Texas Instruments LM3658SD-A/NOPB

Overview

LM3658SD-A/NOPB from Texas Instruments is a dual-source Li-ion/polymer battery charger IC with integrated power FETs, automatic USB/AC wall adapter source selection, and 5–10 hour selectable charge timers. It delivers up to 1000 mA from AC or 500 mA from USB, maintains ±0.35% termination accuracy at 4.2 V, and operates in pre-qualification, constant-current, constant-voltage, top-off, and maintenance modes for portable devices.

For engineers reviewing the LM3658SD-A/NOPB datasheet, LM3658SD-A/NOPB pinout, LM3658SD-A/NOPB application, or LM3658SD-A/NOPB equivalent, key selection considerations include USB_sel–controlled timer selection (5 h vs. 10 h), ISET-resistor programmable AC charge current, thermal regulation at 120°C, open-drain STAT1/STAT2 status outputs, and TS-pin–based battery temperature monitoring using NTC thermistors.

Technical Context

The LM3658SD-A/NOPB implements a fully integrated linear charging architecture with dual-input power path management: CHG_IN (4.5–6.0 V) and USBpwr (4.35–6.0 V), where CHG_IN takes priority when both are present. Its internal thermal regulation dynamically limits charge current to maintain junction temperature at 120°C, independent of ambient conditions.

It supports two distinct operational configurations via USB_sel: pin-high enables 5-hour TCHG and 30-minute TTOPOFF for fast cycling; pin-low extends TCHG to 10 hours and TTOPOFF to 60 minutes-applicable in both CHG_IN and USBpwr modes. Unlike the LM3658SD-B, it does not support LDO mode; floating TS pin triggers suspend mode, not regulator operation.

Key Specifications

Pinout & Package

LM3658SD-A/NOPB uses a thermally enhanced 3 mm × 3 mm WSON-10 package with exposed die-attach pad (DAP) soldered to PCB ground for optimal thermal dissipation (θJA = 54°C/W with proper layout).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGTR and TPS65023RSBR, the LM3658SD-A/NOPB uniquely balances dual-input autonomy, compact WSON-10 packaging, and USB_sel–driven timer flexibility - making it optimal for space-constrained, battery-first portable devices where AC fallback and precise charge control are mandatory.

Availability

LM3658SD-A/NOPB is available at Aetrix Electronics and suitable for smartphones, digital still cameras, PDAs, and USB-powered MP3 players requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LM3658SD-A/NOPB 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in battery charging solutions.

The LM3658 product line targets portable consumer electronics requiring highly integrated, thermally robust, and dual-source–capable Li-ion charging - designed to reduce bill-of-materials count and simplify layout for handheld form factors.

FAQ

What is the function of the USB_sel pin on the LM3658SD-A/NOPB?

The USB_sel pin on the LM3658SD-A/NOPB serves a dual function: it selects USB charge current (100 mA when pulled low, 500 mA when pulled high) and determines charge timer duration (10-hour TCHG and 60-minute TTOPOFF when low; 5-hour TCHG and 30-minute TTOPOFF when high). This behavior applies in both CHG_IN and USBpwr modes, and is a defining feature of the LM3658SD-A/NOPB variant.

Does the LM3658SD-A/NOPB support LDO mode when the TS pin is left floating?

No, the LM3658SD-A/NOPB does not support LDO mode. When the TS pin is left floating, the LM3658SD-A/NOPB enters suspend mode - halting charging and asserting both STAT1 and STAT2 high - unlike the LM3658SD-B version, which invokes LDO mode under the same condition. This distinction is explicitly documented in the TI datasheet SNVS328E.

How is the full-rate AC charge current programmed on the LM3658SD-A/NOPB?

The full-rate AC charge current on the LM3658SD-A/NOPB is programmed using an external resistor (RISET) connected between the ISET pin and GND, per the equation ICHG = 2500 AΩ / RISET. For example, a 5 kΩ resistor yields ~500 mA. This setting is independent of USB_sel and applies only during CHG_IN operation; USB charge current is controlled solely by USB_sel logic level.

What thermal performance can be expected from the LM3658SD-A/NOPB WSON-10 package?

The LM3658SD-A/NOPB WSON-10 package achieves θJA = 54°C/W when the exposed die-attach pad (DAP) is soldered to a grounded thermal land with ≥4 thermal vias (0.33 mm diameter, 1.27 mm pitch). Without this layout, thermal resistance degrades significantly. Internal thermal regulation holds junction temperature at 120°C, dynamically reducing charge current to prevent exceeding this limit.

What happens if the battery voltage drops below 3.94 V after full charge completion on the LM3658SD-A/NOPB?

If the battery voltage drops below 3.94 V (VRESTART threshold) after maintenance mode begins, the LM3658SD-A/NOPB automatically initiates a new full-rate charge cycle - reactivating STAT1 (ON), turning off STAT2, and resetting all timers. This recharge behavior ensures battery voltage remains within operational range without host processor intervention, supporting true "set-and-forget" portable operation.