Rainbow Electronics DS1875 - Manual

General Description
The DS1875 controls and monitors all functions for burst-
mode transmitters, APD receivers, and video receivers.
It also includes a power-supply controller for APD bias
generation, and provides all SFF-8472 diagnostic and
monitoring functionality. The combined solution of the
DS1875 and the MAX3643 laser driver provides APC
loop, modulation current control, and eye safety func-
tionality. Ten ADC channels monitor V
CC , temperature
(both internal signals), and eight external monitor inputs
(MON1–MON8) that can be used to meet transmitter,
digital receiver, video receiver, and APD receiver-signal
monitoring requirements. Four total DAC outputs are
available. A PWM controller with feedback and compen-
sation pins can be used to generate the bias for an APD
or as a step-down converter. Five I/O pins allow addi-
tional monitoring and configuration.
Applications
BPON, GPON, or EPON Optical Triplexers
SFF, SFP, and SFP+ Transceiver Modules
APD Controller
Features
♦ Meets All PON Burst-Timing Requirements for
Burst-Mode Operation
♦ Laser Bias Controlled by APC Loop and
Temperature Lookup Table (LUT)
♦ Laser Modulation Controlled by Temperature LUT
♦ Six Total DACs: Four External, Two Internal
♦ Two 8-Bit DACs, One of Which is Optionally
Controlled by MON4 Voltage
♦ Internal 8-Bit DAC Controlled by a Temperature-
Indexed LUT
♦ PWM Controller
♦ Boost or Buck Mode
♦ Boost Mode: Uses Optional External
Components, Up to 90V Bias Generation
♦ 131kHz, 262kHz, 525kHz, or 1050kHz Selectable-
Switching Frequency
♦ APD Overcurrent Protection Using Optional Fast
Shutdown
♦ 10 Analog Monitor Channels: Temperature, V
CC ,
Eight Monitors
♦ Internal, Factory-Calibrated Temperature Sensor
♦ RSSI with 29dB Electrical Dynamic
♦ Five I/O Pins for Additional Control and
Monitoring Functions, Four of Which are Either
Digital I/O or Analog Monitors
♦ Comprehensive Fault-Measurement System with
Maskable Laser Shutdown Capability
♦ Two-Level Password Access to Protect
Calibration Data
♦ 120 Bytes of Password-1 Protected Memory
♦ 128 Bytes of Password-2 Protected Memory in
Main Device Address
♦ 256 Additional Bytes Located at A0h Slave
Address
♦ I 2 C-Compatible Interface for Calibration and
Monitoring
♦ 2.85V to 3.9V Operating Voltage Range
♦ -40°C to +95°C Operating Temperature Range
♦ 38-Pin TQFN (5mm x 7mm) Package
DS1875
________________________________________________________________ Maxim Integrated Products 1
TOP VIEW
TQFN
(5mm × 7mm × 0.8mm)
13
14
15
16
17
18
19
MON5/D0
MON6/D1
MON7/D2
MON8/D3
MON1
MON2
MON4
38
37
36
35
34
33
32
1 2 3 4 5 6 7 8 9 10 11 12
N.C.
N.C.
N.C.
V CC
SW
GND
GND
LOSI N.C. GND V
CC
TX-D N.C. FETG N.C. TX-F SCL SDA BEN
31 30 29 28 27 26 25 24 23 22 21 20
N.C. MON3N MON3P DAC1 GND M4DAC FB BIAS MOD COMP BMD V CC
+
*EP
*EXPOSED PAD.
DS1875
Pin Configuration
Ordering Information
Rev 1; 10/08
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-free/RoHS-compliant package.
T&R = Tape and reel.
*
EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
DS1875T+ -40°C to +95°C 38 TQFN-EP*
DS1875T+T&R -40°C to +95°C 38 TQFN-EP*
PON Triplexer and SFP Controller