G
N
D
PW
M
PW
M
0
G
N
D
PW
M
PW
M
0
Board Layout
Figure 5. PWM Jumper Settings
J29 - SDA / SCL - These connections allow the user to externally control the I
2
C lines. For independent
control of the I
2
C lines, do not connect the VIO jumper to either the 3.3V or the VIN pin.
2.2
Setup
The input voltage range for the flash driver is 2.7 volts to 5.5 volts. The on-board LEDs should be
connected for proper operation.
2.3
Operation
For proper operation of the LM3639A, the jumpers should be properly configured. The recommended
setting, using shorting blocks is:
VIO to VIN
EN to VIO
STROBE to PWM2 or external signal
PWM to PWM0 or external signal
TX to PWM1 or external signal
LEDs (J11, J12, J13, J20, J21) shorted
In this configuration, the device will power up when power is applied.
USB2ANY ribbon cable inserted into J19
3
Board Layout
,
,
and
show the board layout for the LM3639A EVM. The EVM offers
resistors, capacitors and jumpers to Enable the device and to configure it as desired.
The LM3639A will dissipate power, especially during high current and long duration flash events. Power
will also be dissipated on the flash LEDs. The EVM layout is designed to minimize temperature rise during
operation. It is recommended that in order to prevent overheating, repeated flash events in very short time
intervals is avoided.
4
LM3639AYFQEVM User's Guide
SNVU211 – March 2013
Copyright © 2013, Texas Instruments Incorporated
