Analog Devices Inc. LTC4077EDD#TRPBF

Overview

LTC4077EDD#TRPBF from Analog Devices (formerly Linear Technology) is a dual-input standalone linear Li-Ion battery charger IC that autonomously selects between wall adapter (DCIN) and USB (USBIN) power sources. It delivers up to 800 mA from DCIN and 500 mA from USBIN, regulates float voltage to 4.2 V ±0.6%, and features thermal regulation at 105°C for safe high-power operation in portable electronics.

For engineers reviewing the LTC4077EDD#TRPBF datasheet, LTC4077EDD#TRPBF pinout, LTC4077EDD#TRPBF application, or LTC4077EDD#TRPBF equivalent, key selection criteria include dual-input automatic source selection, programmable charge current via external resistors (IDC/IUSB/IUSBL), C/10 termination, <2 µA battery drain in shutdown, and thermally enhanced 10-lead DFN (3 mm × 3 mm, 0.75 mm height) packaging.

Technical Context

The LTC4077EDD#TRPBF implements a constant-current/constant-voltage (CC/CV) charging algorithm with two internal P-channel MOSFETs-RON-DC = 400 mΩ (DCIN→BAT) and RON-USB = 550 mΩ (USBIN→BAT)-eliminating need for external blocking diodes or sense resistors. Input selection logic prioritizes DCIN when VDCIN > 4.15 V and VDCIN > VBAT + 50 mV; otherwise it defaults to USBIN if VUSBIN > 3.95 V and VUSBIN > VBAT + 50 mV.

Thermal regulation actively reduces charge current when die temperature approaches 105°C, while internal comparators enable trickle charge below 2.9 V, automatic recharge at ~4.1 V, and precise C/10 or C/2 termination depending on HPWR state. Status outputs (PWR, CHRG) are open-drain, 10 mA sink capable.

Key Specifications

Pinout & Package

Package: 10-lead (3 mm × 3 mm) DFN, 0.75 mm profile, exposed pad (Pin 11) soldered to PCB ground for thermal and electrical integrity (θJA = 40°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-input Li-Ion charging applications.

Compared with BQ24075RGTR and MAX1555ESA+, the LTC4077EDD#TRPBF uniquely combines dual-input automatic selection, HPWR-configurable USB current, integrated thermal regulation, and <2 µA battery drain-making it optimal for space-constrained, thermally sensitive portable designs requiring robust dual-source charging.

Availability

LTC4077EDD#TRPBF is available at Aetrix Electronics and suitable for cellular telephones, handheld computers, and portable MP3 players requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LTC4077EDD#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, Inc. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies.

The LTC4077EDD#TRPBF belongs to ADI's Linear Technology legacy battery management product line, designed specifically for compact, thermally constrained portable electronics requiring autonomous dual-input Li-Ion charging with minimal external components.

FAQ

What is the maximum charge current the LTC4077EDD#TRPBF can deliver from a wall adapter input?

The LTC4077EDD#TRPBF delivers up to 800 mA from the DCIN input when programmed with RIDC = 1.24 kΩ (servo voltage = 1 V). This assumes VDCIN ≥ 4.3 V and adequate thermal dissipation; actual current reduces automatically if junction temperature reaches 105°C due to thermal regulation. The LTC4077EDD#TRPBF datasheet specifies RON-DC = 400 mΩ, enabling efficient power delivery within its 10-lead DFN package.

How does the LTC4077EDD#TRPBF handle automatic input source selection between DCIN and USBIN?

The LTC4077EDD#TRPBF continuously monitors both inputs: it selects DCIN if VDCIN > 4.15 V and VDCIN > VBAT + 50 mV (rising), otherwise defaults to USBIN if VUSBIN > 3.95 V and VUSBIN > VBAT + 50 mV. The open-drain PWR output signals valid input presence. The LTC4077EDD#TRPBF requires no external logic or firmware to arbitrate between sources-it operates fully autonomously using internal comparators and MOSFET drivers.

What is the purpose of the HPWR pin on the LTC4077EDD#TRPBF, and how does it affect USB charging?

The HPWR pin on the LTC4077EDD#TRPBF selects between two USB charge current profiles: logic high enables IUSB pin programming (e.g., 500 mA with RIUSB = 2 kΩ), while logic low enables IUSBL pin programming (e.g., 50 mA with RIUSBL = 4.02 kΩ). This allows compliance with USB Battery Charging v1.2 specifications-high-power mode for dedicated chargers, low-power mode for standard USB ports. The LTC4077EDD#TRPBF includes an internal 2 MΩ pulldown, defaulting to low-power mode if HPWR is left floating.

Does the LTC4077EDD#TRPBF support trickle charging for deeply discharged batteries?

Yes-the LTC4077EDD#TRPBF initiates trickle charge when BAT voltage falls below 2.9 V, delivering 1/10th of the full DCIN current or 1/2 of the selected USB current (based on HPWR state) until VBAT rises above 2.9 V. For example, with RIDC = 1.24 kΩ (800 mA full scale) and HPWR = low (50 mA full scale), trickle current is 80 mA or 25 mA respectively. This protects Li-Ion cells from damage during recovery from deep discharge, and the LTC4077EDD#TRPBF implements this entirely in hardware without MCU involvement.

What are the shutdown current specifications for the LTC4077EDD#TRPBF, and how is shutdown activated?

Shutdown is activated by driving the EN pin high, reducing DCIN supply current to 20 µA, USBIN supply current to 10 µA (when VDCIN > VUSBIN) or 18 µA (when VDCIN = 0 V), and battery drain current to <2 µA. These ultra-low currents preserve battery life during storage or transport. The LTC4077EDD#TRPBF includes an internal 2 MΩ pulldown on EN, so leaving EN unconnected defaults the device to active charging mode-no external pull-down resistor is required. All shutdown specs are tested per the LTC4077EDD#TRPBF datasheet at TA = 25°C.