PIN FUNCTIONS
VEE (Pin 10): Lower Rail.
• Boost: Connect to System Ground
• Buck Mode: Connect to Inductor
• Buck-Boost Mode: Connect to Input Supply
LT3003
Exposed Pad (Pin 11): GND. The ground for the IC should
be soldered to a continuous copper ground plane under
the LT3003 die. Soldering the Exposed Pad to the copper
ground plane under the device will reduce thermal resis-
tance and increase the power capability of the LT3003.
BLOCK DIAGRAM
1
LED1
4
VMAX
B1
2
LED2
VIN
B2
3
LED3
+
B3
–
PWM
6
+
0.5V
–
B1 B2 B3
PWM
LOGIC
VEE
BIAS
BG
EXPOSED PAD
11
Figure 1. Block Diagram
3V
0.7V
THERMAL
SHUTDOWN
BG 125°C
150°C
VEE
10
VIN
5
SHDN
9
OT1
7
OT2
8
3003 F01
3003fa
5