User Manual
PD-1021 Hardware Manual (Rev. 1.00 / 2012-JUN-20) 14
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3.6.2 Outputs OUT_0, OUT_1
The eight pin connector of the PD-1021 provides two general purpose outputs. These two outputs are
open-drain outputs and can sink up to 100mA each. The outputs of the N-channel MOSFET transistors are
connected to freewheeling diodes each for protection against voltage spikes especially from inductive
loads (relais etc.).
Both outputs OUT_0 and OUT_1 share pins with two of the four inputs (IN_2 resp. IN_3).
Please take into account the 20k (2x 10k in series) resistance to ground (transistor not active) of the input
voltage divider (figure 4.8) when designing the external “load” circuit.
VDD
OUT_0 / IN_2
OUT_1 / IN_3
microcontroller
GND
+3.3V
microcontroller
10k
10k
1nF
GND
GND GND
Figure 3.8: General purpose outputs