MP1591 – 2A, 32V, 330KHz STEP-DOWN CONVERTER
MP1591 Rev. 2.3
www.MonolithicPower.com
3
9/21/2007
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© 2007 MPS. All Rights Reserved.
ELECTRICAL CHARACTERISTICS
(continued)
V
IN
= 12V, T
A
= +25
°
C, unless otherwise noted.
Parameter Symbol Condition
Min
Typ
Max
Units
Thermal Shutdown
(4)
160
°
C
REF Voltage
I
REF
= 0
5.0
V
REF Load Regulation
(4)
∆
I
REF
= 0 to 1mA
100
mV
REF Line Regulation
(4)
I
REF
= 100
μ
A, V
IN
= 6.5 to 32V
30
mV
Notes:
4) These parameters are guaranteed by design, not production tested.
5) Equivalent output current = 1.5A
≥
50% Duty Cycle
2.0A
≤
50% Duty Cycle
Assumes ripple current = 30% of load current.
Slope compensation changes current limit.
PIN FUNCTIONS
Pin # Name Description
1
BS
High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET
switch. Connect a 10nF or greater capacitor from SW to BS to power the high-side switch.
2
IN
Power Input. IN supplies the power to the IC, as well as the step-down converter switches.
Drive IN with a 6.5V to 32V power source. Bypass IN to GND with a suitably large capacitor to
eliminate noise on the input to the IC. See
Input Capacitor
.
3
SW
Power Switching Output. SW is the switching node that supplies power to the output. Connect
the output LC filter from SW to the output load. Note that a capacitor is required from SW to BS
to power the high-side switch.
4
GND Ground. For the MP1591DN, connect the Exposed Pad to pin 4.
5
FB
Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a resistive
voltage divider from the output voltage. The feedback threshold is 1.230V. See
Setting the
Output Voltage
.
6
COMP Compensation Node. COMP is used to compensate the regulation control loop. Connect a
series RC network from COMP to GND to compensate the regulation control loop. In some
cases, an additional capacitor from COMP to GND is required. See
Compensation.
7
EN
Enable/UVLO. A voltage greater than 2.8V enables operation. For complete low current
shutdown the EN pin voltage needs to be less than 800mV.
8
REF Reference Output. REF is the 5V reference voltage output. It can supply up to 1mA to external
circuitry. If used, bypass REF to GND with 10nF or greater capacitor. Leave REF unconnected
if not used.