Analog Devices Inc. LTC3388EMSE-1#PBF

Overview

LTC3388EMSE-1#PBF from Analog Devices (formerly Linear Technology) is a 20V-input, 50mA synchronous step-down DC/DC converter with nanopower quiescent current, internal high-side PMOS and low-side NMOS switches, and pin-selectable 1.2V/1.5V/1.8V/2.5V output. It operates in hysteretic sleep mode to maintain regulation at loads as low as 10µA and supports keep-alive power for battery-backed sensors.

For engineers reviewing the LTC3388EMSE-1#PBF datasheet, LTC3388EMSE-1#PBF pinout, LTC3388EMSE-1#PBF application, or LTC3388EMSE-1#PBF equivalent, key selection criteria include ultralow 720nA no-load IQ at 4V VIN, 2.7V–20V input range, 10-lead MSOP package thermal performance (θJA = 45°C/W), and precise output voltage selection via D0/D1 logic pins.

Technical Context

The LTC3388EMSE-1#PBF implements a hysteretic synchronous buck architecture 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). Sleep mode uses a low-power comparator to monitor VOUT against ±8mV hysteresis around the selected output voltage.

It features undervoltage lockout (UVLO rising threshold = 2.3V), standby mode that disables switching while preserving PGOOD and sleep monitoring, and open-drain PGOOD with 92% falling threshold. Output voltage selection is static via D0/D1 tied to GND or VIN2 - no dynamic reconfiguration during regulation is required.

Key Specifications

Pinout & Package

Package: 10-Lead Plastic MSOP (MSE) with exposed thermal pad (Pin 11 = GND), θJA = 45°C/W, θJC = 10°C/W. Exposed pad must be soldered to PCB ground plane via multiple vias.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LPWPR and TPS62840DRVR, the LTC3388EMSE-1#PBF uniquely combines 20V input capability, pin-selectable outputs, integrated PGOOD/UVLO, and 720nA IQ - making it the only option for long-life, wide-input, feature-complete nanopower buck regulation in MSOP packaging.

Availability

LTC3388EMSE-1#PBF is available at Aetrix Electronics and suitable for wireless sensor nodes, industrial RTU keep-alive supplies, and portable medical diagnostic devices requiring stable component supply across extended temperature ranges (–40°C to 125°C).

Supply support for LTC3388EMSE-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 acquired Linear Technology in 2017 and maintains its precision analog and power management product lines with full technical documentation and long-term support.

The LTC3388 series was designed specifically for nanopower, wide-input, battery-backed applications - emphasizing ultra-low IQ, integrated protection, and simplified design for space- and energy-constrained systems.

FAQ

What is the maximum input voltage rating for the LTC3388EMSE-1#PBF?

The LTC3388EMSE-1#PBF has an absolute maximum input voltage rating of 22V, with guaranteed operation from 2.7V to 20V. Operation above 20V risks permanent damage, and the device enters UVLO below 2.3V to prevent unstable regulation. This 2.7V–20V range makes LTC3388EMSE-1#PBF suitable for 9V and 12V industrial rails as well as depleted alkaline or lithium primary cells.

How does the LTC3388EMSE-1#PBF achieve 720nA quiescent current?

The LTC3388EMSE-1#PBF achieves 720nA typical input quiescent current through a combination of deep-sleep hysteresis control, gated internal rail generation, and zero-crossing NMOS conduction during inductor freewheeling. In sleep mode, only the VOUT comparator and bias circuitry remain active - all switching, gate drivers, and PGOOD comparators are disabled. This architecture is validated in the LTC3388EMSE-1#PBF's Electrical Characteristics table under "IQ (VIN Quiescent Current When Enabled, Sleep)".

Can the output voltage of the LTC3388EMSE-1#PBF be changed dynamically during operation?

Yes - the LTC3388EMSE-1#PBF allows dynamic output voltage changes via D0 and D1 pins while in regulation, as confirmed in the Applications Information section (Figure 3). When transitioning to a higher output voltage, PGOOD goes low until regulation is re-established; when transitioning lower, PGOOD remains asserted. This behavior is intrinsic to LTC3388EMSE-1#PBF's internal feedback architecture and requires no external sequencing.

What is the purpose of the CAP and VIN2 pins on the LTC3388EMSE-1#PBF?

CAP (Pin 3) is an internal rail regulated at VIN – 4.8V and supplies gate drive to the high-side PMOS switch; VIN2 (Pin 7) is regulated at 4.6V and supplies gate drive to the low-side NMOS switch plus logic high for EN, STBY, D0, and D1. Neither pin is intended as an external supply - both require dedicated bypass capacitors (1µF for CAP, 4.7µF for VIN2) and must not be loaded. This dual-rail generation is fundamental to LTC3388EMSE-1#PBF's ability to operate up to 20V input while using standard-voltage MOSFETs.

Does the LTC3388EMSE-1#PBF require an external feedback resistor network?

No - the LTC3388EMSE-1#PBF uses internal feedback with pin-selectable output voltages (1.2V/1.5V/1.8V/2.5V) determined solely by the logic states of D0 and D1. There is no external resistor divider; the VOUT pin connects directly to the output capacitor. This eliminates resistor tolerance errors, reduces component count, and improves long-term stability - a defining feature of the LTC3388EMSE-1#PBF versus conventional adjustable buck regulators.