IS31LT3505 Datasheet, PDF (1/12 Pages) Integrated Silicon Solution, Inc – 1.0MHZ BOOST CONVERTER WITH 35V INTERNAL NMOS

IS31LT3505
1.0MHZ BOOST CONVERTER WITH 35V INTERNAL NMOS
OCTOBER 2011
DESCRIPTION
The IS31LT3505 is a constant current step-up
converter with internal NMOS. The step-up converter
topology allows series connection of the white LEDs
so the LED currents are identical for uniform
brightness as well as constant output voltage to drive
other devices. The output current of each channel
can be set by an external resistor and dimming the
brightness of LEDs with the PWM signal or DC
voltage. The IS31LT3505 operates with a switching
frequency up to 1 MHz. A low 0.3V feedback voltage
minimizes power loss in the current setting resistor
for better efficiency. With OVP circuit, the chip and
the system can be safe even if the load is not
connected.
IS31LT3505 is available in MSOP-10. It operates
from 6V to 30V over the temperature range of -40°C
to +85°C.
FEATURES
 6V to 30V supply voltage
 High efficiency: 90 % typical
 PWM dimming control
 Fast 1.0MHz switching frequency
 Internal high power 35V NMOS
 Internal soft start
 Adjustable LED Open Protection
 Over-temperature protection
 MSOP-10
APPLICATIONS
 TV monitor backlighting
 PDA, handheld computer
 GPS receiver
TYPICAL APPLICATION CIRCUIT
6.0V~30V
300Ω 100kΩ
L1
10μ H
D1
(Scho ttky , s s2 6)
C IN
C1
22μ F ^1μF
C2
1μF
4
EN
10
LX
9
VDD
6
OVP
IS31LT3505
2
10nF
VP
10μF
1, 3, 5
GND
7
FB
R1
C3
1μF
R2
C OU T
22μ F
RSET
Figure 1 Application Circuit (Constant Current to Drive White LEDs)
Copyright © 2011 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any
time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are
advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products.
Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the
product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not
authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that:
a.) the risk of injury or damage has been minimized;
b.) the user assume all such risks; and
c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances
Integrated Silicon Solution, Inc. – www.issi.com
1
Rev. A, 09/01/2011