LM2687LDX/NOPB

The LM2687LDX/NOPB is a versatile constant-frequency, current mode, DC-DC switching regulator controller that is designed for ease of use with minimal external components.

This switch mode power supply controller features an excellent combination of features including an adjustable switching frequency, a high-side sense input, a per-phase current sense amplifier and a comprehensive selection of protections. The LM2687LDX/NOPB series operates over a wide input voltage range of 6V to 32V and it is available in a space-saving 3mm x 3mm package.

The LM2687LDX/NOPB is designed for a wide range of applications such as satellite and cable TV systems, DSL modems, LCD TVs, printer power supplies, battery chargers and OEM medical systems.

Applications

The LM2687LDX/NOPB is ideal for a range of different purposes including:

• Telecommunications systems
• High-brightness LED (HB LED) drivers
• SMPS/Battery charging
• Battery powered products
• Computer power supplies
• Industrial Power Supplies
• DC-DC Converters

Working principle

The internal linear regulator on the LM2687LDX/NOPB provides very low output voltage noise and good transient response, making it well suited for use in sensitive electronics.

The LM2687LDX/NOPB operates in current mode for fast transient response, voltage mode for easy composition, and hysteretic mode for lower power and output ripple. An adjustable frequency oscillator with a range from 200kHz to 1.2MHz enables the user to optimize the power supply design for any load current.

The LM2687LDX/NOPB features a high-side current sensing amplifier which can be configured to measure either the input or output current. The current sense amplifier is used to provide low-cost and accurate protection features such as over-current protection (OCP), short-circuit protection (SCP) and over-temperature protection (OTP)

Additional features include under-voltage lockout (UVLO), output voltage and current control, thermal shutdown, and hiccup mode. All these features make the LM2687LDX an excellent choice for a wide range of DC-DC conversions.

Conclusion

The LM2687LDX/NOPB is an excellent choice for a wide range of DC-DC converter applications due to its adjustable switching frequency, high-side sense input, per-phase current sense amplifier, and comprehensive selection of protection features. The LM2687LDX/NOPB also operates over a wide input voltage range of 6V to 32V, making it suitable for a variety of applications.