The part number " LM5017MRX/NOPB " corresponds to a DC-DC controller from Texas Instruments. It is part of the LM5017 series, which provides a high-efficiency, wide-input-range buck regulator. The "NOPB" indicates that it is a lead-free (Pb-free) version.
Pin Function Specification and Circuit Principle
The LM5017MRX/NOPB is available in the VQFN-16 package, which has 16 pins. Below is the detailed pinout description for this package:
Pin Function Table for LM5017MRX/NOPB (16-Pin VQFN Package) Pin Number Pin Name Pin Type Function Description 1 VIN Power Input This is the input voltage pin. It connects to the power supply, which typically operates from 6V to 100V. 2 EN Input Enable pin. A high logic level enables the operation, while a low logic level disables the device. 3 PGND Ground Power ground pin for the IC. This pin should be connected to the ground of the input power supply. 4 PGOOD Output Power-good output. This signal is asserted high when the output voltage is within regulation. 5 VOUT Power Output The regulated output voltage pin, which connects to the output load. It is the voltage you are regulating. 6 FB Analog Input Feedback pin. Connects to a voltage divider network to set the output voltage. 7 COMP Analog Input Compensation pin. Used for feedback loop compensation, ensuring stable operation. 8 SW Switch Node Switch node for the internal power switch. Connects to the external inductor and diode. 9 SS Analog Input Soft-start pin. This pin is used to control the ramp-up time of the output voltage during startup. 10 SLOPE Analog Input Slope compensation pin. Used to prevent subharmonic oscillation in certain duty cycles. 11 GND Ground Ground pin. Connect this to the system ground. 12 VCC Power Input Internal regulator output. This pin powers the internal circuitry of the IC. 13 VDD Power Input A second internal power supply pin used to power the control circuitry. 14 LSS Analog Input Low side switch sense pin. Used for sensing the current through the low-side switch. 15 VEE Power Input Voltage input pin used for controlling the output voltage. 16 NC No Connection This pin is not connected internally. It may be left floating in most applications.Principle of Operation
The LM5017 operates as a buck regulator, meaning it steps down a higher input voltage to a lower output voltage. Here is an overview of its working principle:
The input voltage is applied to the VIN pin. The device converts this voltage into a lower output through the SW pin, controlling the inductor and the external components to produce the desired output at VOUT. The FB pin is used to monitor the output voltage and adjust the switching operation to maintain regulation. A soft-start feature, controlled by the SS pin, ensures smooth power-up without excessive inrush current. The PGOOD pin informs the system when the output voltage is within the desired range.FAQ for LM5017MRX/NOPB
Q: What is the function of the EN pin on LM5017MRX/NOPB? A: The EN pin is the enable pin. A high logic level enables the operation of the regulator, while a low logic level disables it. Q: What is the recommended input voltage range for LM5017MRX/NOPB? A: The recommended input voltage range is from 6V to 100V. Q: How does the feedback mechanism work in LM5017MRX/NOPB? A: The feedback pin (FB) monitors the output voltage and adjusts the internal switching to maintain regulation at the desired output. Q: What is the significance of the PGOOD pin in LM5017MRX/NOPB? A: The PGOOD pin indicates when the output voltage is within the specified range, showing the health of the power supply. Q: How does the soft-start function work in the LM5017MRX/NOPB? A: The SS pin controls the soft-start process, which ramps the output voltage gradually to avoid excessive inrush current during power-up. Q: Can the LM5017MRX/NOPB operate without external components? A: No, the LM5017MRX/NOPB requires external components such as inductors, capacitor s, and resistors for proper operation. Q: What is the recommended operating temperature range for LM5017MRX/NOPB? A: The operating temperature range is from -40°C to 125°C. Q: What is the maximum output current for LM5017MRX/NOPB? A: The output current depends on external components, but the device itself can handle up to 2A of output current. Q: How do I select the feedback resistors for the LM5017MRX/NOPB? A: The feedback resistors should be selected to set the output voltage according to the following formula: VOUT = VREF * (1 + R1/R2), where VREF is the reference voltage (typically 0.8V).Q: Is the LM5017MRX/NOPB capable of synchronous operation?
A: Yes, the LM5017 supports both synchronous and asynchronous operation.Q: What is the role of the VCC pin in the LM5017MRX/NOPB?
A: The VCC pin provides power to the internal circuitry of the device.Q: Can I use the LM5017MRX/NOPB to regulate a negative output voltage?
A: No, the LM5017 is designed for positive voltage regulation only.Q: What kind of inductor should be used with the LM5017MRX/NOPB?
A: The inductor should be selected based on the desired output current and the switching frequency, typically in the range of 10µH to 100µH.Q: How does the LM5017MRX/NOPB achieve high efficiency?
A: The high efficiency is achieved through the use of advanced switching techniques, a low quiescent current design, and optimized external components.Q: Is the LM5017MRX/NOPB compliant with RoHS?
A: Yes, the LM5017MRX/NOPB is a lead-free (Pb-free) device and complies with RoHS standards.Q: What is the maximum duty cycle for the LM5017MRX/NOPB?
A: The maximum duty cycle is typically 85%.Q: Can the LM5017MRX/NOPB operate at high switching frequencies?
A: Yes, it can operate at switching frequencies up to 1 MHz.Q: How do I use the SLOPE pin on the LM5017MRX/NOPB?
A: The SLOPE pin is used to provide slope compensation to the regulator. It is typically used when the duty cycle is above 50%.Q: What is the role of the GND pin on the LM5017MRX/NOPB?
A: The GND pin is the ground connection for the power and signal grounds of the device.Q: What is the recommended output capacitor value for LM5017MRX/NOPB?
A: The recommended output capacitor value is typically in the range of 22µF to 100µF, depending on the application and desired output voltage ripple.This explanation provides a detailed breakdown of the LM5017MRX/NOPB, its pin functions, packaging details, and common questions regarding its usage and specifications.