Overview
The LM5121MHX/NOPB is a wide input range synchronous boost controller produced by Texas Instruments. This controller is designed for high-efficiency, high-power boost regulator applications. It employs peak current mode control, which provides inherent line feed-forward and ease of loop compensation. The device features robust integrated 3-A gate drivers with adaptive dead-time control and supports switching frequencies up to 1 MHz, either set by a single resistor or synchronized to an external clock. The LM5121 also includes a range of protection features such as thermal shutdown, hiccup mode over load and short circuit protection, and remote shutdown capability.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit |
|---|---|---|---|---|
| Input Supply Voltage (VIN) | 4.5 | - | 65 | V |
| Output Voltage | - | - | 100 | V |
| Switching Frequency | - | - | 1 MHz | - |
| Junction Temperature (TJ) | -40 | - | 125 | °C |
| High-Side Driver Bias Voltage (BST to SW) | 3.8 | - | 14 | V |
| Low Shutdown Quiescent Current | - | - | 9 μA | - |
| Package Type | - | - | 20-Pin HTSSOP | - |
Key Features
- AEC-Q100 Qualified with an ambient operating temperature range of -40°C to +125°C.
- Maximum input voltage of 65 V and minimum input voltage of 3.0 V (4.5 V for startup).
- Output voltage up to 100 V.
- Bypass operation (VOUT = VIN).
- 1.2-V reference with ±1.0% accuracy.
- Free-run/synchronizable up to 1 MHz.
- Peak current mode control.
- Robust integrated 3-A gate drivers with adaptive dead-time control.
- Optional diode emulation mode.
- Programmable cycle-by-cycle current limit.
- Programmable line UVLO.
- Programmable soft-start.
- Thermal shutdown protection.
- Low shutdown quiescent current: 9 μA.
- Programmable slope compensation.
- Programmable skip cycle mode reduces standby power.
- Supports external VCC bias supply option.
- Load disconnection in shutdown mode (True Shutdown).
- Inrush current limiting.
- Hiccup mode short circuit/overload protection.
- Circuit breaker function.
- Capable of input transient suppression and reverse battery protection.
Applications
- 12-V, 24-V, and 48-V power systems.
- Automotive start-stop systems.
- High current boost power supply.
- Battery-powered systems.
Q & A
- What is the maximum input voltage of the LM5121?
The maximum input voltage of the LM5121 is 65 V. - What is the minimum input voltage required for startup?
The minimum input voltage required for startup is 4.5 V. - What is the maximum output voltage the LM5121 can support?
The LM5121 can support an output voltage up to 100 V. - What control method does the LM5121 use?
The LM5121 uses peak current mode control. - What is the maximum switching frequency of the LM5121?
The maximum switching frequency of the LM5121 is up to 1 MHz. - Does the LM5121 support synchronization with an external clock?
Yes, the LM5121 supports synchronization with an external clock. - What protection features does the LM5121 include?
The LM5121 includes thermal shutdown, hiccup mode over load and short circuit protection, and remote shutdown capability. - What is the quiescent current in shutdown mode?
The quiescent current in shutdown mode is 9 μA. - Does the LM5121 have a true shutdown feature?
Yes, the LM5121 has a true shutdown feature that disconnects the load from the input. - What are some common applications of the LM5121?
The LM5121 is commonly used in 12-V, 24-V, and 48-V power systems, automotive start-stop systems, high current boost power supplies, and battery-powered systems.
