Triple NV Low Step Size Variable

Resistor Plus Memory

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13

Reading Multiple Bytes from a Slave: The read oper-

ation can be used to read multiple bytes with a single

transfer. When reading bytes from the slave, the master

simply ACKs the data byte if it desires to read another

byte before terminating the transaction. After the mas-

ter reads the last byte it must NACK to indicate the end

of the transfer and generates a stop condition.

Application Information

Power Supply Decoupling

To achieve best results, it is highly recommended that a

decoupling capacitor is used on the I.C. power supply

pins. Typical values of decoupling capacitors are 0.01µF

and 0.1µF. Use a high-quality, ceramic, surface-mount

and GND pins of the I.C. to minimize lead inductance.

High Resistor Terminal Voltage

It is permissible to have a voltage on the resistor-high

terminals that is higher than the voltage connected to

more of the resistor high terminals are connected to

5.0V allows a 3V system to control a 5V system. The

5.5V maximum still applies to the limit on the resistor

DS3906

R0

A0

A1

Ω

R1

Ω

R2

H2

H1

H0

Ω

A2

SCL

LED

DRIVERS

SDA

FROM SYSTEM

CONTROLLER

GND

4.7k

Ω

4.7k

Ω

0.1

µF

RED LED PANEL

LED

DRIVERS

GREEN LED PANEL

LED

DRIVERS

BLUE LED PANEL

DESIGN NOTES:

1. IN THIS APPLICATION A NUMBER OF LED DRIVERS ARE SET USING THE DS3906'S VARIABLE RESISTORS.

2. THE PARALLEL COMBINATION OF THE DS3906 VARIABLE RESISTOR R0 AND 105

RESISTOR WITH LINEAR STEP INCREMENTS OF 0.6

Ω RANGING FROM 66Ω TO 101Ω. THE SAME APPLIES FOR RESISTOR 1 (R1).

THE PARALLEL COMBINATION OF R2 AND 310

1

Ω RANGING FROM 187Ω TO 255Ω.

RESISTOR VALUES LOWER THAN THE SHOWN VALUES RESULT IN SMALLER STEP INCREMENTS. REFER TO THE RESISTOR TABLES AND

COMPUTE EQUIVALENT RESISTANCE TO FIND OUT THE RANGES.

Typical Operating Circuit