DS1842A Maxim, DS1842A Datasheet - Page 5

• Manufacturer Part Number: DS1842A
• Description: The DS1842A integrates the discrete high-voltage components necessary for avalanche photodiode (APD) bias and monitor applications
• Manufacturer: Maxim

The DS1842A contains discrete high-voltage compo-
nents required to create an APD bias voltage and to
monitor the APD bias current. The device’s mirror out-
puts are a current that is a precise ratio of the output
current across a large dynamic range. The mirror
response time is fast enough to comply with GPON Rx
burst-mode monitoring requirements. The device has a
built-in current-limiting feature to protect APDs. The
3, 6, 7
8–11
PIN
12
13
14
—
1
2
4
5
TOP VIEW
*EXPOSED PAD.
CLAMP
FBOUT
MIR1
MIR2
GND
GND
GND
1
2
3
4
5
6
7
_______________________________________________________________________________________
MIROUT
CLAMP
FBOUT
NAME
MIRIN
MIR1
MIR2
FBIN
GND
N.C.
EP
Detailed Description
76V, APD, Dual Output Current Monitor
DS1842A
TDFN
Pin Configuration
Current Mirror Monitor Output, 10:1 Ratio
Current Mirror Monitor Output, 5:1 Ratio
Ground Connection for Device. Connect directly to ground plane.
Feedback Output. Resistor-divider output.
Clamp Input. Disables the current mirror output (MIROUT).
No Connection
Feedback Input. Resistor-divider input.
Current Mirror Input
Current Mirror Output. Connect to APD bias pin.
Exposed Pad. Connect directly to the same ground plane as GND.
*EP
14 MIROUT
13
12 FBIN
11
10
9
8
MIRIN
N.C.
N.C.
N.C.
N.C.
APD current can also be shut down by CLAMP or ther-
mal shutdown. The resistor-divider is used in conjunc-
tion with a DC-DC boost controller and FET to precisely
create the APD bias voltage.
The DS1842A has two current mirror outputs. One is a
10:1 mirror connected at MIR1, and the other is a 5:1
mirror connected to MIR2.
CLAMP
FBOUT
FUNCTION
EP
GND
DS1842A
R
2
CURRENT
MIROUT
LIMIT
CURRENT MIRROR
Pin Description
Block Diagram
R
1
SHUTDOWN
THERMAL
Current Mirror
FBIN
MIRIN
MIR1
MIR2
5