Analog Devices Inc. LTC3812IFE-5#PBF

Overview

LTC3812IFE-5#PBF from Analog Devices (formerly Linear Technology) is a 60V input synchronous step-down switching regulator controller using constant on-time valley current mode control. It delivers precise 0.8V ±0.5% reference accuracy, supports up to 25MHz error amplifier bandwidth for fast transient response, and drives dual N-channel MOSFETs with 1Ω gate drivers-ideal for telecom power supplies, automotive DC/DC conversion, and industrial high-voltage step-down systems.

For engineers reviewing the LTC3812IFE-5#PBF datasheet, LTC3812IFE-5#PBF pinout, LTC3812IFE-5#PBF application, or LTC3812IFE-5#PBF equivalent, key selection considerations include its 60V max input rating, no external current sense resistor requirement, programmable minimum on-time (<100ns), adjustable cycle-by-cycle current limit via VRNG pin, and thermally enhanced 16-pin TSSOP package with exposed ground pad.

Technical Context

The LTC3812IFE-5#PBF implements a constant on-time valley current control architecture that eliminates need for a discrete current sense resistor by leveraging bottom MOSFET R_DS(ON) for sensing. Its 25MHz error amplifier enables sub-microsecond load transient recovery, while the ITH pin provides direct control of valley current threshold across 0–2.6V range.

Frequency is set externally via ION pin current (100–3000μA), yielding t_ON from 1.55μs down to <100ns; t_OFF(MIN) is 250–350ns. The controller supports pulse-skipping or forced continuous operation via FCB pin, and integrates dual 1Ω gate drivers capable of 1A peak source/sink for high-current synchronous rectification.

Key Specifications

Pinout & Package

Package: 16-lead plastic TSSOP with exposed thermal pad (Pin 17 = GND), rated for θ_JA = 38°C/W. Exposed pad must be soldered to PCB ground plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Compared with LTC3891EMSE-5#PBF, the LTC3812IFE-5#PBF offers superior thermal performance in TSSOP and retains full 60V capability without integrated bias, while MP2918GL-Z trades input range and sensing architecture for lower unit cost in less demanding 24V systems.

Availability

LTC3812IFE-5#PBF is available at Aetrix Electronics and suitable for telecom power supplies, automotive DC/DC conversion, and industrial control systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3812IFE-5#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.

The LTC3812IFE-5#PBF belongs to Linear's high-voltage synchronous buck controller product line, designed specifically for efficient, robust DC/DC conversion in harsh environments including telecom infrastructure, automotive electronics, and industrial automation.

FAQ

What is the maximum input voltage supported by the LTC3812IFE-5#PBF?

The LTC3812IFE-5#PBF supports a maximum input voltage of 60V, with absolute maximum ratings extending to 70V on SW pin (continuous) and 80V (≤400ms). This makes it suitable for 48V telecom systems and automotive applications experiencing load dump transients. The controller maintains regulation down to 6V input, covering cold-crank conditions. Operation within the 6V–60V range ensures full specification compliance per the datasheet.

Does the LTC3812IFE-5#PBF require an external current sense resistor?

No, the LTC3812IFE-5#PBF does not require an external current sense resistor. It uses the on-resistance (R_DS(ON)) of the bottom N-channel MOSFET as the current sense element, measuring voltage between PGND and SW pins. The VRNG pin sets the maximum sense voltage threshold (60–320mV), enabling accurate cycle-by-cycle current limiting without added component cost or board area. This feature is confirmed in the device description and typical application schematic.

How is the switching frequency programmed on the LTC3812IFE-5#PBF?

The switching frequency of the LTC3812IFE-5#PBF is programmed via the ION pin (Pin 1) using an external resistor from VIN to ION. The current into ION (100–3000μA) sets the one-shot on-time, which ranges from 1.55μs down to <100ns. Frequency varies inversely with input voltage due to constant on-time architecture, but remains stable across line changes. Typical values use 110kΩ for ~250kHz operation, as shown in the front-page application circuit.

What protection features are integrated into the LTC3812IFE-5#PBF?

The LTC3812IFE-5#PBF integrates multiple protection features: cycle-by-cycle current limiting (programmed via VRNG), output overvoltage protection (PGOOD asserts low and M1 turns off), input undervoltage lockout (INTVCC UV+ = 4.2V), thermal shutdown, and foldback current limiting during output short-circuit. These are documented in the Fault Monitoring/Protection section and Absolute Maximum Ratings table, ensuring robust operation in fault conditions without external circuitry.

Can the LTC3812IFE-5#PBF operate in pulse-skipping mode, and how is it enabled?

Yes, the LTC3812IFE-5#PBF supports pulse-skipping mode for improved light-load efficiency. It is enabled by pulling the FCB pin (Pin 4) above 0.8V - typically via a resistor divider from INTVCC or a secondary winding. Below 0.8V, the device operates in forced continuous mode. This behavior is explicitly defined in the PIN FUNCTIONS section and verified in Figure 1 and Figure 2 of the datasheet, with efficiency curves showing >10% improvement at 100mA load in pulse-skipping mode.