Analog Devices Inc. LTC4071EDDB#TRPBF

Overview

LTC4071EDDB#TRPBF from Analog Devices is a Li-ion/polymer shunt battery charger IC with integrated low-battery disconnect, thermal qualification via NTC, and pin-selectable 4.0V/4.1V/4.2V float voltage (±1% accuracy). It operates from 550nA quiescent current, supports up to 50mA internal shunt current, and delivers near-zero leakage (<0.01nA) battery disconnect - enabling energy harvesting, thin-film battery backup, and solar-powered memory retention systems.

For engineers reviewing the LTC4071EDDB#TRPBF datasheet, LTC4071EDDB#TRPBF pinout, LTC4071EDDB#TRPBF application, or LTC4071EDDB#TRPBF equivalent, key selection criteria include programmable low-battery disconnect thresholds (2.7V/3.2V), ultralow ICCQ for intermittent sources, NTC-based thermal float voltage reduction, HBO status output timing, and DFN-8 package thermal performance (θJA = 76°C/W).

Technical Context

The LTC4071EDDB#TRPBF implements a shunt-based charging architecture where input current flows through an external resistor (RIN) into the battery via MP1's body diode until VCC reaches VLBC_VCC (~3.6V), at which point MP1 turns on to reconnect BAT–VCC. Charging terminates dynamically as VBAT approaches VFLOAT_EFF, with up to 50mA actively shunted away from the battery.

Its NTC qualification uses pulsed 30–200µs NTCBIAS biasing (duty cycle < 0.002%) to compare VNTC against four internal reference taps (NTCTH1–NTCTH4), enabling stepwise float voltage reduction (ΔVFLOAT = 50/75/100mV per 10°C above 40°C) depending on ADJ state - all while consuming only 30–50pA average NTCBIAS sink current.

Key Specifications

Pinout & Package

The LTC4071EDDB#TRPBF is housed in an 8-lead plastic DFN package (2mm × 3mm, 0.75mm profile) with exposed thermal pad (Pin 9, unconnected internally but must be soldered to PCB ground). Pinout is validated per Analog Devices Rev. D datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt battery charger applications.

Compared with MAX1555 and BQ29700, the LTC4071EDDB#TRPBF uniquely combines shunt charging, programmable float voltage, NTC thermal qualification, and HBO status in a single 550nA-ICCQ DFN package - making it irreplaceable for ultra-low-power, self-contained battery management in energy-constrained systems.

Availability

LTC4071EDDB#TRPBF is available at Aetrix Electronics and suitable for memory back-up, solar-powered sensor nodes, embedded automotive telematics, and energy-harvesting wearables requiring stable component supply across extended product lifecycles.

Supply support for LTC4071EDDB#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.

The LTC4071EDDB#TRPBF belongs to Analog Devices' Linear Technology legacy battery management product line, engineered specifically for ultra-low-power, single-cell Li-ion/polymer charging and protection in energy-constrained and thermally sensitive applications.

FAQ

What is the maximum shunt current capability of the LTC4071EDDB#TRPBF?

The LTC4071EDDB#TRPBF supports a maximum internal shunt current of 50mA, as specified in its Absolute Maximum Ratings and Electrical Characteristics tables. This value defines the upper limit of current the device can divert away from the battery to regulate VCC at the programmed float voltage. Exceeding 50mA risks violating absolute maximum junction temperature limits, especially in the DFN-8 package where θJA = 76°C/W. Designers must size RIN to ensure ISHUNT_MAX ≤ 50mA under worst-case conditions including NTC-induced VFLOAT_MIN = 3.8V.

How does the LTC4071EDDB#TRPBF achieve near-zero battery disconnect leakage?

The LTC4071EDDB#TRPBF achieves <0.01nA typical battery disconnect leakage (ILEAK) by using a high-impedance PFET (MP1) gate control architecture that fully isolates BAT from VCC when VBAT falls below VLBD. This is validated in the Electrical Characteristics table (ILEAK = 0.01nA min, 25nA max at VBAT = 2.65V). The design eliminates parasitic discharge paths through internal logic or bias networks, making it suitable for preserving charge in low-capacity Li-ion and thin-film batteries over multi-year storage.

Can the LTC4071EDDB#TRPBF be used with non-Vishay NTC thermistors?

Yes, the LTC4071EDDB#TRPBF supports non-Vishay NTC thermistors via two methods: (1) adding a series resistor (RFIX) to shift the RNTC/RNOM ratio to match internal NTCTH thresholds, or (2) adjusting RNOM value to recalibrate trip points. For example, a 100kΩ B3950 thermistor can be adapted using RFIX = 3.92kΩ or RNOM = 88.7kΩ to achieve ~40°C/50°C/60°C/70°C thresholds. The datasheet provides explicit calculation methods and tolerance guidance for both approaches.

What is the purpose of the pulsed NTCBIAS signal in the LTC4071EDDB#TRPBF?

The pulsed NTCBIAS signal (30–200µs width, ~1.5s period, <0.002% duty cycle) minimizes average power consumption in the NTC sensing network while enabling accurate thermistor voltage ratio measurement. By pulsing NTCBIAS to VCC only briefly, the LTC4071EDDB#TRPBF achieves just 30–50pA average sink current - critical for energy-harvesting applications. This technique avoids continuous biasing that would drain microamp-level sources and degrade overall system efficiency.

Does the LTC4071EDDB#TRPBF require external components beyond RIN?

Yes - beyond the mandatory external input resistor (RIN), the LTC4071EDDB#TRPBF requires a minimum 0.1µF decoupling capacitor from VCC to GND. If using NTC functionality, a 10kΩ (or adjusted) bias resistor (RNOM) from NTCBIAS to NTC and a Vishay NTHS0402N02N1002F (or compatible) thermistor from NTC to GND are required. No additional MOSFETs, op-amps, or supervisory ICs are needed - the entire charger + protector function is self-contained.