Overview
The LM5085QMYX/NOPB is a high-efficiency PFET switching regulator controller designed by Texas Instruments. This controller is suitable for developing small, efficient buck regulators for a wide range of applications. It features a PFET gate driver and a constant on-time control scheme, which simplifies the design and enhances performance. The LM5085QMYX/NOPB is available in automotive grade (LM5085-Q1), which is AEC-Q100 Grade 1 qualified, operating from -40°C to 125°C junction temperature.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Voltage (VIN) | 4.5 | 75 | V | |
| Junction Temperature | -40 | 125 | °C | |
| Switching Frequency | Variable, dependent on VIN and RT resistor | Hz | ||
| Maximum Load Current | 10 | A | ||
| Package Types | HVSSOP (8), WSON (8), VSSOP (8) | |||
| Thermal Resistance (θJA) | 153 (HVSSOP), 44.8 (WSON), 54.1 (VSSOP) | °C/W |
Key Features
- Wide Input Voltage Range: 4.5V to 75V, making it versatile for various applications.
- Constant On-Time Control: Ensures a relatively constant switching frequency regardless of input voltage variations.
- PFET Gate Driver: Simplifies gate drive requirements and allows for 100% duty cycle operation at low input voltages.
- High Efficiency: Optimized for high efficiency and fast load transient response due to the absence of loop compensation.
- Automotive Grade: LM5085-Q1 is AEC-Q100 Grade 1 qualified, suitable for automotive applications.
- Thermal Shutdown and Current Limiting: Features thermal shutdown and current limiting to protect the device from overcurrent and overheating conditions.
- Compact Packages: Available in HVSSOP, WSON, and VSSOP packages to aid in heat dissipation and compact design.
Applications
- Automotive Infotainment Systems: Suitable for the high voltage and reliability requirements of automotive systems.
- Battery/Super Capacitor Chargers: Ideal for charging applications due to its wide input voltage range and high efficiency.
- LED Drivers: Can be used in LED lighting systems requiring stable and efficient power supply.
- General Power Supply Applications: Applicable in various power supply designs where high efficiency and reliability are crucial.
Q & A
- What is the input voltage range of the LM5085QMYX/NOPB?
The input voltage range is from 4.5V to 75V.
- What is the maximum load current for the LM5085QMYX/NOPB?
The maximum load current is 10A.
- What are the available package types for the LM5085QMYX/NOPB?
The device is available in HVSSOP, WSON, and VSSOP packages.
- How does the constant on-time control scheme work?
The constant on-time control scheme ensures a relatively constant switching frequency by adjusting the on-time inversely proportional to the input voltage.
- Is the LM5085QMYX/NOPB suitable for automotive applications?
Yes, the LM5085-Q1 version is AEC-Q100 Grade 1 qualified, making it suitable for automotive applications.
- What are the thermal shutdown and current limiting features?
The device features thermal shutdown to protect against overheating and current limiting to protect against overcurrent conditions.
- How does the device handle load transient response?
The device has a very fast load transient response due to the absence of loop compensation in its control scheme.
- Can the LM5085QMYX/NOPB operate at 100% duty cycle?
Yes, the device can operate at 100% duty cycle when the input voltage falls to a level equal to or less than the regulated output voltage.
- What is the purpose of the RT pin in the LM5085QMYX/NOPB?
The RT pin is used to set the switching frequency and can also be used to shutdown the device by grounding it.
- How does the current limiting function work in the LM5085QMYX/NOPB?
The current limiting function operates by sensing the voltage across either the RDS(ON) of Q1 or a sense resistor and comparing it to the voltage across the resistor RADJ.
