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Home > Step Down Switching Regulators
UD05123 Datasheet








UTC UD05123 is a 2.25MHz constant frequency current mode

PWM step-down converter. It is ideal for portable equipment

requiring very high current up to 1.8A from single-cell Lithium-ion

batteries while still achieving over 90% efficiency during peak load

conditions. The 2.5V to 5.5V input voltage range makes UTC

UD05123 ideally suited for single Li-Ion, two to four AA

battery-powered applications. 100% duty cycle provides low

dropout operation, extending battery life in portable systems. Pulse

skipping mode operation provides very low output ripple voltage for

noise sensitive applications. Switching frequency is internally set at

2.25MHz, allowing the use of small surface mount inductors and

capacitors. The internal synchronous switch increases efficiency

and decreases need of an external Schottky diode. Low output

voltages are easily supported with the 0.6V feedback reference





* Input Voltage Range :2.5V~5.5V

* Output Voltage: from 0.6V to VIN

* High Efficiency: Up to 92%

* Constant Frequency Operation: 2.25MHz

* Output Current:1.2A

* Quiescent Current: 50uA (input < 4.2V)

* No Schottky Diode Required

* 100% Duty Cycle in Dropout

* 0.6V Reference Allows Low Output Voltages

* Current Mode Operation for Excellent Line and Load Transient Response

* Current limit, Enable function

* Short Circuit Protect (SCP)

* ≤1μA Shutdown Current

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