FAN5361 — 6MHz, 600mA / 750mA Synchronous Buck Regulator
December 2010
FAN5361
6MHz, 600mA / 750mA Synchronous Buck Regulator
Features
6MHz Fixed-Frequency Operation
35µA Typical Quiescent Current
Best-in-Class Load Transient Response
Best-in-Class Efficiency
600mA or 750mA Output Current Capability
2.3V to 5.5V Input Voltage Range
1.0 to 1.90V Fixed Output Voltage
Low Ripple Light-Load PFM Mode
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
6-pin 2 x 2mm UMLP
Description
The FAN5361 is a 600mA or 750mA, step-down, switching
voltage regulator that delivers a fixed output from a 2.3V to
5.5V input voltage supply. Using a proprietary architecture
with synchronous rectification, the FAN5361 is capable of
delivering a peak efficiency of 92%, while maintaining
efficiency over 80% at load currents as low as 1mA.
The regulator operates at a nominal fixed frequency of
6MHz, which reduces the value of the external components
to 470nH 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 35µA. 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 6MHz. 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 FAN5361 is available in 6-bump, 0.4mm pitch, Wafer-
Level Chip-Scale Package (WLCSP) and a 6-lead 2 x 2mm
ultra-thin MLP package (UMLP).
Applications
Cell Phones, Smart Phones
®
Tablets, Netbooks , Ultra-Mobile PCs
®
®
3G, LTE, WiMAX™, WiBro , and WiFi Data Cards
Gaming Devices, Digital CamerasDC/DC Micro Modules
Typical Applications
Figure 1. Typical Applications
All trademarks are the property of their respective owners.
© 2008 Fairchild Semiconductor Corporation
FAN5361 • Rev. 1.1.0
www.fairchildsemi.com
FAN5361 — 6MHz, 600mA / 750mA Synchronous Buck Regulator
Ordering Information
Part Number
FAN5361UC123X
FAN5361UC182X
FAN5361UMP123X
FAN5361UMP15X
FAN5361UMP182X
Output
(1)
Voltage
1.233V
1.820V
1.233V
1.500V
1.820V
Package
WLCSP-6, 0.4mm Pitch
Temperature Range
Packing
–40 to +85°C
6-Lead, 2 x 2mm UMLP
Tape and Reel
Note:
1. Other voltage options available on request. Contact a Fairchild representative.
Pin Configurations
MODE
SW
FB
A1
B1
A2
B2
VIN
EN
GND
Figure 3. WLCSP, Bumps Facing Up
C1
C2
Figure 2. WLCSP, Bumps Facing Down
Figure 4. UMLP, Leads Facing Down
Pin Definitions
Pin #
WLCSP UMLP
A1
B1
C1
C2
B2
A2
3
2
1
6
5
4
Name Description
MODE.
Logic 1 on this pin forces the IC to stay in PWM mode. A logic 0 allows the IC to
MODE automatically switch to PFM during light loads. The regulator also synchronizes its switching
frequency to four times the frequency provided on this pin. Do not leave this pin floating.
SW
FB
GND
EN
VIN
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.
© 2008 Fairchild Semiconductor Corporation
FAN5361 • Rev. 1.1.0
www.fairchildsemi.com
2
FAN5361 — 6MHz, 600mA / 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
Input Voltage
Voltage on SW Pin
EN and MODE Pin Voltage
Other Pins
ESD
T
J
T
STG
T
L
Electrostatic Discharge
Protection Level
Junction Temperature
Storage Temperature
Parameter
Min.
–0.3
–0.3
–0.3
–0.3
Max.
7.0
V
IN
+ 0.3
V
IN
+ 0.3
V
IN
+ 0.3
4.0
1.5
(2)
(2)
(2)
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:
2. Lesser of 7V 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
Inductor
Input Capacitor
Output Capacitor
Parameter
Min.
2.3
0
Typ.
Max.
5.5
600
Unit
V
mA
µH
µF
0.47
2.2
1.6
–40
–40
4.7
12.0
+85
+125
µF
°C
°C
Operating Ambient Temperature
Operating Junction Temperature
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 temperate T
A
.
Symbol
θ
JA
Parameter
Junction-to-Ambient Thermal Resistance
WLCSP
UMLP
Typical
150
49
Unit
°C/W
°C/W
© 2008 Fairchild Semiconductor Corporation
FAN5361 • Rev. 1.1.0
www.fairchildsemi.com
3
FAN5361 — 6MHz, 600mA / 750mA Synchronous Buck Regulator
Electrical Characteristics
Minimum and maximum values are at V
IN
= V
EN
= 2.3V 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.
Symbol
Power Supplies
I
Q
I
(SD)
V
UVLO
V
UVHYST
V
IH
V
IL
V
LHYST
I
IN
f
SW
f
SYNC
Regulation
Parameter
Conditions
No Load, Not Switching
PWM Mode
V
IN
= 3.6V, EN = GND
Rising V
IN
Min.
Typ.
35
6
0.05
2.15
150
Max.
55
1.00
2.25
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
Logic Input Hysteresis Voltage
Enable Input Leakage Current
Switching Frequency
(3)
(3)
Logic Inputs: EN and MODE Pins
1.2
0.4
100
Pin to V
IN
or GND
V
IN
= 3.6V, T
A
= 25°C
Square Wave at MODE Input
I
LOAD
= 0 to 750mA
PWM Mode
I
LOAD
= 0 to 600mA
PWM Mode
I
LOAD
= 0 to 600mA
PWM Mode
I
LOAD
= 0 to 600mA
PWM Mode
From EN Rising Edge
V
IN
= V
GS
= 3.6V
V
IN
= V
GS
= 3.6V
V
OUT
= 1.233V, 1.5V, 1.82V
V
OUT
= 1.9V
CCM Only
900
5.4
1.3
1.862
1.862
1.784
1.784
1.470
1.470
1.207
1.207
0.01
6.0
1.5
1.900
1.900
1.820
1.820
1.500
1.500
1.233
1.233
180
350
225
1100
1375
150
15
1250
1.00
6.6
1.7
1.957
1.938
1.875
1.856
1.545
1.530
1.272
1.259
300
µs
V
V
mV
µA
MHz
MHz
Switching and Synchronization
MODE Synchronization Range
1.900V
1.820V
1.500V
1.233V
t
SS
Soft-Start
PMOS On Resistance
NMOS On Resistance
PMOS Open-Loop Peak Current
Limit
Thermal Shutdown
Thermal Shutdown Hysteresis
V
O
Output Voltage
Accuracy
Output Driver
R
DS(on)
I
LIM(OL)
T
TSD
T
HYS
mΩ
mA
°C
°C
Notes:
3. Limited by the effect of t
OFF
minimum
(see Figure 14 and Figure 15 in Typical Performance Characteristics).
4. The Electrical Characteristics table reflects open-loop data. Refer to Operation Description and Typical Characteristics for
closed-loop data.
© 2008 Fairchild Semiconductor Corporation
FAN5361 • Rev. 1.1.0
www.fairchildsemi.com
4
FAN5361 — 6MHz, 600mA / 750mA Synchronous Buck Regulator
Typical Performance Characteristics
Unless otherwise noted, V
IN
= V
EN
= 3.6V, V
MODE
= 0V (AUTO Mode), V
OUT
= 1.82V, T
A
= 25°C.
100%
95%
90%
85%
100%
95%
90%
85%
Efficiency
75%
70%
65%
60%
55%
50%
1
10
100
Auto 2.3VIN
Auto 2.7VIN
Auto 3.6VIN
Auto 4.2VIN
Efficiency
80%
80%
75%
70%
65%
60%
55%
50%
-30C
85C
25C
1000
1
10
100
1000
I
LOAD
Output Current (mA)
I
LOAD
Output Current (mA)
Figure 5. Efficiency vs. Load Current and Input Supply Figure 6. Efficiency vs. Load Current and Temperature
100%
95%
90%
85%
100%
95%
90%
85%
Efficiency
80%
75%
70%
65%
60%
55%
50%
1
10
100
1000
VIN=2.3V
VIN=2.7V
VIN=3.6V
VIN=4.2V
Efficiency
80%
75%
70%
65%
60%
55%
50%
1
10
100
1000
Auto PFM/PWM
Forced PWM
I
LOAD
Output Current (mA)
I
LOAD
Output Current (mA)
Figure 7. 1.233V
OUT
Efficiency vs. Load Current
and Supply
Figure 8. Efficiency, Auto PWM/PFM vs. Forced PWM
1.84
1.248
VIN=2.3V
1.243
1.83
VIN=2.7V
VIN=3.6V
V
OUT
(V)
1.238
VIN=4.2V
V
OUT
(V)
1.82
VIN=2.3V
VIN=2.7V
1.81
1.233
VIN=3.6V
VIN=4.2V
1.80
0
100
200
300
400
500
600
1.228
1.223
0.0
0.1
0.2
0.3
0.4
0.5
0.6
Load Current (mA)
I
LOAD
Output Current (A)
Figure 9. Load Regulation
© 2008 Fairchild Semiconductor Corporation
FAN5361 • Rev. 1.1.0
Figure 10. 1.233V
OUT
Load Regulation vs. Input Supply
www.fairchildsemi.com
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