Si1120
16 Rev. 1.0
3. Pin Descriptions—Si1120 (ODFN)
Figure 17. Pin Configurations
Table 5. Pin Descriptions
Pin Name Description
1PRXPWM Output.
Outputs a low-going PWM pulse proportional to signal.
2TXGDTXGD.
Power ground (LED and PRX driver ground return). Must be connected to VSS.
3TXOTransmit Output.
Normally connected to an infrared LED cathode. The output current is a programmable con-
stant current sink. This output can be allowed to saturate, and output current can be limited by
the addition of a resistor in series with the LED.
4STXStrobe.
Initiates PS or ALS measurement. Also used as data input for the M2 internal mode control
flip-flop.
5V
DD
Power Supply.
2.2 to 3.7 V voltage source.
6SCShutdown/Clock.
When high, shuts down the part. When enabling the part, the low-going edge clocks the states
of STX and MD into mode-control D flip-flops M2 and M3.
7MDMode Control.
Controls two mode control bits, one directly and the other indirectly, by providing the data input
for the M3 internal mode control flip-flop.
8 VSS VSS.
Ground (analog ground). Must be connected to TXGD.
MD
VSS
TXO
TXGD
SC
VDD
PRX
STX
1
2
3
4
8
7
6
5
