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IS31LT3135V1, IS31LT3135V2
Dual Ch. (Main/Sub) LED Driver Evaluation Board Guide
Description
The IS31LT3135 is a dual‐channel LED driver that has two
modes of operation; it can function as the main‐channel
driver or as a sub‐channel source. When operating in main
mode, the device functions as a constant current source
that outputs an adjustable current, via an external resistor,
through the main LED. The device is operable with a
dropout voltage of 0.1V while driving a 200mA current.
When operating as a sub‐channel driver, the IC grounds the
LED's cathode. The device normally operates with a single
channel powered on, allowing for quick switching between
the main and sub channel modes. A sweeping power
supply that operates between high and low voltages,
allows for simple switching between sub/main‐channel
modes, even during conditions where the UV pin is below
the 1.17V (typical) UV threshold IS31LT3135‐V1; or 1.23V
(typical) UV threshold for IS31LT3135‐V2. The sweeping
power supply allows sub‐channel to main channel
switching during conditions where the UV pin is ≥80mV
than the UV threshold. In addition, the main channel
features short protection via switching to sub‐channel if
any abnormal behaviors occur in the main‐channel LED
circuitry.
Features
Power supply under‐voltage detection
Main‐channel LED short protection
Over‐temperature protection
Input voltage range: 2.7V to 5.5V
Main/sub‐channel adjustable output current
(Set via user‐configurable external resistors)
Main‐channel dropout VDP=0.1V
Ultra‐low quiescent current
SOP‐8 Package, small PCB footprint size
Ordering Information
Part Number
IS31LT3135‐V1GRLS2‐EB
IS31LT3135‐V2GRLS2‐EB
Customers with inquiries regarding pricing, delivery, part availability, and related information, can
reach ISSI Analog marketing via either of the following methods:
Email: analog_mkt@issi.com
Integrated Silicon Solution, Inc. –
V2, 4/23/2012
−40°C to +85°C (Industrial Grade)
Table 1: Ordering Information for IS31LT3135‐V1/V2 evaluation board.
Phone: +1 (408) 969‐6600
/
http://www.issi.com
Quick Start
Figure 1: Photo of IS31LT3135V1/V2 evaluation board
Recommended Equipment
5VDC Power supply
1W LED
Multi‐meter
Recommended I/O Ratings
Power supply voltage: 3.8VDC
Output of I
MAIN
Output of I
: 20mA per LED
SUB
Note: When the power supply voltage ≥ LED voltage rating, extra voltage
is dissipated through the main‐channel, causing a drop in system
efficiency and an increase in wasted energy.
Absolute Maximum Ratings
Input voltage ≤ 5VDC
Caution: Do not exceed the input voltage conditions listed above to
avoid risking permanent damage to the board.
Temperature Range
: 320mA per LED
IC Package
SOP‐8 (5mm x 4mm)
1
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Summary of Contents for ISSI IS31LT3135-V1
- Page 1 SOP‐8 Package, small PCB footprint size Ordering Information Part Number Temperature Range IC Package IS31LT3135‐V1GRLS2‐EB −40°C to +85°C (Industrial Grade) SOP‐8 (5mm x 4mm) IS31LT3135‐V2GRLS2‐EB Table 1: Ordering Information for IS31LT3135‐V1/V2 evaluation board. Customers with inquiries regarding pricing, delivery, part availability, and related information, can reach ISSI Analog marketing via either of the following methods: Email: analog_mkt@issi.com Phone: +1 (408) 969‐6600 / Integrated Silicon Solution, Inc. – http://www.issi.com V2, 4/23/2012...
- Page 2 Symbol Quantity 10uF±20%,16V, Surface‐mount, 0805 C1 1 Capacitor 100nF±20%,50V, Surface‐mount, 0603 C2 1 51K±1%, Surface‐mount, 0805 (V1) R1 1 47K±1%, Surface‐mount, 0805 (V2) Resistor 30K±1%, Surface‐mount, 0805 R2 1 R3 1 30K±1%, Surface‐mount, 0805 33±1%, Surface‐mount, 0805 R4 1 Diode Schottky type, SS16,1A, 60V, SMA D1 1 HBLED Driver IC IS31LT3135, SOP‐8 Package U1 1 Table 2: IS31LT3135 Bill of Materials. Refer to Figure 2 for specific component locations Integrated Silicon Solution, Inc. – http://www.issi.com V2, 4/23/2012...
- Page 3 To minimize these losses, it is recommended to derive precise values for the resistors so that the end device operates with the highest efficiency rate achievable. ShortCircuit Protection Mechanism When the main‐channel LED is shorted, IS31LT3135 will automatically switch to sub‐channel mode. PCB layout reference The switch should be placed in an area with low voltages, to avoid an instant spark while switching. The traces between GND pin and I pin to real ground should be as short and wide as possible, with the purpose of improving the main LED current accuracy and under voltage threshold accuracy. Adding a 0.1uF, capacitor may also help with this purpose. Integrated Silicon Solution, Inc. – http://www.issi.com V2, 4/23/2012...
- Page 4 IS31LT3135V1, IS31LT3135V2 Dual Ch. (Main/Sub) LED Driver Evaluation Board Guide Figure 3: Component Placement: Top Layer Figure 4: PCB Layout‐ Top Layer Figure 5: Component Placement Guide ‐Bottom Layer Figure 6: Board PCB Layout‐Bottom Layer Copyright© 2012 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: the risk of injury or damage has been minimized; the user assume all such risks; and potential liability of Integrated Silicon Solution, Inc. is adequately protected under the circumstances. Integrated Silicon Solution, Inc. – http://www.issi.com V2, 4/23/2012...
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