PAM2421AECADJR [PAM]
3A,4.5A,5.5A PWM Step-Up DC/DC Converter;
| 型号： | PAM2421AECADJR |
| 厂家： | 
POWER ANALOG MICOELECTRONICS |
| 描述： | 3A,4.5A,5.5A PWM Step-Up DC/DC Converter 开关 光电二极管 输出元件 |
| 文件： | 总9页 (文件大小：210K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Features
General Description
n Greater than 90% Efficiency
n Adjustable Output Voltage Up to 24V
n Internal 24V Power MOSFET
n Peak Current 3A,4.5A,5.5A
n 520kHz Frequency
n Built-in Over-Voltage Protection (OVP)
n Open Protection
The PAM242x devices are high-performance,fixed
frequency, current-mode PWM step-up DC/DC
converter that incorporate internal power
MOSFETs. The PAM242x includes an integrated
power MOSFET that supports peak currents of up
to 3A/4.5A/5.5A.
n Programmable Soft-Start Function
n Thermal Shutdowns
n Under-Voltage-Lockout
n Over-Current Protection
n SOP-8(EP) Package
The PAM242x utilizes simple external loop
compensation allowing optimization between
component size, cost, and AC performance across
a wide range of applications. Additional functions
include an externally programmable soft-start
function for easy inrush current control, internal
over-voltage protection (OVP),cycle-by-cyc le
current limit protection, under voltage lock-out and
thermal shutdown.
Applications
n TFT LCD Monitors
n Battery-Powered Equipment
n Set-Top Boxes
n DSL and Cable Modems and Routers
The PAM242x is available in the small SOP-8(EP)
package.
Typical Application
SS34
L1
VOUT
12V/800mA
VIN
3.6V~5.5V
6.8μH
C1
470μF
C2
10μF
C4
10uF
C5
470uF
PGND
SW
SS
R1
85k
VIN
EN
C8
10nF
C3
1μF
PAM242x
FB
COMP
AGND
R2
10k
R3
51k
C6
47pF
C7
2.2nF
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
1
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Block Diagram
Pin Configuration & Marking Information
Top View
SOP-8(EP)
PGND
VIN
1
2
3
4
8
7
6
5
SW
SS
EN
FB
COMP
AGND
PCN: Product Code of PAM242x
XXX: Internal Code
V:
Y:
Voltage Code
Year
W: Week
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
2
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Pin Descriptions
Pin Number
Name
PGND
IN
Function
1
2
Power Ground
Supply Input.
Enable Control. Connect to a logic high level to enable the IC. Connect to a logic low level
to disable the IC. When unused, connect EN pinto IN (do not leave pin floating).
3
EN
4
5
COMP
AGND
Error Amplifier Compensation Node.
Analog Ground
Feedback Input.Connect this pin a resistor divider from the output to set the output
voltage. FB is regulated to 1.262V.
6
7
8
FB
SS
SW
Soft Start Control Input. Connect a capacitor from this pin to Ground to set soft-start
timing duration. SS is discharged to ground in shutdown. SS may be left unconnectedif
soft start is not desired.
Switch Output. Connect this pin to the inductor and theschottky diode. To minimize EMI,
minimize the PCB trace path between this pin and the input bypass capacitor.
Exposed
PAD
Connected to gound
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.
SW to Ground...................................–0.3V to 28V
VIN, EN, FB, SS, COMP to Ground........................
......................................................–0.3V to 6.5V
Continuous SW Current..............Internally Limited
Operating Temperature Range.............................
...................................................–40C to 150C
Storage Temperature Range......... –55C to 150C
Lead Temperature (Soldering, 10 sec)..........300C
Recommended Operating Conditions
Junction Temperature...................-40℃ to 125℃
Ambient Temperature.....................-40℃ to 85℃
Thermal Information
Parameter
Package
Symbol
Maximum
Unit
Thermal Resistance
(Junction to Case)
Thermal Resistance
(Junction to Ambient)
SOP-8(EP)
θJC
75
℃/W
SOP-8(EP)
θJA
180
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
3
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Electrical Characteristic
At TA=25C ,VIN=VEN=5V,,unless otherwise specified.
CONDITIONS
PARAMETER
Input Voltage
MIN
TYP
MAX
UNIT
2.7
5.5
V
Under Voltage Lockout
Threshold
VIN Rising
2.5
V
Under Voltage Lockout
Hysteresis
200
mV
VFB = 1.4V, Not Switching
VFB = 1.0V, Switching
EN = Ground
0.25
3
0.35
5
Quiescent Supply Current
mA
Supply Current in Shutdown
Switching Frequency
Maximum Duty Cycle
FB Feedback Voltage
FB Input Current
0.1
520
1
uA
kHz
%
85
1.237 1.262 1.287
V
0
80
nA
FB Voltage Line Regulation
VFB from 2.7V to 5.5V
PAM2421
0.05
0.15
%/V
3
VIN=3.2V
Switch Current Limit
Switch On Resistance
A
PAM2422
4.5
5.5
Duty Cycle = 70%
PAM2423
PAM2421
130
100
70
mΩ
PAM2422
PAM2423
Switch Leakage Current
Soft Start Pin Bias Current
Logic High Threshold
Logic Low Threshold
VSW = 10V, EN = Ground
VSS = 1.2V
EN Pin
15
7
uA
uA
V
2
4.5
1.4
EN Pin
0.4
V
EN Pull Down Resistor
1
MΩ
Thermal Shutdown
Temperature
Thermal Shutdown
Hysteresis
160
℃
℃
40
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
4
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Typical Operating Characteristics
At TA=25C ,VIN =VEN =5V,VFREQ =0V,unless otherwise specified.
Efficiency vs Output Current (Vo=12V)
Efficiency vs Output Current (Vo=15V)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Vin=3.6V
Vin=4.2V
Vin=5V
Vin=3.6V
Vin=4.2V
Vin=5V
1
1
3
10
100
1000
10000
5.5
1
10
100
1000
Load Current (mA)
Load Current (mA)
Efficiency vs Output Current (Vo=5V)
Efficiency vs Input Voltage (Vo=5V)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
100%
90%
80%
70%
60%
50%
40%
30%
20%
Io=1mA
Io=10mA
Io=100mA
Io=500mA
Io=1A
Vin=2.7V
Vin=3.6V
Vin=4.2V
10%
0%
10
100
1000
2.5
3
3.5
4
4.5
5
Output Current (mA)
Input Voltage(V )
Efficiency vs Input Voltage (Vo=12V)
Efficiency vs Input Voltage (Vo=15V)
100%
90%
80%
100%
90%
80%
70%
60%
50%
40%
30%
20%
70%
60%
50%
40%
30%
20%
10%
0%
1mA
1mA
10mA
100m A
500m A
10mA
100mA
500mA
1A
10%
0%
3.5
4
4.5
5
3
3.5
4
4.5
5
5.5
Input Voltage (V)
Input Voltage (V)
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
5
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Typical Operating Characteristics
At TA=25C ,VIN =VEN =5V,VFREQ =0V,unless otherwise specified.
Output Voltage vs Output Current (Vo=12V)
Output Voltage vs Output Current (Vo=15V)
15.5
12.5
15
14.5
14
12
11.5
11
Vin=3. 6V
Vin=4. 2V
Vin=5V
10.5
13.5
13
V in=4. 2V
V in=5V
10
0
20 0
400
600
800
1000
0
200
400
600
800
1000
Load Current (mA)
L oad Curre nt (mA)
Quiescent Current (VFB=1.0V)
Quiescent Current (VFB=1.4V)
4
3.5
3
0.25
0.2
2.5
2
0.15
0.1
1.5
1
0.05
0
0.5
0
2
3
4
5
6
2
3
4
5
6
Input Voltage(V)
Input Voltage(V)
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
6
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Application Information
The PAM242x are highly efficient step -up DC/DC
converters that employ a currentmode,fixed
frequency pulse-width modulation (PWM)
architecture with excellent line and load
regulation.The PAM242x operate at constant
switching frequency under medium to high load
current conditions. At light loads, these devices
operate in a pulse-skipping mode in order to
improve light-load efficiency.
Open Protection
Once the outputs achieve regulation, if the
voltage at FB falls below 0.2V the controller will
automatically disable, preventing the controller
from running open-loop and potentiall y
damaging the IC and load.
Shutdown
Drive EN low to disable the IC and reduce the
supply current to just 0.1μA. As with all
nonsynchronous step-up DC/DC converters, the
external Schottky diode provides a DC path from
the input to the output in shutdown. As a result,
the output drops to one diode voltage drop below
the input in shutdown.
Soft-Start
The PAM242x both offer a programmable soft-
start function which minimizes inrush current
during startup. The soft-start period is
programmed by connecting a 10nF capacitor
between SS and Ground. Operation of the soft-
start function is as follows: when the IC is
disabled, SS is actively discharged to Ground.
Upon enabling the IC, CSS is charged with a
4.5μA current so that the voltage at SS increases
in a controlled manner. The peak inductor current
is limited by the voltage at SS, so that the input
current is limited until the soft-start period
expires, and the regulator can achieve its full
output current rating.
Thermal Shutdown
The PAM242x both feature integrated thermal
o v e r l o a d p r o t e c t i o n . B o t h d e v i c e s a r e
automatically disabled when their junction
temperatures exceed 160°C, and automatically
re-enable when the die temperature decreases
by 40°C.
Setting the Output Voltage
The PAM242x both feature external adjustable
output voltages of up to 24V. To program the
output voltage, simply connect a resistive
voltage divider between the output, FB, and
GND, with resistors set according to the
following equ
Where VFB is 1.262V.
Rectifier Selection
For optimal performance, the rectifier should be
a Schottky rectifier that is rated to handle both
the output voltage as well as the peak switch
current.
Over Voltage Protection
The PAM242x features internal automatic over-
voltage protection, when feedback voltage is
higher than 115%.
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
7
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Ordering Information
PAM 242x X X X xxx X
Shipping Package
Output Voltage
Number of Pins
Package Type
Pin Configuration
Pin Configuration
AType
Package Type
Number of Pins
Output Voltage
E: SOP-8(EP)
C: 8
ADJ: Adjustable
Part Number
Peak Current
Package Type
Shipping Package
PAM2421AECADJR
PAM2422AECADJR
PAM2423AECADJR
3A
SOP-8(EP)
SOP-8(EP)
SOP-8(EP)
2,500 Units/Tape & Reel
2,500 Units/Tape & Reel
2,500 Units/Tape & Reel
4.5A
5.5A
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
8
PAM2421,PAM2422,PAM2423
3A,4.5A,5.5A PWM Step-Up DC/DC Converter
Outline Dimension
SOP-8(EP)
Power Analog Microelectronics, Inc
www.poweranalog.com
02/2012 Rev1.1
9
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