Rainbow Electronics DS1842A - Manual

General Description
The DS1842A integrates the discrete high-voltage
components necessary for avalanche photodiode
(APD) bias and monitor applications. A switch FET and
precision voltage-divider network are used in conjunc-
tion with an external DC-DC controller to create a boost
DC-DC converter. A current clamp limits current
through the APD and also features an external shut-
down. The precision voltage-divider network is provid-
ed for precise control of the APD bias voltage. The
device also includes a dual current mirror to monitor
the APD current.
Applications
APD Biasing
GPON ONU and OLT
Features
♦ 76V Maximum Boost Voltage
♦ Switch FET
♦ Current Monitor with a Wide 1µA to 2mA Range,
Fast 50ns Time Constant, and 10:1 and 5:1 Ratio
♦ 2mA Current Clamp with External Shutdown
♦ Precision Voltage Feedback
♦ Multiple External Filtering Options
♦ 3mm x 3mm, 14-Pin TDFN Package with Exposed Pad
DS1842A
76V, APD, Bias Output Stage with
Current Monitoring
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-4994; Rev 0; 10/09
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.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
DS1842AN+ -40°C to +85°C 14 TDFN-EP*
DS1842AN+T&R -40°C to +85°C 14 TDFN-EP*
+ Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
*
EP = Exposed pad.
DS1875
DS1842A
SW
FB
D2
COMP
MON3
LX
GATE
PGND
FBOUT
R 1
R 2
MIRIN
FBIN
MIR1
CLAMP
NOTE: SEE THE LAYOUT CONSIDERATIONS SECTION.
MIROUT GND EP
3.3V
CURRENT MIRROR
CURRENT
LIMIT MIR2
C BULK
C COMP R COMP
EXTERNAL MONITOR
TIA
APD
ROSA
Typical Application Circuit