Analog Devices Inc. LTC4070EDDB#TRPBF

Overview

LTC4070EDDB#TRPBF from Analog Devices is a low-power shunt battery charger IC for Li-ion/polymer cells, featuring 450nA quiescent current, ±1% float voltage accuracy (4.0V/4.1V/4.2V pin-selectable), and integrated NTC-based thermal qualification. It regulates battery voltage via internal 50mA shunt current (expandable to 500mA with external PFET) and delivers precise high/low battery status outputs - ideal for energy harvesting, thin-film battery backup, and solar-powered memory retention systems.

For engineers reviewing the LTC4070EDDB#TRPBF datasheet, LTC4070EDDB#TRPBF pinout, LTC4070EDDB#TRPBF application, or LTC4070EDDB#TRPBF equivalent, key selection criteria include ultra-low ICCQ, NTC-qualified float voltage stepping, shunt-current scalability, thermal qualification thresholds, and DFN-8 package thermal performance at 125°C junction temperature.

Technical Context

The LTC4070EDDB#TRPBF implements a pulsed, ultralow-duty-cycle (≤0.002%) NTC sampling architecture synchronized with ADJ pin state detection every ~1.5s, minimizing bias current to 30pA average. Its shunt regulation uses an internal error amplifier driving a precision current sink, with float voltage dynamically adjusted by both ADJ logic state and NTC thermistor ratio against internal resistor divider taps (NTCTH1–NTCTH4).

Thermal qualification reduces VFLOAT in discrete 50mV/75mV/100mV steps per 10°C above 40°C depending on ADJ setting, down to a minimum 3.8V. Status outputs HBO and LBO are CMOS-compatible with defined hysteresis (100mV and 220–350mV respectively) and operate across full –40°C to 125°C junction range without external components.

Key Specifications

Pinout & Package

The LTC4070EDDB#TRPBF is housed in an 8-lead (3mm × 2mm), 0.75mm profile plastic DFN package with exposed thermal pad (Pin 9), which must be soldered to PCB ground for θJA = 76°C/W thermal performance.

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 LTC4070EDDB#TRPBF uniquely combines sub-µA quiescent operation, programmable thermal qualification, and single-resistor shunt control - making it the sole viable option for energy harvesting and thin-film battery systems requiring >5-year autonomy.

Availability

LTC4070EDDB#TRPBF is available at Aetrix Electronics and suitable for energy harvesting storage, solar-powered memory backup, and automotive telematics backup requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LTC4070EDDB#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. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial automation, and power management.

The LTC4070EDDB#TRPBF belongs to Analog Devices' Power Management family, designed specifically for ultra-low-power battery charging and protection in energy-constrained environments such as IoT edge nodes and maintenance-free sensor systems.

FAQ

What is the maximum shunt current capability of the LTC4070EDDB#TRPBF without external components?

The LTC4070EDDB#TRPBF provides up to 50mA of internal shunt current to regulate battery voltage. This is the absolute maximum continuous current it can sink while maintaining ±1% float voltage accuracy across –40°C to 125°C. Exceeding this requires an external PFET driven by the DRV pin, as documented in the datasheet's recommended devices table (e.g., Si3469DV). The LTC4070EDDB#TRPBF's internal architecture limits dissipation to avoid thermal runaway, so design margins must account for worst-case V_IN–V_FLOAT drop across R_IN.

How does the NTC qualification affect the float voltage of the LTC4070EDDB#TRPBF?

The LTC4070EDDB#TRPBF reduces its programmed float voltage in discrete steps when the NTC thermistor indicates battery temperature exceeds 40°C: 50mV per 10°C for ADJ=GND (4.0V base), 75mV for ADJ=open (4.1V base), or 100mV for ADJ=VCC (4.2V base), down to a minimum of 3.8V. These steps align with internal resistor-divider tap points (NTCTH1–NTCTH4) and are verified across temperature using Vishay NTHS0402N02N1002F thermistors. The LTC4070EDDB#TRPBF samples NTC only periodically (~1.5s interval) to preserve ultralow ICCQ.

Can the LTC4070EDDB#TRPBF be used with multi-cell battery stacks?

Yes - the LTC4070EDDB#TRPBF supports stacked-cell configurations via series connection: the GND pin of an upper LTC4070EDDB#TRPBF connects directly to the VCC pin of the lower device, enabling independent regulation of each cell. Two devices regulate a 2-cell stack (e.g., 8.4V total) with matched float voltages. Status outputs (HBO/LBO) of upper devices are floating relative to system ground and require level-shifting or isolated monitoring. The LTC4070EDDB#TRPBF's shunt architecture inherently balances cells without additional circuitry, unlike series-charge ICs.

What is the purpose of the DRV pin on the LTC4070EDDB#TRPBF, and what FET parameters matter most?

The DRV pin on the LTC4070EDDB#TRPBF drives the gate of an external P-channel MOSFET to extend shunt current beyond the internal 50mA limit - enabling up to 500mA total shunt capacity. Critical FET parameters include low gate charge (Q_g < 4nC), high threshold voltage (|V_TH| > 0.8V), and low R_DS(ON) (< 0.1Ω) to minimize conduction loss. Leakage at the DRV node must be <1nA; hence PCB layout demands short traces, guard rings, and clean solder mask. The LTC4070EDDB#TRPBF datasheet lists qualified devices including Si3469DV and DMP3015LSS.

Does the LTC4070EDDB#TRPBF require external capacitors or compensation components?

No - the LTC4070EDDB#TRPBF operates with zero external compensation components. Only one external resistor (R_IN) is required to set charge current, and optional NTC/bias network (10kΩ + thermistor) for thermal qualification. A minimum 0.1µF ceramic capacitor is recommended between VCC and GND when no battery is present to stabilize regulation. All internal references, oscillators, and error amplifiers are fully integrated; the LTC4070EDDB#TRPBF's architecture eliminates need for loop compensation, current-sense resistors, or voltage dividers.