LM3478Q-Q1 40V Wide Vin low-side N-channel controller for switching Regulators with 10µA shutdown current | TI.com

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40V Wide Vin low-side N-channel controller for switching Regulators with 10µA shutdown current


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  • LM5155-Q1  - The device has the SAME FUNCTIONALITY as the compared device, but is not pin-for-pin equivalent and may not be parametrically equivalent.   For applications requiring lower quiescent current or higher efficiency


The LM3478Q-Q1 is a versatile Low-Side N-Channel MOSFET controller for switching regulators. It is suitable for use in topologies requiring a low side MOSFET, such as boost, flyback, SEPIC, etc. Moreover, the LM3478Q-Q1 can be operated at extremely high switching frequency in order to reduce the overall solution size. The switching frequency of the LM3478Q-Q1 can be adjusted to any value between 100 kHz and 1 MHz by using a single external resistor. Current mode control provides superior bandwidth and transient response, besides cycle-by-cycle current limiting. Output current can be programmed with a single external resistor.

The LM3478Q-Q1 has built in features such as thermal shutdown, short-circuit protection, over voltage protection, etc. Power saving shutdown mode reduces the total supply current to 5 µA and allows power supply sequencing. Internal soft-start limits the inrush current at start-up.


  • LM3478Q-Q1 is AEC-Q100 Qualified and Manufactured on an Automotive Grade Flow
  • 8-lead VSSOP-8
  • Internal Push-Pull Driver With 1-A Peak Current Capability
  • Current Limit and Thermal Shutdown
  • Frequency Compensation Optimized With a Capacitor and a Resistor
  • Internal Soft Start
  • Current Mode Operation
  • Undervoltage Lockout With Hysteresis
  • Create a Custom Design Using the LM3478 with the WEBENCH Power Designer

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Part number Order Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Regulated outputs (#) Switching frequency (Min) (kHz) Switching frequency (Max) (kHz) Iq (Typ) (mA) Features Duty cycle (Max) (%) Operating temperature range (C) Rating Type Package Group
LM3478Q-Q1 Order now 2.97     40     1.26     500     1     100     1000     2.7     Adjustable Current Limit
Frequency Synchronization
Light Load Efficiency
Pre-Bias Start-Up    
100     -40 to 125     Automotive     Controller     VSSOP | 8