MP1522 MPS, MP1522 Datasheet - Page 3

• Manufacturer Part Number: MP1522
• Description: 25v Step-up Converter In A Sot23-5 Package
• Manufacturer: MPS

PIN FUNCTIONS
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
regulation and low operating current. The 550ns
minimum off-time is extended to 1.6µs during
MP1522 Rev. 2.0
9/21/2007
Pin #
1
2
3
4
5
OFF ON
V
IN
Name
BIAS
GND
SW
EN
FB
architecture
C1
Description
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.
Ground.
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.
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.
Internal Power Input. BIAS powers the internal circuitry. Connect BIAS to the output for
enhancement on the internal MOSFET gate at low V
3.0V, BIAS can be connected to the input source to reduce power consumption.
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
R3
EN
4
for
Figure 1—Functional Block Diagram
CONTROL
LOGIC
MP1522 – 25V STEP-UP CONVERTER IN A SOT23-5 PACKAGE
improved
© 2007 MPS. All Rights Reserved.
www.MonolithicPower.com
BIAS
REGULATOR
CURRENT
5
ERROR
AMP
C4
INTERNAL
POWER
--
+
--
+
1.23V
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
consumption due to quiescent current.
450mA
L1
GND
SW
input
1
2
IN
. If the input source remains above
source
3
FB
D1
for
R2
R1
reduced
C2
C3
V
GND
OUT
power
3