TX9123 General Description:
The TX9123 using the external NMOSFET. It is a high efficiency boost converter with 600mV feedback voltage. A switching frequency of 550KHz minimizes solution footprint by allowing the use of tiny low profile inductors and ceramic capacitors.
The current mode PWM/PFM design is internally compensated, and the device has a 1.6V startup voltage with 1mA load. It needs few external components, only inductance, resistance and capacitance can meet the driving capacity.
TX9123 Features:
Min1.6V Startup @1mA Load
600mV Feedback Voltage
550KHz Internal Oscillator
Soft Startup: 10mS Typical
Peak Current Programmable by Bottom Sensing Resistor
300μA Typical Iq
Internal PWM/PFM Auto Mode Switching
Up to 90% Efficiency l External Enable
Power OFF Current<1μA
Over Voltage Protection
140℃ Thermal Shut Down, 20℃ Hysteresis
TX9123 Applications:
USB Charger
TX9123 Block Diagram：
TX9123 Pin Assignment：
TX9123 Application Circuits
1) Power supply tied to VOUT
2) Power supply tied to VIN(VIN>2.8V)
3) External Component Recommendation:
1) Rlim=50mOhm *(2)
2) Cin=22uF
3) Cout=10uF *(1)
4) L=2.2uH
5) CF=0.1uF
*(1) Cout needs to increase when reducing Rlim value. For example, Rlim=25mOh -> Cout=20uF
*(2) Selection table
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Test Condition: Vin=3.3V, Vout=5V, L=3.3uH
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Rlim (mOhm)
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Max load current (A)
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200
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0.5
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100
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1
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50
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2
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25
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3
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