MP1522 View Datasheet(PDF) - Monolithic Power Systems
Part Name
Description
Manufacturer
MP1522 Datasheet PDF : 7 Pages
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MP1522 – 25V STEP-UP CONVERTER IN A SOT23-5 PACKAGE
PIN FUNCTIONS
Pin # Name Description
1
SW Power Switch Output. SW is the drain of the internal MOSFET switch. Connect the power
inductor and output rectifier to SW. SW can swing between GND and 25V.
2
GND Ground.
3
FB Feedback Input. Connect a resistive voltage divider from the output voltage to FB to set
the output voltage. The feedback regulation threshold is 1.23V.
4
EN Regulator On/Off Control Input. A high voltage at EN turns on the converter, and a low
voltage turns it off. When not used, connect EN to the input source for automatic startup. If
EN is driven over 6V, place a 100kΩ resistor in series with EN.
5
BIAS Internal Power Input. BIAS powers the internal circuitry. Connect BIAS to the output for
more enhancement on the internal MOSFET gate at low VIN. If the input source remains
above 3.0V, BIAS can be connected to the input source to reduce power consumption.
OPERATION
The MP1522 is a step-up converter that
operates from an input voltage as low as 2.7V
and generates an output voltage up to 25V. The
0.5Ω internal N-Channel MOSFET power switch
is driven with a variable frequency, constant-
peak-current architecture for improved
regulation and low operating current. The 550ns
minimum off-time is extended to 1.6µs during
start-up to yield a smooth glitch free turn-on.
Start-up mode is activated at initial power-up or
when exiting the 1µA shutdown state. The
MP1522 features an internal regulator allowing
it to be powered from the output for improved
low-input voltage operation, or powered from
the input source for reduced power
consumption due to quiescent current.
VIN
C1
R3
C4
BIAS
(5)
L1
SW
(1)
D1
VOUT
R2 C2 C3
OFF ON
EN
REGULATOR
(4)
CONTROL
LOGIC
INTERNAL
POWER
GND
CURRENT --
+
450mA
ERROR
AMP --
+
FB
(3)
R1
1.23V
GND
(2)
Figure 1—Functional Block Diagram
MP1522_BD01
MP1522 Rev. 1.9
www.MonolithicPower.com
3
12/9/2005
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2005 MPS. All Rights Reserved.
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