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PDF APW8804E Data sheet ( Hoja de datos )
| Número de pieza | APW8804E | |
| Descripción | Synchronous Buck Converter | |
| Fabricantes | ANPEC | |
| Logotipo |  |
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APW8804E
3A 5V 1MHz Synchronous Buck Converter
Features
General Description
• High Efficiency up to 95%
APW8804E is a 3A synchronous buck converter with inte-
- Automatic PFM/PWM Mode Operation
grated 65mΩ high side and 55mΩ low side power
•
Adjustable Output Voltage from 0.6V to V
PVDD
MOSFETs. The APW8804E, design with a current-mode
• Integrated 65mΩ High Side / 55mΩ Low Side control scheme, can convert wide input voltage of 2.6V to
MOSFETs
• Low Dropout Operation: 100% Duty Cycle
• Stable with Low ESR Ceramic Capacitors
• Power-On-Reset Detection on VDD and PVDD
5.5V to the output voltage adjustable from 0.6V to 5.5V to
provide excellent output voltage regulation.
The APW8804E is equipped with an automatic PFM/PWM
mode operation. At light load , the IC operates in the PFM
mode to reduce the switching losses. At heavy load, the
• Integrated Soft-Start and Soft-Stop
IC works in PWM mode. At PWM mode, the switching
• Over-Temperature Protection
frequency is set by the external resistor.
• Over-Voltage Protection
The APW8804E is also equipped with Power-on-reset,
• Under-Voltage Protection
• High/ Low Side Current Limit
• Power Good Indication
• Enable/Shutdown Function
• TDFN3x3-10 Package
soft-start, soft-stop, and whole protections (under-voltage,
over-voltage, over-temperature and current-limit) into a
single package.
This device, available TDFN3x3-10 , provides a very com-
pact system solution external components and PCB area.
• Lead Free and Green Devices Available
(RoHS Compliant)
Simplified Application Circuit
Applications
• Notebook Computer & UMPC
• LCD Monitor/TV
• Set-Top Box
• DSL, Switch HUBr
• Portable Instrument
VIN
ON
OFF
PVDD
LX
VDD
FB
APW8804E
POK
GND
EN
VOUT
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and
advise customers to obtain the latest version of relevant information to verify before placing orders.
Copyright © ANPEC Electronics Corp.
Rev. A.2 - Dec., 2016
1
www.anpec.com.tw
1 page  
APW8804E
Pin Description
PIN
NO. NAME
FUNCTION
1 NC No Connection.
2,3
LX
Power Switching Output. LX is the Junction of the high-side and low-side Power MOSFETs to
supply power to the output LC filter.
4
POK
Power Good Output. This pin is open-drain logic output that is pulled to the ground when the output
voltage is out of regulation point.
5
EN
Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the
regulator, drive it low to turn it off.
Output Feedback Input. The APW8804E senses the feedback voltage via FB and regulates the
6 FB voltage at 0.6V. Connecting FB with a resistor-divider from the converter’s output sets the output
voltage.
7 NC No connection.
8
VDD
Signal Input. VDD supplies the control circuitry, gate drivers. Connecting a ceramic bypass
capacitor from VDD to GND to eliminate switching noise and voltage ripple on the input to the IC.
9,10
PVDD
Power Input. PVDD supplies the step-down converter switches. Connecting a ceramic bypass
capacitor from PVDD to GND to eliminate switching noise and voltage ripple on the input to the IC.
11
GND
Ground and Exposed pad. Connect the exposed pad to the system ground plan with large copper
(Exposed Pad) area for dissipating heat into the ambient air.
Copyright © ANPEC Electronics Corp.
Rev. A.2 - Dec., 2016
5
www.anpec.com.tw
5 Page 
APW8804E
Function Description
VDD and PVDD Power-On-Reset (POR)
The APW8804E keeps monitoring the voltage on VDD
and PVDD pins to prevent wrong logic operations which
may occur when VDD or PVDD voltage is not high enough
for internal control circuitry to operate. The VDD POR ris-
ing threshold is 2.4V (typical) with 0.2V hysteresis and
PVDD POR rising threshold is 1.7V with 0.2V hysteresis.
During start-up, the VDD and PVDD voltage must exceed
the POR threshold. Then, the IC starts a start-up process
and ramps up the output voltage to the voltage target.
with a 50oC hysteresis to lower the average TJ during
continuous thermal overload conditions, increasing life-
time of the APW8804E.
Current-Limit Protection
The APW8804E monitors the output current, flows through
the high-side and low-side power MOSFETs, and limits
the current peak at current-limit level to prevent the IC
from damaging during overload, short-circuit and over-
voltage conditions. Typical high side power MOSFET cur-
rent limit is 5A, and low side MOSFET current limit is -1A.
Output Under-Voltage Protection (UVP)
In the operational process, if a short-circuit occurs, the
output voltage will drop quickly. Before the current-limit
circuit responds, the output voltage will fall out of the re-
quired regulation range. The under-voltage continually
monitors the FB voltage after soft-start is completed. If a
load step is strong enough to pull the output voltage lower
than the under-voltage threshold, the IC shuts down
converter’s output.
The under-voltage threshold is 66% of the nominal out-
put voltage. APW8804E will be latched after under-volt-
age protection.
Over-Voltage Protection (OVP)
The over-voltage function monitors the output voltage by
FB pin. When the FB voltage increases over 125% of the
reference voltage due to the high-side MOSFET failure or
for other reasons, the over-voltage protection comparator
will trigger soft-stop function and shutdown the converter
output.
Soft-Start
The APW8804E has a built-in soft-start to control the rise
rate of the output voltage and limit the input current surge
during start-up. During soft-start, an internal voltage ramp
connected to one of the positive inputs of the error
amplifier, rises up to replace the reference voltage (0.6V)
until the voltage ramp reaches the reference voltage. Dur-
ing soft-start without output over-voltage, the APW8804E
converter’s sinking capability is disabled until the output
voltage reaches the voltage target.
Soft-Stop
At the moment of shutdown controlled by EN signal or
over-voltage event, the APW8804E initiates a soft-stop
process to discharge the output voltage in the output
capacitors. Certainly, the load current also discharges
the output voltage. During soft-stop, the low side MOSFET
turns on each cycle to discharge the output voltage.
Therefore, the output voltage falls down slowly at the light
load. After the soft-stop interval elapses, the soft-stop pro-
cess ends and the IC turns off.
Over-Temperature Protection (OTP)
The over-temperature circuit limits the junction tempera-
ture of the APW8804E. When the junction temperature
exceeds TJ=+160oC, a thermal sensor turns off the both
power MOSFETs, allowing the devices to cool. The ther-
mal sensor allows the converters to start a start-up pro-
cess and to regulate the output voltage again after the
junction temperature cools by 50oC. The OTP is designed
Enable and Shutdown
Driving EN to ground places the APW8804E in shutdown.
In shutdown mode, the internal power MOSFETs turn off,
all internal circuitry shuts down and the quiescent supply
current reduces to less than 1µA.
Copyright © ANPEC Electronics Corp.
Rev. A.2 - Dec., 2016
11
www.anpec.com.tw
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet APW8804E.PDF ] | |
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