(Note 1)

Note 1: All devices are 100% production tested at TA= +25°C and guaranteed by design for TA= T

MIN

to T

MAX

.

Note 2: Bandwidth is measured from H to W at the -6dB wiper tap position (see Typical Operating Characteristics).
Note 3: These specifications are only valid for I

W

less than 100nA of continuous wiper current.

Note 4: Measured with 20pF load capacitor.
Note 5: Absolute tolerance is defined as the variation of the attenuation for any given tap from its expected value.
Note 6: Tap-to-tap tolerance is defined as the variation between any two adjacent taps from the typical value of 1dB.
Note 7: Supply current when f

TOGGLE

= 2MHz.

Note 8: Supply current when wiper position is not changing.

Typical Operating Characteristics

(VDD= +5V, TA = +25°C, unless otherwise noted.)

100

150

250

200

300

350

021345

WIPER RESISTANCE vs.

WIPER VOLTAGE

MAX5407 toc01

WIPER VOLTAGE (V)

WIPER RESISTANCE (Ω)

VDD = +3V

VDD = +5V

-0.25

-0.20

-0.15

-0.10

-0.05

0

0.05

0.10

0.15

-40 -15 10 35 60 85

END-TO-END RESISTANCE %

CHANGE vs. TEMPERATURE

MAX5407 toc02

TEMPERATURE (°C)

ENE-TO-END RESISTANCE CHANGE (%)

-35

-30

-20

-25

-10

-5

-15

0

08124 1620242832

ATTENUATION vs. TAP POSITION

MAX5407 toc03

TAP POSITION

ATTENUATION (dB)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

POWER SUPPLIES

Supply Voltage V

Supply Current I

DD

DD

All digital
inputs are
set to 0

Active (Note 7) 100

S tand b y ( N ote 8) 0.35 1

2.7 5.5 V

µA