LM3488MM/NOPB IC

Technical Specifications of LM3488MM/NOPB

Datasheet	LM3488MM/NOPB datasheet
Category	Integrated Circuits (ICs)
Family	PMIC – Voltage Regulators – DC DC Switching Controllers
Manufacturer	Texas Instruments
Series	–
Packaging	Tape & Reel (TR)
Part Status	Active
Output Type	Transistor Driver
Function	Step-Up, Step-Up/Step-Down
Output Configuration	Positive
Topology	Boost, Flyback, SEPIC
Number of Outputs	1
Output Phases	1
Voltage – Supply (Vcc/Vdd)	2.97 V ~ 40 V
Frequency – Switching	100kHz ~ 1MHz
Duty Cycle (Max)	100%
Synchronous Rectifier	No
Clock Sync	Yes
Serial Interfaces	–
Control Features	Enable, Frequency Control
Operating Temperature	-40°C ~ 125°C (TJ)
Package / Case	8-TSSOP, 8-MSOP (0.118″, 3.00mm Width)
Supplier Device Package	8-VSSOP

LM3488MM/NOPB Introduction

The LM3488 is a high-performance low-side N-FET controller designed for switching regulators. This device can operate at extremely high switching frequencies and is suited for boost, flyback, or SEPIC topologies, making it a great alternative for applications requiring low-side FETs. The LM3488 is a dependable and efficient voltage regulator with various built-in features such as thermal shutdown, short-circuit protection, and overvoltage protection. The LM3488 is an excellent choice for automotive applications because of its automotive-grade product and AEC-Q100 approval.

General Description

The LM3488 is a high-performance low-side N-FET controller for switching regulators. This device is appropriate for boost, flyback, or SEPIC topologies requiring low-side FETs. Furthermore, the LM3488 may be operated at exceptionally high switching frequencies, reducing total solution size. By utilizing a single external resistor or syncing it to an external clock, the LM3488 switching frequencycan be modified to any value between 100 kHz and 1 MHz. Aside from cycle-by-cycle current limitation, current mode control provides greater bandwidth and transient response. A single external resistor can be used to program the output current.

Thermal shutdown, short-circuit, and overvoltage protection are all included in the LM3488. Power-saving shutdown mode limits total supply current to 5 A and enables power supply sequencing. Internal soft-start reduces inrush current at startup.

Features

• AEC-Q100 qualified product of automotive grade.
• VSSOP Package with 8 Leads.
• Internal Push-Pull Driver Capable of 1-A Peak Current.
• Thermal shutdown and current limit.
• A Capacitor and a Resistor are used to optimize frequency compensation.
• Internal Soft-Beginning.
• Operation in Current Mode.
• With hysteresis, an undervoltage lockout is achieved.

Detailed Description

The LM3488 voltage regulator has a fixed frequency, pulse width modulated (PWM), and current mode control design. The peak current of an external MOSFET is monitored using an external sense resistor in a typical application design, and the voltage across this resistor is sent into the ISEN pin. This voltage is subsequently level-shifted and applied to the PWM comparator’s positive input. The feedback voltage is monitored and sent into the error amplifier’s negative input (feedback pin, FB) through an external feedback resistor divider network. The error amplifier’s output (COMP pin) is then added to the slope correction ramp and given to the PWM comparator’s negative input.

The oscillator uses the SET/Blank-out and switches logic blocks to set the RS latch at the start of each switching cycle. This causes a high signal on the DR Pin (the external MOSFET’s gate), causing the external MOSFET to turn on. When the voltage on the PWM comparator’s positive input exceeds the voltage on the negative input, the RS latch is reset, and the external MOSFET is turned off.

However, it is crucial to note that the voltage detected across the sense resistor frequently contains spurious noise spikes.

To ensure the LM3488’s dependable operation, precautions are required to prevent spurious noise spikes from prematurely resetting the RS latch. Spikes in the voltage measured across the external sensing resistor, supplied into the PWM comparator, can cause these spikes. To overcome this issue, the IC includes a blank-out circuit that temporarily disables the PWM comparator’s ability to reset the latch after it has been set. This blank-out time, which lasts about 150ns, prevents the latch from resetting prematurely due to spurious noise spikes.

When the external MOSFET is turned on during the blank-out period, and there is little or no load, the output capacitor’s energy may exceed what the load requires, resulting in an over-voltage condition. To avoid this, the LM3488 has an over-voltage comparator that monitors the feedback voltage (FB pin) and resets the RS latch if the output voltage becomes too high. The latch is reset until the output voltage has decayed to its nominal value.

Power Supply Recommendations

The LM3488 is a versatile DC-DC converter that may power various sources, including a car battery. However, the VIN input must be protected from reverse voltage and voltage spikes greater than 48 volts. It’s also critical to ensure the input supply rail’s impedance is low enough to prevent voltage drops below the VIN UVLO threshold caused by input current transients. Additional bulk capacitance and the regular input capacitor may be necessary to maintain stable operation when the input supply is connected through lengthy cables. If these instructions are followed, the LM3488 can deliver reliable and efficient power conversion from various DC power sources.

Layout

● Layout Guidelines

The arrangement should limit the loop area between the power switches and the sense resistor to minimize the effect of switching noise. This can be accomplished by positioning the sense resistor near the MOSFET switch and reducing the length and size of the traces connecting the sense resistor and the LM3488. To decrease the loop area, the output capacitor should also be placed as close to the device as practicable. A ground plane should also offer a low-impedance channel for return currents and reduce the loop area for high-current paths.

Additionally, the placement and routing of the input and output filter capacitors are critical for EMI reduction. The capacitors should be as close to the LM3488 as possible, with short, wide traces connecting them. Traces should also be maintained away from high-impedance nodes like the feedback loop and voltage divider network.

Finally, ensure the gadget is thermally coupled to a ground plane or a heatsink. This can be accomplished by connecting the device’s thermal pad to the ground plane or heatsink via vias placed right beneath the thermal pad. Thermal management is critical for preventing device overheating and ensuring reliable operation. The most critical layout criterion is keeping the alternating current loops as short as feasible.

Conclusion

The LM3488 is a high-performance controller with several built-in capabilities, making it an excellent choice for various applications. Its capacity to work at extremely high switching frequencies and the ease with which it may be changed make it an appealing alternative for those seeking efficient power conversion solutions. The LM3488 can deliver dependable and efficient power conversion from various DC power sources if followed by layout guidelines and power supply recommendations. It is a dependable and efficient voltage regulator due to its thermal management and built-in protection features.

ICRFQ is the place to be if you need to buy LM3488MM/NOPB or any other electrical component. Our qualified professionals give skilled help at a reasonable cost to ensure the success of your project. Contact us now to learn more and get the best components for your needs. Allow us to help you make your ideas a reality.

The Latest And Most Popular Parts That You May Also Like