D E M O 9 0 8 L B 8
M A R C H 2 4 , 2 0 0 5
11
Figure 5: TB1 Terminal Block Connector
J1 Power Input
Positions J1-1 and J1-3 connect to the power rails on the board. The PWR_SEL jumper en-
ables the connection between the +5V power rail and J1-1. This connection allows the board
to either source power through connector J1 or supply power to external circuitry through con-
nector J1.
Input voltage applied to the board at connector J1 must be reg5V, ±5%. Exercise cau-
tion when using this feature. This input provides no over-current or over-voltage protection.
The board may be damaged if over-driven.
When used to power external circuitry, connector J1 supplies voltage directly from the on-
board voltage regulator. This output provides a reg5V, ±5% output to connector J1.
The current limit of the regulator must be considered when using this feature.
PWR_SEL
Power routing on the DEMO908LB8 is determined by the PWR_SEL option header. The
PWR_SEL header is also be used to configure the board to supply voltage to off-board cir-
cuitry. The figure below details the different configuration options available to the user.
CAUTION:
Board damage may occur if the connector J1 power input pins (J1-1,
J1-3) are over-driven.
The PWR_SEL option jumper supports 3 possible configurations; source power from TB1,
source power from J1, or source power from TB1 and supply power to J1.
+6V -
+20V
GND
2 Position, Screw-
Type Terminal Block
MCU_PORT
J1
+
