SML2120
Pin Number Pin Type
Pin Name
Description
Pin Descriptions
12
O
VBRIDGE
Connection to an external Full-Bridge Sensor when used with the Thermistor pin.
Two of the full-bridge resistors are internal. See the Bridge Circuit Diagram in
Figure 1 and 3. Voltage level is 0.2V with respect to VSS.
Current output resulting from Lookup Table 0. User-programmable to either sink
(to VSS) or source (to VDD) up to 2.5mA.
Current output resulting from Lookup Table 1. User-programmable to either sink
(to VSS) or source (to VDD) up to 2.5mA.
VDD is the positive rail for most internal functions.
Place a capacitor (C
INT
) between C1 and C2 to increase the time constant for the
APC integrator.
Monitor Photo Diode anode input. Connect a resistor between MPD and C1 to
work in conjunction with C
INT
to establish the integrator time constant.
In burst mode, this input supplies a ballast current that allows the SML2120 to
quickly restart when ENA# is asserted.
Supplies the main laser current as controlled by the APC circuit; capable of
sinking up to 100mA to VSS.
VSS must be tied to the lowest system voltage potential.
APC Override pin.
This input can be configured to sense either a voltage or current generated from
an external temperature monitoring device.
VDD is the positive rail for most internal functions.
In dual-voltage rail systems, VHI is tied to the system logic high potential. It is the
logic high reference for all pins marked with an asterisk (*).
Analog output voltage indicating the state of the Monitor Photo Diode (MPD)
input.
Analog output voltage proportional to the temperature as sensed by the
EXT_TEMP or THERMISTOR input.
Analog output voltage proportional to BIAS current.
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
I/O
I/O
PWR
I
I
I
I
I
PWR
I/O
I
PWR
PWR
O
O
O
ILU0
ILU1
VDD
C2
C1
MPD
VBURST
BIAS
VSS
VAPC
EXT_TEMP
VDD
VHI
POWERMON
*
TEMPMON
*
BIASMON
*
* See VLOW and VHI pin descriptions.
Summit Microelectronics
2066 6.3 1/22/04
5
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
