© 2013 Sem ic o nduc t or C om ponent s I ndus t ries , LLC Publication Order Num ber:
October-2017,Rev. 2 FAN48623/D
FAN48623 — 2500 mA Synchronous TinyBoost® Regulator with Bypass M ode
FAN48623 — 2500 mA, Synchronous TinyBoost®
Regulator with Bypass Mode
Features
Max imum Continuous Load Cur rent: 2500 mA
at V IN of 2.5 V Boosting VOUT to 3.3 V
Maximum Pulse Load Current of 3.5 A f or GSM PAs
(1 Slot) and PMIC support simul taneously, VIN=3.1 V,
VOUT=3.4 V
Up to 97% Effic ient
4 External Components: 2520 case 0.47 µH Inductor
and 0603 Cas e Size Input and Output Capacitors
Input V oltage Range: 2.5 V to 5.5 V
Fixed Output Voltage Options: 3.0 V to 5.0 V
True Bypass Operation when VIN > Target V OUT
Integrated Sync hronous Rec tif ier
True Load Disc onnect
Forced Bypass Mode
VSEL Control to Optimize Target VOUT
Short-Circuit Protection (SCP)
Low Operating Quiescent Current
16-Bump, 1.81 mm x 1.81 mm, 0.4 mm Pitch, WLCSP
Applications
Boost for Low -Voltage Li-ion Batteries, Brownout
Prevention, Sys tem PMIC LDOs Supplies, and
2G/3G/4G RF PA Supplies
Smart Phones, Tablets, Portable Devices
Description
The FAN48623 allows systems to take advantage of new
battery chemistries that can supply significant energy w hen
the battery voltage is lower than the required voltage for
system pow er ICs. By combining built-in pow er transistors,
synchronous rectification, and low supply current, this IC
provides a compact solution for systems using advanced Li-
Ion battery chemistries.
The FAN48623 is a boost regulator designed to provide a
minimum output voltage from a single-cell Li-Ion battery,
even w hen the battery voltage is below system minimum.
The output voltage regulation is guaranteed up to a
maximum load current of 2500 mA. The regulator transitions
smoothly betw een Bypass and normal Boost Mode. The
device can be forced into Bypas s Mode to reduc e quiesc ent
current.
The FAN48623 is available in a 16-bump, 0.4 mm pitch,
Wafer-Lev el Chip-Scale Package (WLCSP).
Fi gure 1. Typical Application
Ordering Information
Part Number
Output
Voltage(1)
VSEL0 / VSEL1
Operating
Temperature
Package Packing
Device
Marking
FAN48623UC315X
3.150 / 3.330
-40°C to 85°C 16-Ball, 4x4 Array, 0.4 mm Pitch, 250 µm Ball,
Wafer-Lev el Chip-Scale Package (WLCSP) Tape &
Reel
JK
FAN48623UC32JX
3.20 / 3.413
JD
FAN48623UC33X
3.300 / 3.489
JE
FAN48623UC35X
3.5 / 3.7
JF
FAN48623UC36FX
3.64/ 3.709
JG
FAN48623UC50X
5.000 / 5.286
JL
FAN48623UC50GX
5.000 / 5.190
JM
Note:
1. Other output voltages are availabl e on request. Please contact a ON Semiconductor Semiconductor representative.
FAN48623
VOUT
PGND
C
OUT
L1
PG
0.47µH
2x22µF
VIN
10µF
SW
VSEL
EN
C
IN
+
Battery SYSTEM
LOAD
AGND
BYP
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FAN48623 — 2500 mA Synchronous TinyBoost® Regulator with Bypass M ode
Typical Application
Fi gure 2. Block Diagr am
Tab le 1. R ec ommended C om ponents
Component
Description
Vendor
Parameter
Typ.
Unit
L1 0.47 µH, 20%, 5.3 A, 2520 Toko: DFE252010P-R47M
L
0.47
µH
DCR ( S e r ie s R)
27
mΩ
CIN
10 µF, 20%, 10 V, X5R, 0603
TDK: C1608X5R1A106M
C
10
µF
COUT
2 x 22 µF, 20%, 10 V, X5R, 0603
TDK: C1608X5R1A226M080AC
C
44
µF
EN
L1
Q2
VIN
SW
C
IN
GND
Q1
Q1B Q1A
PG
C
OUT
Q3
Q3B Q3A
VSEL
BYP
BYPASS
CONTROL
MODULATOR
LOGIC
AND CONTROL
VOUT
Synchronous
Rectifier
Control
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FAN48623 — 2500 mA Synchronous TinyBoost® Regulator with Bypass M ode
Pin Configur ation
Fi gure 3. Top-Through View (Bumps Down)
Fi gure 4. Bottom View (Bumps Up)
Pin De finitions
Pi n #
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
I nput Voltage. Connect to Li-Ion batter y input power s ourc e.
B1
VSEL
O utput Voltage Select. When boos t is running, this pin can be us ed to s elect the output voltage.
B3, B4
VOUT
Output Voltage. P lace C
OUT
as close as possible to the device.
C1 BYP Bypass. This pin can be us ed to ac tivate Forc ed Bypas s Mode. When this pin is LOW, the bypass
sw itches (Q3 and Q1) are tur ned on and the IC is other wise inactive.
C3, C4
SW
Switching Node. Connect to i nductor.
D1 AGND Analog Ground. This is the signal ground r ef erence for the IC. A ll voltage levels are meas ured
with respect to thi s pi n. AGND s hould be c onnected to PGND at a s ingle point.
D2 — D4 PGND
Power Ground. T his is the power return for the IC. The C
OUT
bypas s capac itor s hould be returned
with the s hortest path poss ible to thes e pins.
B2 , C2
NC
No Internal Connection. Note: Bumps are pr esent and should be tied to PGND.
VIN
VSEL
PG
AGND PGND
NC SW
NC VOUT
EN
B1 B2
C2
A1 A2
B3
A3
C3
D1 D2 D3
C1
A4
B4
C4
D4
BYP
B4
A4
D4
C4
B3
C3
D3
A3
B2
A2
C2
D2
A1
C1
D1
B1
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FAN48623 — 2500 mA Synchronous TinyBoost® Regulator with Bypass M ode
Absolute Maximum Ratings
Stres ses exc eeding the abs olute max imum r atings may damage the dev ice. The dev ice may not f unction 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 onl y.
Symbol Parameter Min. Max. Unit
V
IN
V
IN
Input Voltage
-0.3
6.5
V
V
OUT
V
OUT
Output V oltage
6.0
V
VSW SW Node Voltage
DC
-0.3
6.0
V
Transient: 10
ns, 3
MHz
-1.0
8.0
Other Pins
-0.3
6.5(2)
V
ESD Electrostatic Discharge
Protection Level
Human Body Model, ANSI/ESDA/JEDEC JS-001-2012
2.0
kV
Charged Device Model per JESD22-C101
1.5
T
J
Junction Temperature
-40
+150
°C
T
STG
Storage Temperature
-65
+150
°C
T
L
Lead Soldering Temperature, 10 Sec onds
+260
°C
Note:
2. Lesser of 6.5 V or VIN + 0.3 V.
Rec ommended 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. ON Semiconductor does not
rec ommend ex ceeding them or designing to absolute maximum ratings.
Symbol Parameter Min. Max. Unit
V
IN
Supply Voltage
2.5
4.5
V
I
OUT
Output Current
0
2500
mA
T
A
Ambient Temperature
-40
+85
°C
T
J
Junction Temperature
-40
+125
°C
T he rmal Pr ope rtie s
Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured w ith four-layer ON
Semiconductor evaluation boards (1 oz copper on all layers). Special attention must be paid not to exceed junction
temperature TJ(max) at a giv en ambient temperate TA.
Symbol Parameter Typical Unit
θ
JA
Junction-to-Ambient Thermal Resistance
60
°C/W
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FAN48623 — 2500 mA Synchronous TinyBoost® Regulator with Bypass M ode
Ele ctrical Spe cifications
Unless otherw ise noted and per Figure 1 minimum and maximum values are from VIN=2.5 V to 4.5 V and TA=-40°C t
o +85°C.
Typical values are at VIN = 3.0 V and TA = 25°C f or all output voltage options .
Symbol Parameter Conditions Min. Typ. Max.
Unit
IQ VIN Quiescent Current
Automatic Bypass Mode, VOUT_TARGET =3.3 V,
VIN=3.6 V 140 190 µA
Boost Mode, V
OUT
=3.3 V, V
IN
=3.0 V
135
180
µA
Shutdown, EN=0 V, V
IN
=3.0 V
4.0
12.0
µA
Forced Bypass Mode, V
IN
=3.6 V
6.0
12.0
µA
I
LK
V
OUT
to V
IN
Revers e Leakage
V
OUT
=5.0 V, EN=0 V, V
IN
=0 V
0.5
1.0
µA
I
LK_OUT
V
IN
to V
OUT
Leakage Current
V
OUT
=0 V, EN=0 V, V
IN
=4.2 V
0.1
1.5
µA
VUVLO
Under-Voltage Lockout
V
IN
Rising
2.20
2.35
V
V
UVLO_HYS
Under-V oltage Loc kout Hy steres is
200
mV
V
IH
Logic Level High EN, V SEL, BY P
1.05
V
V
IL
Logic Level Low EN, V SEL, BYP
0.4
V
RLOW Logic Control Pin Pull Downs
(LOW Ac tiv e) BY P, V SEL, EN 300 kΩ
I
PD
Weak Current Source Pull-Down
BY P, V SEL, EN
100
nA
VREG Output V oltage A cc urac y
2.5 V ≤ VIN ≤ V OUT_TARGET -100 mV, DC, 0 to
2500 mA -1.0 4.0 %
2.5 V ≤ V
IN
≤ V
OUT_TARGET
-100 mV, DC, PWM
(CCM) Operation -1.0 2.5 %
I
V_LIM
Boost V alley Curr ent Limit
V
IN
=2.5 V, V
OUT
=3.3 V
4.7
5.3
A
IV_LIM_SS
Boost V alley Curr ent Limit During
Soft Start VIN=2.5 V, VOUT=3.3 V 2.6 A
tSS Soft-Start EN HIGH to Regulation
50 Ω Load, V
OUT_TARGET
= 3.3 V (Time from
EN Rising Edge to 90% of VOUT_TARGET) 300 µs
t
RST
FAULT Res tart Timer
20
ms
Note:
3. Minimu m and Max imum limits ar e verif ied by design, tes t, or s tatistical analysis. Ty pical (Ty p.) number s are not v erif ied,
but repres ent ty pical res ults .
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FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Typical Characteristics
Unless otherw ise speci fied, TA = 25°C; c irc uit and c omponents acc ording to Figure 1.
Fi gure 5. Efficiency vs. Load Current a nd Input
Voltage, VOUT=3.15 V
Fi gure 6. Efficiency vs. Load Current and Temperature,
VIN=3.0 V, VOUT=3.15 V
Fi gure 7. Efficiency vs. Load Current and Input
Voltage, VOUT=3.3 V Fi gure 8. Efficiency vs. Load Current and
Temperature, VIN=3.0 V, VOUT=3.3 V
Fi gure 9. Efficiency vs. Load Current and Input
Voltage, VOUT=3.5 V Figure 10. Efficiency vs. Load C urrent and
Temperature, VIN=3.0 V, VOUT=3.5 V
86%
88%
90%
92%
94%
96%
98%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
86%
88%
90%
92%
94%
96%
98%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
-40C
+25C
+85C
82%
84%
86%
88%
90%
92%
94%
96%
98%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
86%
88%
90%
92%
94%
96%
98%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
-40C
+25C
+85C
82%
84%
86%
88%
90%
92%
94%
96%
98%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
3.3 VIN
86%
88%
90%
92%
94%
96%
98%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
-40C
+25C
+85C
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FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Typical Characteristics (Continued)
Unless otherw ise specified, TA = 25°C; circuit and c omponents ac cor ding to Figure 1.
Figure 11. Efficiency v s. Load Current and Input
Voltage, VOUT=5.0 V Figure 12. Efficiency vs. Load Current and Temperature,
VIN=3.6 V, VOUT=5.0 V
Figure 13. Output Regulation vs. Load Current and
Input Voltage, VOUT=3.15 V
Figure 14. Output Regulation vs. Load Current and
Temperature, VIN=3.0 V, VOUT=3.15 V
Figure 15. Output Regulation vs. Load Current and
I nput Voltage, VOUT=3.3 V
Figure 16. Output Regulation vs. Load Current and
Temperature, VIN=3.0 V, VOUT=3.3 V
78%
80%
82%
84%
86%
88%
90%
92%
94%
96%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
2.5 VIN
3.0 VIN
3.6 VIN
4.2 VIN
84%
86%
88%
90%
92%
94%
96%
0500 1000 1500 2000 2500
Efficiency
Load Current (mA)
-40C
+25C
+85C
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output Regulation
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output Regulation
Load Current (mA)
-40C
+25C
+85C
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output Regulation
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output Regulation
Load Current (mA)
-40C
+25C
+85C
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FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Typical Characteristics (Continued)
Unless otherw ise specified, TA = 25°C; circuit and c omponents ac cor ding to Figure 1.
Figure 17. Output Regulation vs. Load Current and Input
Voltage, VOUT=3.5 V
Figure 18. Output Regulation vs. Load Current and
Temperature, VIN=3.0 V, VOUT=3.5 V
Figure 19. Output Regulation vs. Load Current and Input
Voltage, VOUT=5.0 V
Figure 20. Output Regulation vs. Load Current and
Temperature, VIN=3.6 V, VOUT=5.0 V
Figure 21. Quiescent Current vs. Input Voltage and
Temperature, VOUT=3.15 V, Auto Bypass Figure 22. Quiescent Current vs. Input Volta ge and
Temperature, VOUT=5.0 V, Auto Bypass
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output R e gula tion
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
3.3 VIN
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output R e gula tion
Load Current (mA)
-40C
+25C
+85C
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output Regulation
Load Current (mA)
2.5 VIN
3.0 VIN
3.6 VIN
4.2 VIN
-2.0%
-1.0%
0.0%
1.0%
2.0%
3.0%
4.0%
0500 1000 1500 2000 2500
Output Regulation
Load Current (mA)
-40C
+25C
+85C
100
120
140
160
180
200
2.5 3.0 3.5 4.0 4.5
Quiescent Current (uA)
Input V oltage (V)
-40C
+25C
+85C
120
140
160
180
200
220
2.5 3.0 3.5 4.0 4.5 5.0 5.5
Quiescent Current (uA)
Input V oltage (V)
-40C
+25C
+85C
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FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Typical Characteristics (Continued)
Unless otherw ise specified, TA = 25°C; c ircuit and c omponents acc ording to Figure 1.
Figure 23. Quiescent Current vs. Input Voltage and
Temperature, VOUT=3.3 V, Forced Bypass Figure 24. Typical Maximum Continuous Load
vs. Input
Vol tage, Temperature and Output Vol tage
Figure 25. Output Ri pp le vs. Load C urrent and
I nput Voltage, VOUT=3.15 V Figure 26. Frequency vs. Load Current and Input
Voltage, VOUT=3.15 V
Figure 27. Output Ri pple vs. Load Current and
I nput Voltage, VOUT=3.3 V
Figure 28. Frequency vs. L oad Current and Input
Voltage, VOUT=3.3 V
0
2
4
6
8
10
12
2.5 3.0 3.5 4.0 4.5
Quiescent Current (uA)
Input V oltage (V)
-40C
+25C
+85C
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
2.5 3.0 3.5 4.0 4.5
Ma x C ontinuous Loa d (A )
Input V oltage (V)
3.3VO UT, 25C
3.3VO UT, 60C
3.3VO UT, 85C
5.0VO UT, 25C
5.0VO UT, 60C
5.0VO UT, 85C
5.2VO UT, 25C
5.2VO UT, 60C
5.2VO UT, 85C
0
10
20
30
40
0500 1000 1500 2000 2500
Ripple (mV )
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
0
500
1,000
1,500
2,000
2,500
0500 1000 1500 2000 2500
Frequency(kHz)
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
0
10
20
30
40
0500 1000 1500 2000 2500
Ripple (mV )
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
0
500
1,000
1,500
2,000
2,500
0500 1000 1500 2000 2500
Frequency(kHz)
Load Current (mA)
2.5 VIN
2.7 VIN
3.0 VIN
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FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Typical Characteristics (Continued)
Unless otherw ise specified, TA = 25°C; c irc uit and c omponents acc ording to Figure 1.
Figure 29. Output Ri pp le vs. Load C urrent and Input
Voltage, VOUT=5.0 V Figure 30. Frequency vs. Load Current and Input
Voltage, VOUT=5.0 V
Figure 31. Startup, 50 Ω Load, V
IN
=2.5 V, V
OUT
=3.15 V
Figure 32. Startup, 50 Ω Load, V
IN
=3.0 V, V
OUT
=5.0 V
Figure 33. Overload Protection, V
IN
=3.0 V, V
OUT
=5.0 V
Figure 34. Output Fault, V
IN
=3.0 V, V
OUT
=3.3 V
0
10
20
30
40
50
0500 1000 1500 2000 2500
Ripple (mV )
Load Current (mA)
2.5 VIN
3.0 VIN
3.6 VIN
4.2 VIN
0
500
1,000
1,500
2,000
2,500
3,000
0500 1000 1500 2000 2500
Frequency(kHz)
Load Current (mA)
2.5 VIN
3.0 VIN
3.6 VIN
4.2 VIN
IIN
(500mA/div)
V
OUT (1V/div)
EN
(2V/div)
PG
(5V/div)
I
IN (500mA/div)
V
OUT (2V/div)
EN
(2V/div)
PG
(5V/div)
I
L (2A/div)
V
OUT (1V/div)
PG
(2V/div)
IL (2A/div)
VOUT (1V/div)
PG(2V/div)
100µs/div
100µs/div
50µs/div
5ms/div
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FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Typical Characteristics (Continued)
U nless otherw ise specified
, TA = 25°C; c irc uit and c omponents acc ording to Figure 1
Figure 35. Load Transient, 150-2000 mA, 10 µs Edge,
VIN=3.0 V, VOUT=3.3 V Figure 36. Load Transient, 150-1000 mA, 10 µs Edge,
VIN=3.6 V, VOUT=5.0 V
Figure 37. Line Transi ent, 3.0-3.6 VIN, 10 µs Edge,
500 mA Load, VOUT=3.3 V Figure 38. Line Transi ent, 2.7-3.0 VIN, 10 µs Edge,
500 mA Load, VOUT=3.3 V
Figure 39. V
SEL
Step, V
IN
=3 V, V
OUT
=3.3 V, 500 mA Load
I
OUT (1A/div)
V
OUT (200mV/div)
IOUT (1A/div)
VOUT (200mV/div)
VOUT (200mV/div)
VIN(200mV/div)
VOUT (50mV/div)
VIN(200mV/div)
V
OUT (100mV/div)
V
SEL (2V/div)
3.3V
5.0V
100
µ
s/div
100µs/div
20µs/div
20µs/div
20µs/div
3.0V
2.7V
3.2V
3.3V
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FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Circuit D e scription
FAN48623 is a synchronous boost regulator, typically
operating at 2.5 MHz in Continuous Conduction Mode
(CCM), w hich occurs at moderate to heavy load current and
low VIN voltages. At light load, the regulator operates at
Discontinuous Conduction Mode (DCM) to maintain high
efficiency.
FAN48623 uses a current-mode modulator to achieve
excellent trans ient res ponse and s mooth tr ansitions betw een
CCM a n d DCM operation.
The regulator includes a Bypass Mode that automatically
activates w hen VIN is above the boost regulator’s set point.
Tab le 2. Operatin g States
Startup and Shutdown (EN Pin)
If EN is LOW, all bias circuits are off and the regulator is in
Shutdown Mode. During s hutdown, cur rent flow is prev ented
from VIN to VOUT, as w ell as reverse flow from VOUT to
VIN. During startup, keep DC current draw below 500 mA
until the device successfully executes startup. It is
recommended not to connect EN directly to VIN but use a
GPIO voltage of 1.8 V to set the logic for the EN pin. The
f ollowing table desc ribes the s tartup s equence.
Tab le 3. B oost Start up Seque nce
Start
Mode
Entry Exit End
Mode
Timeout
(µs)
LIN1 VIN > VUVLO,
EN=1
V
OUT
> V
IN
-300 mV
SS
TIMEOUT
LIN2
512
LIN2 LIN1 Exit
V
OUT
> V
IN
-300 mV
SS
TIMEOUT FAUL
T 1024
SS LIN1 or
LIN2 Exit VOUT=VOUT_TARGET
BST
Linear S t artup (LIN)
When EN is HIGH and VIN > VUVLO, the regulator attempts to
bring VOUT w ithin 300 mV of VIN using the internal fixed
current source from VIN (Q3). The current is limited to the
LIN1 (~1 A) set poi nt.
If VOUT reaches VIN-300 mV during LIN1 Mode, SS Mode is
initiated. Otherwise, LIN1 times out after 512 µs and LIN2
Mode is enter ed.
In LIN2 Mode, the current source is incremented to
approximately 2 A. If VOUT fails to reach VIN-300 mV after
1024 µs, a fault state is declared.
Soft-Start Mode (SS)
Upon successful completion of the LIN Mode (VOUT>VIN-
300 mV ), SS Mode begins and the r egulator starts switching
with boost valley current limited to 50% of nominal level at
Boost Mode.
During SS Mode, VOUT is ramped up by stepping the internal
reference. If VOUT fails to reach the voltage required during
the SS ramp s equence w ithin 64 µs, a fault state is declared.
Boost Mode (BST)
This is a normal operating state of the regulator.
Bypass M ode (BPS)
If V IN is above VOUT_TARGET when the SS Mode suc ces sf ully
completes, the dev ice tr ansitions direc tly to BPS Mode.
Tab le 4. E N and BYP Logic Ta bl e
EN BYP
Mode VOUT
0
0
Shutdown
0
1
Shutdown
0
1
0
Forc ed Bypass
V
IN
1 Auto Bypass
V
OUT_TARGET
or V
IN
(if VIN > VOUT_TARGET)
FAULT State
The regulator enters the FAULT state under any of the
following conditi ons:
VOUT f ails to ac hieve the v oltage required to advanc e f rom
LIN s tate to SS state.
VOUT f ails to ac hieve the v oltage required to advanc e f rom
SS state to BST state.
Boost valley current lim it triggers for 2 ms during the BST
state.
VIN to V OUT voltage drop exceeds 160 mV during BPS
state.
VIN < VUVLO
If a fault is triggered, the regulator stops sw itching and
presents a high-impedance path between VIN and VOUT.
After waiting 20 ms, a n automatic restart is attempted.
P ower Good
Power good is defined as a 0-FAULT, 1-POWER GOOD,
open-drain output. The Pow er Good pin (PG) signals when
the regulator has successfully completed soft-start w ith no
faults occurring. Pow er Good also functions as a warning
flag for high die temperature.
PG is released HIGH when the soft-start sequence is
successfully completed.
Any FAULT state causes PG to be de-asserted.
PG is not asserted during Forced Bypass exit to Boost
Mode until the soft-start sequence is successfully
completed.
Mode
Description
I nvoke d W hen
LIN
Linear Startup
V
IN
> V
OUT
SS Soft-Start Mode
V
IN
<V
OUT
<
VOUT_TARGET
BST
Boost Operating Mode
V
OUT
= V
OUT_TARGET
BPS
Bypass Mode
V
IN
> V
OUT_TARGET
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13
FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Over-Temperature
When the die temperature exceeds 125°C, PG de-asserts
and the output r emains regulated. PG is re-asserted w hen
the device cools by approximately 20°C.
The regulator shuts down if the die temperature exceeds
150°C. Restart occurs w hen the IC has cooled by
approximately 20°C.
Automatic Bypass
In normal operation, the device automatically transitions from
Boost Mode to Bypas s Mode if V IN goes above VOUT_TARGET.
In Bypass Mode, the device fully enhances both Q1 and Q3
to provide a very low impedance path from VIN to VOUT.
Entry into the Bypass Mode is triggered when VIN >
VOUT_TARGET and no sw itching has occurred during the past
10 µs. To sof ten the entry into Bypas s Mode, Q3 is driven as
a linear c urrent s ourc e f or the firs t 5 µs. Bypas s Mode ex it is
triggered w hen VOUT r eaches VOUT_TARGET. During A utomatic
Bypas s Mode, the device is s hort-circuit protec ted by v oltage
compar ator trac king the v oltage drop from V IN to V OUT; if the
drop ex ceeds 160 mV, a fault state is declared.
With sufficient load to enforce CCM operation, the Bypass
Mode to Boost Mode transition occurs at the target VOUT.
The Bypass Mode exit threshold has a 50 mV hysteresis
imposed at VOUT to prevent cycling between modes. The
cor res ponding input v oltage at the trans ition point is :
(1
)
The Bypass Mode entry threshold has a 30 mV hysteresis
imposed at VOUT to prevent cycling between modes. The
transition from Boost Mode to Bypass Mode occurs at the
target V OUT+30 mV. The corres ponding input v oltage is :
(2
)
Forced By pass
Forced Bypass Mode is activated by pulling BYP pin LOW.
Forced Bypass Mode initiates w ith a current limit on Q3 and
then proc eeds to the Bypas s Mode with both Q1 and Q3 f ully
enhanced. To prevent reverse current to the battery, the
device w aits until output discharges below VIN before
entering Forced Bypass Mode.
After the transition is complete, most of the internal circuitry
is disabled to minimize quiescent current. OCP, UVLO and
OTP are inactive in Forc ed Bypass Mode.
By pulling BYP pin HIGH, the part transitions from Forced
Bypass Mode to Boost Mode. Dur ing the trans ition, Q1 is of f
and Q3 is dr iven as a linear c urr ent sourc e f or the f irst 5 µs
before entering Boost Mode.
.
mV50R||)RDCR(IVV
BYP)ON(DSP)ON(DSLLOADOUTIN
−+•+≤
mV30)RDCR(IVV
P)ON(DSLLOADOUTIN
++•+≥
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14
FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Application Information
Output C apacitanc e (COUT)
Stability
The effective capacitance (CEFF(4)) of small, high-value,
ceramic capacitors decrease as bias voltage increases, as
illustrated in Figure 40.
Figure 40. CEFF for 22
µ
F, 0603, X5R, 10 V-Rated
Capacitor (TDK C1608X5R1A226M080AC)
Stable operation is guaranteed w ith the minimum value of
CEFF (CEFF(MIN)), as outlined in Table 5.
Tab le 5. Minimum CEFF R equ ired for Stabil ity
Ope rating Conditions
CEFF(MIN) (
µ
F)
VOUT (V) ILOAD (mA)
3.15
0 to 2500
9
5.0
0 to 2500
6
Note:
4. CEFF var ies with manuf ac turer, mater ial, and c ase s ize.
Induc tor Selec t io n
Rec ommended nominal inductanc e value is 0.47 µH.
The FAN48623 employs valley-current limiting. Peak
inductor current can reach 6.5 A for a short duration during
overload conditions. Saturation effects cause the inductor
current ripple to become higher under high loading as only
the vall ey of the inductor current ripple is controlled.
Startup Inrush C urre nt Limit
Input current limiting is in ef f ec t during sof t-s tar t, w hic h limits
the current available to charge COUT and any additional
capacitance on the VOUT line. If the output fails to achieve
regulation within the set limit, a FAULT occurs, causing the
circuit to shut down then restart after 20 ms. If the total
combined output c apacitanc e is v ery high, the c ircuit may not
start on the firs t attempt, but ev entually ac hieves 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
l oad when in a FAULT state.
Out put Volt age R ip pl e
Output voltage ripple is inversely proportional to COUT.
During tON, w hen the boost sw itch is on, all load current is
supplied by COUT. Output ripple is calculated as:
and (3)
therefore:
(4)
and
(5)
(6)
As can be seen from Equation (5), the maximum VRIPPLE
occurs w hen VIN is at minimum and ILOAD is at maximum.
Voltage at VOUT
For applications where a foreign voltage source could be
applied at V OUT, c are s hould be taken to ensure VOUT never
exceeds the A bsolute Max imum Rating.
Layout Recommendations
The layout recommendations below highlight various layers
using different colors.
To minimize s pikes at V OUT, COUT mus t be placed as close as
possibl e to PGND and VOUT, as show n in Figure 41.
For thermal reasons, it is suggested to maximize the pour
area f or all planes other than SW. Es pecially the gr ound pour
should be s et to f ill all available PCB surfac e area and tied to
i nternal layers wi th a cluster of thermal vias.
Figure 41. Layout Recommendati o n
Refer to the section below for detailed layout
recommendati ons for each layer.
0
4
8
12
16
20
24
012345678910
Capacitance (uF)
DC Bi a s(V)
OUT
)( C
I
tV LOAD
ONPPRIPPLE •=
−
−•=•=
OUT
IN
SWSWON V
V
tDtt 1
OUT
)(
1C
I
V
V
tV
LOAD
OUT
IN
SWPPRIPPLE
•
−•=
−
SW
SW f
t1
=
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15
FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Figure 42. Top Layer
Layer 2 s hould be a s olid ground layer, to s hield V OUT
f rom c apacitive c oupling of the f as t edges of SW node.
Logic signals c an be routed on this layer.
Figure 43. Layer 2
Figure 44. Layer 3
Put as many as possibl e vias
connect ed t o gr ound plane(layer 2) ,
to help dissipate heat.
VOUT trace should be as wi de
and as short as possible, for
low impedance.
The ground area should
be made as large as
possible to help
dissipate heat.
VIN trace should go
through CIN before going
to VIN pins.
Connect AGND direct ly t o
GND layer through a via.
SW trace should be as wide and as short as
possible, and be isolat ed with G ND area
from any other sensitive traces.
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16
FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Product-Spe cific Dime nsions
Product
D
E
X
Y
FAN48623UC315X
1.810 ±0.030
1.810 ±0.030
0.305
0.305
FAN48623UC32JX
1.810 ±0.030
1.810 ±0.030
0.305
0.305
FAN48623UC33X
1.810 ±0.030
1.810 ±0.030
0.305
0.305
FAN48623UC35X
1.810 ±0.030
1.810 ±0.030
0.305
0.305
FAN48623UC36FX
1.810 ±0.030
1.810 ±0.030
0.305
0.305
FAN48623UC50X
1.810 ±0.030
1.810 ±0.030
0.305
0.305
FAN48623UC50GX
1.810 ±0.030
1.810 ±0.030
0.305
0.305
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17
FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
Physical Dimensions
Figure 45. 16-Ball, 4x4 Array, 0.4 mm Pitch, 250 µm Ball, Wafer-Level Chip-Scale Package (WLCSP)
NOTES
A. NO JEDEC REGISTRATION APPLIES.
B. DIMENSIONS ARE IN MILLIMETERS.
C. DIMENSIONS AND TOLERANCE PER
ASME Y14.5M, 1994.
D. DATUM C IS DEFINED BY THE
SPHERICAL CROWNS OF THE BALLS.
E. PACKAGE NOMINAL HEIGHT IS
586 ± 39 MICRONS (547-625 MICRONS).
F. FOR DIMENSIONS D,E,X, AND Y SEE
PRODUCT DATASHEET.
G. DRAWING FILNAME: MKT-UC016AF rev1
BOTTOM VIEW
SIDE VIEWS
TOP VIEW RECOMMENDED LAND PATTERN
BALL A1
INDEX AREA
1234
A
B
C
D
SEATING
PLANE
16X
A1
0.005 C A B
F
(NSMD PAD TYPE)
Ø0.260±0.02
0.40
0.40
(X) ±0.018
(Y) ±0.018
0.625
0.547
0.06 C
0.05 CE
D
F
0.378±0.018
0.208±0.021
0.03 C
2X
0.03 C
2X
E
D
B
C
A
0.40
0.40
(Ø0.21)
Cu Pad
(Ø0.30) Solder
Mask Opening
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18
FAN48623 — 2500 mA Synchronous TinyBoost™ R egulator with B ypass Mode
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