User's Manual

P440 Data Sheet / User Guide DRAFT 31
Fig. 17: Increase in P440 power consumption with increased supply voltage
When selecting a power supply to drive the P440, the system designer should take both of these
factors into consideration and apply a safety margin. For example, a P440 which is intended to
operate at 5 volts and at a maximum board temperature of 85°C should be provided with at least 2.8
watts. If the same system was operated at 48 volts and 85°C, then the P440 should be provided with
at least 144% more power or 4.032 watts. These values do not include any additional safety margin
which the application might require.
The P440 also has an idle state during which it is neither transmitting nor receiving. In this idle state
the power consumption is reduced by approximately 30%.
4.4 Host to P440 Interface Options
The P440 supports five different host interfaces: USB, Serial, SPI, Ethernet, and CAN. This wide
choice of interfaces provides the user with the freedom to experiment with and to optimize the means
by which the overall system (P440 plus the user Host) communicates for their specific application.
The characteristics of these interfaces are summarized below. For information on pin assignments see
Section 4.2 – Connector Pinouts.
Supply
(Volts)
Current
(ma)
Power
Consumption
(Watts)
Power increase
due to loss in
efficiency
5.06 395 1.999 100%
5.95 337 2.005 100%
7.02 287 2.015 101%
8.04 253 2.034 102%
9.07 225 2.041 102%
10.04 205 2.058 103%
12.16 171 2.079 104%
14.07 150 2.111 106%
16.04 134 2.149 108%
18.03 121 2.182 109%
20.07 111 2.228 111%
22.09 102 2.253 113%
24.01 95 2.281 114%
26.05 89 2.318 116%
28.07 84 2.358 118%
30.06 80 2.405 120%
32.15 76 2.443 122%
34.12 73 2.491 125%
36.05 70 2.524 126%
38.07 68 2.589 130%
40.08 66 2.645 132%
42.03 64 2.690 135%
44.07 62 2.732 137%
46.08 61 2.811 141%
48.03 60 2.882 144%