Analog Devices Inc. LTC4056ETS8-4.2#TRMPBF

Overview

LTC4056ETS8-4.2#TRMPBF from Analog Devices (formerly Linear Technology) is a single-cell Li-Ion battery charger controller IC with programmable termination timer, ±0.6% float voltage accuracy (4.2V), and external charge current programming via PROG pin resistor (200–700mA). It operates in constant-current/constant-voltage mode, supports trickle charging for low-battery recovery, and integrates undervoltage charge current limiting for USB-powered systems.

For engineers reviewing the LTC4056ETS8-4.2#TRMPBF datasheet, LTC4056ETS8-4.2#TRMPBF pinout, LTC4056ETS8-4.2#TRMPBF application, or LTC4056ETS8-4.2#TRMPBF equivalent, key selection considerations include its 8-pin SOT-23 (ThinSOT™) package, manual shutdown capability via TIMER/SHDN pin, CHRG open-drain status output, thermal/current protection, and absence of required external sense resistor or blocking diode.

Technical Context

The LTC4056ETS8-4.2#TRMPBF implements a linear charging architecture using an external PNP pass transistor, where ISENSE senses emitter current and DRIVE provides controlled base sink current. Its dual-loop control regulates both charge current (via PROG pin virtual 1V reference and internal 110mΩ sense resistor) and float voltage (via precision 1.2V internal reference and BAT pin divider).

Charge termination is governed by a capacitor-resistor–programmed timer on the TIMER/SHDN pin, with automatic recharge triggered when BAT falls below 4.05V. The IC enters near-zero-current shutdown (<1µA battery drain) when TIMER/SHDN is grounded or VCC drops below 4.275V (UVLO falling threshold), and supports trickle charge at ~2% of full-scale current when BAT < 2.8V.

Key Specifications

Pinout & Package

The LTC4056ETS8-4.2#TRMPBF is housed in an 8-lead, low-profile (1mm height) SOT-23 (ThinSOT™) package, optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Li-Ion charger controller applications.

Compared with MCP73831T-2DCI/OT and BQ24075RGTR, the LTC4056ETS8-4.2#TRMPBF offers superior design flexibility through external PNP selection (supporting >700mA), fully programmable timer, and undervoltage charge current limiting-critical for marginal USB power sources-while maintaining minimal external component count.

Availability

LTC4056ETS8-4.2#TRMPBF is available at Aetrix Electronics and suitable for cellular telephones, digital cameras, charging docks and cradles, handheld computers, and low-cost standalone Li-Ion chargers requiring stable component supply, long-term lifecycle support, and consistent parametric performance.

Supply support for LTC4056ETS8-4.2#TRMPBF 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 LTC4056ETS8-4.2#TRMPBF belongs to Linear's legacy Li-Ion charger controller family, designed specifically for cost-sensitive, space-constrained portable devices requiring accurate, autonomous, and robust single-cell charging without microcontroller supervision.

FAQ

What is the exact float voltage accuracy of the LTC4056ETS8-4.2#TRMPBF?

The LTC4056ETS8-4.2#TRMPBF delivers a nominal 4.2V float voltage with guaranteed accuracy of ±0.6% over temperature (–40°C to 85°C), corresponding to 4.175V to 4.225V at 10mA load. This tight tolerance ensures safe and optimal charging of standard single-cell Li-Ion batteries without overvoltage stress.

How is charge current programmed on the LTC4056ETS8-4.2#TRMPBF?

Charge current is set using a single resistor (R_PROG) between the PROG pin and GND. The LTC4056ETS8-4.2#TRMPBF maintains a virtual 1V reference at PROG, so I_CHG ≈ 915 × (1V / R_PROG). For example, R_PROG = 1.3kΩ yields ~700mA. Beta compensation (e.g., for low-β PNP transistors) is supported via minor R_PROG adjustment.

Does the LTC4056ETS8-4.2#TRMPBF require an external blocking diode?

No, the LTC4056ETS8-4.2#TRMPBF does not require an external blocking diode. Its architecture uses an external PNP pass transistor configured in high-side mode, and internal circuitry prevents reverse current flow from battery to input, eliminating diode voltage drop and associated power loss.

What happens when input voltage drops below UVLO on the LTC4056ETS8-4.2#TRMPBF?

When VCC falls below the UVLO falling threshold (4.275V typical), the LTC4056ETS8-4.2#TRMPBF enters sleep mode, reducing battery drain current to <1µA and disabling all outputs. The CHRG pin goes high-impedance, and the IC remains in this ultra-low-power state until VCC rises above 4.325V (rising UVLO threshold).

Can the LTC4056ETS8-4.2#TRMPBF support automatic recharge after charge termination?

Yes, the LTC4056ETS8-4.2#TRMPBF automatically restarts charging when the battery voltage falls below the recharge threshold (V_RECHRG = V_FLOAT – 150mV ≈ 4.05V). This shortened recharge cycle runs for 50% of the original programmed time, optimizing runtime in intermittently used portable devices.