Analog Devices Inc. LT8616IUDE#PBF

Overview

LT8616IUDE#PBF from Analog Devices (formerly Linear Technology) is a dual-channel synchronous monolithic step-down regulator with independent 1.5A and 2.5A output capability, 3.4V–42V input range, 6.5µA quiescent current in Burst Mode, and 35ns minimum on-time. It delivers stable 5V/3.3V rails for automotive infotainment power supplies where low-noise, high-efficiency standby operation is critical.

For engineers reviewing the LT8616IUDE#PBF datasheet, LT8616IUDE#PBF pinout, LT8616IUDE#PBF application, or LT8616IUDE#PBF equivalent, key selection criteria include channel-specific current limits (CH1: 4.2A peak, CH2: 5.5A peak), 180° out-of-phase switching to reduce input ripple, TSSOP/QFN package thermal performance, and BIAS pin optimization for <1mA bias current at light load.

Technical Context

The LT8616IUDE#PBF integrates two independent peak-current-mode buck regulators sharing internal bias circuitry but with separate VIN, EN/UV, PG, TR/SS, FB, and SW paths. Channel 1 supports up to 1.5A with 310mΩ top/190mΩ bottom FETs; Channel 2 supports up to 2.5A with 145mΩ top/120mΩ bottom FETs. Both channels feature internal compensation, adjustable 200kHz–3MHz switching via RT resistor, and 180° phase offset.

Burst Mode operation enables ultralow 6.5µA total IQ with both channels regulating - achieved by disabling gate drivers and control logic between energy pulses while maintaining ±10% output regulation via PG monitoring. The SYNC/MODE pin selects Burst Mode (ground), pulse-skipping (≥2.4V), or external clock synchronization (250kHz–3MHz), with CH1 aligned to rising edge and CH2 to falling edge of external clock.

Key Specifications

Pinout & Package

LT8616IUDE#PBF uses a thermally enhanced 28-lead 3mm × 6mm plastic QFN package (UDE) with exposed GND pad soldered to PCB for θJC(PAD) = 5°C/W. Pin 29 is the exposed thermal pad and must be connected to system GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3375EFE#PBF and MPQ4436AGL-AEC1-P, the LT8616IUDE#PBF uniquely combines 42V input tolerance, true dual-channel independence with separate EN/UV/PG/SS, and 6.5µA IQ - making it the only option for high-reliability automotive dual-rail designs requiring cold-crank operation and battery backup longevity.

Availability

LT8616IUDE#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLCs, portable medical monitors, and test equipment requiring stable component supply with guaranteed long-term availability and AEC-Q200-aligned manufacturing controls.

Supply support for LT8616IUDE#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 high-performance power management portfolio with rigorous automotive-grade validation and long-lifecycle support.

The LT8616IUDE#PBF belongs to the LT86xx family of ultralow-IQ synchronous buck regulators designed specifically for automotive and industrial applications demanding extended battery life, wide input range, and robust transient performance under harsh electrical conditions.

FAQ

What is the minimum input voltage required for LT8616IUDE#PBF to operate both channels?

VIN1 must be ≥3.4V to enable either channel; VIN2 has no minimum requirement if VIN1 ≥3.4V. This allows LT8616IUDE#PBF to power CH2 from a lower intermediate rail while maintaining CH1 operation from battery - critical for multi-stage automotive power architectures.

How does the BIAS pin reduce quiescent current in LT8616IUDE#PBF?

The BIAS pin supplies internal circuitry when connected to ≥3.1V (e.g., VOUT2). This shifts bias current from VIN1 to the BIAS rail, reducing total input current by ~7mA under full load. For LT8616IUDE#PBF, connecting BIAS to 3.3V output cuts no-load IQ from ~13µA to 6.5µA in Burst Mode.

Can LT8616IUDE#PBF synchronize both channels to an external clock while maintaining 180° phase offset?

Yes. When an external clock is applied to the SYNC/MODE pin, LT8616IUDE#PBF aligns CH1's positive switching edge to the clock's rising edge and CH2's to the falling edge - preserving 180° phase separation. This eliminates beat frequencies and reduces input ripple in synchronized multi-converter systems.

What is the purpose of the TR/SS pins in LT8616IUDE#PBF, and how do they differ between channels?

TR/SS1 and TR/SS2 provide independent soft-start ramp generation (via external capacitor) or output voltage tracking (via resistor divider from another rail). Each pin sources 2µA internally; voltage <0.79V forces FB regulation to match TR/SS voltage. In LT8616IUDE#PBF, this enables precise power sequencing - e.g., ramping CH2 before CH1 to avoid backfeed.

Why does LT8616IUDE#PBF specify different peak current limits for CH1 (4.2A) and CH2 (5.5A)?

CH1 and CH2 use different internal MOSFETs optimized for their rated currents: CH1's 310mΩ/190mΩ FETs support 1.5A continuous with 4.2A peak limit; CH2's lower RDS(ON) 145mΩ/120mΩ FETs support 2.5A continuous with 5.5A peak limit. This asymmetry allows LT8616IUDE#PBF to deliver higher current on the main SoC rail while minimizing silicon area and thermal stress.