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Description
The PAM3108 is a high performance positive voltage regulator
designed for use in applications requiring very low Input voltage and
very low dropout voltage at up to 1.5A. It operates with a V
as 1.1V and V
as 0.8V. The significant feature includes ultra low dropout, ideal for
applications where V
enable pin to further reduce power dissipation while shutdown. The
PAM3108 provides excellent regulation over variations in line, load,
temperature and provides a power OK signal to indicate if the voltage
level of Vo reaches 90% of its rating value.
The PAM3108 is available with SOP-8 (Exposed Pad) and WDFN-
10L 3x3 packages.
voltage 3V with output voltage programmable as low
DD
is very close to VIN. Additionally, there is an
OUT
as low
IN
Features
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PAM3108
MAXIMUM 1.5A, ULTRA LOW DROPOUT REGULATOR
Pin Assignments
• Maximum 1.5A Low-Dropout Voltage Regulator
• High Accuracy Output Voltage ±1.5%
• Typically 150mV Dropout at 1.5A
• Power Good Output
• Output Voltage Pull Low Resistance when Disabled
• Thermal and Over Current Protection
• RoHS Compliant and 100% Lead (Pb)-Free
Typical Applications Circuit
Applications
• Front Side Bus VTT (1.2V/1.5A)
• NoteBook PC Applications
• Motherboard Applications
= 0.8V*(1+R1/R2)
V
O
PAM3108
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Pin Configuration and Description
Pin Name
VIN 3
EN 2
CTRL 4
POK 1
ADJ 7
VOUT 6
NC
GND
Exposed Pad (9)
Pin Number
SOP-8(EP) W-DFN3x3-10
7, 8, 9 Supply Input Voltage.
6 Chip Enable (Active-High).
10 Supply Voltage of ControlCircuitry.
5 Power Good Open Drain Output.
4
1, 2, 3 Output Voltage.
5
8,
— No Internal Connection.
Exposed Pad
(11)
Functional Block Diagram
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PAM3108
Function
Set the output voltage by the feedback resistors. V
Ground. The exposed pad must be soldered to a large PCB and connected to GND
formaximum powe r dissipation.
= 0.8V x (R1 + R2)/R2.
O
PAM3108
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PAM3108
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 Voltage VIN, CTRL 6.0 V
Output Current 1.5 A
Output Pin Voltage
Lead Soldering Temperature 260, (5sec) °C
Storage Temperature -65 to +150 °C
ESD Rating Class B —
Recommended Operating Conditions (@T
Parameter Rating Unit
Max. Supply Voltage 5.5 V
Junction Temperature -40 to +125
Operation Temperature -40 to +85
= +25°C, unless otherwise specified.)
A
GND -0.3 to V
+0.3
IN
= +25°C, unless otherwise specified.)
A
V
°C
Thermal Information
Parameter Symbol Package Max Unit
Thermal Resistance Junction to Case)
Thermal Resistance (Junction to Ambient)
Internal Power Dissipation (@TA = 25°C) PD
θ
θ
JC
JA
W-DFN3x3-10 8.5
SOP-8(EP) 11
W-DFN3x3-10 60
SOP-8(EP) 90
W-DFN3x3-10 1600
SOP-8(EP) 1100
°C/W
mW
PAM3108
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PAM3108
Electrical Characteristics (@T
Parameter Symbol Test Conditions Min Typ Max Units
VIN Input Voltage
CTRL Input Voltage
POR Threshold
POR Hysteresis
Quiescent Current
CTRL Input Current in Shutdown
CTRL Input Current in Shutdown
Output Voltage Accuracy
Current Limit
Short Current
Feedback Voltage
Feedback Leakage Current
Dropout Voltage
Line Regulation LNR
Load Regulation LDR
VOUT Pull Low Resistor
Temperature Coefficient
Over Temperature Shutdown OTS
Over Temperature Hysteresis OTH
Power Supply Ripple Rejection PSRR
EN Bias Current
EN Input High Threshold
EN Input Low Threshold
POK Threshold Voltage
POK Hysteresis 3 10 %
POK Pull_Low Voltage POK sinks 5mA Current 0.2 0.4 V
POK Delay Time
Notes: 1. Output current is limited by PD, maximum IO = PD/(V
PAM3108
Document number: DSxxxxx Rev. 1 - 0
V
= +25°C, VIN = VO +0.5V, V
A
V
V
IN
V
CTRL
V
V
V
I
TH_CTRL
TH_VIN
YHS_CTRL
YHS_VIN
I
IO = 0mA
Q
VEN = 0V
SD_CTRL
I
VEN = 0V
SD_VIN
V
IO = 1mA to 1.5A
O
I
O
I
VO = 0V
SHORT
V
VO = V
REF
I
REF
V
DROP
R
VEN = 0V
PL
T
IO = 1mA
C
I
VEN = VCTRL = 5V
EN
V
VIN = 2.5V to 5V
IH
V
VIN = 2.5V to 5V
IL
V
V
TH_OK
T
From V
DELAY
= V
OUT
3 A
20 nA
= 1A
I
O
IO = 1.5A
I
= 1mA, VIN = VO =0.5V to 5.5V
O
V
= VO +1V, IO = 1mA to 1.5A
IN
I
= 1mA
O
I
= 1mA
O
V
= 200mV
PP
Rising
REF
REF
REF
= V
REF
TY_OK
– VO).
IN(MAX)
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= VEN = 5V, CIN = CO = 10µF, unless otherwise specified.)
CTRL
1.1 5.5 V
3 5.5 V
2.5 2.7
0.8 0.9
0.4
0.5
0.5 1.2 mA
5 µA
1 µA
-1.5 1.5 %
1 A
0.788 0.8 0.812 V
100
150
-0.15 0.1 0.15 %/V
-2.0 +0.2 +2.0 %
100 Ω
40 ppm/°C
170 °C
40 °C
f = 100Hz 65
f = 1kHz 60
5 µA
1.5 V
0.3 V
90 94 %
to rising edge of the V
POK
1 2 4 mS
V
mV
dB
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Typical Performance Characteristics (@T
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= +25°C, CIN = CO = 10µF, unless otherwise specified.)
A
PAM3108
PAM3108
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Typical Performance Characteristics (cont.) (@T
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= +25°C, CIN = CO = 10µF, unless otherwise specified.)
A
PAM3108
PAM3108
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(
)
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PAM3108
Application Information
Capacitor Selection and Regulator Stability
Similar to any low dropout regulator, the external capacitors used with the PAM3108 must be carefully selected for regulator stability and
performance.
A capacitor C
distance between C
Capacitors with larger values and lower ESR (equivalent series resistance) provide better PSRR and line-transient response.
The PAM3108 is designed specifically to work with low ESR ceramic output capacitors in order to save space and improve performance. Using
an output ceramic capacitor whose value is >10µF with ESR5>mΩ ensures stability.
Shutdown Input Operation
The PAM3108 is shut down by pulling the EN input low, and is turned on by tying the EN input to CTRL or leaving the EN input floating.
Input-Output (Dropout) Voltage
A regulator's minimum input-output voltage difference (or dropout voltage) determines the lowest usable supply voltage. The PAM3108 has a
typical 150mV dropout voltage.
Current Limit and Short Circuit Protection
The PAM3108 features a current limit, which monitors and controls the gate voltage of the pass transistor. The output current can be limited to
3A by regulating the gate voltage. The PAM3108 also has a built-in short circuit current limit.
Thermal Considerations
Thermal protection limits power dissipation in the PAM3108. When the junct ion temperature exceeds 170°C, the OTP (Over Temperature
Protection) starts the thermal shutdown and turns the pass transistor off. The pass transistor resumes operation after the junction temperature
drops below 130°C.
For continuous operation, the junction temperature should be maintained below +125°C. The power dissipation is defined as:
of more than 10μF can be employed in the input pin, while there is no upper limit for the capacitance of CIN. Please note that the
IN
and the input pin of the PAM3108 should not exceed 0.5 inch. Ceramic capacitors are suitable for the PAM3108.
IN
()
*
VVP
*
+−=
I
VI
GNDINOOUTIND
The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surrounding airflow and temperature
difference between junction and ambient. The maximum power dissipation can be calculated by the following formula:
Where T
junction to the ambient.
is the maximum allowable junction temperature +125°C, TA is the ambient temperature and is the thermal resistance from the
J(MAX)
PAM3108
Document number: DSxxxxx Rev. 1 - 0
−=
/
θ
TTP
A)MAX(J)MAX(D
JA
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Ordering Information
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PAM3108
Part Number Output Voltage Package Type Output Voltage
PAM3108AJEADJR ADJ W-DFN3x3-10 3000 Units/Tape&Reel
PAM3108BECADJR ADJ SOP-8(EP) 2500 Units/Tape&Reel
Marking Information
PAM3108
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Package Outline Dimensions (All dimensions in mm.)
SOP-8(EP)
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PAM3108
PAM3108
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Package Outline Dimensions (cont.) (All dimensions in mm.)
W-DFN3x3-10
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PAM3108
PAM3108
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PAM3108
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
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
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
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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.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
noted herein may also be covered by one or more United States, international or foreign trademarks.
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
failure of the life support device or to affect its safety or effectiveness.
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
PAM3108
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