Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - Digital potentiometer linear Non-permanent SOT 23 8

General Description

The MAX5400/MAX5401 digital potentiometers offer

256-tap SOT-PoT™ digitally controlled variable resis-

tors in tiny 8-pin SOT23 packages. Each device func-

tions as a mechanical potentiometer, consisting of a

fixed resistor string with a digitally controlled wiper con-

tact. They operate from +2.7V to +5.5V single-supply

voltages and use an ultra-low supply current of 0.1µA.

These devices also provide glitchless switching

between resistor taps, as well as a convenient power-

on reset that sets the wiper to the midscale position at

power-up. A low 5ppm/°C ratiometric temperature coef-

ficient makes it ideal for applications requiring low drift.

The MAX5400/MAX5401 serve well in applications

requiring digitally controlled resistors, including

adjustable voltage references and programmable gain

amplifiers (PGAs). A nominal end-to-end resistor tem-

perature coefficient of 50ppm/°C allows these parts to

be used as variable resistors in applications such as

low-tempco adjustable gain and other circuit configura-

tions.

Two resistance values are available: 50kΩ (MAX5400)

and 100kΩ (MAX5401). Each device is guaranteed over

the extended industrial temperature range (-40°C to

+85°C).

________________________Applications

Mechanical Potentiometer Replacement

Low-Drift PGAs

Adjustable Voltage References

Features

♦ Miniature 8-Pin SOT23 (3mm x 3mm)

♦ 256 Tap Positions

♦ Ultra-Low 0.1µA Supply Current

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

♦ Low Ratiometric Temperature Coefficient:

5ppm/°C

♦ Power-On Reset: Wiper Goes to Midscale

(Position 128)

♦ Glitchless Switching Between the Resistor Taps

♦ 3-Wire SPI™-Interface Compatible

♦ 50kΩ/100kΩ Resistor Values

MAX5400/MAX5401

256-Tap SOT-PoT,

Low-Drift Digital Potentiometers in SOT23

________________________________________________________________ Maxim Integrated Products 1

19-1848; Rev 0; 10/00

Ordering Information

SOT-PoT is a trademark of Maxim Integrated Products.

SPI is a trademark of Motorola, Inc.

Pin Configuration appears at end of data sheet.

PART

TEMP.

RANGE

PIN-

PACKAGE

R (kΩ)

MAX5400EKA-T -40°C to +85°C 8-SOT23 50

MAX5401EKA-T -40°C to +85°C 8-SOT23 100

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.

MAX5400/MAX5401

POR

8-BIT

SHIFT

CLOCK

LOGIC

8-BIT

LATCH

SCLK

DIN

DECODER

GND

Functional Diagram

Summary of content (8 pages)

PAGE 1
9-1848; Rev 0; 10/00 256-Tap SOT-PoT, Low-Drift Digital Potentiometers in SOT23 Features ♦ Miniature 8-Pin SOT23 (3mm x 3mm) ♦ 256 Tap Positions ♦ Ultra-Low 0.1µA Supply Current ♦ Single-Supply Operation: +2.7V to +5.
PAGE 2
MAX5400/MAX5401 256-Tap SOT-PoT, Low-Drift Digital Potentiometers in SOT23 ABSOLUTE MAXIMUM RATINGS VDD to GND ............................................................. -0.3V to +6V DIN, SCLK, CS to GND ............................................-0.3V to +6V H, L, W to GND...........................................-0.3V to (VDD + 0.3V) Maximum Continuous Current into Pins H, L, and W ...........................................................
PAGE 3
256-Tap SOT-PoT, Low-Drift Digital Potentiometers in SOT23 (VDD = +5V, VH = VDD, VL = 0, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise noted. Parameters are measured at TA = +25°C. Values over full temperature range are guaranteed by design.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DIGITAL INPUTS Input High Voltage VIH VCC = 5V Input Low Voltage VIL VCC = 5V Input High Voltage VIH VCC = 3V Input Low Voltage VIL VCC = 3V 0.7 ✕ VDD V 0.3 ✕ VDD 0.7 ✕ VDD V 0.
PAGE 4
Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) END-TO-END RESISTANCE % CHANGE vs. TEMPERATURE 200 100 MAX5400toc02 50kΩ -0.03 -0.05 -0.07 0 1 2 3 4 VARIABLE RESISTOR DNL vs. INPUT CODE (50kΩ) MAX5400 Toc04 0.020 0.015 (LSB) 30 25 20 15 5 0 96 0.15 0.10 0.005 0.05 0 -0.005 -0.05 -0.010 -0.10 -0.015 -0.15 -0.20 0 32 64 96 128 160 192 224 256 0 32 64 96 128 160 192 224 256 INPUT CODE-DECIMAL VARIABLE RESISTOR DNL vs.
PAGE 5
256-Tap SOT-PoT, Low-Drift Digital Potentiometers in SOT23 TAP-to-TAP SWITCHING TRANSIENT (FROM CODE 127 toc CODE 128) SUPPLY CURRENT vs. INPUT LOGIC VOLTAGE MAX5400 Toc10 MAX5400 Toc11 10 10mV/div 2.5V 5V/div CS 0 SUPPLY CURRENT (mA) 1 VW-L VDD = +5V 0.1 0.01 VDD = +3V 0.001 0.0001 0 1 2 3 4 5 DIGITAL INPUT VOLTAGE (V) VOLTAGE DIVIDER DNL vs. INPUT CODE (50kΩ) 0.08 0.06 VDD = +2.7V to +5.5V 0.15 0.10 0.04 0.05 (LSB) 0.02 (LSB) MAX5400 Toc13 0.20 MAX5400 Toc12 0.
PAGE 6
MAX5400/MAX5401 256-Tap SOT-PoT, Low-Drift Digital Potentiometers in SOT23 POT REGISTER LOADED CS SCLK 8TH CLOCK PULSE 1ST CLOCK PULSE DIN D7 D6 D5 D4 D3 D2 D1 D0 LSB MSB TIME Figure 2. Serial Interface Timing Diagram CS tCSW tCSO tCS1 tCSS tCH tCL tCP tCSH SCLK tDS tDH DIN Figure 3. Detailed Serial Interface Timing Diagram Detailed Description The MAX5400/MAX5401 consists of 255 fixed resistors in series between pins H and L.
PAGE 7
256-Tap SOT-PoT, Low-Drift Digital Potentiometers in SOT23 B0 (D7) B1 (D6) B2 (D5) B3 (D4) B4 (D3) B5 (D2) B6 (D1) (MSB) FIRST BIT IN B7 (D0) (LSB) LAST BIT IN Figure 4. Serial Data Format Applications Information The MAX5400/MAX5401 are intended for a variety of circuits that require accurate, fine-tuning adjustable resistance, such as adjustable voltage or adjustable gain circuit configurations.
PAGE 8
MAX5400/MAX5401 256-Tap SOT-PoT, Low-Drift Digital Potentiometers in SOT23 Chip Information +5V TRANSISTOR COUNT: 3769 TECHNOLOGY: BiCMOS VIN VO REF OUT MAX6160 ADJ H W GND L VO = 1.23V × 100kΩ FOR MAX5401 R2(kΩ) VO = 1.23V × 50kΩ FOR MAX5400 R2(kΩ) Figure 7.