Analog Devices Inc. LTC3388IDD-1#PBF

Overview

LTC3388IDD-1#PBF from Analog Devices (formerly Linear Technology) is a 20V-input, 50mA synchronous step-down DC/DC converter with nanopower quiescent current (720nA at 4V input, no load), pin-selectable 1.2V/1.5V/1.8V/2.5V outputs, and integrated high-side PMOS and low-side NMOS switches. It delivers regulated power for ultra-low-power sensor nodes and battery-backed systems where sleep-state IQ and UVLO (2.3V threshold) are critical.

For engineers reviewing the LTC3388IDD-1#PBF datasheet, LTC3388IDD-1#PBF pinout, LTC3388IDD-1#PBF application, or LTC3388IDD-1#PBF equivalent, key selection criteria include its 720nA no-load IQ, hysteretic control architecture, 10-lead 3mm × 3mm DFN package with exposed thermal pad, standby mode for ripple-sensitive loads, and precise output voltage selection via D0/D1 logic inputs.

Technical Context

The LTC3388IDD-1#PBF implements a hysteretic synchronous buck topology with internal rail generation: CAP (gate drive for PMOS, regulated at VIN – 4.8V) and VIN2 (gate drive for NMOS and logic reference, regulated at 4.6V above GND). It operates in burst-mode sleep cycles-switching only when VOUT falls below the sleep threshold-to maintain regulation while minimizing average IQ.

Its UVLO circuit disables the converter below 2.3V (typical), reducing IQ to 400nA; EN and STBY pins enable full shutdown and low-ripple standby modes respectively. The PGOOD open-drain output asserts Hi-Z when VOUT exceeds 92% of the selected voltage and remains asserted during input dropout if VOUT stays above threshold.

Key Specifications

Pinout & Package

Package: 10-Lead (3mm × 3mm) Plastic DFN with exposed thermal pad (Pin 11 = GND, must be soldered to PCB ground plane).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nanopower step-down regulator applications.

Compared with TPL7407LPWPR and TPS62840DLCR, the LTC3388IDD-1#PBF uniquely combines 20V input tolerance, pin-selectable 1.2V–2.5V outputs, 720nA IQ, and hardware standby mode in a thermally enhanced 3mm × 3mm DFN-making it optimal for rugged, flexible, and long-life embedded power designs.

Availability

LTC3388IDD-1#PBF is available at Aetrix Electronics and suitable for wireless sensor nodes, industrial process monitoring, and portable medical wearables requiring stable component supply across extended temperature ranges (–40°C to 125°C) and long product lifecycles.

Supply support for LTC3388IDD-1#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors for precision, industrial, and automotive applications.

The LTC3388 series was designed specifically for ultra-low-power, wide-input-voltage DC/DC conversion in battery- and energy-harvesting–powered edge devices-emphasizing nanopower IQ, robust UVLO, and minimal external component count.

FAQ

What is the maximum input voltage rating for the LTC3388IDD-1#PBF?

The LTC3388IDD-1#PBF has an absolute maximum input voltage rating of 22V, with guaranteed operation from 2.7V to 20V. Operating continuously at 20V is supported across the full –40°C to 125°C junction temperature range, and the device maintains sub-1µA no-load IQ even at 20V input.

How does the LTC3388IDD-1#PBF achieve 720nA quiescent current?

The LTC3388IDD-1#PBF achieves 720nA typical input quiescent current through a combination of hysteretic control (eliminating continuous oscillator and error amplifier bias), deep sleep mode (disabling all switching and most internal circuits between regulation events), and optimized internal rail generation. Its 400nA UVLO current further reduces drain during battery exhaustion.

Can the output voltage of the LTC3388IDD-1#PBF be changed dynamically during operation?

Yes-the LTC3388IDD-1#PBF allows dynamic output voltage reconfiguration via D0 and D1 pins while in regulation. As shown in the datasheet's Figure 3, changing D0/D1 states causes PGOOD to briefly assert low only when transitioning to a higher output voltage; transitions to lower voltages maintain PGOOD high throughout, enabling seamless voltage scaling in adaptive power systems.

What is the purpose of the CAP and VIN2 pins on the LTC3388IDD-1#PBF?

CAP (Pin 3) provides gate drive for the internal high-side PMOS switch and is regulated at VIN – 4.8V; VIN2 (Pin 7) provides gate drive for the low-side NMOS and serves as the logic reference for EN, STBY, D0, and D1-regulated at 4.6V above GND. Neither pin is intended as a system supply rail; each requires its own dedicated bypass capacitor (1µF for CAP, 4.7µF for VIN2) and must not be loaded externally.

Does the LTC3388IDD-1#PBF require an external feedback resistor network?

No-the LTC3388IDD-1#PBF uses an internal precision feedback network tied to the VOUT pin. Output voltage is selected solely by the logic states of D0 and D1 pins (GND or VIN2), eliminating external resistors, trimming, and associated tolerance errors. This architecture ensures ±1% initial accuracy and tight temperature drift across all four output options (1.2V, 1.5V, 1.8V, 2.5V).