Analog Devices Inc. LTC3536IMSE#PBF

Overview

LTC3536IMSE#PBF from Analog Devices (formerly Linear Technology) is a 1.8V–5.5V input, synchronous 4-switch buck-boost DC/DC converter delivering up to 1A continuous output current at ±1% voltage accuracy with programmable 300kHz–2MHz switching frequency and 32µA quiescent current in Burst Mode. It operates seamlessly across buck, boost, and buck-boost regions-ideal for battery-powered RF and precision measurement systems where input voltage may dip below or rise above the regulated output.

For engineers reviewing the LTC3536IMSE#PBF datasheet, LTC3536IMSE#PBF pinout, LTC3536IMSE#PBF application, or LTC3536IMSE#PBF equivalent, key selection criteria include its low-noise fixed-frequency PWM/Burst Mode operation, internal soft-start, output disconnect in shutdown, and thermal performance in the 12-pin MSOP package with exposed PGND pad.

Technical Context

The LTC3536IMSE#PBF implements a proprietary 4-switch buck-boost topology with two integrated P-channel and two N-channel MOSFETs, enabling regulation when VIN is above, below, or equal to VOUT without mode transition artifacts. Its voltage-mode control loop uses an internal error amplifier (90dB AVOL) with external Type III compensation via VC–FB network.

Switching is governed by a resistor-programmable oscillator (RT pin) or external synchronization via MODE/SYNC pin (0.3–2MHz range), while dual current limiting-input current limit (2.5A typ.) and peak switch current limit (3.4A typ.)-protects against overload and short-circuit faults. Reverse current limiting (0.55A typ.) prevents damage during output precharge or supply back-driving.

Key Specifications

Pinout & Package

The LTC3536IMSE#PBF is housed in a thermally enhanced 12-lead plastic MSOP package (MSE) with exposed PGND pad (Pin 13), rated for θ_JA = 40°C/W. The exposed pad must be soldered to PCB ground for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck-boost regulator applications.

Compared with LTC3536IMSE#PBF, TPS63020DSJR offers lower cost but sacrifices current capability and reverse current protection, while MAX20034ATPA/VY+ adds automotive reliability at the expense of programmability and ultra-low IQ - making LTC3536IMSE#PBF optimal for portable precision electronics demanding seamless buck-boost operation and minimal standby drain.

Availability

LTC3536IMSE#PBF is available at Aetrix Electronics and suitable for wireless inventory terminals, handheld medical instruments, and supercapacitor backup power supplies requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3536IMSE#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 legacy of high-performance power management ICs with rigorous characterization and application support.

The LTC3536IMSE#PBF belongs to Linear's precision buck-boost regulator family, engineered specifically for battery-powered instrumentation and RF systems where input voltage variability, low noise, and ultra-low quiescent current are critical design constraints.

FAQ

What is the maximum continuous output current supported by the LTC3536IMSE#PBF?

The LTC3536IMSE#PBF delivers up to 1A continuous output current when VIN ≥ 3V and VOUT = 3.3V, as verified in the Electrical Characteristics table under "Input Current Limit" (2.5A typ.) and "Peak Current Limit" (3.4A typ.). At lower input voltages-e.g., VIN = 1.8V-the max continuous output drops to 300mA due to increased conduction losses and reduced duty cycle headroom. Thermal derating applies above 85°C ambient.

Does the LTC3536IMSE#PBF support output voltage adjustment, and what is the minimum programmable output?

Yes, the LTC3536IMSE#PBF supports adjustable output voltage from 1.8V to 5.5V using an external resistor divider on the FB pin, based on the equation VOUT = 0.6V × (1 + RTOP/RBOT). The minimum programmable output is 1.8V, confirmed in both the Absolute Maximum Ratings and Applications sections of the datasheet, and is limited by the 0.6V internal reference and practical resistor tolerance constraints.

How does the MODE/SYNC pin function in the LTC3536IMSE#PBF, and what happens when it is left floating?

The MODE/SYNC pin on the LTC3536IMSE#PBF selects between PWM mode (logic low), Burst Mode (logic high), or external clock synchronization (AC-coupled square wave). If left floating, the pin's internal pull-down (not explicitly stated but inferred from functional behavior and typical Linear design practice) defaults to PWM mode. However, datasheet Note 1 warns against floating this pin due to potential noise susceptibility-designs must actively drive it to a defined logic level.

What thermal considerations apply to the LTC3536IMSE#PBF in the 12-lead MSOP package?

The LTC3536IMSE#PBF in the MSE package has θ_JA = 40°C/W and TJ_MAX = 125°C. To sustain 1A output continuously, the PCB must incorporate the exposed PGND pad (Pin 13) soldered to ≥2 cm² of inner-layer ground copper. Without adequate thermal relief, junction temperature rises ~40°C per watt of dissipation-so at 1A/3.3V (≈1.5W loss at 85% efficiency), ambient must stay ≤65°C to avoid thermal shutdown.

Can the LTC3536IMSE#PBF safely regulate when the output is precharged to a voltage higher than the target VOUT?

Yes, the LTC3536IMSE#PBF includes active reverse current limiting that disables PMOS switch D if reverse current exceeds 0.55A, protecting internal FETs during output precharge scenarios. When VOUT is precharged above 90% of the target, the internal soft-start is skipped and regulation begins immediately-verified in the Operation section under "Soft-Start" and "Reverse Current Limit."