NXP Semiconductors MC34673AEPR2

Overview

MC34673AEPR2 from Freescale Semiconductor is a fully-integrated, high-input-voltage Li-Ion/Li-Polymer battery charger IC with programmable 1.2A constant-current mode, ±0.7% 4.2V output voltage accuracy over –20°C to 70°C, integrated power MOSFET and thermal foldback protection. It enables compact, cost-effective charging in space-constrained portable electronics such as digital still cameras and PDAs.

For engineers reviewing the MC34673AEPR2 datasheet, MC34673AEPR2 pinout, MC34673AEPR2 application, or MC34673AEPR2 equivalent, key selection considerations include its 28V max input rating, 8-pin UDFN package with exposed thermal pad, 2.6V minimum operating voltage, 6.8V over-voltage protection threshold, and open-drain status outputs (PPR/CHG/FAST) for MCU or LED interfacing.

Technical Context

The MC34673AEPR2 integrates a power MOSFET, charge control logic, VIN-BAT comparator, die temperature sensor, and three open-drain status outputs. Its internal architecture implements trickle → constant-current → constant-voltage charge sequencing with automatic transition at 2.7V battery threshold and end-of-charge detection at 10% of programmed I_CHG.

It features dual input monitoring: a 2.6V falling power-on-reset (POR) threshold and 6.8V rising over-voltage protection (OVP) with 400mV hysteresis. Charge current is set via external resistor on ISET (1.0V reference), enabling real-time monitoring using V_ISET = 1.0V × I_BAT/I_CHG.

Key Specifications

Pinout & Package

MC34673AEPR2 is housed in an 8-pin, 2 mm × 3 mm, thermally enhanced UDFN package with exposed pad (EPAD) that must be electrically connected to GND and soldered to a large PCB ground plane for effective thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGTR and TPS65023RSBR, the MC34673AEPR2 delivers higher input voltage resilience (28V vs. ≤6.5V), integrated OVP, and simpler external component count - making it optimal for cost-sensitive, adapter-agnostic portable chargers where dedicated charging performance is prioritized over system power integration.

Availability

MC34673AEPR2 is available at Aetrix Electronics and suitable for digital still cameras, PDAs, portable video game players, and MCU-based mobile devices requiring stable component supply and long-term production continuity.

Supply support for MC34673AEPR2 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

Freescale Semiconductor (now part of NXP Semiconductors) is a global leader in embedded processing and analog power solutions, delivering high-performance, energy-efficient semiconductor products for automotive, industrial, and consumer applications.

The MC34673AEPR2 belongs to Freescale's analog power management IC portfolio, designed specifically for cost-sensitive, space-constrained Li-ion charging in portable consumer electronics with emphasis on input voltage flexibility and minimal external component count.

FAQ

What is the maximum input voltage the MC34673AEPR2 can tolerate?

The MC34673AEPR2 supports an absolute maximum input voltage of 28V on the VIN pin. Its internal over-voltage protection activates at 6.8V (rising threshold), disabling charging to prevent damage. This 28V rating eliminates the need for external OVP components when used with common unregulated or multi-voltage adapters, a key advantage of the MC34673AEPR2 in portable device designs.

How is the charge current programmed on the MC34673AEPR2?

The MC34673AEPR2 charge current is programmed using an external resistor (RISET) connected between the ISET pin and GND. The relationship is I_CHG ≈ 4000 / (RISET + 96), where RISET is in ohms. For example, a 3.23 kΩ resistor sets ~1.2A. The ISET pin maintains a 1.0V reference during CC mode, enabling real-time current monitoring - a core capability of the MC34673AEPR2.

Does the MC34673AEPR2 require an external MOSFET or blocking diode?

No, the MC34673AEPR2 does not require an external MOSFET or reverse-blocking diode. It integrates a power MOSFET with typical R_DS(ON) of 330 mΩ and internal reverse-current protection logic. This integration reduces bill-of-materials cost and PCB footprint - a defining feature of the MC34673AEPR2 versus discrete or semi-integrated charger solutions.

What happens when the battery voltage falls below 2.7V on the MC34673AEPR2?

When the battery voltage drops below 2.7V, the MC34673AEPR2 enters trickle-charge mode, delivering 20% of the programmed constant-current value to safely recover deeply discharged Li-ion cells. This behavior is automatic and defined by the internal V_TRKL threshold. The FAST pin goes high-impedance during trickle mode, distinguishing it from fast-charge operation - a critical diagnostic function of the MC34673AEPR2.

How does the MC34673AEPR2 indicate end-of-charge (EOC)?

The MC34673AEPR2 signals end-of-charge by driving the CHG pin to high-impedance (open-drain release) when the battery current falls to 10% of the programmed CC value and the battery voltage reaches 4.2V. This state persists until the battery voltage drops below the recharge threshold (typically 4.10V), at which point CHG pulls low again. This precise EOC detection is intrinsic to the MC34673AEPR2's charge control architecture.