Analog Devices Inc. ADP3806JRUZ-R7

Overview

ADP3806JRUZ-R7 from Analog Devices is a high-frequency synchronous buck-mode Li-ion battery charger IC supporting 3-cell (12.6 V) or 4-cell (16.8 V) configurations with ±0.4% end-of-charge voltage accuracy at 25°C, rail-to-rail current sense amplifier, and programmable charge current via ISET pin. It integrates bootstrapped NMOS gate drivers, 7 V BSTREG, 6 V analog regulator, and 2.5 V precision reference for notebook computer and fast-charger applications.

For engineers reviewing the ADP3806JRUZ-R7 datasheet, ADP3806JRUZ-R7 pinout, ADP3806JRUZ-R7 application, or ADP3806JRUZ-R7 equivalent, key selection criteria include battery voltage selectability (12.6/16.8 V), ±0.6% accuracy over 5°C–55°C, 250 kHz typical oscillator frequency, soft-start capability, and system current sense output (ISYS) with reverse input protection.

Technical Context

The ADP3806JRUZ-R7 implements constant-current/constant-voltage (CCCV) charging using dual error amplifiers: gm1 regulates charge current by comparing ISET voltage to amplified CS+–CS− differential signal (gain = 25 V/V), while gm2 controls final battery voltage by comparing BAT to internal 2.5 V reference. BATSEL pin selects 3-cell (12.6 V) or 4-cell (16.8 V) mode with internal 2 µA pull-up.

Oscillator frequency is set by CT capacitor (180 pF → 250 kHz) and supports SYNC input for external clock alignment. Bootstrapped synchronous driver uses DRVH/BST/SW/DRVL pins to drive external NMOS FETs with 6 Ω typical on-resistance, 35 ns rise/fall time, and 50 ns overlap protection delay. LC open-drain output signals low-current termination when VCS ≤ 20 mV and VBAT ≥ 95% of final voltage.

Key Specifications

Pinout & Package

ADP3806JRUZ-R7 is housed in a 24-lead TSSOP package (JEDEC MO-153, 0.65 mm pitch) with exposed thermal pad (EP). Pin 1 is marked by dot; pin count proceeds counter-clockwise. AGND and PGND are separate analog/digital ground pins requiring independent routing to minimize noise coupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Li-ion battery charger applications.

Compared with BQ24725ARSMR and MP2617GR-Z, ADP3806JRUZ-R7 uniquely combines hardware-selectable 3S/4S voltage, system current sense telemetry, and ultra-low shutdown leakage (<1 µA), making it optimal for portable equipment requiring both safety and system-level power awareness.

Availability

ADP3806JRUZ-R7 is available at Aetrix Electronics and suitable for portable computers, fast chargers, and industrial portable equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing for medical and aerospace-qualified designs.

Supply support for ADP3806JRUZ-R7 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 industrial, automotive, communications, and healthcare markets since 1965.

The ADP3806JRUZ-R7 belongs to Analog Devices' battery management IC product line, designed specifically for high-accuracy, high-efficiency Li-ion charging in space-constrained portable systems with demanding thermal and reliability requirements.

FAQ

What battery configurations does the ADP3806JRUZ-R7 support?

The ADP3806JRUZ-R7 supports both 3-cell (12.6 V) and 4-cell (16.8 V) Li-ion battery packs. Selection is made via the BATSEL pin: logic-high (e.g., tied to REG) configures 12.6 V output, while logic-low (e.g., grounded) configures 16.8 V output. The ADP3806JRUZ-R7 variant is factory-configured for this dual-voltage option and does not require external resistor dividers for either setting.

How is charge current programmed on the ADP3806JRUZ-R7?

Charge current is programmed using the ISET pin, which accepts a dc voltage from 0 V to 4.0 V. The internal current sense amplifier has a fixed gain of 25 V/V, so charge current I_CHG = (V_ISET × 25) / R_CS, where R_CS is the external sense resistor value. For example, with R_CS = 40 mΩ and V_ISET = 3.0 V, ADP3806JRUZ-R7 delivers 1.875 A. Accuracy is ±1.0% at full-scale ISET voltage.

Does the ADP3806JRUZ-R7 provide system-level current monitoring?

Yes, the ADP3806JRUZ-R7 includes a dedicated system current sense amplifier (AMP2) with inputs SYS+ and SYS− and output ISYS. It provides a linear 50 V/V gain output (0–5 V) proportional to the differential voltage across an external sense resistor. Critically, this block remains fully operational during IC shutdown, enabling continuous system load monitoring independent of charging state.

What is the purpose of the LC pin on the ADP3806JRUZ-R7?

The LC pin is an open-drain logic output that signals low-current termination. It pulls high when the charge current falls below 12.5% of full scale (i.e., V_CS ≤ 20 mV) AND the battery voltage reaches ≥95% of its final regulated value. This dual-condition requirement prevents false triggering during soft-start or transient events. An external pull-up resistor (e.g., to REF) is required for proper logic level translation.

Can the ADP3806JRUZ-R7 drive external NMOS transistors directly?

Yes, the ADP3806JRUZ-R7 integrates a bootstrapped synchronous driver with DRVH and DRVL outputs specifically designed to drive external NMOS FETs. DRVH switches between BST and SW (enabling high-side NMOS), while DRVL switches between REG (6 V) and PGND (enabling low-side NMOS). The 7 V BSTREG output powers the bootstrap circuit, and a 0.1 µF BST–SW capacitor is mandatory for reliable high-side gate drive.