Rainbow Electronics DS3904 - Manual

General Description
The DS3904 contains three nonvolatile (NV) low tem-
perature coefficient variable digital resistors. Each
resistor has 128 user-selectable positions. Additionally,
the DS3904 has a high-impedance option that allows
each resistor to function as a digital switch. The
DS3904 can operate over a 2.7V to 5.5V supply voltage
range, and communication with the device is achieved
through a 2-wire serial interface. An address pin allows
two DS3904s to operate on the same bus. The low-cost
and small size of the DS3904 make it an ideal replace-
ment for conventional mechanical trimming resistors.
Applications
Power-Supply Calibration
Cell Phones and PDAs
Fibre Optic Transceiver Modules
Portable Electronics
Small and Low-Cost Replacement for
Conventional Mechanical Trimming Resistors
Test Equipment
Features
♦ Three 20k Ω , 128-Position Linear Digital Resistors
♦ Resistor Settings are Stored in NV Memory
♦ Each Resistor has a High-Impedance Setting for
Switch Operation to Control Digital Logic
♦ Low Temperature Coefficient
♦ 2-Wire Serial Interface
♦ 2.7V to 5.5V Operating Range
♦ Industrial Temperature Range: -40°C to +85°C
♦ Packaging: 8-Pin µSOP
DS3904
Triple 128-Position Nonvolatile
Variable Digital Resistor/Switch
_____________________________________________ Maxim Integrated Products 1
8
6
5
1
3
4
SDA A0
7 2 SCL H0
H1
H2
µ SOP
V CC
GND
DS3904
Pin Configuration
0.1µF
4.7kΩ
2-WIRE
MASTER
V CC
V CC
H0
H1
H2
RHIZ
1.75kΩ
V CC
SCL
SDA
RESISTOR 0
20kΩ
ADDR F8h
RESISTOR 1
20kΩ
ADDR F9h
RESISTOR 2
20kΩ
ADDR FAh
A0
GND
4.7kΩ
VARIABLE RESISTANCE
FOR ADJUSTABLE
CURRENT SOURCE
2-WIRE
ADDRESSABLE
SWITCH (USING 00h
AND RHIZ)
GAIN
CONTROL
V IN
DS3904
V CC
RHIZ
RHIZ
5.1kΩ DIGITAL
LOGIC
20kΩ
Typical Operating Circuit
Ordering Information
Rev 0; 1/03
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.
PART TEMP RANGE
PIN-
PACKAGE RESISTANCE
DS3904 -40
°
C to +85
°
C 8 µSOP 20k Ω + Hi-Z