PAM3108 Description Features Pin Assignments Applications

A Product Line of
Diodes Incorporated
PAM3108
MAXIMUM 1.5A, ULTRA LOW DROPOUT REGULATOR
Description
Pin Assignments
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 VIN as low
as 1.1V and VDD voltage 3V with output voltage programmable as low
as 0.8V. The significant feature includes ultra low dropout, ideal for
applications where VOUT is very close to VIN. Additionally, there is an
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 WDFN10L 3x3 packages.
Features
•
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
Applications
•
Front Side Bus VTT (1.2V/1.5A)
•
NoteBook PC Applications
•
Motherboard Applications
Typical Applications Circuit
VO = 0.8V*(1+R1/R2)
PAM3108
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PAM3108
Pin Configuration and Description
Pin Name
VIN
EN
CTRL
POK
ADJ
VOUT
NC
GND
Pin Number
SOP-8(EP)
W-DFN3x3-10
3
2
4
1
7
6
5
8,
Exposed Pad (9)
7, 8, 9
6
Function
Supply Input Voltage.
Chip Enable (Active-High).
10
Supply Voltage of ControlCircuitry.
5
Power Good Open Drain Output.
4
Set the output voltage by the feedback resistors. VO = 0.8V x (R1 + R2)/R2.
1, 2, 3
—
Exposed Pad
(11)
Output Voltage.
No Internal Connection.
Ground. The exposed pad must be soldered to a large PCB and connected to GND
formaximum powe r dissipation.
Functional Block Diagram
PAM3108
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PAM3108
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.)
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
Input Voltage VIN, CTRL
Output Current
Output Pin Voltage
Lead Soldering Temperature
Storage Temperature
ESD Rating
Rating
6.0
1.5
Unit
V
A
GND -0.3 to VIN +0.3
260, (5sec)
-65 to +150
Class B
°C
°C
—
V
Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.)
Rating
Unit
Max. Supply Voltage
Parameter
5.5
V
Junction Temperature
-40 to +125
Operation Temperature
-40 to +85
°C
Thermal Information
Parameter
Symbol
Thermal Resistance Junction to Case)
θJC
Thermal Resistance (Junction to Ambient)
θJA
Internal Power Dissipation (@TA = 25°C)
PD
PAM3108
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Package
Max
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
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Unit
°C/W
mW
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PAM3108
Electrical Characteristics (@TA = +25°C, VIN = VO +0.5V, VCTRL = VEN = 5V, CIN = CO = 10µF, unless otherwise specified.)
Parameter
VIN Input Voltage
CTRL Input Voltage
POR Threshold
POR Hysteresis
Quiescent Current
Symbol
VIN
Test Conditions
VOUT = VREF
Min
Typ
V
5.5
V
VCTRL
VTH_CTRL
2.5
2.7
VTH_VIN
0.8
0.9
VYHS_CTRL
0.4
VYHS_VIN
0.5
IQ
IO = 0mA
0.5
CTRL Input Current in Shutdown
ISD_CTRL
VEN = 0V
5
CTRL Input Current in Shutdown
ISD_VIN
VEN = 0V
VO
Current Limit
IO
Short Current
ISHORT
Feedback Voltage
VREF
Feedback Leakage Current
IREF
-1.5
IO = 1mA to 1.5A
V
1.2
µA
µA
1.5
%
A
1
VO = 0V
0.788
0.8
IO = 1A
100
IO = 1.5A
150
mA
1
3
VO = VREF
Units
5.5
3
Output Voltage Accuracy
Max
1.1
A
0.812
V
20
nA
Dropout Voltage
VDROP
Line Regulation
LNR
IO = 1mA, VIN = VO =0.5V to 5.5V
-0.15
0.1
0.15
%/V
Load Regulation
LDR
VIN = VO +1V, IO = 1mA to 1.5A
-2.0
+0.2
+2.0
%
VOUT Pull Low Resistor
RPL
VEN = 0V
100
Ω
Temperature Coefficient
TC
IO = 1mA
40
ppm/°C
Over Temperature Shutdown
OTS
IO = 1mA
170
°C
Over Temperature Hysteresis
OTH
IO = 1mA
40
°C
65
60
dB
5
µA
Power Supply Ripple Rejection
PSRR
VPP = 200mV
EN Bias Current
IEN
VEN = VCTRL = 5V
EN Input High Threshold
VIH
VIN = 2.5V to 5V
EN Input Low Threshold
VIL
VIN = 2.5V to 5V
POK Threshold Voltage
VTH_OK
POK Hysteresis
POK Pull_Low Voltage
POK Delay Time
Notes:
f = 100Hz
f = 1kHz
1.5
3
POK sinks 5mA Current
TDELAY
V
0.3
V
94
%
10
0.2
0.4
%
V
2
4
mS
90
VREF Rising
From VREF = VTY_OK to rising edge of the VPOK
mV
1
1. Output current is limited by PD, maximum IO = PD/(VIN(MAX) – VO).
PAM3108
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Typical Performance Characteristics (@TA = +25°C, CIN = CO = 10µF, unless otherwise specified.)
PAM3108
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Typical Performance Characteristics (cont.) (@TA = +25°C, CIN = CO = 10µF, unless otherwise specified.)
PAM3108
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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 CIN 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
distance between CIN and the input pin of the PAM3108 should not exceed 0.5 inch. Ceramic capacitors are suitable for the PAM3108.
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:
PD = (VIN − V OUT ) * IO + VIN * IGND
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:
(
)
PD(MAX ) = TJ(MAX ) − T A / θJA
Where TJ(MAX) is the maximum allowable junction temperature +125°C, TA is the ambient temperature and is the thermal resistance from the
junction to the ambient.
PAM3108
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PAM3108
Ordering Information
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)
PAM3108
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Package Outline Dimensions (cont.) (All dimensions in mm.)
W-DFN3x3-10
PAM3108
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