Analog Devices Inc. LTC3550EDHC-1#TRPBF

Overview

LTC3550EDHC-1#TRPBF from Analog Devices (formerly Linear Technology) is a dual-input Li-ion battery charger with integrated 600mA synchronous buck converter. It autonomously selects between USB and wall adapter inputs, delivers ±0.6% accurate 4.2V float voltage, supports up to 800mA wall-adapter charge current (RIDC = 1.25kΩ), and regulates VOUT to 1.875V at 1.5MHz switching frequency - used in compact portable electronics requiring single-cell battery management and on-board power conversion.

For engineers reviewing the LTC3550EDHC-1#TRPBF datasheet, LTC3550EDHC-1#TRPBF pinout, LTC3550EDHC-1#TRPBF application, or LTC3550EDHC-1#TRPBF equivalent, key selection criteria include dual-input source arbitration, thermal-regulated linear charging, integrated buck regulation without external MOSFETs or sense resistors, and 16-pin DFN package compatibility with high-density PCB layouts.

Technical Context

The LTC3550EDHC-1#TRPBF integrates two independent functional blocks: a linear battery charger with automatic DCIN/USBIN priority selection and die-temperature-based current regulation, and a constant-frequency (1.5MHz) current-mode synchronous buck regulator with internal P/N-channel MOSFETs. Both blocks share ground and thermal sensing but operate with separate control loops and status outputs.

Charging uses CC/CV profile with programmable termination via ITERM resistor and automatic recharge at 65–135mV below float voltage. The buck stage operates in Burst Mode® at light loads (20µA quiescent) and transitions to continuous conduction above ~100mA, delivering regulated 1.875V output from VCC (2.5–5.5V) with ±0.4% line/load regulation.

Key Specifications

Pinout & Package

Package: 16-lead (5mm × 3mm) plastic DFN with 0.75mm profile and exposed thermal pad (Pin 17 = GND). Requires soldering of exposed pad to PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-input Li-ion charger + integrated DC/DC converter applications.

Compared with MAX1555 and BQ24075, the LTC3550EDHC-1#TRPBF uniquely combines dual-input autonomy, thermal-regulated charging, and monolithic 600mA buck conversion in one 5mm×3mm DFN - reducing component count, PCB area, and thermal design effort for space-constrained portable systems.

Availability

LTC3550EDHC-1#TRPBF is available at Aetrix Electronics and suitable for smartphones, wearable health monitors, portable medical sensors, and industrial handheld terminals requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC3550EDHC-1#TRPBF 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. Linear pioneered high-performance battery management ICs with integrated power conversion.

The LTC3550EDHC-1#TRPBF belongs to Linear's Power Management family, designed specifically for portable electronics needing autonomous dual-source charging and compact, efficient on-board power generation without external MOSFETs or sense components.

FAQ

What is the maximum charge current supported by the LTC3550EDHC-1#TRPBF from the wall adapter input?

The LTC3550EDHC-1#TRPBF supports up to 840mA (typical) from the DCIN input when RIDC = 1.25kΩ. This value is derived from the 1.0V servo voltage at the IDC pin and the formula IBAT = 1V / RIDC. Absolute maximum DCIN current is rated at 950mA, and thermal regulation dynamically reduces current if junction temperature exceeds ~105°C.

Does the LTC3550EDHC-1#TRPBF require external MOSFETs or sense resistors for charging or regulation?

No, the LTC3550EDHC-1#TRPBF does not require external MOSFETs, sense resistors, or blocking diodes. It integrates P-channel FETs for both DCIN and USBIN charging paths, plus internal synchronous buck switches (P- and N-channel), eliminating all external power components needed for either function.

How does the LTC3550EDHC-1#TRPBF determine which input source (DCIN or USBIN) to use for charging?

The LTC3550EDHC-1#TRPBF uses hardware-based arbitration: it selects DCIN if VDCIN > 4.15V and VDCIN > BAT + 50mV (rising) or 180mV (falling); otherwise, it selects USBIN if VUSBIN > 3.95V and VUSBIN > BAT + 50mV. No firmware or external logic is required - behavior is defined by internal comparators and thresholds.

What is the purpose of the RUN pin on the LTC3550EDHC-1#TRPBF, and what voltage levels enable/disable the buck converter?

The RUN pin controls the synchronous buck converter independently of the charger. Driving RUN > 1.5V enables the 1.875V output; pulling RUN < 0.3V disables it, reducing VCC supply current to <1µA. The pin must not be left floating - internal biasing is not provided, and undefined states may cause erratic regulation or increased quiescent current.

Can the LTC3550EDHC-1#TRPBF operate safely in high-temperature environments such as inside sealed enclosures?

Yes, the LTC3550EDHC-1#TRPBF includes die-temperature-based thermal regulation that automatically reduces charge current when junction temperature approaches 105°C. Combined with its thermally enhanced DFN package (exposed pad soldered to PCB ground), it maintains reliable operation in ambient temperatures up to 85°C - validated in typical portable device enclosures.