LT3971AIMSE-5#PBF

Overview

The LT3971AIMSE-5#PBF is a monolithic buck switching regulator from Analog Devices, featuring a 38V maximum input voltage and 1.2A output current capability. It operates at a 2MHz switching frequency with ultra-low quiescent current of 2.8µA during regulation and 1.7µA in standby. The device uses Burst Mode operation to maintain high efficiency at light loads while keeping output ripple below 15mV. It includes an internally compensated current-mode topology for fast transient response, a 0.33Ω internal switch, and a power good flag. The part is housed in a 10-lead MSOP package with an exposed thermal pad.

Feature Summary

• Ultra-low quiescent current design consumes only 2.8µA while regulating with no load, reducing to 700nA when shutdown via the enable pin.
• Burst Mode operation maintains high efficiency at low output currents while ensuring output ripple remains below 15mV in typical applications.
• Internally compensated current-mode topology provides fast transient response and stable loop performance without external compensation components.
• Accurate reference voltage and specified VOUT pin current make the -5 suffix variant suitable for strict USB application requirements.

Applications

• USB-powered portable devices requiring efficient step-down conversion
• Battery-operated equipment needing extended runtime through low quiescent current
• Space-constrained designs utilizing small MSOP packaging

Procurement Notes

Verify the specific suffix '-5' indicates the variant with specified VOUT pin current and ABSMAX current parameters, which are critical for USB compliance. Confirm the 'I' grade denotes industrial temperature range operation from -40°C to +85°C. Ensure the '#PBF' suffix confirms lead-free RoHS-compliant packaging. Cross-reference the manufacturer datasheet for any recent PCN updates regarding epoxy changes or marking modifications before finalizing procurement orders.

Selection Notes

Select this component when input voltages reach up to 38V and output currents around 1.2A are required. The adjustable frequency feature allows optimization for size versus efficiency trade-offs. Choose the -5 variant over standard versions if precise output pin current specifications are mandatory for the target application interface. Consider the exposed pad for thermal management in high-power density layouts.

Part Context

This part belongs to the LT3971 family of high-efficiency buck regulators. The LT3971A series offers improved reference accuracy compared to earlier LT3971 models. The -5 designation specifically addresses USB application needs by defining stricter output pin current limits. The AIMSE package variant combines industrial temperature rating with the compact MSOP form factor.

Replacement Considerations

LT3971IMSE-5#PBF serves as a direct equivalent with commercial temperature rating instead of industrial. LT3971EMSE-5#PBF offers extended military/industrial temperature range options. Standard LT3971 variants lack the specific VOUT pin current specifications required for certain USB implementations.