Zakładka z wyszukiwarką danych komponentów
  Polish  ▼
ALLDATASHEET.PL

X  

FAN5353MPX Arkusz danych(PDF) 9 Page - Fairchild Semiconductor

Numer części FAN5353MPX
Szczegółowy opis  3MHz, 3A Synchronous Buck Regulator
Download  13 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Producent  FAIRCHILD [Fairchild Semiconductor]
Strona internetowa  http://www.fairchildsemi.com
Logo FAIRCHILD - Fairchild Semiconductor

FAN5353MPX Arkusz danych(HTML) 9 Page - Fairchild Semiconductor

Back Button FAN5353MPX Datasheet HTML 5Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 6Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 7Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 8Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 9Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 10Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 11Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 12Page - Fairchild Semiconductor FAN5353MPX Datasheet HTML 13Page - Fairchild Semiconductor  
Zoom Inzoom in Zoom Outzoom out
 9 / 13 page
background image
© 2009 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FAN5353 • Rev. 1.0.2
9
Operation Description
The FAN5353 is a step-down switching voltage regulator
that delivers an adjustable output from an input voltage
supply of 2.7V to 5.5V. Using a proprietary architecture with
synchronous rectification, the FAN5353 is capable of
delivering 3A at over 80% efficiency. The regulator operates
at a nominal frequency of 3MHz at full load, which reduces
the value of the external components to 470nH for the output
inductor and 20µF for the output capacitor.
Control Scheme
The FAN5353 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.
Setting the Output Voltage
The output voltage is set by the R1, R2, and VREF (0.8V):
REF
REF
OUT
V
V
V
2
R
1
R
=
(1)
R1 must be set at or below 100KΩ. Therefore:
()
8
.
0
V
8
.
0
1
R
2
R
OUT
=
(2)
For example, for VOUT = 1.2V, R1 = 100KΩ, R2 = 200KΩ.
Enable and Soft Start
When the EN pin is LOW, the IC is shut down, all internal
circuits are off, and the part draws very little current. Raising
EN above its threshold voltage activates the part and starts
the soft-start cycle. During soft-start, the modulator’s internal
reference is ramped slowly to minimize any large surge
currents on the input and prevents any overshoot of the
output voltage.
If large values of output capacitance are used, the regulator
may fail to start. If VOUT fails to achieve regulation within
320
μs from the beginning of soft-start, the regulator shuts
down and waits 1200
μs before attempting a restart. If the
regulator is at its current limit for more than about 60
μs, the
regulator shuts down before restarting 1200
μs later. This
limits the COUT capacitance when a heavy load is applied
during the startup. For a typical FAN5353 starting with a
resistive load:
)
A
(
I
100
400
)
F
(
COUT
LOAD
MAX
μ
where
LOAD
OUT
LOAD
R
V
I
=
(3)
Synchronous rectification is inhibited during soft-start,
allowing the IC to start into a pre-charged load.
PGOOD Pin
The PGOOD pin is an open drain output that indicates the IC
is in regulation when its state is open. PGOOD requires an
external pull-up resistor. PGOOD pulls LOW under the
following conditions:
1.
The IC has operated in cycle-by-cycle current limit for
eight or more consecutive PWM cycles.
2.
The circuit is disabled; either after a fault occurs, or
when EN is LOW.
3.
The IC is performing a soft-start.
Under-Voltage Lockout
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.
Input Over-Voltage Protection (OVP)
When VIN exceeds VSDWN (about 6.2V) the IC stops
switching, to protect the circuitry from internal spikes above
6.5V. An internal 40
μs filter prevents the circuit from shutting
down due to noise spikes. For the circuit to fully protect the
internal circuitry, the VIN slew rate above 6.2V must be
limited to no more than 15V/ms when the IC is switching.
The IC protects itself if VIN overshoots to 7V during initial
power-up as long as the VIN transition from 0 to 7V occurs in
less than 10
μs (10% to 90%).
Current Limiting
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 switch. Upon reaching this point,
the high-side switch turns off, preventing high currents from
causing damage. 16 consecutive PWM cycles in current limit
cause the regulator to shut down and stay off for about
1200
μs before attempting a restart.
In the event of a short circuit, the soft-start circuit attempts to
restart and produces an over-current fault after about 50
μs,
which results in a duty cycle of less than 10%, providing
current into a short circuit.
Thermal Shutdown
When the die temperature increases, due to a high load
condition and/or a high ambient temperature, the output
switching is disabled until the temperature on the die has
fallen sufficiently. The junction temperature at which the
thermal shutdown activates is nominally 150°C with a 20°C
hysteresis.


Podobny numer części - FAN5353MPX

ProducentNumer częściArkusz danychSzczegółowy opis
logo
ON Semiconductor
FAN5353MPX ONSEMI-FAN5353MPX Datasheet
1Mb / 15P
   3 MHz, 3 A Synchronous Buck Regulator
December 2013 Rev. 1.0.3
More results

Podobny opis - FAN5353MPX

ProducentNumer częściArkusz danychSzczegółowy opis
logo
Fairchild Semiconductor
FAN5354 FAIRCHILD-FAN5354_11 Datasheet
1Mb / 14P
   3MHz, 3A Synchronous Buck Regulator
FAN5354 FAIRCHILD-FAN5354 Datasheet
785Kb / 14P
   3MHz, 3A Synchronous Buck Regulator
logo
Micrel Semiconductor
MIC23451 MICREL-MIC23451 Datasheet
3Mb / 20P
   3MHz, 2A Triple Synchronous Buck Regulator
logo
Unisonic Technologies
USR1021 UTC-USR1021 Datasheet
183Kb / 4P
   3A SYNCHRONOUS BUCK REGULATOR
USR1021 UTC-USR1021_15 Datasheet
183Kb / 4P
   3A SYNCHRONOUS BUCK REGULATOR
logo
Fairchild Semiconductor
FAN5362 FAIRCHILD-FAN5362 Datasheet
1Mb / 14P
   3MHz, 500mA / 750mA Synchronous Buck Regulator
logo
ON Semiconductor
FAN5362 ONSEMI-FAN5362 Datasheet
1Mb / 16P
   3MHz, 500mA / 750mA Synchronous Buck Regulator
Rev. 1.0.5
logo
Microchip Technology
MIC28511 MICROCHIP-MIC28511 Datasheet
1Mb / 34P
   60VIN, 3A Synchronous Buck Regulator
07/14/15
logo
Alpha & Omega Semicondu...
AOZ1031AI AOSMD-AOZ1031AI Datasheet
925Kb / 15P
   EZBuck??3A Synchronous Buck Regulator
AOZ1033AI AOSMD-AOZ1033AI Datasheet
908Kb / 15P
   EZBuck??3A Synchronous Buck Regulator
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13


Arkusz danych Pobierz

Go To PDF Page


Link URL




Polityka prywatności
ALLDATASHEET.PL
Czy Alldatasheet okazała się pomocna?  [ DONATE ] 

O Alldatasheet   |   Reklama   |   Kontakt   |   Polityka prywatności   |   Linki   |   Lista producentów
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com