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Description
The PAM2808 is a 5W high power HBLED driver with 1.5A constant
current. It features high efficiency and low quiescent current, making it
ideal for battery powered applications.
The PAM2808 features over current protection and over temperature
shutdown. The PAM2808 is stable with a ceramic output capacitor of
4.7µF or higher.
PAM2808 is available in SOP-8(EP) package.
Features
Pin Assignments
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PAM2808
5W HIGH POWER HBLED DRIVER
• High Output Current Up to 1.5A
• Low Feedback Voltage: 0.1V
• Stable with a Ceramic Output Capacitor
• Low Quiescent Current
• Open Load LED Protection
• Over Temperature Shutdown
• Low Temperature Coefficient
• Standard SOP-8(EP) Packages
• Pb-Free Package
Typical Applications Circuit
Applications
• High Bright LED Driver
• White LED Torch (Flashlight)
PAM2808
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Pin Description
Pin
Number
1
2
3
4
5 NC Not Connected
6 FB Feedback
7 VOUT Output Voltage
8 NC Not Connected
Pin
Name
NC
VIN Input Voltage
EN Enabled
GND Ground
Not Connected
Block Diagram
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PAM2808
Function
Absolute Maximum Ratings (@T
These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may
affect device reliability. All voltages are with respect to ground.
Parameter Rating Unit
Input Pin Voltage 6.5
EN, FB VOUT Pin Voltage
Maximum Output Current
Storage Temperature -65 to +150
Maximum Junction Temperature 150
Lead Soldering Temperature 300
PAM2808
Document number: DSxxxxx Rev. 1 - 0
= +25°C, unless otherwise specified.)
A
-0.3 to V
P
/(VIN – VO)
D
+0.3
IN
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V
—
°C
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PAM2808
Recommended Operating Conditions (@T
Parameter Rating Unit
Maximum Supply Voltage 6 V
Junction Temperature Range -40 to +125
Ambient Temperature Range -40 to +85
= +25°C, unless otherwise specified.)
A
°C
Thermal Information
Parameter Symbol Package Max Unit
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
Electrical Characteristics (@T
Parameter Symbol Test Conditions Min Typ Max Units
Input Voltage Range
FB Reference Voltage
Output Current
Over Temperature Shutdown OTS 150 °C
Over Temperature Hysteresis OTH 40 °C
EN Input High Threshold
EN Input Low Threshold
Shutdown Current
V
IN
V
REF
I
O
V
EH
V
VIN = 2.5V to 5V
EL
I
VEN = 0V
SD
θ
JC
θ
JA
= +25°C, VIN = 4.5V, CIN = 4.7µF, CO = 4.7µF, unless otherwise specified.)
A
0.1 V
= 0.3Ω
R
S
RS = 0.14Ω
RS = 0.1Ω
RS = 0.067Ω
VIN = 2.5V to 5V
PAM2808
Document number: DSxxxxx Rev. 1 - 0
SOP-8(EP) 11
SOP-8(EP) 90
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°C/W
2.5 6.0 V
330
700
1000
1500
1.5 V
0.3 V
1 µA
© Diodes Incorporated
mA
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Typical Performance Characteristics (@T
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= +25°C, CIN = 4.7µF, CO = 4.7µF, unless otherwise specified.)
A
PAM2808
PAM2808
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(
)
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PAM2808
Application Information
External Capacitor Requirements
A 4.7μF or larger ceramic input bypass capacitor, connected between VIN and GND and located close to the PAM2808, is required for stability. A
4.7µF minimum value capacitor from V
additional 10μF or larger, low ESR capacitor is recommended at the output. A higher-value, low ESR output capacitor may be necessary if large,
fast-rise-time load transients are anticipated and the device is located several inches from the power source, especially if the minimum input
voltage of 2.5V is used.
Regulator Protection
The PAM2808 features internal current limiting, thermal protection and short circuit protection. During normal operation, the PAM2808 limits
output current to about 2.5A. When current limiting engages, the output voltage scales back linearly until the over current condition ends. While
current limiting is designed to prevent gross device failure, care should be taken not to exceed the power dissipation ratings of the package. If the
temperature of the device exceeds +150°C, thermal-protection circuitry will shut down. Once the device has cooled down to approximately +40°C
below the high temp trip point, regulator operation resumes.
Thermal Information
The amount of heat generates is:
All integrated circuits have a maximum allowable junction temperature (T
must design the operating environment so that the operating junction temperature (T
). The two main environmental variables that a designer can use to improve thermal performance are air flow and external heat sinks. The
(T
J MAX
purpose o f this information is to aid the designer in determining the proper operating environment for a linear regulator that is operating at a
specific power level.
In general, the maximum expected power (P
()
−=
IVVP
OOIND
VVP
to GND is also required. To improve transient response, noise rejection, and ripple rejection, an
O
) above which normal operation is not assured. A system designer
J MAX
) does not exceed the maximum junction temperature
J
) consumed by a linear regulator is computed as:
D(MAX)
x
+−=
x
VI
I
)Q()AVG(I)AVG(O)AVG(O)AVG(IDMAX
Where:
V
V
I
I
The quiescent current is insignificant compared to the average output current; therefore, the term V
junction temperature is computed by adding the ambient temperature (T
dissipation. The temperature rise is computed by multiplying the maximum expected power dissipation by the sum of the thermal resistances
between the junction and the case (R
how effectively an object dissipates heat. Typically, the larger the device, the more surface area available for power dissipation so that the
object’s thermal resistance will be lower.
is the average input voltage.
I(AVG)
is the average output voltage.
O(AVG)
is the average output current.
O(AVG)
is the quiescent current.
(Q)
), the case to heatsink (R
θJC
) and the increase in temperature due to the regulator's power
A
), and the heatsink to ambient (R
θJS
x I
I(AVG)
θJA
can be neglected. The operating
(Q)
). Thermal resistances are measures of
PAM2808
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Ordering Information
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PAM2808
Part Number Marking Package Type Standard Package
PAM2808BLBR
P2808
XXXYW
SOP-8(EP) 2500 Units/Tape&Reel
Marking Information
PAM2808
Document number: DSxxxxx Rev. 1 - 0
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Package Outline Dimensions (All dimensions in mm.)
SOP-8(EP)
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PAM2808
PAM2808
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PAM2808
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
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without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
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website, harmless against all damages.
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indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
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This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
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Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and
any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its
representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or
systems.
Copyright © 2012, Diodes Incorporated
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IMPORTANT NOTICE
LIFE SUPPORT
PAM2808
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