POWER LP3202

LP3202
1.5MHz, 650mA, High Efficiency Synchronous
PWM Step-Down DC/DC Convert
General Description
The LP3202 is a constant frequency, current mode,
PWM step-down converter. The device integrates a
main switch and a synchronous rectifier for high
efficiency. The 2.1V to 5.5V input voltage range
makes the LP3202 is ideally suited for portable
electronic devices that are powered from 1-cell
Li-ion battery or from other power sources within
the range such as cellular phones, PDAs and
handy-terminals.
Internal synchronous rectifier with low RDS(ON)
dramatically reduces conduction loss at PWM mode.
The internal synchronous switch increases
efficiency while eliminate the need for an external
Schottky diode.The switching ripple is easily
smoothed-out by small package filtering elements
due to a fixed operation frequency of 1.5MHz. This
along with small SOT-23-5 package provide small
PCB area application. Other features include soft
start, lower internal reference voltage with 2%
accuracy, over temperature protection, and over
current protection.
Features
High Efficiency: 93%
1.5MHz Fixed-Frequency PWM Operation
Adjustable Output From 0.6V to VIN
1.2V, 1.5V, 1.8V, 2.5V, 2.8V and 3.3V Fixed
650mA Output Current, 1.1A Peak Current
No Schottky Diode Required
100% Duty Cycle Low Dropout Operation
Available in SOT23-5 Package
Short Circuit and Thermal Protection
Over Voltage Protection
Low than 1µA Shutdown Current
Applications
Portable Media Players/MP3 players
Cellular and Smart mobile phone
PDA
DSC
Wireless Card
Pin Configurations
Ordering Information
LP3202
- □ □ □ □ □ □
F:Pb-free
Package Type
B5: SOT-23-5
Output Voltage:
12: 1.2V
18: 1.8V
25: 2.5V
28: 2.8V
33: 3.3v
Output Type:
A:Adjustable Output
LP3202-01 datasheet
Oct.-2006
Marking Information
Please See website.
1 -1
LP3202
Typical Application Circuit
LP3202-01 datasheet
Oct.-2006
2 -2
LP3202
Functional Pin Description
Function Block Diagram
Absolute Maximum Ratings
LP3202-01 datasheet
Oct.-2006
3 -3
LP3202
Electrical Characteristics
(VIN = 3.6V, VOUT = 2.5V, VREF = 0.6V, L = 2.2µH, CIN= 4.7µF, COUT= 10µF, TA= 25°C, IMAX = 650mA unless
otherwise specified)
Parameter
Symbol
Input Voltage Range
VIN
Quiescent Current
IQ
Shutdown Current
ISHDN
EN = GND
Reference Voltage
VREF
For adjustable output voltage
Adjustable Output Range
VOUT
Δ
VOUT
Δ
VOUT
Fix
Δ
VOUT
Output
Voltage
Accuracy
Δ
VOUT
Δ
VOUT
Δ
VOUT
Test Conditions
Min
Max
Units
5.5
V
270
370
μA
0.1
1
μA
0.6
0.612
V
VREF
VIN −
0.2
V
VIN = 2.2 to 5.5V, VOUT = 1.0V 0A <
IOUT < 600mA
−3
+3
%
VIN = 2.2 to 5.5V, VOUT = 1.2V 0A <
IOUT < 600mA
−3
+3
%
VIN = 2.2 to 5.5V, VOUT = 1.5V 0A <
IOUT < 600mA
−3
+3
%
VIN = 2.2 to 5.5V, VOUT = 1.8V 0A <
IOUT < 600mA
−3
+3
%
VIN = 2.8 to 5.5V, VOUT = 2.5V 0A <
IOUT < 600mA
−3
+3
%
VIN = 3.5 to 5.5V, VOUT = 3.3V 0A <
IOUT < 600mA
−3
+3
%
−3
+3
%
−3
+3
%
-30
30
nA
0.38
Ω
2.5
IOUT = 0mA, VFB = VREF + 5%
VIN = VOUT + 0.2V to 5.5V, VIN ≧
Adjustable
Typ
Δ
3.5V 0A < IOUT < 600mA
VOUT
VIN = VOUT + 0.4V to 5.5V, VIN ≧
2.2V 0A < IOUT < 600mA
0.588
FB Input
Current
IFB
VFB =
VIN
PMOSFET
RON
PRDS(ON)
IOUT =
200mA
VIN = 3.6V
0.20
NMOSFET
RON
NRDS(ON)
IOUT =
200mA
VIN = 3.6V
0.25
P-Channel
Current
Limit
IP(LM)
VIN =
2.2 to
5.5 V
EN
Threshold
EN Leakage
Current
Ω
1
1.2
1.4
VEN
0.3
1.0
1.5
VENL
--
LP3202-01 datasheet
Oct.-2006
4 -4
1
V
uA
LP3202
Typical Operating Characteristics
LP3202-01 datasheet
Oct.-2006
5 -5
LP3202
LP3202-01 datasheet
Oct.-2006
6 -6
LP3202
LP3202-01 datasheet
Oct.-2006
7 -7
LP3202
Applications Information
The basic LP3202 application circuit is shown in
Typical Application Circuit. External component
selection is determined by the maximum load current
and begins with the selection of the inductor value
and operating frequency followed by CIN and COUT.
LP3202-01 datasheet
Oct.-2006
8 -8
LP3202
LP3202-01 datasheet
Oct.-2006
9 -9
LP3202
Checking Transient Response
The regulator loop response can be checked by looking at the load transient response. Switching
regulators take several cycles to respond to a step in load current. When a load step occurs, VOUT
immediately shifts by an amount equal to ∆ILOAD (ESR), where ESR is the effective series resistance of COUT.
∆ILOAD also begins to charge or discharge COUT generating a feedback error signal used by the regulator to
return VOUT to its steady-state value. During this recovery time, VOUT can be monitored for overshoot or
ringing that would indicate a stability problem.
Layout Considerations
Follow the PCB layout guidelines for optimal performance of LP3202.
For the main current paths as indicated in bold lines, keep their traces short and wide.
Put the input capacitor as close as possible to the device pins (VIN and GND).
LX node is with high frequency voltage swing and should be kept small area. Keep analog components
away from LX node to prevent stray capacitive noise pick-up.
Connect feedback network behind the output capacitors. Keep the loop area small. Place the feedback
components near the LP3202.
Connect all analog grounds to a command node and then connect the command node to the power
ground behind the output capacitors.
LP3202-01 datasheet
Oct.-2006
10 -10
LP3202
LP3202-01 datasheet
Oct.-2006
11 -11