PAM2303
3A Low Noise Step-Down DC-DC Converter
Features
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Output Current: Up to 3A
Output Voltage: 0.6V to V
IN
Input Voltage: 2.7 to 5.5V
Efficiency up to 95%
42
μ
A (Typ) No Load Quiescent Current
Shutdown Current: <1
μ
A
100% Duty Cycle Operation
1.5MHz Switching Frequency
Analog Soft Start
No external Compensation Required
Current Limit Protection
Thermal Shutdown
SOP-8(EP), DFN3X3-10 and QFN3X3-16
Package
Description
T h e PA M 2 3 0 3 i s a 3 A s t e p - d o w n D C - D C
converter. It operates in two different modes:
PSM and PWM modes. At light load, it
automactically enters into the PSM mode to
improve efficiency. At heavy load, the constant-
frequency P WM control per for ms exc ellent
stability and transient response. No external
compensation components are required
.
The PAM2303 supports a range of input voltages
fr om 2.7 V to 5.5 V. The ou tput v olta ge is
adjustable from 0.6V to the input voltage. The
PAM2303 employs internal power switch and
synchronous rectifier to minimize external part
c o u n t a n d r e a l i z e h i g h e ff i c i e n c y. D u r i n g
shutdown, the input is disconnected from the
output and the shutdown current is less than 1
μ
A.
Other key features include over-temperature and
sh or t c ir c uit p r otec ti on , and u nde r -v ol tag e
lockout to prevent deep battery discharge.
The PAM2303 delivers 3A maximum output
current while consuming only 42
μ
A of no-load
quiescent current. Ultra-low RDS(ON) integrated
MOSFETs and 100% duty cycle operation make
the PAM2303 an ideal choice for high output
voltage, high current applications which require a
low dropout threshold.
T h e PA M 2 3 0 3 i s a v a i l a b l e i n S O P - 8 ( E P ) ,
DFN3X3-10, and QFN3X3-16 package.
Applications
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5V or 3.3V Point of Load Conversion
Telecom/Networking Equipment
Set Top Boxes
Storage Equipment
Video Cards
DDR Power Supply
Typical Application
U1
L1
VIN
R3
PVIN
SW
2
1
C3
R1 100pF
FB
R2
C2
VOUT
1k
C1
PAM2307
VIN
PAM2303
EN
40uF
22uF
C4
30uF
22uF
1uF
TEST
R
1
V
O
=
0.6
1
+
R
2
Power Analog Microelectronics
,
Inc
www.poweranalog.com
11/2011 Rev1.2
1
PAM2303
3A Low Noise Step-Down DC-DC Converter
Block Diagram
1.5M
OSC
SLOPE
COMP
VIN
+
IAMP
-
PVIN
FB
FREQ
SHIFT
R1
-
EA
R2
VIN
OSC
MAIN
SWITCH
(
PCH
)
S Q
R Q
RS LATCH
+
COMP
SWITCHING
LOGIC
AND
BLANKING
CIRCUIT
ANTI
-
SHOOT
-
THRU
SYNCHRONOUS
RECTIFIER
(
NCH
)
SW
EN
0.6VREF
SHUTDOWN
+
IRCMP
-
PGND
GND
TEST
Pin Configuration & Marking Information
Top View
QFN 3X3-16
16 15 14 13
Top View
SOP-8(EP)
8
12
7
6
5
A/B: Pin Configuration
Y: Year
W: Week
X: Internal Code
4
PGND
PGND
PGND
FB
1
2
3
4
5
6
7
8
PVIN
P2303B
XXXYW
P2303A
XXXYW
PVIN
10
PVIN
9
VIN
11
1
2
3
Pin Description
Name
PGND
FB
GND
NC
EN
Test
VIN
PVIN
SW
QFN3X3-16
1,2,3
4
5
6,16
7
8
9
10,11,12
13,14,15
SOP-8(EP)
2
3
4
-
5
6
7
8
1
Main power ground pin
Feedback voltage to internal error amplifier, the threshold voltage is 0.6V.
Signal ground for small signal components.
No connected
Enable control input. Force this pin voltage above 1.5V, enables the chip,
and below 0.3V shuts down the device.
Test mode. “
Low”connection is recommended.
Bias supply. Chip main power supply pin
Input supply for power stage. Must be closely decoupled to PGND
The drains of the internal main and synchronous power MOSFET.
Function
Power Analog Microelectronics
,
Inc
www.poweranalog.com
11/2011 Rev1.2
2
PAM2303
3A Low Noise Step-Down DC-DC Converter
Pin Configuration & Marking Information
Top View
DFN3X3-10
SW
SW
SW
GND
EN
1
2
3
4
5
10
9
VIN
VIN
VIN
NC
FB
P2303C
XXXYW
8
7
6
C:
Y:
W:
X:
Pin Configuration
Year
Week
Internal Code
GND
(Exposed Pad)
Pin Description
Name
SW
GND
EN
FB
NC
VIN
DFN3X3-10
1,2,3
4
5
6
7
8,9,10
GND
Enable control input. Force this pin voltage above 1.5V, enables the chip, and
below 0.3V shuts down the device.
Feedback voltage to internal error amplifier, the threshold voltage is 0.6V.
No connec ted
Bias supply. Chip main power supply pin
Function
The drains of the internal main and synchronous power MOSFET.
Absolute Maximum Ratings
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.
Input Voltage PV
IN
,V
IN
......................................6V
SW Pin Voltage......................-0.3V to (PV
IN
+0.3V)
FB Pin Voltage.........................-0.3V to (V
IN
+0.3V)
EN Pin Voltage...................................- 0.3V to -6V
Maximum Junction Temperature..................150°
C
Storage Temperature Range...........-65° to 150°
C
C
Soldering Temperature.......................300° 5sec
C,
Recommended Operating Conditions
Supply Voltage..................................2.7V to 5.5V
Junction Temperature Range..........-40 ° to 125 °
C
C
Ambient Temperature Range...........-40 ° to 85 °
C
C
Thermal Information
Parameter
Thermal Resistanc e (Junction to Ambient)
Symbol
θ
JA
Package
SOP-8(EP)
DFN3X3-10
QFN3X3-16
SOP-8(EP)
Thermal Resistance (Junction to Case)
θ
JC
DFN3X3-10
QFN3X3-16
Maximum
90
60
35
11
8.5
11
°
C/W
°
C/W
Unit
Power Analog Microelectronics
,
Inc
www.poweranalog.com
11/2011 Rev1.2
3
PAM2303
3A Low Noise Step-Down DC-DC Converter
Electrical Characteristic
T
A
=25 ° ,
Vin=3.6V, Vo=1.8V, Cin=33uF,Co=22uF, L=2.2uH,
unless otherwise noted.
C
PARAMETER
Input Voltage Range
Output Voltage Range
UVLO Threshold
Regulated Output Voltage Accuary
Regulated Feedback Voltage
FB Leak age Current
Output Voltage Line Regulation
Output Voltage Load Regulation
Quiescent Current
Shutdown Current
Current Limit
Oscillator Frequency
Drain-Source On-State Resistanc e
High Efficiency
PSM Threshold
Analog Soft Start Time
EN Threshold High
EN Threshold Low
EN Leakage Current
Over Temperature Protection
OTP
Hysteresis
SYMBOL
V
IN
V
O
V
IN
Rising
V
UV LO
V
O
V
F B
I
F B
LNR
LDR
I
Q
I
S D
I
LIM
f
O SC
R
DS (ON)
η
I
T H
t
S
V
E H
V
E L
I
E N
OTP
OTH
V
IN
=V
EN
= 0V
-1.0
150
30
Vin=3.3V,Vo=1.2V,L=1uH
From enable to output
regulation
1.5
0.3
1.0
0.5
High Side
Low Side
1.2
V
O
=1V
V
IN
= 2.5V to 5V
I
O
=0A to 3A
No load
V
E N
= 0V
4
1.5
85
60
95
450
1.8
Hys teresis
V
IN
Falling
I
O
= 0 to 3A
1.8
-3
0.591
-50
0.2
0.5
42
90
1
0.6
+3
0.609
+50
Test Conditions
MIN
2.7
0.6
2.4
240
TYP
MAX
5.5
V
IN
2.5
UNITS
V
V
V
mV
V
%
V
nA
%/V
%/A
µA
µA
A
MHz
mΩ
mΩ
%
mA
ms
V
V
µA
°
C
°
C
Power Analog Microelectronics
,
Inc
www.poweranalog.com
11/2011 Rev1.2
4
PAM2303
3A Low Noise Step-Down DC-DC Converter
Typical Performance Characteristics
T
A
=25 ° , C
IN
=33uF,Co=22
μ
F unless otherwise noted.
C
Efficiency vs Output Current (Vo=1.2V)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
10000
Efficienvy VS Input Voltage (Vo=1.2V)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
1
3.3V
4.2V
5V
0.1A
1A
3A
2
2.5
3
3.5
4
4.5
5
5.5
6
10
100
1000
Output Current (m A)
Input Voltage (V)
Efficiency vs Output Current (Vo=1.8V )
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
1
10
100
Output Current (m A)
1000
10000
3.3V
4.2V
5V
Efficienvy VS Input Voltage (Vo=1.8V)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
2
2.5
3
3.5
4
4.5
5
Input Voltage (V)
0.1A
1A
3A
5.5
6
110%
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Efficiency vs Output Current (Vo=3.3V)
Efficienvy VS Input Voltage (Vo=3.3V)
4.2V
5V
5.5V
1
10
100
Output Current (mA)
1000
10000
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
3
3.5
4
4.5
5
Input Voltage (V)
0.1A
1A
3A
5.5
6
Power Analog Microelectronics
,
Inc
www.poweranalog.com
11/2011 Rev1.2
5
