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DS1841T+TR Datasheet

Download or read online Maxim Integrated DS1841T+TR Temperature-Controlled, NV, I2C, Logarithmic Resistor pdf datasheet.



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Rev 0; 11/07
General Description
The DS1841 is a 7-bit, logarithmic, nonvolatile (NV) digi-
tal resistor that features an on-chip temperature sensor
and associated analog-to-digital converter (ADC). The
integrated temperature sensor indexes a 72-byte NV
lookup table (LUT) encompassing a temperature range
from -40°C to +100°C. The LUT output can drive the
resistor directly or be added to an NV initial-value regis-
ter (IVR) to drive the resistor. This flexible LUT-based
architecture allows the DS1841 to provide a tempera-
ture-compensated resistor output with arbitrary slope.
Programming is accomplished by an I
interface, which can operate at speeds of up to 400kHz.
Optical Transceivers
Linear and Nonlinear Compensation
Instrumentation and Industrial Controls
Mechanical Potentiometer Replacement
Registers and Modes are capitalized for clarity.
Typical Operating Circuit
4.7kΩ
4.7kΩ
SDA
V
CC
SCL
GND
DS1841
RH
RW
A1
RGND
A0
APD BIAS CONTROL APPLICATION
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Temperature-Controlled, NV, I
Logarithmic Resistor
♦ 22kΩ to 3.7kΩ Adjustable Logarithmic Resistor
with a 3.6kΩ Fixed Resistor
♦ 128 Wiper Tap Points
♦ On-Chip Temperature Sensor and ADC
♦ 72-Byte Lookup Table (LUT)
♦ I
2
C-Compatible Serial Interface
♦ Address Pins Allow Up to Four DS1841s to Share
the Same I
♦ Digital Supply of 2.7V to 5.5V
2
C-compatible
♦ -40°C to +100°C Operating Range
♦ 3mm x 3mm, 10-Pin TDFN Package
Applications
PART
DS1841T+
DS1841T+T&R
+ Denotes a lead-free package.
T&R = Tape and reel.
TOP VIEW
3.3V
V
APD
V
OUT
0.1μF
DC-DC
CONVERTER
FB
100pF
*EXPOSED PAD
2
Features
2
C Bus
Ordering Information
TEMP RANGE
PIN-PACKAGE
-40°C to +100°C
10 TDFN
-40°C to +100°C
10 TDFN
Pin Configuration
SCL
N.C.
RH
RW
RGND
10
9
8
7
6
DS1841
*EP
1
2
3
4
5
SDA
GND
V
A1
A0
CC
TDFN
×
×
3.0mm
3.0mm
0.8mm
C,
1

Summary of Contents

Page 1

... RGND A0 APD BIAS CONTROL APPLICATION ___ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. Temperature-Controlled, NV, I Logarithmic Resistor 22kΩ to 3.7kΩ Adjustable Logarithmic Resistor with a 3.6kΩ Fixed Resistor ♦ ...

Page 2

Temperature-Controlled, NV, I www.DataSheet4U.com Logarithmic Resistor ABSOLUTE MAXIMUM RATINGS Voltage Range on SDA, SCL, and V Relative to GND ...-0.5V to 6.0V CC Voltage Range on RH, RW, A0, and A1 Relative to GND ...-0. Operating Temperature Range ...

Page 3

TEMPERATURE SENSOR CHARACTERISTICS (V 2.7V to 5.5V -40°C to 100°C, unless otherwise noted PARAMETER SYMBOL Temperature Error Update Rate (Temperature and t FRAME Supply Conversion Time) ANALOG VOLTAGE MONITORING CHARACTERISTICS (V 2.7V to ...

Page 4

Temperature-Controlled, NV, I www.DataSheet4U.com Logarithmic Resistor ELECTRICAL CHARACTERISTICS (See Figure 3) (continued 2.7V to 5.5V -40°C to 100°C, timing referenced PARAMETER SYMBOL EEPROM Write Time A0, A1 Setup ...

Page 5

T 25°C, unless otherwise noted SUPPLY CURRENT vs. SUPPLY VOLTAGE 250 200 LUT MODE AND LUT ADDER MODE LUT MODE AND LUT ADDER MODE UPDATE MODE BIT 1 UPDATE MODE ...

Page 6

Temperature-Controlled, NV, I www.DataSheet4U.com Logarithmic Resistor PIN NAME 2 1 SDA I C Serial Data. Input/output for I 2 GND Ground 3 V Power Supply Address Select Inputs. Determines I Slave Address Byte and Address Pins sections ...

Page 7

LUT Adder Mode (Default) LUT Adder Mode is selected by setting the Update Mode bit to 1 and the Adder Mode bit to 1. This mode operates similar to LUT Mode with one major difference (see the LUT Mode ...

Page 8

Temperature-Controlled, NV, I www.DataSheet4U.com Logarithmic Resistor LUT Mode and LUT Adder Mode Block Diagram (Update Mode Bit GND CONTROL SCL LOGIC/ REGISTERS SDA INTERFACE A0 A1 DATA TEMP SENSOR ADC V CC VOLTAGE ...

Page 9

DECREASING LUT34 TEMPERATURE LUT33 LUT32 INCREASING LUT31 TEMPERATURE LUT30 1°C HYSTERESIS WINDOW TEMPERATURE (°C) Figure 1. LUT Hysteresis MSB SLAVE ADDRESS THE SLAVE ADDRESS IS DETERMINED BY ADDRESS PINS ...

Page 10

Temperature-Controlled, NV, I www.DataSheet4U.com Logarithmic Resistor Memory Description The DS1841s internal memory consists of both volatile and NV registers that are organized into eight byte Register 00h: Initial Value Register (IVR) FACTORY DEFAULT (IVR) 00h MEMORY TYPE NV MEMORY TYPE ...

Page 11

Register 03h: Control Register 1 (CR1) FACTORY DEFAULT 00h MEMORY TYPE Shadowed NV 03h Reserved Reserved Bit 7 Bits Reserved. Adder Mode This bit is valid only if the Update Mode bit 1. Bit 1 ...

Page 12

Temperature-Controlled, NV, I www.DataSheet4U.com Logarithmic Resistor Register 0Ah: Control Register 2 (CR2) FACTORY DEFAULT 00h MEMORY TYPE Volatile 0Ah Reserved Reserved Bit 7 Bits Reserved. Wiper Access Control This bit is valid only in LUT Mode and ...

Page 13

Registers 80h to C7h: Temperature Lookup Register (LUT) FACTORY DEFAULT 00h MEMORY TYPE NV 80h to C7h Bit 7 These registers at location 80h to C7h are NV and serve to temperature compensate RW over the operating temperature range ...

Page 14

Temperature-Controlled, NV, I www.DataSheet4U.com Logarithmic Resistor SDA t BUF t LOW SCL t HD:STA STOP START NOTE: TIMING IS REFERENCE TO V AND V IL(MAX) IH(MIN) Figure Timing Diagram Byte read: A byte read is an ...

Page 15

Writing multiple bytes to a slave multiple bytes can also be performed. During a sin- gle write sequence bytes in one page can be written at one time. If more than eight bytes are ...

Page 16

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 16 ___Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2007 Maxim Integrated Products ...

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