DS1857 Datasheet, PDF (1/22 Pages) Maxim Integrated Products – Dual Temperature-Controlled Resistors with External Temperature Input and Monitors

Rev 1; 6/04
Dual Temperature-Controlled Resistors with
External Temperature Input and Monitors
General Description
The DS1857 dual temperature-controlled nonvolatile
(NV) variable resistors with external temperature input
and monitors consists of two 50kΩ 256-position linear
variable resistors, two analog monitor inputs (MON1,
MON2), and an external temperature sensor input. The
device provides an ideal method for setting and tem-
perature-compensating bias voltages and currents in
control applications using minimal circuitry. The vari-
able resistor settings are stored in EEPROM memory
and can be accessed over the 2-wire serial bus.
Applications
Optical Transceivers
Optical Transponders
Instrumentation and Industrial Controls
RF Power Amps
Diagnostic Monitoring
Features
♦ Four Total Monitored Channels (Temperature,
V_CC, MON1, MON2)
♦ Two External Analog Inputs (MON1, MON2)
♦ Interface to External Temperature Sensor (LM50)
♦ Two 50kΩ, Linear, 256-Position, Nonvolatile
Temperature-Controlled Variable Resistors
♦ Resistor Settings Changeable Every 2°C
♦ Access to Monitoring and ID Information
Configurable with Separate Device Addresses
♦ Resistor Disable (Open-Circuit) Function
♦ 2-Wire Serial Interface
♦ Three Address Lines for Multiple Devices
♦ Operates from a 3.3V or 5V Supply
♦ SFF-8472 Compatible
Ordering Information
PART
DS1857E-050
TEMP RANGE PIN-PACKAGE
-40°C to +95°C 16 TSSOP
DS1857E-050/T&R
-40°C to +95°C
16 TSSOP
(Tape-and-Reel)
DS1857B-050
-40°C to +95°C 16 Ball CSBGA
Typical Operating Circuit
V_CC
V_CC = 3.3V
4.7kΩ
4.7kΩ
2-WIRE
INTERFACE
V_CC
1 _SDA
2 _SCL
3 _A0**
4 _A1**
GROUND TO
DISABLE WRITE
PROTECT
Tx DISABLE
5 _A2**
6 _WPEN
7 _RHIZ
8 _GND
V_CC ¹⁶
0.1µF
DECOUPLING
CAP
15
H1
14
L1
TO LASER BIAS
CONTROL
DS1857
13
H0
12
L0
TO LASER MODULATION
CONTROL
11
EXTTMP
TO EXTERNAL TEMPERATURE
SENSOR, SUCH AS LM50
MON2 ^{10 Rx POWER*} DIAGNOSTIC
MON1 ^{9 Tx BIAS*}
INPUTS
0 TO 2.5V FS
*Rx POWER AND Tx BIAS CAN BE ARBITRARILY
ASSIGNED TO THE MON INPUTS.
**ADDRESS INPUTS DETERMINE THE MAIN DEVICE 2-WIRE
SLAVE ADDRESS WHEN ADFIX = 0. THIS ADDRESS MUST BE
DIFFERENT THAN THE AUX DEVICE ADDRESS WHEN ADEN = 0.
Pin Configurations
TOP VIEW
A
A1
SCL V_CC
H1
B _{A2 SDA H0}
L1
C _{RHIZ WPEN A0 EXTTMP}
D GND L0 MON1 MON2
1
2
3
4
16-BALL CSBGA (4mm x 4mm)
1.0mm PITCH
1 SDA
2 SCL
3 A0
4 A1
5 A2
6 WPEN
7 RHIZ
8 GND
V_CC 16
H1 15
L1 14
DS1857
H0 13
L0 12
EXTTMP 11
MON2 10
MON1 ₉
16 TSSOP
______________________________________________ Maxim Integrated Products 1
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