Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - Digital potentiometer linear Permanent uMAX 8

General Description

The DS3902 features a dual, nonvolatile (NV), low tem-

perature-coefficient, variable digital resistor with 256

user-selectable positions. The DS3902 can operate

over a wide supply range of 2.4V to 5.5V, and commu-

nication with the device is achieved through an I

compatible serial interface. Internal address settings

allow the DS3902 slave address to be programmed to

one of 128 possible addresses. The low cost and the

small size of the DS3902 make it an ideal replacement

for conventional mechanical-trimming resistors.

Applications

Optical Transceivers

Optical Transponders

Instrumentation and Industrial Controls

RF Power Amps

Audio Power-Amp Biasing

Replacement for Mechanical Variable Resistors

and DIP Switches

Features

♦ Dual 256-Position Linear Digital Resistors

♦ Available as 50kΩ/30kΩ or 50kΩ/15kΩ

♦ Resistor Settings Stored in NV Memory

♦ Low Temperature Coefficient

♦ I

C-Compatible Serial Interface

♦ Wide Operating Voltage (2.4V to 5.5V)

♦ Software Write Protection

♦ User-EEPROM Memory

♦ Programmable Slave Address

♦ Operating Temperature Range: -40°C to +95°C

♦ Small 8-Pin µSOP Package

DS3902

Dual, NV, Variable Resistors

with User EEPROM

______________________________________________ Maxim Integrated Products 1

SCL

SDA

ADD_SEL

GND

2-WIRE

MASTER

4.7kΩ

0.1μF

OUT-

OUT+

BIAS+

BIAS-

IN+

IN-

TX_FAULT

TX_DISABLE

BIASMAX

APCSET

MODSET

PC_MON

BS_MON

BIAS SET

MOD SET

NOTES:

1. WITH ADD_SEL TIED TO GND, THE SLAVE ADDRESS WILL BE A2H.

2. FOR A DETAILED APPLICATION DIAGRAM OF A SPECIFIC LD,

CONSULT THE LASER DRIVER DATA SHEET.

LASER

DRIVER IC

DS3902

Typical Operating Circuit

Rev 1; 2/06

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.

Ordering Information

Pin Configuration appears at end of data sheet.

PART

RESISTOR

VALUES

(R0, R1)

TOP

MARK

PIN-

PACKAGE

DS3902U-530

30kΩ, 50kΩ 3902A

8 µSOP

DS3902U-515

15kΩ, 50kΩ 3902B

8 µSOP

Ordering Information continued at end of data sheet.

Summary of content (11 pages)

PAGE 1
Rev 1; 2/06 Dual, NV, Variable Resistors with User EEPROM The DS3902 features a dual, nonvolatile (NV), low temperature-coefficient, variable digital resistor with 256 user-selectable positions. The DS3902 can operate over a wide supply range of 2.4V to 5.5V, and communication with the device is achieved through an I2C compatible serial interface. Internal address settings allow the DS3902 slave address to be programmed to one of 128 possible addresses.
PAGE 2
DS3902 Dual, NV, Variable Resistors with User EEPROM ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC, SDA, SCL, H0, and H1 Relative to Ground................................-0.5V to +6.0V Voltage Range on ADD_SEL Relative to Ground ...............-0.5V to (VCC + 0.5V), not to exceed 6.0V Resistor Current ....................................................................3mA Operating Temperature Range ...........................-40°C to +95°C Programming Temperature Range .........................
PAGE 3
Dual, NV, Variable Resistors with User EEPROM (VCC = +2.4V to +5.5V, TA = -40°C to +95°C, unless otherwise noted. Timing referenced to VIL(MAX) and VIH(MIN).) PARAMETER SYMBOL CONDITIONS TYP 0 MAX UNITS 400 kHz fSCL Bus Free Time Between STOP and START Conditions tBUF 1.3 µs tHD:STA 0.6 µs Low Period of SCL tLOW 1.3 µs High Period of SCL tHIGH 0.
PAGE 4
Typical Operating Characteristics (VCC = +3.3V, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. SCL FREQUENCY 120 VCC = +3V 100 80 60 ASEL = GND H0, H1, OPEN SDA = SCL = VCC 0 -20 0 20 40 60 80 25 20 15 40 10 20 5 0 0 100 150 200 250 300 350 400 50 H0 (-530 VERSION) 0 25 50 75 100 125 150 175 200 225 250 RESISTOR SETTING (DEC) TEMPERATURE COEFFICIENT vs. POSITION POSITION FFh RESISTANCE PERCENT CHANGE FROM +25°C vs.
PAGE 5
Dual, NV, Variable Resistors with User EEPROM H0 ABSOLUTE LINEARITY vs. POSITION 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.1 DS3902 toc11 H0 ABSOLUTE LINEARITY (LSB) 0.09 H0 RELATIVE LINEARITY (LSB) DS3902 toc10 0.1 H0 RELATIVE LINEARITY vs. POSITION 0.08 0.06 0.04 0.02 0.01 0 0 50 100 150 200 50 100 150 200 POSITION (DEC) POSITION (DEC) H1 ABSOLUTE LINEARITY vs. POSITION H1 RELATIVE LINEARITY vs. POSITION 0.08 0.06 0.04 0.02 0 0.1 250 DS3902 toc13 DS3902 toc12 0.
PAGE 6
Dual, NV, Variable Resistors with User EEPROM DS3902 Pin Description PIN NAME 1 H0 2 SDA The block diagram of the DS3902 is shown in the Block Diagram section. Detailed descriptions of major components follow. FUNCTION Resistor 0 High Terminal I2C Serial-Data Open-Drain Input/Output 3 SCL I2C Serial-Clock Input 4 GND Ground 5 Detailed Description Memory Map A memory map of the DS3902 is shown in Table 1.
PAGE 7
Dual, NV, Variable Resistors with User EEPROM DESCRIPTION ADDR BINARY MSB SLAVE ADDRESS LSB FACTORY DEFAULT Slave Address 00h Configuration 01h X X X X Resistor 0 02h b7 b6 b5 Resistor 1 03h b7 b6 b5 Password Entry 04h PW MSB FFh 05h PW LSB FFh Password Setting 06h PW MSB FFh 07h PW LSB FFh No Memory 08h– 0Fh — User Memory 10h– 1Fh 16 BYTES OF GENERAL PURPOSE EEPROM ACCESS W/O PW W/PW DS3902 Table 1.
PAGE 8
DS3902 Dual, NV, Variable Resistors with User EEPROM SDA tBUF tHD:STA tLOW tR tSP tF SCL tHD:STA STOP tSU:STA tHIGH tSU:DAT START tHD:DAT REPEATED START tSU:STO NOTE: TIMING IS REFERENCED TO VIL(MAX) AND VIH(MIN) Figure 1. I2C Timing Diagram START Condition: A START condition is generated by the master to initiate a new data transfer with a slave. Transitioning SDA from high to low while SCL remains high generates a START condition. See the timing diagram for applicable timing.
PAGE 9
Dual, NV, Variable Resistors with User EEPROM I2C Communication Writing a Single Byte to a Slave: The master must generate a START condition, write the slave address byte (R/W = 0), write the memory address, write the byte of data and generate a STOP condition. Remember the master must read the slave’s acknowledgement during all byte write operations.
PAGE 10
DS3902 Dual, NV, Variable Resistors with User EEPROM TYPICAL 2-WIRE WRITE TRANSACTION MSB START 1 LSB 0 1 0 SLAVE ADDRESS* 0 0 1 R/W MSB SLAVE ACK b7 LSB b6 READ/ WRITE b5 b4 b3 b2 b1 b0 MSB SLAVE ACK b7 LSB b6 b5 b4 REGISTER ADDRESS b3 b2 b1 b0 SLAVE ACK STOP DATA * THE ADDRESS IS DETERMINED BY THE ADD_SEL PIN. THE EXAMPLES ASSUME ADD_SEL IS TIED TO GND. IF THE ADD_SEL PIN WERE INSTEAD CONNECTED TO VCC. THEN THE ADDRESS WOULD BE DETERMINED BY THE SLAVE ADDRESS REGISTER.
PAGE 11
Dual, NV, Variable Resistors with User EEPROM RESISTOR VALUES (R0, R1) TOP MARK PINPACKAGE DS3902U-515+ 15kΩ, 50kΩ 3902B 8 µSOP DS3902U-515+T&R 15kΩ, 50kΩ 3902B 8 µSOP DS3902U-530+ 30kΩ, 50kΩ 3902A 8 µSOP DS3902U-530+T&R 30kΩ, 50kΩ 3902A 8 µSOP DS3902U-530/T&R 30kΩ, 50kΩ 3902A 8 µSOP PART Pin Configuration TOP VIEW H0 1 8 VCC SDA 2 7 N.C. 3 6 H1 GND 4 5 ADD_SEL DS3902 SCL +Denotes lead-free package. T&R denotes tape-and-reel package.