Fairchild FAN48630UC45X 2.5 mhz, 1500 ma, synchronous tinyboostâ ¢ regulator with bypass mode Datasheet

FAN48630 — 2.5 MHz, 1500 mA, Synchronous TinyBoost™
Regulator with Bypass Mode
Features
Description

Few External Components: 0.47 µH Inductor and
0603 Case Size Input and Output Capacitors



Input Voltage Range: 2.35 V to 5.5 V
The FAN48630 allows systems to take advantage of new
battery chemistries that can supply significant energy when
the battery voltage is lower than the required voltage for
system power ICs. By combining built-in power transistors,
synchronous rectification, and low supply current; this IC
provides a compact solution for systems using advanced
Li-Ion battery chemistries.









Up to 96% Efficient
Fixed Output Voltage Options: 3.0 V to 5.0 V
Maximum Continuous Load Current: 1500 mA
at VIN of 2.6 V Boosting VOUT to 3.5 V
The FAN48630 is a boost regulator designed to provide a
minimum output voltage (VOUT(MIN)) from a single-cell Li-Ion
battery, even when the battery voltage is below system
minimum. Output voltage regulation is guaranteed to a
maximum load current of 1500 mA. Quiescent current in
Shutdown Mode is less than 3 µA, which maximizes battery
life. The regulator transitions smoothly between Bypass and
normal Boost Mode. The device can be forced into Bypass
Mode to reduce quiescent current.
True Bypass Operation when VIN > Target VOUT
Internal Synchronous Rectifier
Soft-Start with True Load Disconnect
Forced Bypass Mode
VSEL Control to Optimize Target VOUT
The FAN48630 is available in a 16-bump, 0.4 mm pitch,
Wafer-Level Chip-Scale Package (WLCSP).
Short-Circuit Protection
Low Operating Quiescent Current
16-Bump, 0.4 mm Pitch WLCSP
L1
Applications

Boost for Low-Voltage Li-ion Batteries, Brownout
Prevention, Boosted Audio, USB OTG, and LTE / 3G
RF Power

Cell Phones, Smart Phones, Portable Instruments
Figure 1. Typical Application
Ordering Information
Part Number
Output Voltage(1)
VSEL0 / VSEL1
SoftStart
Forced
Bypass
FAN48630UC315X
3.15 / 3.33
FAST
Low IQ
FAN48630UC33X
3.30 / 3.49
FAST
Low IQ
FAN48630UC35X
3.50 / 3.70
FAST
Low IQ
FAN48630UC37AX
3.70 / 3.77
FAST
Low IQ
FAN48630UC45X
4.50 / 4.76
SLOW
OCP On
FAN48630UC50X
5.00 / 5.29
SLOW
OCP On
Operating
Temperature
Package(2)
Packing
-40°C to 85°C
16-Ball, 4x4 Array,
0.4 mm Pitch,
250 µm Ball,
Wafer-Level ChipScale Package
(WLCSP)
Tape and Reel
Notes:
1. Other output voltages are available on request. Please contact a Fairchild Semiconductor representative.
2. Includes backside laminate.
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
November 2012
Q3B Q3A
VIN
CIN
Q3
L1
BYPASS
CONTROL
Q1B
Q1A
SW
VOUT
Q2
GND
Q1
COUT
Synchronous
Rectifier
Control
VSEL
EN
BYP
MODULATOR
LOGIC
AND CONTROL
PG
Figure 2. Block Diagram
Table 1.
Recommended Components
Component
Description
Vendor
Parameter
Typ.
Unit
0.47
µH
0.47 µH, 30%
Toko: DFE201612C
DFR201612C
Cyntec: PIFE20161B
L
L1
DCR (Series R)
40
m
CIN
4.7 µF, 10%, 6.3 V, X5R,
0603
Murata: GRM188R60J475K
TDK: C1608X5R0J475K
C
4.7
µF
COUT
2 x 10 µF, 20%, 10 V, X5R,
0603
TDK: C1608X5R1A106M
C
20
µF
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
2
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Block Diagram
EN
PG
A1
A2
VSEL AGND
B1
VIN
VOUT
B2
B3
C2
C3
AGND
D1
B4
SW
BYP
C1
A4
A3
C4
PGND
D2
D3
D4
Figure 3. Top Through View (Bumps Down)
Figure 4. Bottom View (Bumps Up)
Pin Definitions
Pin #
Name
Description
A1
EN
Enable. When this pin is HIGH, the circuit is enabled.
A2
PG
Power Good. This is an open-drain output. PG is actively pulled LOW if output falls out of
regulation due to overload or if thermal protection threshold is exceeded.
A3–A4
VIN
Input Voltage. Connect to Li-Ion battery input power source.
B1
VSEL
Output Voltage Select. When boost is running, this pin can be used to select output voltage.
B2, C2
D1
AGND
Analog Ground. This is the signal ground reference for the IC. All voltage levels are measured
with respect to this pin.
B3–B4
VOUT
Output Voltage. Place COUT as close as possible to the device.
C1
BYP
Bypass. This pin can be used to activate Forced Bypass Mode. When this pin is LOW, the
bypass switches (Q3 and Q1) are turned on and the IC is otherwise inactive.
C3–C4
SW
Switching Node. Connect to inductor.
D2–D4
PGND
Power Ground. This is the power return for the IC. The COUT bypass capacitor should be
returned with the shortest path possible to these pins.
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
3
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Pin Configuration
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
VIN
VOUT
Parameter
VIN Input Voltage
Min.
Max.
Unit
-0.3
6.5
V
6.0
V
8.0
V
VOUT Output Voltage
SW Node
DC
-0.3
Transient: 10 ns, 3 MHz
Other Pins
-1.0
8.0
V
-0.3
6.5(3)
V
Human Body Model per JESD22-A114
3.0
kV
ESD
Electrostatic Discharge
Protection Level
TJ
Junction Temperature
–40
+150
°C
TSTG
Storage Temperature
–65
+150
°C
+260
°C
TL
Charged Device Model per JESD22-C101
1.5
Lead Soldering Temperature, 10 Seconds
kV
Note:
3. Lesser of 6.5 V or VIN + 0.3 V.
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
VIN
IOUT
Parameter
Supply Voltage
Output Current
Min.
Max.
Unit
2.35
5.50
V
0
1500
mA
TA
Ambient Temperature
–40
+85
°C
TJ
Junction Temperature
–40
+125
°C
Thermal Properties
Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer
Fairchild evaluation boards (1 oz copper on all layers). Special attention must be paid not to exceed junction temperature TJ(max) at
a given ambient temperate TA.
Symbol
Parameter
Typical
JA
Junction-to-Ambient Thermal Resistance
80
JB
Junction-to-Board Thermal Resistance
42
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
Unit
°C/W
www.fairchildsemi.com
4
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Absolute Maximum Ratings
Recommended operating conditions, unless otherwise noted, circuit per Figure 1, VIN = 2.35 V to VOUT, TA = -40˚C to 85˚C.
Typical values are given VIN = 3.0 V and TA = 25˚C.
Symbol
IQ
Parameter
VIN Quiescent Current
Conditions
Typ.
Max.
Bypass Mode VOUT=3.5 V, VIN=4.2 V
140
190
A
Boost Mode VOUT=3.5 V, VIN=2.5 V
150
250
A
Shutdown: EN=0, VIN=3.0 V
1.5
5.0
A
Low IQ
4
10
A
OCP On
45
90
A
Forced Bypass Mode
VOUT=3.5 V, VIN=3.5 V
ILK
ILK_OUT
VUVLO
VUVLO_HYS
Min.
Unit
VOUT to VIN Reverse Leakage
VOUT=5 V, EN=0
0.2
1.0
A
VOUT Leakage Current
VOUT=0, EN=0, VIN=4.2 V
0.1
1.0
A
Under-Voltage Lockout
VIN Rising
2.20
2.35
Under-Voltage Lockout Hysteresis
200
V
mV
VPG(OL)
PG Low
IPG=5 mA
0.4
V
IPG_LK
PG Leakage Current
VPG=5 V
1
µA
VIH
Logic Level HIGH EN, VSEL, BYP
VIL
Logic Level LOW EN, VSEL, BYP
1.2
V
0.4
V
Logic Control Pin Pull Downs
(LOW Active)
BYP, VSEL, EN
300
k
Weak Current Source Pull-Down
BYP, VSEL, EN
100
nA
VREG
Output Voltage Accuracy
Referred to GND, DC, VOUT-VIN >
100 mV
VTRSP
Load Transient Response
500 – 1250 mA, VIN=3.6 V, VOUT=5.0 V
±4
%
tON
On-Time
VIN=3.0 V, VOUT=3.5 V, Load >1000 mA
80
ns
fSW
Switching Frequency
VIN=3.6 V, VOUT=5.0 V, Load=1000 mA
2.0
2.5
3.0
MHz
Boost Valley Current Limit
VIN=2.6 V
2.6
2.9
3.1
A
Boost Valley Current Limit During
SS
VIN=2.6 V
1.6
A
VOUT=5.0 V, TJ < 120˚C
3.0
V
VOUT=4.5 V, TJ < 120˚C
2.8
V
VOUT=3.5 V, TJ < 120˚C
2.35
V
VOUT=3.15 V, TJ < 120˚C
2.35
V
RLOW
IPD
IV_LIM
IV_LIM_SS
VMIN_1.5A
Minimum VIN for 1500 mA Load
(Short Term)
350
mA
800
mA
Slow
700
mA
Fast
1600
mA
Slow, 50  Load
1300
s
Fast, 50  Load
600
s
VIN=5.0 V, VIN-VOUT
200
mV
Soft-Start Input Peak Current Limit
Soft-Start EN HIGH to Regulation
%
Slow
LIN2
tSS
4
Fast
LIN1
ISS_PK
–2
VOCP
OCP Comparator Threshold
VOVP
Output Over-Voltage Protection
Threshold
6.0
VOVP_HYS
Output Over-Voltage Protection
Hysteresis
300
6.3
V
mV
Continued on the following page…
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
5
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Electrical Specifications
Recommended operating conditions, unless otherwise noted, circuit per Figure 1, VIN = 2.35 V to VOUT, TA = -40˚C to 85˚C.
Typical values are given VIN = 3.0 V and TA = 25˚C.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
RDS(ON)N
N-Channel Boost Switch RDS(ON)
VIN=3.5 V, VOUT=3.5 V
85
120
mΩ
RDS(ON)P
P-Channel Sync Rectifier RDS(ON)
VIN=3.5 V, VOUT=3.5 V
65
85
mΩ
65
85
mΩ
RDS(ON)P_BYP P-Channel Bypass Switch RDS(ON)
VIN=3.5 V, VOUT=3.5 V
T120A
T120 Activation Threshold
120
°C
T120R
T120 Release Threshold
100
°C
T150T
T150 Threshold
150
°C
T150H
T150 Hysteresis
20
°C
tRST
FAULT Restart Timer
20
ms
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
6
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Electrical Specifications (Continued)
Unless otherwise specified; VIN = 3.6 V, and VOUT = 5 V, and TA = 25°C; circuit and components according to Figure 1.
100%
96%
94%
96%
92%
Efficiency
Efficiency
92%
88%
2.5 VIN
3.0 VIN
84%
90%
88%
86%
84%
- 40C
3.3 VIN
82%
4.2 VIN
+25C
+85C
80%
80%
0
250
500
750
1000
1250
0
1500
250
500
750
1000
1250
1500
Load Current (mA)
Load Current (mA)
Figure 5. Efficiency vs. Load Current and Input Voltage,
VOUT=3.5 V
Figure 6. Efficiency vs. Load Current and Temperature,
VIN=3.0V, VOUT=3.5 V
96%
96%
92%
92%
Efficiency
Efficiency
88%
84%
88%
84%
80%
2.5 VIN
- 40C
80%
3.0 VIN
76%
3.6 VIN
+25C
4.2 VIN
72%
0
250
500
750
1000
1250
+85C
76%
1500
0
250
Load Current (mA)
500
750
1000
1250
1500
Load Current (mA)
Figure 7. Efficiency vs. Load Current and Input Voltage
Figure 8. Efficiency vs. Load Current and Temperature
100%
100%
96%
96%
Efficiency
Efficiency
92%
92%
88%
88%
84%
5.0 VOUT
5.0 VOUT
84%
4.5 VOUT
4.5 VOUT
80%
3.5 VOUT
3.5 VOUT
3.15 VOUT
3.15 VOUT
80%
2.0
2.5
3.0
3.5
4.0
76%
4.5
2.0
Input Voltage (V)
2.5
3.0
3.5
4.0
4.5
Input Voltage (V)
Figure 9. Efficiency vs. Input Voltage and Output Voltage, Figure 10. Efficiency vs. Input Voltage and Output Voltage,
200 mA Load
1000 mA Load
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
7
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Typical Characteristics
3
3
2
2
Output Regulation (%)
Output Regulation (%)
Unless otherwise specified; VIN = 3.6 V, VOUT = 5 V, and TA = 25°C; circuit and components according to Figure 1.
1
0
2.5 VIN
3.0 VIN
-1
1
0
- 40C
-1
3.6 VIN
+25C
4.2 VIN
-2
+85C
-2
0
250
500
750
1000
1250
1500
0
250
Load Current (mA)
1250
1500
- 40C Auto
+25C Auto
+85C Auto
- 40C Bypass
+25C Bypass
+85C Bypass
200
Input Current (A)
Input Current (A)
250
150
100
50
150
100
50
0
0
2.0
2.5
3.0
3.5
4.0
4.5
2.0
2.5
Input Voltage (V)
3.0
3.5
4.0
Figure 14. Quiescent Current vs. Input Voltage,
Temperature and Mode, VOUT=3.5 V, Forced Bypass, Low IQ
3,000
50
2,500
Switching Frequency (KHz)
60
40
30
20
2.5 VIN
3.0 VIN
10
3.6 VIN
2,000
1,500
1,000
2.5 VIN
3.0 VIN
500
3.6 VIN
4.2 VIN
0
0
250
500
750
1000
1250
4.2 VIN
0
1500
0
Load Current (mA)
250
500
750
1000
1250
1500
Load Current (mA)
Figure 15. Output Ripple vs. Load Current and Input
Voltage
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
4.5
Input Voltage (V)
Figure 13. Quiescent Current vs. Input Voltage,
Temperature and Mode, VOUT=5.0 V, Forced Bypass,
OCP Active
Output Ripple (mVpp)
1000
Figure 12. Output Regulation vs. Load Current and
Temperature (Normalized to 3.6 VIN, 500 mA Load,
TA=25°C)
- 40C Auto
+25C Auto
+85C Auto
- 40C Bypass
+25C Bypass
+85C Bypass
200
750
Load Current (mA)
Figure 11. Output Regulation vs. Load Current and Input
Voltage (Normalized to 3.6 VIN, 500 mA Load)
250
500
Figure 16. Frequency vs. Load Current and Input Voltage
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8
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Typical Characteristics (Continued)
Unless otherwise specified, VIN = 3.6 V; VOUT = 5 V, and TA = 25°C; circuit and components according to Figure 1.
Figure 17. Startup, 50 Ω Load
Figure 18. Startup, 50  Load, VIN=2.5 V, VOUT=3.5 V
Figure 19. Overload Protection
Figure 20. Load Transient, 100-500 mA, 100 ns Edge
Figure 21. Load Transient, 500-1250 mA, 100 ns Edge
Figure 22. Load Transient, 100-500 mA, 100 ns Edge,
VIN=3 V, VOUT=3.5 V
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
9
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Typical Characteristics (Continued)
Unless otherwise specified, VIN = 3.6 V, VOUT = 5 V, TA = 25°C; circuit and components according to Figure 1.
Figure 23. Load Transient, 500-1950 mA, 100 ns Edge,
VIN=3 V, VOUT=3.5 V
Figure. 24 Line Transient, 3.0-3.6 VIN, 10 µs Edge,
500 mA Load, VOUT=3.15 V
Figure 25. Line Transient, 3.0-3.6 VIN, 10 µs Edge,
1,000 mA Load, VOUT=3.5 V
Figure 26. Line Transient, 3.3-3.9 VIN, 10 µs Edge,
500 mA load, VOUT=3.5 V
Figure. 27 Bypass Entry / Exit, Slow VIN Ramp 1 ms Edge,
500 mA Load, VOUT=3.5 V, 3.2 - 3.8 VIN
Figure 28. VSEL Step, VIN=3 V, VOUT=3.5 V, 500 mA Load
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
10
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Typical Characteristics (Continued)
FAN48630 is a synchronous boost regulator, typically
operating at 2.5 MHz in Continuous Conduction Mode (CCM),
which occurs at moderate to heavy load current and low VIN
voltages. The regulator includes a Bypass Mode that activates
when VIN is above the boost regulator’s setpoint.
In LIN2 Mode, the current source is incremented to 2A. If VOUT
fails to reach VIN-300 mV after 1024 s, a fault condition is
declared.
SS State
Upon the successful completion of the LIN state (VOUT>VIN300 mV), the regulator begins switching with boost pulses
current limited to 50% of nominal level.
In anticipation of a heavy load transition, the setpoint can be
adjusted upward by fixed amounts with the VSEL pin to
reduce the required system headroom during lighter-load
operation to save power.
During SS state, VOUT is ramped up by stepping the internal
reference. If VOUT fails to reach regulation during the SS ramp
sequence for more than 64 µs, a fault condition is declared. If
large COUT is used, the reference is automatically stepped
slower to avoid excessive input current draw.
Table 2. Operating States
Mode
Description
Invoked When
LIN
Linear Startup
VIN > VOUT
SS
Boost Soft-Start
VOUT < VOUT(MIN)
This is a normal operating state of the regulator.
BST
Boost Operating Mode
VOUT = VOUT(MIN)
BPS State
BPS
True Bypass Mode
VIN > VOUT(MIN)
BST State
If VIN is above VREG when the SS Mode successfully
completes, the device transitions directly to BPS Mode.
Boost Mode
FAST and SLOW Soft-Start Options
The FAN48630 uses a current-mode modulator to achieve
excellent transient response and smooth transitions between
CCM and Discontinuous Conduction Mode (DCM) operation.
During CCM operation, the device maintains a switching
frequency of about 2.5 Mhz. In light-load operation (DCM),
frequency is reduced to maintain high efficiency.
FAN48630UC315X, FAN48630UC33X, FAN48630UC35X,
and FAN48630UC37AX feature fast startup with EN to
regulation time of 500 µs. LIN1 and LIN2 phase currents are
doubled compared to SLOW options, SS phase is also faster.
Table 3.
FAN48630UC45X and FAN48630UC50XS feature low startup
with EN to regulation time of 1300 s to reduce inrush current.
Boost Startup Sequence
Start
State
Entry
Exit
End
State
LIN1
VIN > UVLO,
EN=1
VOUT > VIN300 mV
SS
LIN2
LIN2
SS
LIN1 Exit
LIN1 or
LIN2 Exit
VOUT > VIN300 mV
SS
TIMEOUT
FAULT
VOUT=VOUT(MIN)
BST
OVERLOAD
TIMEOUT
FAULT
FAULT State
Timeout
(µs)
The regulator enters the FAULT state under any of the
following conditions:

VOUT fails to achieve the voltage required to advance from
LIN state to SS state.
512

VOUT fails to achieve the voltage required to advance from
SS state to BST state.
1024


Boost current limit triggers for 2 ms during the BST state.
VDS protection threshold is exceeded during BPS state.
Once a fault is triggered, the regulator stops switching and
presents a high-impedance path between VIN and VOUT. After
waiting 20 ms, a restart is attempted.
64
Power Good
Shutdown and Startup
Power good is 0 FAULT, 1 POWER GOOD, open-drain input.
The Power good pin is provided for signaling the system when
the regulator has successfully completed soft-start and no
faults have occurred. Power good also functions as an early
warning flag for high die temperature and overload conditions.
If EN is LOW, all bias circuits are off and the regulator is in
Shutdown Mode. During shutdown, current flow is prevented
from VIN to VOUT, as well as reverse flow from VOUT to VIN.
During startup, it is recommended to keep DC current draw
below 500 mA.

PG is released HIGH when the soft-start sequence is
successfully completed.
When EN is HIGH and VIN > UVLO, the regulator attempts to
bring VOUT within 300 mV of VIN using the internal fixed current
source from VIN (Q3). The current is limited to LIN1 set point.

PG is pulled LOW when PMOS current limit has triggered
for 64 µs OR the die the temperature exceeds 120°C. PG
is re-asserted when the device cools below to 100°C.
If VOUT reaches VIN-300 mV during LIN1 Mode, the SS state is
initiated. Otherwise, LIN1 times out after 512 s and LIN2
Mode is entered.

Any FAULT condition causes PG to be de-asserted.
LIN State
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
11
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Circuit Description
The regulator shuts down when the die temperature exceeds
150°C. Restart occurs when the IC has cooled by
approximately 20°C.
Bypass Operation
OCP in Forced Bypass Mode is available for
FAN48630UC45X and FAN48630UC50X. During Forced
Bypass Mode, the device is short-circuit protected by a
voltage comparator tracking the voltage drop from VIN to
VOUT. If the drop exceeds 200 mV, a FAULT is declared. The
over-temperature protection is also active.
In normal operation, the device automatically transitions from
Boost Mode to Bypass Mode, if VIN goes above target VOUT. In
Bypass Mode, the device fully enhances both Q1 and Q3 to
provide a very low impedance path from VIN to VOUT. Entry
to the Bypass Mode is triggered by condition where VIN > VOUT
and no switching has occurred during past 5 µs. To soften the
entry to Bypass Mode, Q3 is driven as a linear current source
for the first 5 µs. Bypass Mode exit is triggered when VOUT
reaches the target VOUT voltage. During Automatic Bypass
Mode, the device is short-circuit protected by voltage
comparator tracking the voltage drop from VIN to VOUT; if the
drop exceeds 200 mV, FAULT is declared.
In Forced Bypass Mode, VOUT can follow VIN below VOUT(MIN).
VSEL
VSEL can be asserted in anticipation of a positive load
transient. Raising VSEL increases VOUT(MIN) by a fixed amount
and VOUT is stepped to the corresponding target output voltage
in 20 µs. The functionality can also be utilized to mitigate
undershoot during severe line transients, while minimizing
VOUT during more benign operating conditions to save power.
Forced Bypass
Entry to Forced Bypass Mode initiates with a current limit on
Q3 and then proceeds to a true bypass state. To prevent
reverse current to the battery, the device waits until output
discharges below VIN before entering Forced Bypass Mode.
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
12
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Low-IQ
Forced
Bypass
Mode
is
available
for
FAN48630UC315X, FAN48630UC33X, FAN48630UC35X,
and FAN48630UC37AX. After the transition is complete, most
of the internal circuitry is disabled to minimize quiescent
current draw. Short-circuit, UVLO, output OVP and overtemperature protections are inactive in Forced Bypass Mode.
Over-Temperature
Output Capacitance (COUT)
VRIPPLE ( P  P )  tON 
Stability
The effective capacitance (CEFF) of small, high-value, ceramic
capacitors decreases as bias voltage increases.
FAN48630 is guaranteed for stable operation with the
minimum value of CEFF (CEFF(MIN)) outlined in Table 4 below.
and
Table 4.
therefore:
VOUT (V)
ILOAD (mA)
CEFF(MIN)
(F)
3.15
0 to 1500
12
3.5
0 to 1500
9
4.5 and 5
0 to 1500
6
EQ. 1

V
tON  t SW  D  t SW  1  IN
 VOUT
Minimum CEFF Required for Stability
Operating Conditions
I LOAD
COUT

V
VRIPPLE ( P  P )  t SW  1  IN
 VOUT



EQ. 2
 I LOAD
 
 COUT
EQ. 3
and
t SW 
CEFF varies with manufacturer, material, and case size.
1
EQ. 4
f SW
As can be seen from EQ. 3, the maximum VRIPPLE occurs
when VIN is minimum and ILOAD is maximum.
Inductor selection
Recommended nominal inductance value is 0.47 H.
Layout Recommendations
FAN48630 employs valley-current limiting; peak inductor
current can reach 3.8 A for a short duration during overload
conditions. Saturation effects cause the inductor current ripple
to become higher under high loading as only valley of the
inductor current ripple is controlled.
The layout recommendations below highlight various topcopper pours using different colors.
To minimize spikes at VOUT, COUT must be placed as close as
possible to PGND and VOUT, as shown in Figure 29.
For FAN48630UC315X and FAN48630UC33X, a 0.33 H
inductor can be used for improved transient performance.
For thermal reasons, it is suggested to maximize the pour
area for all planes other than SW. Especially the ground pour
should be set to fill all available PCB surface area and tied to
internal layers with a cluster of thermal vias.
Startup
Input current limiting is in effect during soft-start, which limits
the current available to charge COUT and any additional
capacitance on the VOUT line. If the output fails to achieve
regulation within the limits described in the Startup section, a
FAULT occurs, causing the circuit to shut down then restart
after a significant time period. If the total combined output
capacitance is very high, the circuit may not start on the first
attempt, but eventually achieves regulation if no load is
present. If a high-current load and high capacitance are both
present during soft-start, the circuit may fail to achieve
regulation and continually attempts soft-start, only to have
the output capacitance discharged by the load when in a
FAULT state.
VIN
VOUT
SW
Output Voltage Ripple
Output voltage ripple is inversely proportional to COUT. During
tON, when the boost switch is on, all load current is supplied by
COUT. Output ripple is calculated as:
GND
Figure 29. Layout Recommendation
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
13
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Application Information
0.03 C
2X
E
F
A
B
0.40
A1
BALL A1
INDEX AREA
(Ø0.20)
Cu Pad
D
0.40
(Ø0.30) Solder
Mask Opening
0.03 C
2X
RECOMMENDED LAND PATTERN
(NSMD PAD TYPE)
TOP VIEW
0.06 C
0.625
0.547
0.05 C
C
SEATING
PLANE
0.378±0.018
0.208±0.021
E
SIDE VIEWS
D
NOTES:
A. NO JEDEC REGISTRATION APPLIES.
0.005
B. DIMENSIONS ARE IN MILLIMETERS.
C A B
Ø0.260±0.02
16X
0.40
D
C
B
0.40
C. DIMENSIONS AND TOLERANCE
PER ASME Y14.5M, 1994.
D. DATUM C IS DEFINED BY THE SPHERICAL
CROWNS OF THE BALLS.
(Y) ±0.018
A
E. PACKAGE NOMINAL HEIGHT IS 586 MICRONS
±39 MICRONS (547-625 MICRONS).
F
1 2 3 4
(X) ±0.018
F. FOR DIMENSIONS D, E, X, AND Y SEE
PRODUCT DATASHEET.
BOTTOM VIEW
G. DRAWING FILNAME: MKT-UC016AArev2.
Figure 30. 16-Ball, 4x4 Array, 0.4 mm Pitch, 250 µm Ball, Wafer-Level Chip-Scale Package (WLCSP)
Product-Specific Dimensions
Product
D
E
X
Y
FAN48630UCX
1.780 ±0.030
1.780 ±0.030
0.290
0.290
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without
notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most
recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which
covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
14
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
Physical Dimensions
FAN48630 — 2.5MHz, 1500mA Synchronous TinyBoost™ Regulator with Bypass Mode
© 2011 Fairchild Semiconductor Corporation
FAN48630 • Rev. 1.0.1
www.fairchildsemi.com
15
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