LT3593ES6#PBF Linear Technology, LT3593ES6#PBF Datasheet - Page 9

• Manufacturer Part Number: LT3593ES6#PBF
• Manufacturer: Linear Technology

Specifications of LT3593ES6#PBF

• Operating Supply Voltage (typ): 3.3/5V
• Number Of Segments: 10
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Package Type: TSOT-23
• Pin Count: 6
• Mounting: Surface Mount
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Compliant

APPLICATIONS INFORMATION
Overvoltage Protection
The LT3593 has an internal open-circuit protection circuit.
In the case of an output open circuit, when the LEDs are
disconnected from the circuit or the LEDs fail open, V
is clamped at 38V. The LT3593 will then switch at a very
low frequency to minimize input current. V
current during output open circuit are shown in the Typical
Performance Characteristics. Figure 5 shows the transient
response when the LEDs are disconnected.
200mA/DIV
20V/DIV
20V/DIV
V
V
CAP
SW
Figure 5. Output Open-Circuit Waveform
I
L
V
FRONT PAGE
APPLICATION CIRCUIT
IN
= 3.6V
400μs/DIV
LEDs DISCONNECTED
AT THIS INSTANT
3593 F05
CAP
and input
CAP
Low Input Voltage Applications
The LT3593 can be used in low input voltage applications.
The input supply voltage to the LT3593 must be 2.7V or
higher, but the inductor can be run off a lower battery
voltage. This technique allows the LEDs to be powered off
two alkaline cells. Most portable devices have a 3.3V logic
supply voltage which can be used to power the LT3593.
The LEDs can be driven straight from the battery, resulting
in higher effi ciency.
Figure 6 shows three LEDs powered by two AA cells.
The battery is connected to the inductors and the chip is
powered off a 3.3V logic supply voltage.
2 AA CELLS
2V TO 3.2V
CURRENT CONTROL
SHUTDOWN AND
3.3V
Figure 6. Two AA Cells to Three White LEDs
C1: TAIYO YUDEN EMK107B5105MA
C2: MURATA GRM31MR71H105KA88
L1: MURATA LQH43CN100
D1: CENTRAL CMDSH05-4
C1
1μF
C3
1μF
10μH
V
CTRL
L1
IN
LT3593
GND
SW
CAP
LED
D1
3593 F06
LT3593
C2
1μF
9
3593f