X RP 6 6 5 8
1A 1.5MHz PFM/PWM Synchronous Step-Down Converter
September 2011
Rev. 1.5.0
GENERAL DESCRIPTION
The XRP6658 is a synchronous current mode
PWM step down (buck) converter capable of
delivering up to 1 Amp of current and
optimized
for
portable
battery-operated
applications.
Based on a current mode 1.5MHz constant
frequency PWM control scheme, the XRP6658
reduces the overall component count and
solution footprint as well as provides a low
output voltage ripple and excellent line and
load regulation. It also implements a PFM
mode to improve light load efficiency as well
as a 100% duty cycle LDO mode. Output
voltage is adjustable to as low as 0.6V with a
better than 3% accuracy while a low quiescent
current supports the most stringent battery
operating conditions.
Built-in over temperature and under voltage
lock-out protections insure safe operations
under abnormal operating conditions.
The XRP6658 is offered in a RoHS compliant,
“green”/halogen free 5-pin SOT23 package.
APPLICATIONS
Portable Equipments
Battery Operated Equipments
Audio-Video Equipments
Networking & Telecom Equipments
FEATURES
Guaranteed 1A Output Current
Input Voltage: 2.5V to 5.5V
1.5MHz PWM Current Mode Control
PFM Mode Operations at Light Load
100% Duty Cycle LDO Mode Operations
Achieves 97% Efficiency
Adjustable Output Voltage Range
As Low as 0.6V with ±3% Accuracy
Internal Compensation Network
15µA Quiescent Current
Over Temperature & UVLO Protections
RoHS Compliant “Green”/Halogen Free
5-Pin SOT23 Package
TYPICAL APPLICATION DIAGRAM
Fig. 1: XRP6658 Application Diagram
Exar Corporation
48720 Kato Road, Fremont CA 94538, USA
www.exar.com
Tel. +1 510 668-7000 – Fax. +1 510 668-7001
X RP 6 6 5 8
1A 1.5MHz PFM/PWM Synchronous Step-Down Converter
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of
the device at these ratings or any other above those
indicated in the operation sections of the specifications
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect
reliability.
Input Voltage V
IN
...................................... -0.3V to 6.0V
EN, V
FB
Voltages .......................................... -0.3V to V
IN
SW Voltage .................................... -0.3V to (V
IN
+ 0.3V)
Storage Temperature .............................. -65°C to 150°C
Lead Temperature (Soldering, 10 sec) ................... 260°C
ESD Rating (HBM - Human Body Model) .................... 2kV
ESD Rating (MM - Machine Model) ...........................200V
Junction Temperature (Notes 1, 3) ....................... 150°C
OPERATING RATINGS
Input Voltage Range V
IN
............................... 2.5V to 5.5V
Operating Temperature Range .................. -40°C to 85°C
Thermal Resistance ......................................................
θ
JA
(5 Pin SOT23) ....................................... 134.5°C/W
θ
JC
(5 Pin SOT23) ........................................... 81°C/W
ELECTRICAL SPECIFICATIONS
Specifications with standard type are for an Ambient Temperature of T
A
= 25°C only; limits applying over the full Operating
Temperature range are denoted by a “•”. Minimum and Maximum limits are guaranteed through test, design, or statistical
correlation. Typical values represent the most likely parametric norm at T
A
= 25°C, and are provided for reference purposes
only. Unless otherwise indicated, V
IN
= 3.6V, T
A
= 25°C.
Parameter
Input Voltage Range
Feedback Current
Regulated Feedback Voltage
Output Voltage Accuracy
Output Voltage Accuracy
Reference Voltage Line Regulation
Reference Voltage Line Regulation
Output Voltage Line Regulation
Output Voltage Line Regulation
Peak Inductor Current
PWM Quiescent Current (Note 2)
PFM Quiescent Current
Shutdown
Oscillator Frequency
Short-Circuit Oscillator Frequency
R
DS(ON)
of PMOS
R
DS(ON)
of NMOS
Under Voltage Lock Out
SW Leakage
Enable Threshold
Shutdown Threshold
EN Leakage Current
0.4
+1
1.2
1.5
2.3
188
15
0.1
1.5
900
0.24
0.21
1.8
+1
1.2
1
1.8
0.588
-3
-3
0.600
Min.
2.5
Typ.
Max.
5.5
+100
0.612
+3
+3
0.4
0.4
0.4
0.4
Units
V
nA
V
%
%
%/V
%/V
%/V
%/V
A
µA
µA
µA
MHz
kHz
Ω
Ω
V
µA
V
V
µA
•
•
•
V
RUN
= 0V, V
SW
= 0V or 5V, V
IN
= 5V
I
OUT
=100mA, V
IN
= 2.5V to 3.0V
• I
OUT
=100mA, V
IN
= 3.0V to 5.5V
V
IN
= 2.5V to 3.0V
• V
IN
= 3.0V to 5.5V
V
IN
= 2.5V to 3.0V
• V
IN
= 3.0V to 5.5V
V
FB
= 0.5V or V
OUT
= 90%
V
FB
= 0.5V or V
OUT
= 90%
V
FB
= 0.65V or V
OUT
= 108%
V
RUN
= 0V, V
IN
= 4.2V
• V
FB
= 0.6V or V
OUT
= 100%
• V
FB
= 0V or V
OUT
= 0V
I
SW
= 100mA
I
SW
= –100mA
Conditions
Note 1: T
J
is a function of the ambient temperature T
A
and power dissipation P
D
: (T
J
= T
A
+ (P
D
*
θ
JA
))
Note 2: Dynamic quiescent current is higher due to the gate charge being delivered at the switching frequency.
Note 3: This IC is built-in over-temperature protection to avoid damage from overload conditions.
Note 4:
θ
JA
is measured in the natural convection at T
A
=25 on a high effective thermal conductivity test board (2 layers,
2S0P) of JEDEC 51-5 thermal measurement standard.
Note 5:
θ
JC
represents the resistance to the heat flows the chip to package top case.
© 2011 Exar Corporation
2/11
Rev. 1.5.0
X RP 6 6 5 8
1A 1.5MHz PFM/PWM Synchronous Step-Down Converter
BLOCK DIAGRAM
Fig. 2: XRP6658 Block Diagram
PIN ASSIGNMENT
Fig. 3: XRP6658 Pin Assignment
© 2011 Exar Corporation
3/11
Rev. 1.5.0
X RP 6 6 5 8
1A 1.5MHz PFM/PWM Synchronous Step-Down Converter
PIN DESCRIPTION
Name
VIN
GND
EN
VFB
SW
Pin Number
1
2
3
4
5
Description
Power Input Pin.
Must be closely decoupled to GND pin with a 4.7μF or greater ceramic capacitor.
Ground Signal
Enable Pin.
Minimum 1.2V to enable the device. Maximum 0.4V to shutdown the device.
Feedback Pin.
Receives the feedback voltage from an external resistive divider across the output.
Switch Pin.
Must be connected to Inductor. This pin connects to the drains of the internal main and
synchronous power MOSFET switches.
ORDERING INFORMATION
Part Number
XRP6658ISTR-F
XRP6658EVB
Temperature
Range
-40°C≤T
A
≤+85°C
Marking
HCWW
Package
5-Pin SOT23
Packing
Quantity
3K/Tape & Reel
Note 1
RoHS Compliant
Halogen Free
Note 2
XRP6658 Evaluation Board
“WW” = Work Week
Note that the XRP6658 series is packaged in Tape and Reel with a reverse part orientation as per
the following diagram
© 2011 Exar Corporation
4/11
Rev. 1.5.0
X RP 6 6 5 8
1A 1.5MHz PFM/PWM Synchronous Step-Down Converter
TYPICAL PERFORMANCE CHARACTERISTICS
All data taken at V
IN
= 3.6V, T
J
= T
A
= 25°C, unless otherwise specified - Schematic and BOM from Application Information
section of this datasheet.
Fig. 4: Efficiency vs Output Current (V
OUT
=3.3V)
Fig. 5: Efficiency vs Output Current (V
OUT
=1.2V)
Fig. 6: Oscillator Frequency vs Temperature
Fig. 7: Oscillator Frequency vs Supply Voltage
Fig. 8: R
DS(ON)
vs Temperature
Fig. 9: R
DS(ON)
vs Input Voltage
© 2011 Exar Corporation
5/11
Rev. 1.5.0
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