DS1856M Datasheet, PDF (1/28 Pages) Maxim Integrated Products – Dual, Temperature-Controlled Resistors with Calibrated Monitors and Password Protection

19-6395; Rev 0; 7/12
EVAALVUAAILTAIOBNLEKIT
Dual, Temperature-Controlled Resistors with
Calibrated Monitors and Password Protection
General Description
The DS1856M dual, temperature-controlled, nonvolatile
(NV) variable resistors with three monitors consists of
two 256-position, linear, variable resistors; three analog
monitor inputs (MON1, MON2, MON3); and a direct-to-
digital temperature sensor. The device provides an
ideal method for setting and temperature-compensating
bias voltages and currents in control applications using
minimal circuitry. The variable resistor settings are
stored in EEPROM memory and can be accessed over
the 2-wire serial bus.
The DS1856M includes 128 bytes of EEPROM memory
at A2h slave address, Table 00/01. The DS1856M also
includes three-levels of password protection. The
DS1856-01 includes 256 bytes of A0h EEPROM memo-
ry. The DS1856B-M50+ and DS1856E-M50+ are drop-
in replacements for the DS1856B-050+ and
DS1866E-050+, respectively. The enhancements
include 256 bytes of EEPROM at A0h; selectable
MON2, MON3 references; and a 13-bit ADC. These are
backward compatible by default with the
DS1856B-050+/DS1856E-050+.
Applications
Optical Transceivers
Optical Transponders
Instrumentation and Industrial Controls
RF Power Amps
Diagnostic Monitoring
Ordering Information appears at end of data sheet.
Features
♦ SFF-8472 Compatible
♦ 13-Bit ADC
♦ Two Linear, 256-Position, Nonvolatile
Temperature-Controlled Variable Resistors with
2°C Resolution
♦ Three Levels of Security
♦ Access to Monitoring and ID Information
Configurable with Separate Device Addresses
♦ 2-Wire Serial Interface
♦ Two Buffers with TTL/CMOS-Compatible Inputs
and Open-Drain Outputs
♦ Operates from a 3.3V or 5V Supply
♦ -40°C to +95°C Operating Temperature Range
Typical Operating Circuit
V_CC
V_CC = 3.3V
4.7kΩ
2-WIRE
INTERFACE
Tx-FAULT
LOS
4.7kΩ
1
SDA
2
SCL
3
OUT1
4
IN1
5
OUT2
6
IN2
7
N.C.
8
GND
DS1856M
16
V_CC
15
H1
14
L1
13
H0
12
L0
0.1μF
DECOUPLING
CAPACITOR
TO LASER BIAS
CONTROL
TO LASER
MODULATION
CONTROL
11 Rx POWER*
MON3
10 _{Tx POWER*}
MON2
MON1 ^{9 Tx BIAS*}
DIAGNOSTIC
INPUTS
*SATISFIES SFF-8472 COMPATIBILITY
For pricing, delivery, and ordering information, please contact Maxim Direct
1
at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.