DATA SHEET
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Synchronous Buck
Regulator, 1 A
6 MHz, 600 mA
WLCSP6 1.16 y 0.86 y 0.586
CASE 567QE
FAN53601, FAN53611
Description
The FAN53601/11 is a 6 MHz, step−down switching voltage
regulator, available in 600 mA or 1 A options, that delivers a fixed
output from an input voltage supply of 2.3 V to 5.5 V. Using
a proprietary architecture with synchronous rectification,
the FAN53601/11 is capable of delivering a peak efficiency of 92%,
while maintaining efficiency over 80% at load currents as low as
1 mA.
The regulator operates at a nominal fixed frequency of 6 MHz,
which reduces the value of the external components to as low
as 470 nH for the output inductor and 4.7 mF for the output capacitor.
In addition, the Pulse Width Modulation (PWM) modulator can be
synchronized to an external frequency source.
At moderate and light loads, Pulse Frequency Modulation (PFM) is
used to operate the device in Power−Save Mode with a typical
quiescent current of 24 mA. 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 6 MHz. In Shutdown Mode, the supply current
drops below 1 mA, reducing power consumption. For applications that
require minimum ripple or fixed frequency, PFM Mode can be
disabled using the MODE pin.
The FAN53601/11 is available in 6−bump, 0.4 mm pitch,
Wafer−Level Chip−Scale Package (WLCSP).
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
April, 2022 − Rev. 3
MARKING DIAGRAM
xx&K
&.&2&Z
xx
&K
&.
&2
Z
= Device Code
= 2−Digits Lot Run Traceability Code
= Pin One Dot
= 2−Digit Date Code
= Assembly Site
MODE
L1
470nH
4.7 mF
SW
FB
A1
A2
B1
B2
C1
C2
VIN
EN
GND
CIN
2.2 mF
COUT
Figure 1. Typical Application
ORDERING INFORMATION
600 mA or 1 A Output Current Capability
24 mA Typical Quiescent Current
6 MHz Fixed−Frequency Operation
Best−in−Class Load Transient Response
Best−in−Class Efficiency
2.3 V to 5.5 V Input Voltage Range
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
Optional Output Discharge
6−Bump WLCSP, 0.4 mm Pitch
These are Pb−Free and Halid Free Devices
© Semiconductor Components Industries, LLC, 2010
WLCSP6 1.16 y 0.86 y 0.586
CASE 567RQ
See detailed ordering and shipping information on page 2 of
this data sheet.
Applications
• 3G, 4G, WiFi®, WiMAXt, and WiBrot
Data Cards
• Tablets
• DSC, DVC
• Netbooks, Ultra−Mobile PCs
1
Publication Order Number:
FAN53611/D
FAN53601, FAN53611
ORDERING INFORMATION
Output Voltage
(Note 1)
Max. Output
Current
Active Discharge
(Note 2)
Max. VIN
Package
FAN53601AUC10X
1.000 V
600 mA
Yes
5.5 V
FAN53601AUC105X
1.050 V
600 mA
Yes
WLCSP6
(Pb−Free)
FAN53611AUC11X
1.100 V
1A
Yes
FAN53611AUC115X
1.150 V
1A
Yes
FAN53611AUC13X
1.300 V
1A
Yes
FAN53611AUC135X
1.350 V
1A
Yes
FAN53611UC123X
1.233 V
1A
No
FAN53601UC182X
1.820 V
600 mA
No
FAN53611AUC205X
2.050 V
1A
Yes
FAN53611AUC123X
1.233 V
1A
Yes
FAN53611AUC12X
1.200 V
1A
Yes
FAN53611AUC18X
1.800 V
1A
Yes
Part Number
Temperature
Range
−40 to +85°C
Shipping†
3000 / Tape
& Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specification Brochure, BRD8011/D.
1. Other voltage options available on request. Contact a onsemi representative.
2. All voltage and output current options are available with or without active discharge. Contact a onsemi representative.
Pin Configurations
MODE
A1
A2
VIN
VIN
A2
A1
MODE
SW
B1
B2
EN
EN
B2
B1
SW
FB
C1
C2
GND
GND
C2
C1
FB
Figure 2. Bumps Facing Down
Figure 3. Bumps Facing Up
PIN DEFINITIONS
Pin No.
Name
A1
MODE
Description
MODE. 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 four times the frequency
provided on this pin. Do not leave this pin floating.
B2
SW
Switching Node. Connect to output inductor.
C1
FB
Feedback / VOUT. Connect to output voltage.
C2
GND
B2
EN
Enable. The device is in Shutdown Mode when voltage to this pin is < 0.4 V and enabled when > 1.2 V. Do not leave
this pin floating.
A2
VIN
Input Voltage. Connect to input power source.
Ground. Power and IC ground. All signals are referenced to this pin.
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2
FAN53601, FAN53611
ABSOLUTE MAXIMUM RATINGS
Symbol
Min
Max
Unit
VIN
Input Voltage
−0.3
7.0
V
VSW
Voltage on SW Pin
−0.3
VIN + 0.3
(Note 3)
V
EN and MODE Pin Voltage
−0.3
VIN + 0.3
(Note 3)
V
Other Pins
−0.3
VIN + 0.3
(Note 3)
V
VCTRL
ESD
Parameter
Electrostatic Discharge Protection
Level
Human Body Model per JESD22−A114
2.0
Charged Device Model per JESD22−C101
1.5
kV
TJ
Junction Temperature
−40
+150
°C
TSTG
Storage Temperature
−65
+150
°C
−
+260
°C
TL
Lead Soldering Temperature, 10 Seconds
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
3. Lesser of 7 V or VIN +0.3 V.
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Min
Typ
Max
Unit
2.3
−
5.5
V
Output Current for FAN53601
0
−
600
mA
Output Current for FAN53611
0
−
1
A
Inductor
−
470
−
nH
Input Capacitor
−
2.2
−
mF
VCC
Supply Voltage Range
IOUT
L
CIN
COUT
Output Capacitor
1.6
4.7
12.0
mF
TA
Operating Ambient Temperature
−40
−
+85
°C
TJ
Operating Junction Temperature
−40
−
+125
°C
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond
the Recommended Operating Ranges limits may affect device reliability.
THERMAL CHARACTERISTICS
Symbol
qJA
NOTE:
Parameter
Junction−to−Ambient Thermal Resistance
Value
Unit
125
°C/W
Junction−to−ambient thermal resistance is a function of application and board layout. This data is measured with four−layer 2s2p
boards in accordance to JEDEC standard JESD51. Special attention must be paid to not exceed junction temperature TJ(max) at a
given ambient temperature TA.
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3
FAN53601, FAN53611
ELECTRICAL CHARACTERISTICS
Minimum and maximum values are at VIN = VEN = 2.3 V to 5.5 V, VMODE = 0 V (AUTO Mode), TA = −40°C to +85°C; circuit of Figure 1,
unless otherwise noted. Typical values are at TA = 25°C, VIN = VEN = 3.6 V.
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
No Load, Not Switching
−
24
50
mA
PWM Mode
−
8
−
mA
POWER SUPPLIES
IQ
I(SD)
Quiescent Current
Shutdown Supply Current
EN = GND, VIN = 3.6 V
−
0.25
1.00
mA
VUVLO
Under−Voltage Lockout Threshold
Rising VIN
−
2.15
2.27
V
VUVHYST
Under−Voltage Lockout Hysteresis
−
200
−
mV
−
−
V
LOGIC INPUTS: EN AND MODE PINS
VIH
Enable HIGH−Level Input Voltage
1.2
VIL
Enable LOW−Level Input Voltage
−
−
0.4
V
VLHYST
Logic Input Hysteresis Voltage
−
100
−
mV
IIN
Enable Input Leakage Current
−
0.01
1.00
mA
Pin to VIN or GND
SWITCHING AND SYNCHRONIZATION
fSW
Switching Frequency (Note 4)
VIN = 3.6 V, TA = 25C, PWM Mode,
ILOAD = 10 mA
5.4
6.0
6.6
MHz
fSYNC
MODE Synchronization Range
(Note 4)
Square Wave at MODE Input
1.3
1.5
1.7
MHz
Output Voltage Accuracy
ILOAD = 0 to 600 mA
0.953
1.000
1.048
V
PWM Mode
0.967
1.000
1.034
ILOAD = 0 to 1 A
1.298
1.350
1.402
PWM Mode
1.309
1.350
1.391
ILOAD = 0 to 1 A
1.185
1.233
1.281
PWM Mode
1.192
1.233
1.274
ILOAD = 0 to 600 mA
1.755
1.820
1.885
PWM Mode
1.781
1.820
1.859
ILOAD = 0 to 1 A
1.054
1.100
1.147
PWM Mode
1.061
1.100
1.140
ILOAD = 0 to 1 A
1.250
1.300
1.350
PWM Mode
1.259
1.300
1.341
ILOAD = 0 to 1 A
1.104
1.150
1.196
PWM Mode
1.110
1.150
1.190
ILOAD = 0 to 600 mA
1.003
1.050
1.097
PWM Mode
1.016
1.050
1.084
ILOAD = 0 to 1 A, VIN = 2.7 to 5.5 V
1.973
2.050
2.127
PWM Mode, VIN = 2.7 to 5.5 V
2.004
2.050
2.096
ILOAD = 0 to 1 A
1.152
1.200
1.248
PWM Mode
1.160
1.200
1.240
ILOAD = 0 to 1 A
1.732
1.800
1.868
PWM Mode
1.756
1.800
1.844
−
180
300
REGULATION
VO
1.000 V
1.35 V
1.233 V
1.820 V
1.100 V
1.300 V
1.150 V
1.050 V
2.050 V
1.200 V
1.800 V
tSS
Soft−Start
VIN = 4.5 V, from EN Rising Edge
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4
ms
FAN53601, FAN53611
ELECTRICAL CHARACTERISTICS (continued)
Minimum and maximum values are at VIN = VEN = 2.3 V to 5.5 V, VMODE = 0 V (AUTO Mode), TA = −40°C to +85°C; circuit of Figure 1,
unless otherwise noted. Typical values are at TA = 25°C, VIN = VEN = 3.6 V. (continued)
Symbol
Parameter
Test Condition
Min
Typ
Max
Unit
mW
OUTPUT DRIVER
RDS(on)
ILIM(OL)
PMOS On Resistance
VIN = VGS = 3.6 V
−
175
−
NMOS On Resistance
VIN = VGS = 3.6 V
−
165
−
PMOS Peak Current Limit
Open−Loop for FAN53601,
VIN = 3.6 V, TA = 25°C
900
1100
1250
Open−Loop for FAN53611,
VIN = 3.6 V, TA = 25°C
1500
1750
2000
−
230
−
W
−
150
−
°C
15
−
°C
RDIS
Output Discharge Resistance
TTSD
Thermal Shutdown
THYS
Thermal Shutdown Hysteresis
EN = GND
mA
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
4. Limited by the effect of tOFF minimum (see Operation Description section).
5. The Electrical Characteristics table reflects open−loop data. Refer to the Operation Description and Typical Characteristics Sections for
closed−loop data.
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5
FAN53601, FAN53611
TYPICAL CHARACTERISTICS
Unless otherwise noted, VIN = VEN = 3.6 V, VMODE = 0 V (AUTO Mode), VOUT = 1.82 V, and TA = 25°C.
95%
Efficiency
Efficiency
90%
85%
80%
2.7 VIN
3.6 VIN
4.2 VIN
5.0 VIN
75%
70%
0
200
400
600
800
1000
92%
90%
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
68%
66%
64%
62%
60%
−40°C, AUTO
+25°C, AUTO
+85°C, AUTO
−40°C, PWM
+25°C, PWM
+85°C, PWM
0
200
2.7 VIN
3.6 VIN
4.2 VIN
5.0 VIN
200
400
600
800
1000
90%
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
68%
66%
64%
62%
60%
0
200
Efficiency
Output Regulation (%)
0
−1
−2
0
100
200
300
400
600
1000
800
Figure 7. Efficiency vs. Load Current and
Temperature, VOUT = 1.23 V, Auto Mode,
Dotted for FPWM
2.7 VIN, AUTO
3.6 VIN, AUTO
4.2 VIN, AUTO
5.0 VIN, AUTO
2.7 VIN , PWM
3.6 VIN , PWM
4.2 VIN , PWM
5.0 VIN, PWM
1
400
Load Current (mA)
Figure 6. Efficiency vs. Load Current and
Input Voltage, VOUT = 1.23 V, Auto Mode,
Dotted for Decreasing Load
2
1000
−40°C, AUTO
+25°C, AUTO
+85°C, AUTO
−40°C, PWM
+25°C, PWM
+85°C, PWM
Load Current (mA)
3
800
Figure 5. Efficiency vs. Load Current and
Temperature, Auto Mode, Dotted for FPWM
Efficiency
Efficiency
Figure 4. Efficiency vs. Load Current and Input
Voltage, Auto Mode, Dotted for Decreasing Load
0
600
Load Current (mA)
Load Current (mA)
90%
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
68%
66%
64%
400
500
600
90%
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
68%
66%
64%
2.7 VIN
3.6 VIN
4.2 VIN
5.0 VIN
0
100
200
300
400
500
600
Load Current (mA)
Load Current (mA)
Figure 9. Efficiency vs. Load Current,
VOUT = 1.00 V, Dotted for Decreasing Load
Figure 8. Output Regulation vs. Load Current,
VOUT = 1.00 V, Dotted for Auto Mode
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FAN53601, FAN53611
TYPICAL CHARACTERISTICS (continued)
Unless otherwise noted, VIN = VEN = 3.6 V, MODE = 0 V (AUTO Mode), VOUT = 1.82 V, and TA = 25°C.
3
2.7 VIN, AUTO
3.6 VIN, AUTO
4.2 VIN, AUTO
5.0 VIN, AUTO
2.7 VIN , PWM
3.6 VIN , PWM
4.2 VIN , PWM
5.0 VIN, PWM
2
1
0
Output Regulation (%)
Output Regulation (%)
3
−1
−2
0
200
400
600
800
2
1
0
−1
−2
1000
2.7 VIN, AUTO
3.6 VIN, AUTO
4.2 VIN, AUTO
5.0 VIN, AUTO
2.7 VIN , PWM
3.6 VIN , PWM
4.2 VIN , PWM
5.0 VIN, PWM
0
200
400
350
350
300
300
250
200
150
2.5
3.5
4.0
4.5
5.0
250
200
150
100
PWM
PFM
3.0
PWM
PFM
50
2.5
5.5
3.0
3.5
Figure 12. PFM / PWM Boundary vs. Input Voltage
5.0
5.5
15
−40°C, EN = VIN
+25°C, EN = VIN
+85°C, EN = VIN
−40°C, EN = 1.8 V
+25°C, EN = 1.8 V
+85°C, EN = 1.8 V
12
25
20
−40°C
+25°C
+85°C
9
6
3
15
2.5
4.5
Figure 13. PFM / PWM Boundary vs. Input
Voltage, VOUT = 1.23 V
Input Current (mA)
Input Current (mA)
30
4.0
Input Voltage (V)
Input Voltage (V)
35
1000
Figure 11. DVOUT (%) vs. Load Current and Input
Voltage, VOUT = 1.23 V, Normalized to 3.6 VIN,
500 mA Load, FPWM, Dotted for Auto Mode
Load Current (mA)
Load Current (mA)
Figure 10. DVOUT (%) vs. Load Current and Input
Voltage, Normalized to 3.6 VIN, 500 mA Load, FPWM,
Dotted for Auto Mode
50
800
Load Current (mA)
Load Current (mA)
100
600
0
3.0
3.5
4.0
4.5
5.0
2.5
5.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Input Voltage (V)
Figure 15. Quiescent Current vs. Input Voltage
and Temperature, Mode = EN = VIN (FPWM)
Figure 14. Quiescent Current vs. Input Voltage
and Temperature, Auto Mode; EN = VIN Solid,
Dotted for EN = 1.8 V (−405C, +255C, +855C)
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FAN53601, FAN53611
TYPICAL CHARACTERISTICS (continued)
Unless otherwise noted, VIN = VEN = 3.6 V, MODE = 0 V (AUTO Mode), VOUT = 1.82 V, and TA = 25°C.
7.500
2.7 VIN, AUTO
3.6 VIN, AUTO
5.0 VIN, AUTO
2.7 VIN , PWM
3.6 VIN , PWM
5.0 VIN , PWM
20
15
Switching Frequency (kHz)
Output Ripple (mVpp)
25
10
5
0
0
200
400
600
800
6.000
4.500
2.7 VIN, AUTO
3.6 VIN, AUTO
5.0 VIN, AUTO
2.7 VIN , PWM
3.6 VIN , PWM
5.0 VIN , PWM
3.000
1.500
0
1000
0
200
400
600
800
1000
Load Current (mA)
Load Current (mA)
Figure 16. Output Ripple vs. Load Current and
Input Voltage, FPWM, Dotted for Auto Mode
Figure 17. Frequency vs. Load Current and
Input Voltage, Auto Mode, Dotted for FPWM
Figure 18. Load Transient, 10−200−10 mA,
100 ns Edge
Figure 19. Load Transient, 200−800−200 mA,
100 ns Edge
Figure 20. Line Transient, 3.3−3.9−3.3 VIN,
10 ms Edge, 36 mA Load
Figure 21. Line Transient, 3.3−3.9−3.3 VIN,
10 ms Edge, 600 mA Load
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FAN53601, FAN53611
TYPICAL CHARACTERISTICS (continued)
Unless otherwise noted, VIN = VEN = 3.6 V, MODE = 0 V (AUTO Mode), VOUT = 1.82 V, and TA = 25°C.
Figure 22. Combined Line / Load Transient, 3.9−3.3 VIN,
10 ms Edge, 36−400 mA Load, 100 ns Edge
Figure 23. Combined Line / Load Transient, 3.3−3.9 VIN,
10 ms Edge, 400−36 mA Load, 100 ns Edge
Figure 24. Startup, 50 W Load
Figure 25. Startup, 3 W Load
Figure 27. Shutdown, No Load, Output Discharge
Enabled
Figure 26. Shutdown, 10 kW Load, No Output
Discharge
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FAN53601, FAN53611
TYPICAL CHARACTERISTICS (continued)
Unless otherwise noted, VIN = VEN = 3.6 V, MODE = 0 V (AUTO Mode), VOUT = 1.82 V, and TA = 25°C.
Figure 28. Over−Current, Load Increasing Past
Current Limit, FAN53601
Figure 29. 250 mW Fault, Rapid Fault,
Hiccup, FAN53601
Figure 30. Over−Current, Load Increasing
Past Current Limit, FAN53611
Figure 31. 250 mW Fault, Rapid Fault,
Hiccup, FAN53611
70
70
36 mA Load
600 mA Load
60
PSRR (dB)
PSRR (dB)
60
50
40
0.1
50
40
30
30
20
24 mA Load
500 mA Load
1
10
100
20
0.1
1000
1
10
100
1000
Frequency (kHz)
Frequency (kHz)
Figure 33. PSRR, 50 W and 3 W Load, VOUT = 1.23 V
Figure 32. PSRR, 50 W and 3 W Load
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FAN53601, FAN53611
OPERATION DESCRIPTION
The current−limit fault response protects the IC in the
event of an over−current condition present during soft−start.
As a result, the IC may fail to start if heavy load is applied
during startup and/or if excessive COUT is used.
The current required to charge COUT during soft−start
commonly referred to as “displacement current” is given as:
The FAN53601/11 is a 6 MHz, step−down switching
voltage regulator available in 600 mA or 1 A options that
delivers a fixed output from an input voltage supply of 2.3 V
to 5.5 V. Using a proprietary architecture with synchronous
rectification, the FAN53601/11 is capable of delivering a
peak efficiency of 92%, while maintaining efficiency over
80% at load currents as low as 1 mA.
The regulator operates at a nominal fixed frequency of
6 MHz, which reduces the value of the external components
to as low as 470 nH for the output inductor and 4.7 mF for the
output capacitor. In addition, the PWM modulator can be
synchronized to an external frequency source.
I DISP + C OUT @
dV
dt
(eq. 1)
dV
refers to the soft−start slew rate.
dt
To prevent shut down during soft−start, the following
condition must be met:
where
Control Scheme
I DISP ) I LOAD t I MAX(DC)
The FAN53601/11 uses a proprietary, non−linear,
fixed−frequency PWM modulator to deliver a fast load
transient response, while maintaining a constant switching
frequency over a wide range of operating conditions. The
regulator performance is independent of the output
capacitor ESR, allowing for the use of ceramic output
capacitors. Although this type of operation normally results
in a switching frequency that varies with input voltage and
load current, an internal frequency loop holds the switching
frequency constant over a large range of input voltages and
load currents.
For very light loads, the FAN53601/11 operates in
Discontinuous Current Mode (DCM) single−pulse PFM
Mode, which produces low output ripple compared with
other PFM architectures. Transition between PWM and
PFM is seamless, allowing for a smooth transition between
DCM and CCM.
Combined with exceptional transient response
characteristics, the very low quiescent current of the
controller maintains high efficiency; even at very light
loads; while preserving fast transient response for
applications requiring tight output regulation.
(eq. 2)
where IMAX(DC) is the maximum load current the IC is
guaranteed to support.
Startup into Large COUT
Multiple soft−start cycles are required for no−load startup
if COUT is greater than 15 mF. Large COUT requires light
initial load to ensure the FA N53601/11 starts appropriately.
The IC shuts down for 1.3 ms w hen IDISP exceeds ILIMIT for
more than 200 ms of current limit. The IC then begins a new
soft−start cycle. Since COUT retains its charge w hen the IC
is off, the IC reaches regulation after multiple soft−start
attempts.
MODE Pin
Logic 1 on this pin forces the IC to stay in PWM Mode.
A logic 0 allow s the IC to automatically sw itch to PFM
during light loads. If the MODE pin is toggled w ith a
frequency between 1.3 MHz and 1.7 MHz, the converter
synchronizes its sw itching frequency to four times the
frequency on the MODE pin.
The MODE pin is internally buffered w ith a Schmitt
trigger, which allows the MODE pin to be driven w ith slow
rise and fall times. An asymmetric duty cycle for frequency
synchronization is also permitted as long as the minimum
time below VIL(MAX) or above VIH(MAX) is 100 ns.
Enable and Soft−Start
When EN is LOW, all circuits are off and the IC draws
~250 nA of current. When EN is HIGH and VIN is above its
UVLO threshold, the regulator begins a soft−start cycle. The
output ramp during soft−start is a fixed slew rate of
50 mV/ms from Vout = 0 to 1 V, then 12.5 mV/ms until the
output reaches its setpoint. Regardless of the state of the
MODE pin, PFM Mode is enabled to prevent current from
being discharged from COUT if soft−start begins when COUT
is charged.
In addition, all voltage options can be ordered with a
feature that actively discharges FB to ground through a
230 W path when EN is LOW. Raising EN above its
threshold voltage activates the part and starts the soft−start
cycle. During soft−start, the internal reference is ramped
using an exponential RC shape to prevent overshoot of the
output voltage. Current limiting minimizes inrush during
soft−start.
Current Limit, Fault Shutdown, and Restart
A heavy load or short circuit on the output causes the
current in the inductor to increase until a maximum current
threshold is reached in the high−side sw itch. Upon reaching
this point, the high−side sw itch turns off, preventing high
currents from causing damage. The regulator continues to
limit the current cycle−by−cycle. After 16 cycles of current
limit, the regulator triggers an over−current fault, causing
the regulator to shut dow n for about 1.3 ms before
attempting a restart.
If the fault is caused by short circuit, the soft−start circuit
attempts to restart and produces an over−current fault after
about 200 ms, which results in a duty cycle of less than 15%,
limiting pow er dissipation.
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FAN53601, FAN53611
The closed−loop peak−current limit is not the same as the
open−loop tested current limit, ILIM(OL), in the Electrical
Characteristics table. This is primarily due to the effect of
propagation delays of the IC current limit comparator.
The calculation for switching frequency is given by:
f SW + min
where:
Under−Voltage Lockout (UVLO)
When EN is HIGH, the under−voltage lockout keeps the
part from operating until the input supply voltage rises high
enough to properly operate. This ensures no misbehavior of
the regulator during startup or shutdown.
tOFF(MIN) is 40 ns. This imposes constraints on the
V
maximum OUT that the FAN53601/11 can provide or the
V IN
maximum output voltage it can provide at low VIN while
maintaining a fixed switching frequency in PWM Mode.
When VIN is LOW, fixed switching is maintained as long as:
V OUT
v * t OFF(MIN) @ f SW [ 0.7.
V IN
The switching frequency drops when the regulator cannot
provide sufficient duty cycle at 6 MHz to maintain
regulation. This occurs when VOUT is 1.82 V and VIN is
below 2.7 V at high load currents (see Figure 34).
Switching Frequency (kHz)
7.500
6.000
4.500
3.000
1.500
400
600
800
V OUT ) I OUT @ R OFF
V IN * I OUT @ R ON * V OUT
where:
ROFF = RDSON_N + DCRL
RON = RDSON_P + DCRL
Minimum Off−Time Effect on Switching Frequency
200
Ǔ
(eq. 3)
Ǔ
(eq. 4)
When the die temperature increases, due to a high load
condition and/or a high ambient temperature; the output
switching is disabled until the die temperature falls
sufficiently. The junction temperature at which the thermal
shutdown activates is nominally 150°C with a 15°C
hysteresis.
0
1
, 6 MHz
t SW(MAX)
t SW(MAX) + 40 ns @ 1 )
Thermal Shutdown (TSD)
0
ǒ
ǒ
1000
Load Current (mA)
Figure 34. Frequency vs. Load Current to
Demonstrate tOFFMIN Effect, VIN = 2.3 V and 2.7 V,
VOUT = 1.82 V, Auto Mode, FPWM Dotted
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12
FAN53601, FAN53611
APPLICATIONS INFORMATION
Selecting the Inductor
The increased RMS current produces higher losses
through the RDS(ON) of the IC MOSFETs, as well as the
inductor DCR.
Increasing the inductor value produces lower RMS
currents, but degrades transient response. For a given
physical inductor size, increased inductance usually results
in an inductor with lower saturation current and higher DCR.
Table 1 shows the effects of inductance higher or lower
than the recommended 1 mH on regulator performance.
The output inductor must meet both the required
inductance and the energy−handling capability of the
application. The inductor value affects average current limit,
the PWM−to−PFM transition point, output voltage ripple,
and efficiency.
The ripple current (DI) of the regulator is:
DI [
V OUT
V IN
@
ǒ
V IN * V OUT
L @ f SW
Ǔ
(eq. 5)
Output Capacitor
The maximum average load current, IMAX(LOAD), is
related to the peak current limit, ILIM(PK), by the ripple
current, given by:
I MAX(LOAD) + I LIM(PK) *
DI
2
Table 2 suggests 0402 capacitors. 0603 capacitors may
further improve performance in that the effective
capacitance is higher. This improves transient response and
output ripple.
Increasing COUT has no effect on loop stability and can
therefore be increased to reduce output voltage ripple or to
improve transient response. Output voltage ripple, DVOUT,
is:
(eq. 6)
The transition between PFM and PWM operation is
determined by the point at which the inductor valley current
crosses zero. The regulator DC current when the inductor
current crosses zero, IDCM, is:
I DCM +
DI
2
DV OUT + DI L
ǸI
OUT(DC)
f SW @ C OUT @ ESR 2
2 @ D @ (1 * D)
(eq. 7)
2
)
DI 2
12
)
1
8 @ f SW @ C OUT
ƫ
(eq. 9)
The FAN53601/11 is optimized for operation with
L = 470 nH, but is stable with inductances up to 1 mH
(nominal). The inductor should be rated to maintain at least
80% of its value at ILIM(PK).
Efficiency is affected by the inductor DCR and inductance
value. Decreasing the inductor value for a given physical
size typically decreases the DCR; but because DI increases,
the RMS current increases, as do the core and skin effect
losses.
I RMS +
ƪ
Input Capacitor
The 2.2 mF ceramic input capacitor should be placed as
close as possible between the VIN pin and GND to minimize
the parasitic inductance. If a long wire is used to bring power
to the IC, additional “bulk” capacitance (electrolytic or
tantalum) should be placed between CIN and the power
source lead to reduce the ringing that can occur between the
inductance of the power source leads and CIN.
The effective capacitance value decreases as VIN
increases due to DC bias effects.
(eq. 8)
Table 1. EFFECTS OF CHANGES IN INDUCTOR VALUE (FROM 470 nH RECOMMENDED VALUE) ON REGULATOR
PERFORMANCE
Inductor Value
IMAX(LOAD)
DVOUT
Transient Response
Increase
Increase
Decrease
Degraded
Decrease
Decrease
Increase
Improved
Table 2. RECOMMENDED PASSIVE COMPONENTS AND THEIR VARIATION DUE TO DC BIAS
Component
Description
Vendor
Min
Typ
Max
L1
470 nH,
2012, 90 mW,
1.1 A
Murata LQM21PNR47MC0
Murata LQM21PNR54MG0
Hitachi Metals HLSI 201210R47
300 nH
470 nH
520 nH
CIN
2.2 mF, 6.3 V,
X5R, 0402
Murata or Equivalent GRM155R60J225ME15
GRM188R60J225KE19D
1.0 mF
2.2 mF
−
COUT
4.7 mF, X5R,
0402
Murata or Equivalent GRM155R60G475M
GRM155R60E475ME760
1.6 mF
4.7 mF
−
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13
FAN53601, FAN53611
PCB Layout Guidelines
IC do not behave erratically due to excessive noise. This
reduces switching cycle jitter and ensures good overall
performance. It is important to place the common GND of
CIN and COUT as close as possible to the C2 terminal. There
is some flexibility in moving the inductor further away from
the IC; in that case, VOUT should be considered at the COUT
terminal.
There are only three external components: the inductor
and the input and output capacitors. For any buck switcher
IC, including the FAN53601/11, it is important to place a
low−ESR input capacitor very close to the IC, as shown in
Figure 35. The input capacitor ensures good input
decoupling, which helps reduce noise appearing at the
output terminals and ensures that the control sections of the
Figure 35. PCB Layout Guidance
The following information applies to the WLCSP
package dimensions on the next page:
PRODUCT−SPECIFIC DIMENSIONS
D
E
X
Y
1.160 ±0.030
0.860 ±0.030
0.230
0.180
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MECHANICAL CASE OUTLINE
PACKAGE DIMENSIONS
WLCSP6 1.16x0.86x0.586
CASE 567QE
ISSUE O
DOCUMENT NUMBER:
DESCRIPTION:
98AON13324G
WLCSP6 1.16x0.86x0.586
DATE 31 OCT 2016
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Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.
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are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.
ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding
the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically
disclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor the
rights of others.
© Semiconductor Components Industries, LLC, 2019
www.onsemi.com
MECHANICAL CASE OUTLINE
PACKAGE DIMENSIONS
WLCSP6 1.16x0.86x0.586
CASE 567RQ
ISSUE A
DOCUMENT NUMBER:
DESCRIPTION:
98AON16583G
WLCSP6 1.16x0.86x0.586
DATE 12 JAN 2018
Electronic versions are uncontrolled except when accessed directly from the Document Repository.
Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.
PAGE 1 OF 1
ON Semiconductor and
are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.
ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding
the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically
disclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor the
rights of others.
© Semiconductor Components Industries, LLC, 2019
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