FAN5362 — 3MHz, 500mA / 750mA Synchronous Buck Regulator
November 2010
FAN5362
3MHz, 500mA / 750mA Synchronous Buck Regulator
Features
3MHz Fixed-Frequency Operation
45µA Typical Quiescent Current
1.80 to 3.6V Fixed Output Voltage
500mA or 750mA Output Current Capability
2.7V to 5.5V Input Voltage Range
Smooth Transitions to/from 100% Duty Cycle
when V
IN
Drops
PFM Mode for High Efficiency in Light Load
Best-in-Class Load Transient Response
Best-in-Class Efficiency
Forced PWM and External Clock Synchronization
Internal Soft-Start
Input Under-Voltage Lockout (UVLO)
Thermal Shutdown and Overload Protection
6-Bump WLCSP, 0.4mm Pitch or 6-Lead 2 x 2mm
Ultrathin Molded Leadless Package
Description
The FAN5362 is a 500mA or 705mA, step-down, switching
voltage regulator that delivers a fixed output voltage from
an input voltage supply of 2.7V to 5.5V. Using a proprietary
architecture with synchronous rectification, the FAN5362 is
capable of delivering a peak efficiency of 96%, while
maintaining efficiency over 90% with load currents as
low as 1mA.
This regulator transitions seamlessly into and out of 100%
duty cycle operation when the supply dips to or below the
regulation setpoint and smoothly recovers full regulation
without overshoot when the supply recovers.
The regulator operates at a nominal fixed frequency of
3MHz, which reduces the value of the external components
to 1µH for the output inductor and 4.7µF for the output
capacitor. The PWM modulator can be synchronized to an
external frequency source.
At moderate and light loads, pulse frequency modulation is
used to operate the device in power-save mode with a
typical quiescent current of 45µA. Even with such a low
quiescent current, the part exhibits excellent transient
response during large load swings. At higher loads, the
system automatically switches to fixed-frequency control,
operating at 3MHz. In shutdown mode, the supply current
drops below 1µA, reducing power consumption. For
applications that require minimum ripple or fixed frequency,
PFM mode can be disabled using the MODE pin.
The FAN5362 is available in 6-bump, 0.4mm pitch, Wafer-
Level Chip-Scale Package (WLCSP) and 6-Lead 2 x 2mm
Ultrathin Molded Leadless Package (UMLP).
Applications
SD Flash Memory Power Supply
RF Transeiver Power
Cell Phones, Smart Phones
Tablets, Netbooks , Ultra-Mobile PCs
3G, LTE, WiMAX™, WiBro , and WiFi Data Cards
Gaming Devices, Digital CamerasDC/DC Micro Modules
®
®
®
Figure 1. Typical Application
Trademarks are the property of their respective owners.
© 2009 Fairchild Semiconductor Corporation
FAN5362 • Rev. 1.0.1
www.fairchildsemi.com
FAN5362 — 3MHz, 500mA / 750mA Synchronous Buck Regulator
Ordering Information
Part Number
FAN5362UC21X
FAN5362UC25X
FAN5362UC27X
(2)
(2)
(2)
Output Voltage
2.1
2.5
2.7
2.9
3.3
2.9
3.3
(1)
Operating Temperature Range
Package
Packing Method
WLCSP-6, 0.4mm Pitch
-40 to 85°C
Tape and Reel
FAN5362UC29X
FAN5362UC33X
FAN5362UMP29X
FAN5362UMP33X
6-Lead, 2 x 2mm UMLP
Note:
1. Other voltage options available on request. Contact a Fairchild representative.
2. Preliminary; not full production release at this time. Contact a Fairchild representative for information.
Table 1. Recommended Components for Circuit in Figure 1
Component
L1
C
IN
C
OUT
Description
1μH, 2012, 190mΩ, 800mA
2.2μF, 6.3V, X5R, 0402
2.2μF, 6.3V, X5R, 0603
4.7μF, X5R, 0603
10μF, X5R, 0603
Example Part
Murata LQM21PN1R0MC0
Murata GRM155R60J225ME15
GRM188R60J225KE19D
Murata GRM188R60J475M
Murata GRM188R60J106ME47D
Typical
1μH
2.2μF
4.7μF
10.0μF
Pin Configuration
Figure 2. WLCSP, Bumps Facing Down
Figure 3. WLCSP, Bumps Facing Up
Pin Definitions
Pin #
A1
B1
C1
C2
B2
A2
Name
MODE
SW
FB
GND
EN
VIN
Description
Logic 1 on this pin forces the IC to stay in PWM mode. A logic 0 allows the IC to automatically switch
to PFM during light loads. The regulator also synchronizes its switching frequency to two times the
frequency provided on this pin. Do not leave this pin floating.
Switching Node.
Connect to output inductor.
Feedback / V
OUT
. Connect to output voltage.
Ground.
Power and IC ground. All signals are referenced to this pin.
Enable.
The device is in shutdown mode when voltage to this pin is <0.4V and enabled when >1.2V.
Do not leave this pin floating.
Input Voltage.
Connect to input power source.
© 2009 Fairchild Semiconductor Corporation
FAN5362 • Rev. 1.0.1
www.fairchildsemi.com
2
FAN5362 — 3MHz, 500mA / 750mA Synchronous Buck Regulator
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable
above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition,
extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute
maximum ratings are stress ratings only.
Symbol
V
IN
V
SW
V
CTRL
V
FB
ESD
T
J
T
STG
T
L
Input Voltage
Voltage on SW Pin
EN and MODE Pin Voltage
FB Pin
Electrostatic Discharge
Protection Level
Junction Temperature
Storage Temperature
Parameter
Min.
–0.3
–0.3
–0.3
–0.3
Max.
6.5
V
IN
+ 0.3
V
IN
+ 0.3
4
3.0
1.5
(3)
(3)
Unit
V
V
V
V
kV
Human Body Model per JESD22-A114
Charged Device Model per JESD22-C101
–40
–65
+150
+150
+260
°C
°C
°C
Lead Soldering Temperature, 10 Seconds
Note:
3. Lesser of 6.5V or V
IN
+0.3V.
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating
conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend
exceeding them or designing to Absolute Maximum Ratings.
Symbol
V
CC
I
OUT
L
C
IN
C
OUT
T
A
T
J
Supply Voltage Range
Output Current for 2.1V
Parameter
Min.
2.7
0
0
(4)
Typ.
Max.
5.5
750
500
Unit
V
mA
µH
µF
Output Current for 2.5V, 2.7V, 2.9V, 3.3V
Inductor
Input Capacitor
Output Capacitor
Operating Ambient Temperature
Operating Junction Temperature
1
2.2
10
–40
–40
24
+85
+125
µF
°C
°C
Note:
4. Minimum V
IN
= V
OUT
+ 200mV or 2.7V, whichever is greater.
Thermal Properties
Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer
1s2p boards in accordance to JEDEC standard JESD51. Special attention must be paid not to exceed junction temperature
T
J(max)
at a given ambient temperature T
A
.
Symbol Parameter
θ
JA
Junction-to-Ambient Thermal Resistance
WLSCP
UMLP
Typical
150
49
Unit
°C/W
© 2009 Fairchild Semiconductor Corporation
FAN5362 • Rev. 1.0.1
www.fairchildsemi.com
3
FAN5362 — 3MHz, 500mA / 750mA Synchronous Buck Regulator
Electrical Characteristics
Minimum and maximum values are at V
IN
= V
EN
= 2.7V to 5.5V, V
MODE
= 0V (AUTO Mode), T
A
= -40°C to +85°C; circuit of
Figure 1, unless otherwise noted. Typical values are at T
A
= 25°C, V
IN
= V
EN
= 3.6V, V
MODE
= 0V, C
OUT
=10µF.
Symbol
Power Supplies
I
Q
I
(SD)
V
UVLO
V
UVHYST
V
(ENH)
V
(ENL)
I
(EN)
V
(MH)
V
(ML)
I
(M)
f
SW
f
SYNC
Parameter
Conditions
No Load, Not Switching, V
IN
> 3V
PWM Mode
EN = GND
Rising V
IN
Min.
Typ.
45
5
0.05
2.5
175
Max.
75
1.00
2.6
Unit
µA
mA
µA
V
mV
V
Quiescent Current
Shutdown Supply Current
Under-Voltage Lockout
Threshold
Under-Voltage Lockout
Hysteresis
Enable HIGH-Level Input Voltage
Enable LOW-Level Input Voltage
Enable Input Leakage Current
MODE HIGH-Level Input Voltage
MODE LOW-Level Input Voltage
MODE Input Leakage Current
Switching Frequency
(5)
(5)
1.05
0.4
EN to V
IN
or GND
1.05
0.4
MODE to V
IN
or GND
V
IN
= 3.6V, T
A
= 25°C
Square Wave at MODE Input
2.7
1.3
2.037
(-3%)
2.375
(-5%)
2.425
(-3%)
-5%
-3%
180
330
300
1375
800
1000
150
15
1150
0.01
3.0
1.5
1.00
3.3
1.7
2.163
(+3%)
2.575
(+3%)
2.575
(+3%)
+3%
+3%
300
0.01
1.00
V
µA
V
V
µA
MHz
MHz
Switching and Synchronization
MODE Synchronization Range
Regulation
2.10V
I
LOAD
= 0 to 750mA
I
LOAD
= 0 to 400mA, V
IN
≥
V
OUT
+
200mV
I
LOAD
= 0 to 500mA, V
IN
≥
V
OUT
+
300mV
I
LOAD
= 0 to 400mA, V
IN
≥
V
OUT
+
150mV
I
LOAD
= 0 to 500mA, V
IN
≥
V
OUT
+
300mV
From EN Rising Edge
V
IN
= V
GS
= 3.6V
V
IN
= V
GS
= 3.6V
(5)
2.100
2.500
2.500
V
O
Output Voltage
Accuracy
2.50V
V
2.70V, 2.90V,
3.30V
t
SS
Soft-Start
PMOS On Resistance
NMOS On Resistance
PMOS Peak Current Limit
Thermal Shutdown
Thermal Shutdown Hysteresis
µs
mΩ
mΩ
mA
mA
°C
°C
Output Driver
R
DS(on)
I
LIM(OL)
T
TSD
T
HYS
V
OUT
= 2.1V
V
OUT
= 2.5V, 2.7V, 2.9V, 3.3V
Notes:
5. Limited by the effect of t
OFF
minimum
(see Figure 7 in Typical Performance Characteristics).
6. The Electrical Characteristics table reflects open-loop data. Refer to the Operation Description and Typical Characteristics
for closed-loop data.
© 2009 Fairchild Semiconductor Corporation
FAN5362 • Rev. 1.0.1
www.fairchildsemi.com
4
FAN5362 — 3MHz, 500mA / 750mA Synchronous Buck Regulator
Typical Characteristics
Unless otherwise noted, V
IN
=V
EN
=3.6V,V
MODE
=0 (AUTO), V
OUT
=2.9V, C
OUT
=10µF, and T
A
=25°C.
100%
98%
96%
94%
2.910
2.905
Efficiency
90%
88%
86%
84%
82%
80%
1
10
100
I
LOAD
Output Current (mA)
VIN = 3.2, Mode=0
VIN = 3.6, Mode=0
VIN = 4.2, Mode=0
VIN = 3.2, Mode=1
VIN = 3.6, Mode=1
VIN = 4.2, Mode=1
VOUT (V)
92%
2.900
2.895
2.890
Auto 3.6VIN
Auto 3.2VIN
1000
2.885
-
100
200
300
400
500
I
LOAD
Output Current (mA)
Figure 4. Efficiency vs. Load Current and Input Supply
90
80
70
60
50
40
30
20
Figure 5. Load Regulation
3500
3.2VIN_Auto
3.6VIN_AUTO
3000
Switching Frequency(kHz)
2500
2000
1500
1000
500
3.2VIN_AUTO
3.6VIN_AUTO
3.6VIN_FPWM
3.2VIN_FPWM
VOUT
ripple(mVpp
)
10
0
0
0
100
200
300
400
500
0
50
100
150
200
250
300
350
400
450
500
Load current (mA)
Load Current(mA)
Figure 6. Ripple
Figure 7. Effect of t
OFF(MIN)
on Reducing Switching
Frequency
1300
500
450
400
350
Peak Inductor Current (mA)
100
%
d.c
.
1200
1100
1000
900
800
700
Load Current (mA)
300
250
200
150
100
50
0
3
3.5
Hysteresis
Always PWM
Always PFM
‐40C
+25C
+85C
4
4.5
5
5.5
600
2.5
3.0
3.5
4.0
Input Voltage (V)
4.5
5.0
5.5
Input Voltage(V)
Figure 8. PFM / PWM Boundaries
Figure 9. Peak Inductor Current
© 2009 Fairchild Semiconductor Corporation
FAN5362 • Rev. 1.0.1
www.fairchildsemi.com
5
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