MP1494 – SYNCHRONOUS STEP-DOWN CONVERTER
PIN FUNCTIONS
Package
Pin #
Name Description
Advanced Asynchronous Modulation. Connect to a voltage supply through 2 resistor
dividers to force the MP1494 into non-synchronous mode under light loads. Drive AAM
pin high (VCC) to force the MP1494 into CCM.
1
AAM
Supply Voltage. The MP1494 operates from a 4.5V-to-16V input rail. Requires C1 to
decouple the input rail. Connect using a wide PCB trace.
2
3
4
IN
SW
Switch Output. Connect using a wide PCB trace.
System Ground. Reference ground of the regulated output voltage. Requires special
consideration during PCB layout. Connect to GND with copper traces and vias.
GND
Bootstrap. Requires a capacitor between SW and BST pins to form a floating supply
across the high-side switch driver. A 10Ω resistor placed between SW and BST cap is
strongly recommended to reduce SW spike voltage.
5
BST
EN high to enable the MP1494. Apply an external clock can to the EN pin to change the
switching frequency.
6
7
EN/SYNC
VCC
Bias Supply. Decouple with a 0.1μF-to-0.22μF capacitor. The capacitance should not
exceed 0.22μF. VCC capacitor should be put closely to VCC pin and GND pin.
Feedback. Connect to the tap of an external resistor divider from the output to GND to set
the output voltage. The frequency fold-back comparator lowers the oscillator frequency
when the FB voltage is below 400mV to prevent current-limit run-away during a short-
circuit fault condition.
8
FB
MP1494 Rev. 1.04
12/26/2012
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