MP1527
2A, 1.3MHz
Step-Up Converter
Monolithic Power Systems
Pin Descriptions
FAULT
14
NC
NC
IN
SW
PGND
SGND
FAULT
1
2
3
4
5
6
7
14
13
12
11
10
9
8
SGND
EN
BP
NC
COMP
FB
SS
16
15
COMP
NC
BP
EN
1
2
3
5
4
13
12
SGND
PGND
PGND
SW
SW
11
10
8
9
6
SS
FB
Top
View
7
SGND
NC
Table 1: Pin Description
QFN
Pin
1
2, 6, 7
3
4
5, 13
8
9, 10
11, 12
TSSOP
Pin
10
1, 2, 11
12
13
6, 14
3
4
5
Name
Function
Compensation Node. COMP is the output of the internal transconductance error
amplifier. Connect a series RC network from COMP to SGND to compensate the
regulator control loop.
No Connect
Output of the internal 2.4V low dropout regulator. Connect a 10nF bypass
capacitor between BP and SGND. Do not apply an external load to BP.
Regulator On/Off Control Input. A logic high input (V
EN
>1.5V) turns on the
regulator, a logic low puts the MP1527 into low current shutdown mode.
Signal Ground
Input Supply
Output Switching Node. SW is the drain of the internal n-channel MOSFET.
Connect the inductor and rectifier to SW to complete the step-up converter.
Power Ground
Fault Input/Output.
FAULT
is an Input/Output that indicates that the MP1527
detected a fault and shuts the regulator off once a fault is indicated. Connect the
FAULT
input/outputs together for all MP1527 regulators to force all regulators off
when any one regulator detects a fault. Once a fault is detected, cycle EN or the
input power to restart the regulator. Pull
FAULT
to the input voltage through a
100kΩ resistor. Up to 20
FAULT
input/outputs can be connected in parallel.
Soft-Start Input. Connect a 10nF to 22nF capacitor from SS to SGND to set the
soft-start and fault timer periods. SS sources 2
µ
A to an external soft-start
capacitor during start-up and when a fault is detected. As the voltage at SS
increases to 1.2V, the voltage at COMP is clamped to 0.7V above the voltage at
SS limiting the startup current. Under a fault condition, SS ramps at the same rate
as in soft-start. When the voltage at SS reaches 1.2V,
FAULT
is asserted and the
regulator is disabled. The external capacitor at SS is discharged to ground when
not in use or when under voltage lockout or thermal shutdown occurs.
Regulation Feedback Input. Connect to external resistive voltage divider from the
output voltage to FB to set output voltage.
COMP
NC
BP
EN
SGND
IN
SW
PGND
14
7
FAULT
15
8
SS
16
9
FB
MP1527 Rev 1.8_8/31/05
Monolithic Power Systems, Inc.
NC
IN
3
MPS [ MONOLITHIC POWER SYSTEMS ]
