DS1856 Datasheet, PDF (1/31 Pages) Maxim Integrated Products – Dual, Temperature-Controlled Resistors with Internally Calibrated Monitors and Password Protection

Rev 1; 4/05
Dual, Temperature-Controlled Resistors with Inter-
nally Calibrated Monitors and Password Protection
General Description
The DS1856 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.
Relative to other members of the family, the DS1856 is
essentially a DS1859 with a DS1852-friendly memory
map. In particular, the DS1856 can be configured so
the 128 bytes of internal Auxiliary EEPROM memory is
mapped into Main Device Table 00h and Table 01h,
maintaining compatibility between both the
DS1858/DS1859 and the DS1852. The DS1856 also
features password protection equivalent to the DS1852,
further enhancing compatibility between the two.
Applications
Optical Transceivers
Optical Transponders
Instrumentation and Industrial Controls
RF Power Amps
Diagnostic Monitoring
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
DS1856
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
Features
♦ SFF-8472 Compatible
♦ Five Monitored Channels (Temperature, V_CC,
MON1, MON2, MON3)
♦ Three External Analog Inputs (MON1, MON2, MON3)
That Support Internal and External Calibration
♦ Scalable Dynamic Range for External Analog Inputs
♦ Internal Direct-to-Digital Temperature Sensor
♦ Alarm and Warning Flags for All Monitored
Channels
♦ Two Linear, 256-Position, Nonvolatile Temperature-
Controlled Variable Resistors
♦ Resistor Settings Changeable Every 2°C
♦ 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
Ordering Information
PART
RES0/RES1
RESISTANCE
(kΩ)
PIN-PACKAGE
DS1856E-050
50/50
16 TSSOP
DS1856E-050/T&R
50/50
16 TSSOP
DS1856B-050
50/50
16-Ball CSBGA
Ordering Information continued at end of data sheet.
+Denotes lead free.
*Future product—contact factory for availability.
T&R denotes tape-and-reel.
All parts operate at the -40°C to +95°C temperature range.
Pin Configurations
TOP VIEW
A _IN1
SCL VCC
H1
B _{OUT2 SDA}
H0
L1
C _{N.C. IN2 OUT1 MON3}
D GND L0 MON1 _MON2
1
2
3
4
CSBGA (4mm x 4mm)
1.0mm PITCH
SDA ₁
SCL 2
OUT1 3
IN1 4
OUT2 5
IN2 6
N.C. 7
GND 8
DS1856
TSSOP
16 V_CC
15 H1
14 L1
13 H0
12 L0
11 MON3
10 MON2
9 MON1
______________________________________________ Maxim Integrated Products 1
For pricing delivery, and ordering information please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.