NXP Semiconductors MC34674BEPR2

Overview

MC34674BEPR2 from Freescale Semiconductor is a fully integrated, factory-programmed Li-Ion/Li-Polymer battery charger IC optimized for travel and cradle chargers. It delivers 850 mA constant-current (CC) charge with ±0.4% output voltage accuracy at 4.2 V, supports up to 28 V input, and integrates NTC thermistor interface, dual-color LED status indication, and smart battery connection verification. It operates in trickle/CC/CV modes and features internal thermal foldback and input over-voltage protection (11 V threshold).

For engineers reviewing the MC34674BEPR2 datasheet, MC34674BEPR2 pinout, MC34674BEPR2 application, or MC34674BEPR2 equivalent, key selection considerations include its fixed 850 mA CC current, 2×3 mm² UDFN-EP package with exposed thermal pad, -40°C to +85°C operating range, and compatibility with current-limited AC/DC adapters due to its 2.6 V falling POR threshold.

Technical Context

The MC34674BEPR2 implements a three-stage charging algorithm-trickle (10% of CC = 85 mA), constant-current (850 mA), and constant-voltage (4.2 V)-with end-of-charge detection at 85 mA (10% I_CHG) sustained for ≥500 ms. Its internal power MOSFET has R_DS(ON) of 265–450 mΩ and enables direct battery connection without external FETs or sense resistors.

Charge control is governed by multiple safety layers: VIN-BAT comparator with 60–22 mV offset (V_OS), die temperature regulation at 110°C, programmable NTC window via V_REF-biased TEMP pin, and independent 4.6-hour fast-charge safety timer. Logic-level EN input is active-low with 100 ms debounce and internal pull-down.

Key Specifications

Pinout & Package

MC34674BEPR2 is housed in an 8-lead, 2×3 mm², 0.5 mm pitch UDFN package with exposed thermal pad (EPAD). The EPAD must be soldered to a large GND copper area for thermal performance and electrical grounding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGTR and MP2617GQZ, the MC34674BEPR2 offers fixed 850 mA charging with no external sense resistor or communication interface-ideal for cost-sensitive, high-reliability travel chargers where thermal safety, wide input range, and autonomous operation are critical.

Availability

MC34674BEPR2 is available at Aetrix Electronics and suitable for USB travel chargers, portable medical devices, wireless headset cradles, and industrial handheld scanners requiring stable component supply and long-term lifecycle support.

Supply support for MC34674BEPR2 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 analog and mixed-signal power management ICs, with deep expertise in battery charging, motor control, and automotive systems.

The MC34674BEPR2 belongs to Freescale's dedicated travel charger IC family, designed specifically to replace discrete charger solutions in compact, cost-sensitive consumer and industrial portable equipment.

FAQ

What is the factory-programmed charge current of the MC34674BEPR2?

The MC34674BEPR2 is factory-programmed for a constant-current (CC) charge output of 850 mA, with ±8% tolerance. This value is fixed and cannot be adjusted externally-no current-setting resistor or digital interface is required. The corresponding trickle-charge current is 85 mA (10% of CC), and end-of-charge (EOC) threshold is 85 mA, verified for ≥500 ms. This specification is confirmed in Table 1 (Device Variations) and Table 4 (Static Electrical Characteristics) of the MC34674 datasheet Rev. 2.0.

Does the MC34674BEPR2 require an external MOSFET or current-sense resistor?

No, the MC34674BEPR2 integrates a power MOSFET with R_DS(ON) of 265–450 mΩ and does not require an external FET, reverse-blocking diode, or current-sense resistor. All charge control-including trickle, CC, and CV regulation-is handled internally. This integration reduces BOM count, PCB area, and thermal design complexity. The absence of external sensing elements is explicitly stated in the "Features" section and validated in the internal block diagram (Figure 2) and functional description of the MC34674BEPR2.

How does the MC34674BEPR2 implement battery temperature monitoring?

The MC34674BEPR2 uses its TEMP and VREF pins to interface with an external NTC thermistor circuit. VREF provides a stable 1.2 V bias to power a resistor divider including the NTC; TEMP reads the resulting voltage. Thresholds for low/high temperature faults are defined as fractions of VREF (e.g., 2/3 VREF for low-temp, 1/3 VREF for high-temp), enabling user-configurable windows like 0°C–50°C. This analog NTC interface is detailed in Table 4, Figure 19, and the NTC Interface section of the MC34674BEPR2 datasheet.

What is the purpose of the GRN and RED pins on the MC34674BEPR2?

The GRN and RED pins are open-drain LED drivers, each capable of sinking up to 6 mA, designed to drive the green and red segments of a dual-color LED. GRN illuminates green during charge completion or recharge; RED illuminates red during trickle or fast-charge modes; simultaneous activation yields yellow for fault conditions (OVP, thermal, NTC, timeout). Their behavior is sequenced during power-up (red → green → yellow → off) and dynamically controlled by internal logic-no external driver circuitry is needed for status indication in the MC34674BEPR2.

Can the MC34674BEPR2 operate with a current-limited AC/DC adapter?

Yes, the MC34674BEPR2 is specifically optimized for use with current-limited AC/DC adapters due to its 2.6 V falling power-on-reset (POR) threshold. This allows the IC to remain enabled even when input voltage sags under load-a common behavior of low-cost, unregulated adapters. Its wide 4.3–28 V input range and internal thermal foldback further ensure stable operation without overheating. These characteristics are highlighted in the device overview and Functional Device Operation section of the MC34674BEPR2 datasheet.