Rainbow Electronics DS1841 - Manual

DS1841
Temperature-Controlled, NV, I 2 C,
Logarithmic Resistor
Rev 0; 11/07
________________________________________________________________ Maxim Integrated Products 1
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.
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
2 C-compatible
interface, which can operate at speeds of up to 400kHz.
Applications
Optical Transceivers
Linear and Nonlinear Compensation
Instrumentation and Industrial Controls
Mechanical Potentiometer Replacement
Features
♦ 22kΩ to 3.7kΩ Adjustable Logarithmic Resistor
with a 3.6k
Ω 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 2 C Bus
♦ Digital Supply of 2.7V to 5.5V
♦ -40°C to +100°C Operating Range
♦ 3mm x 3mm, 10-Pin TDFN Package
1 3 4
10 8 7
SCL RH RW
SDA
*EP
*EXPOSED PAD
V
CC
A1
2
9
N.C.
GND
5
6
RGND
A0
TDFN
3.0mm × 3.0mm × 0.8mm
TOP VIEW
DS1841
Pin Configuration
Ordering Information
0.1 μF
3.3V
APD BIAS CONTROL APPLICATION
V CC
V OUT
FB
SDA
SCL
A1
A0
GND
100pF
RW
RGND
RH
V APD
4.7k Ω
4.7k Ω
DC-DC
CONVERTER
DS1841
Typical Operating Circuit
+ Denotes a lead-free package.
T&R = Tape and reel.
Registers and Modes are capitalized for clarity.
PART TEMP RANGE PIN-PACKAGE
DS1841T+ -40°C to +100°C 10 TDFN
DS1841T+T&R -40°C to +100°C 10 TDFN