DS1841 Просмотр технического описания (PDF) - Maxim Integrated

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DS1841

Temperature-Controlled, NV, I2C, Logarithmic Resistor

Maxim Integrated 

Temperature-Controlled, NV, I2C,

Logarithmic Resistor

Pin Description

PIN

NAME

FUNCTION

1

SDA

I2C Serial Data. Input/output for I2C data.

2

GND

Ground

3

VCC

Power Supply

4

A1

Address Select Inputs. Determines I2C slave address. Device address is 01010A1A0X (see the

5

A0

Slave Address Byte and Address Pins sections for more details).

6

RGND Low Terminal of Resistor. Must be connected to GND.

7

RW

Wiper Terminal

8

RH

Terminal with Fixed Resistor Added in Series with Digital Resistor

9

N.C.

No Connection

10

SCL

I2C Serial Clock. Input for I2C clock.

—

EP

Exposed Paddle. Must be connected to ground.

Detailed Description

The DS1841 operates in one of two modes: LUT Mode

and LUT Adder Mode. In LUT Mode and LUT Adder

Mode, the resistor’s wiper position is controlled as a

function of the temperature measured by the DS1841’s

internal temperature sensor. The difference between

the two LUT modes is the way the resistor’s wiper posi-

tion is calculated. Detailed descriptions of these two

modes, as well as additional features of the DS1841,

are discussed in subsequent sections.

Digital Resistor Description

The DS1841’s resistor consists of 128 resistive steps

between RW and RGND with a series resistor, RS,

between RH and RW. The wiper position and the output

seen on RW are decoded based on the value in the

wiper register (WR). The step size of each position is

optimized to produce a linear response when used in

the feedback network of a DC-DC converter.

Mode Selection

The DS1841 mode of operation is determined by the

Update Mode bit (Control Register 1, address 03h, bit 0)

and the Adder Mode bit (Control Register 1, address

03h, bit 1). Table 1 illustrates how the two control bits

are used to select the operating mode. When shipped

from the factory, the DS1841 is programmed with the

Update Mode and Adder Mode bits set to 1, hence con-

figuring the DS1841 in LUT Adder Mode. See Appendix

A for a detailed table of the control logic bit functions.

Table 1. Operating Modes

UPDATE MODE

BIT

1

1

ADDER MODE BIT

0

1

MODE

LUT Mode

LUT Adder Mode

(Default)

6 _______________________________________________________________________________________

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