Rainbow Electronics DS3903 User Manual

General Description

The DS3903 contains three nonvolatile (NV) low temperature coefficient digital potentiometers, which can be accessed through a 2-wire bus. It operates in both 3V and 5V systems, and it features a write-protect pin that can lock the positions of the potentiometers. An address pin allows two DS3903s to be placed on the same 2-wire bus.

Applications

Power-Supply Calibration

Mobile Phones and PDAs

Fiber Optics Transceiver Modules

Portable Electronics

A Small, Low-Cost Replacement for Mechanical Potentiometers

Features

♦ Three 128-Position Linear Potentiometers

(Two 10kΩ, One 90kΩ)

♦ NV Wiper Storage

♦ 0 to 5.5V on Any Potentiometer Terminal

Independent of V

♦ Low End-to-End Temperature Coefficient

♦ Operates on an Industry-Standard 2-Wire Bus

♦ Write-Protect Pin

♦ Supply Voltage: 3V or 5V

♦ Operating Temperature Range: -40°C to +85°C

♦ Packaging: 20-Pin TSSOP

DS3903

Triple 128-Position Nonvolatile

Digital Potentiometer

_____________________________________________ Maxim Integrated Products 1

SDA

192

SCL

N.C.

TSSOP

N.C.

GND

DS3903

Pin Configuration

0.1µF

4.7kΩ

2-WIRE

MASTER

VREF1

VREF2

5.1kΩ

Iref

SCL

SDA

POTENTIOMETER 2 10kΩ ADDDR FAh

POTENTIOMETER 0 10kΩ ADDDR F9h

POTENTIOMETER 1 90kΩ ADDDR F8h

GND

4.7kΩ

VARIABLE RESISTANCE FOR ADJUSTABLE CURRENT SOURCE

HIGH-OUTPUT-IMPEDANCE VOLTAGE REFERENCE

BUFFERED VOLTAGE REFERENCE

MAX427

DS3903

Typical Operating Circuit

Ordering Information

Rev 0; 6/02

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

DS3903E-020

20 TSSOP

DS3903E-020/T&R

20 TSSOP (Tape-and-Reel)

-40°C to +85°C

DS3903

Triple 128-Position Nonvolatile Digital Potentiometer

2 ______________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

RECOMMENDED DC OPERATING CONDITIONS

(TA= -40° to +85°C)

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.

Voltage on VCCPin Relative to Ground.................-0.5V to +6.0V

Voltage on SDA, SCL, A0, and WP

Relative to Ground ...........................................................-0.5V to

+ 0.5V Voltage on L0, L1, L2, W0, W1, W2, H0, H1, and

H2 Relative to Ground ...........................................-0.5V to +6.0V

Current Through W0, W1, and W2......................................±4mA

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

Programming Temperature Range .........................0°C to +70°C

Storage Temperature Range .............................-55°C to +125°C

Soldering Temperature ....................See IPC/JEDEC J-STD-020A

Specification

PARAMETER

SYMBOL

CONDITIONS MIN TYP MAX

UNITS

Supply Voltage V

(Note 1) +2.7 +5.5 V

Input Logic 1 V

(Notes 2, 3)

Input Logic 0 V

(Notes 2, 3) -0.3

Wiper Current I

-3 +3 mA

Resistor Terminals L0, L1, L2, W0, W1, W2, H0, H1, H2

= +2.7V to +5.5V -0.3 +5.5 V

DC ELECTRICAL CHARACTERISTICS

(VCC= 2.7V to 5.5V, TA= -40°C to +85°C.)

PARAMETER

CONDITIONS MIN TYP MAX

UNITS

Input Leakage I

-1 +1 µA

= 3V (Note 2) 100 200

Standby Supply Current I

stby

= 5V (Note 2) 150 250

µA

OL1

3mA sink current 0 0.4 V

Low-Level Output Voltage (SDA)

OL2

6mA sink current 0 0.6 V

I/O Capacitance C

I/O

10 pF

WP Internal Pullup Resistance R

35 65 110 kΩ

SYMBOL

0.7 x V

0.3 x V

+ 0.3

DS3903

Triple 128-Position Nonvolatile

Digital Potentiometer

_____________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS

(VCC= 2.7V to 5.5V, TA= -40°C to +85°C.)

PARAMETER

SYMBOL

CONDITIONS MIN

TYP

MAX

UNITS

Fast mode (Note 4) 0

SCL Clock Frequency f

SCL

Standard mode (Note 4) 0

kHz

Fast mode (Note 4) 1.3

Bus Free Time Between Stop and Start Conditions

BUF

Standard mode (Note 4) 4.7

µs

Fast mode (Notes 4, 5) 0.6

Hold Time (Repeated) Start Condition

Standard mode (Notes 4, 5) 4.0

µs

Fast mode (Note 4) 1.3

Low Period of SCL Clock t

LOW

Standard mode (Note 4) 4.7

µs

Fast mode (Note 4) 0.6

High Period of SCL Clock t

HIGH

Standard mode (Note 4) 4.0

µs

Fast mode (Notes 4, 6, 7) 0 0.9

Data Hold Time

Standard mode (Notes 4, 6, 7) 0 0.9

µs

Fast mode (Note 4) 100

Data Set-Up Time

Standard mode (Note 4) 250

Fast mode 0.6

Start Set-Up Time t

SU:STA

Standard mode 4.7

µs

Fast mode (Note 8)

Rise Time of Both SDA and SCL Signals

Standard mode (Note 8)

Fast mode (Note 8)

Fall Time of Both SDA and SCL Signals

Standard mode (Note 8)

Fast mode 0.6

Set-Up Time for Stop Condition

Standard mode 4.7

µs

Capacitive Load for Each Bus

(Note 8)

EEPROM Write Time t

(Note 9) 10 ms

Startup Time t

2ms

ANALOG RESISTOR CHARACTERISTICS

(VCC= 2.7V to 5.5V, TA= -40°C to +85°C.)

PARAMETER

SYMBOL

CONDITIONS MIN TYP MAX UNITS

End-to-End Resistance Tolerance

+25°C -20 +20 %

10kΩ Pot 10.5

End-to-End Resistance

90kΩ Pot 90

kΩ

Factory-Default Wiper Setting Position 127 (max resistance)

Wiper Resistance R

250 500 Ω

Absolute Linearity (Note 10) -1.0 +1.0 LSB

Relative Linearity (Note 11) -0.25 +0.25 LSB

End-to-End Temperature Coefficient

-300 0 +300

ppm/°C

Ratiometric Temperature Coefficient

±30

ppm/°C

HD:STA

HD:DAT

SU:DAT

20 + 0.1C

400

100

300

1000

300

SU:STO

400

DS3903

Triple 128-Position Nonvolatile Digital Potentiometer

4 ______________________________________________________________________

Note 1: All voltages are referenced to ground. Note 2: I

STBY

specified for VCCequal to 3.0V and 5.0V while control port logic pins are driven to the appropriate logic levels. Appropriate logic levels specify that logic inputs are within a 0.5V of ground or VCCfor the corresponding inactive state. WP must be disconnected or connected high.

Note 3: I/O pins of fast mode devices must not obstruct the SDA and SCL lines if V

is switched off.

Note 4: A fast mode device can be used in a standard mode system, but the requirement t

SU:DAT

> 250ns must then be met. This is automatically the case if the device does not stretch the low period of the SCL signal. If such a device does stretch the low period of the SCL signal, it must output the next data bit to the SDA line t

RMAX

+ t

SU:DAT

= 1000ns + 250ns = 1250ns before the SCL line is released.

Note 5: After this period, the first clock pulse is generated. Note 6: The maximum t

HD:DAT

has only to be met if the device does not stretch the low period (t

LOW

) of the

SCL signal.

Note 7: A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the V

IN MIN

the SCL signal) in order to bridge the undefined region of the falling edge of SCL.

Note 8: C

—total capacitance of one bus line in picofarads, timing referenced to 0.9 x VCCand 0.1 x VCC.

Note 9: EEPROM write begins after a stop condition occurs. Note 10: Absolute linearity is used to measure expected wiper voltage as determined by wiper position in a

voltage-divider configuration.

Note 11: Relative linearity is used to determine the change of wiper voltage between two adjacent wiper positions

in a voltage-divider configuration.

Typical Operating Characteristics

(VCC= 5.0V, 10kΩ plots apply to both pot0 and pot2, TA = +25°C unless otherwise noted.)

100

W-L RESISTANCE

vs. WIPER SETTING (90k

Ω)

DS3903 toc03

WIPER SETTING

W-L RESISTANCE (kΩ)

1251007550250

W-L RESISTANCE

vs. WIPER SETTING (10k

Ω)

DS3903 toc02

WIPER SETTING

W-L RESISTANCE (kΩ)

125100755025

STANDBY SUPPLY CURRENT

vs. TEMPERATURE

DS3903 toc01

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

5040-30 -20 -10 10 20030

100

120

140

160

-40 60 70 80

VCC = 5V

VCC = 3V

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