Datasheet

ManualsBrandsMaxim ManualsDigital PotentiometersNon Volatile Digital Potentiometer 10 kOhm Serial/3-Wire/SPI TSSOP

10-Bit, Nonvolatile, Linear-Taper Digital

Potentiometers

SPI-Compatible Serial Interface

Drive SPI/UD high to enable the 3-wire SPI-compatible

serial interface (see Figure 3). This write-only interface

contains three inputs: chip select (CS), data in

(DIN(U/D)), and data clock (SCLK(INC)). Drive CS low

to load the data at DIN(U/D) synchronously into the shift

The WRITE command (C1, C0 = 00) requires 24 clock

cycles to transfer the command and data (Figure 4a).

The COPY commands (C1, C0 = 10 or 11) use either

eight clock cycles to transfer the command bits (Figure

4b) or 24 clock cycles with the last 16 data bits disre-

garded by the device.

After loading the data into the shift register, drive CS

high to latch the data into the appropriate control regis-

ter. Keep CS low during the entire serial data stream to

avoid corruption of the data. Table 2 shows the com-

mand decoding.

Write Wiper Register

Data written to this register (C1, C0 = 00) controls the

wiper position. The 10 data bits (D9–D0) indicate the

position of the wiper. For example, if DIN(U/D) = 00 0000

0000, the wiper moves to the position closest to L. If

DIN(U/D) = 11 1111 1111, the wiper moves closest to H.

This command writes data to the volatile random

access memory (RAM), leaving the NV register

unchanged. When the device powers up, the data

stored in the NV register transfers to the wiper register,

moving the wiper to the stored position. Figure 5 shows

how to write data to the wiper register.

CLOCK EDGE 1 2 345678910111213141516171819…24

Bit Name — — C1 C0 — — — — D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 — … —

Write Wiper Register 0 0 000000D9D8D7D6D5D4D3D2D1D0X…X

Copy Wiper Register

to NV Register

00100000———————————…—

Copy NV Register to

Wiper Register

00110000———————————…—

Table 2. Command Decoding*

D9 is the MSB and D0 is the LSB.

X = Don’t care.

CSO

CSS

CSH

CSW

CS1

SCLK(INC)

DIN(U/D)

Figure 3. SPI-Compatible Serial-Interface Timing Diagram (SPI/UD = 1)

MAX5481–MAX5484

Maxim Integrated