Rainbow Electronics DS1874 - Manual

General Description
The DS1874 controls and monitors all functions for SFF,
SFP, and SFP+ modules including all SFF-8472 func-
tionality. The combination of the DS1874 with the
MAX3798/MAX3799 laser driver/limiting amplifier pro-
vides APC loop, modulation current control, and eye
safety functionality. The DS1874 continuously monitors
for high output current, high bias current, and low and
high transmit power to ensure that laser shutdown for
eye safety requirements are met without adding external
components. Six ADC channels monitor V
CC , tempera-
ture, and four external monitor inputs (MON1–MON4)
that can be used to meet all monitoring requirements.
MON3 is differential with support for common mode to
V
CC . Two digital-to-analog (DAC) outputs with tempera-
ture-indexed lookup tables (LUTs) are available for addi-
tional monitoring and control functionality.
Applications
SFF, SFP, and SFP+ Transceiver Modules
Features
♦ Meets All SFF-8472 Control and Monitoring
Requirements
♦ Laser Bias Controlled by APC Loop and
Temperature LUT to Compensate for Tracking
Error
♦ Laser Modulation Controlled by Temperature LUT
♦ Six Analog Monitor Channels: Temperature, V
CC ,
MON1–MON4
MON1–MON4 Support Internal and External
Calibration
Scalable Dynamic Range
Internal Direct-to-Digital Temperature Sensor
Alarm and Warning Flags for All Monitored
Channels
♦ Two 9-Bit Delta-Sigma Outputs with 36 Entry
Temperature LUTs
♦ Digital I/O Pins: Five Inputs, Five Outputs
♦ Comprehensive Fault-Measurement System with
Maskable Laser Shutdown Capability
♦ Flexible, Two-Level Password Scheme Provides
Three Levels of Security
♦ 256 Additional Bytes Located at A0h Slave
Address
♦ I 2 C-Compatible Interface
♦ 3-Wire Master to Communicate with the MAX3798/
MAX3799 Laser Driver/Limiting Amplifier
♦ +2.85V to +3.9V Operating Voltage Range
♦ -40°C to +95°C Operating Temperature Range
♦ 28-Pin TQFN (5mm x 5mm) Package
DS1874
________________________________________________________________ Maxim Integrated Products 1
THIN QFN
(5mm × 5mm × 0.8mm)
TOP VIEW
26
27
25
24
10
9
11
SCL TXF LOS IN1 TXD
12
RSELOUT
DAC2 REFIN GND GND MON2 V
CC
1 2
SCLOUT
4 5 6 7
20 21 19 17 16 15
SDAOUT
LOSOUT
MON3P
MON4
TXDOUT
RSEL
SDA
DAC1
3
18
28 8 OUT1 GND
CSELOUT
23 13 MON3N V CC
22 14 MON1 N.C.
DS1874
*EP
+
*EXPOSED PAD.
Pin Configuration
Ordering Information
19-4691; Rev 0; 6/09
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.
+ Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
*
EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
DS1874T+ -40°C to +95°C 28 TQFN-EP*
DS1874T+T&R -40°C to +95°C 28 TQFN-EP*
SFP+ Controller with Digital LDD Interface