NXP Semiconductors 74LV4799D,118

Overview

74LV4799D,118 from NXP Semiconductors (formerly Philips) is a low-voltage CMOS battery management IC designed specifically for NiCd and NiMH charger control. It integrates a 17-stage divider, 10-stage up/down counter, precision oscillator with external RC timing, automatic power-on reset, and dual enable outputs (EN/EN) for driving external bipolar transistors. Key confirmed parameters include 0.9–6.0 V supply range, ±7% oscillator frequency tolerance, 36 µA typical operating current at 3.3 V, and support for charge times from 4 to 16 hours in domestic shavers and cordless telephones.

For engineers reviewing the 74LV4799D,118 datasheet, 74LV4799D,118 pinout, 74LV4799D,118 application, or 74LV4799D,118 equivalent, this page delivers verified technical context, exact pin functions, real-world timing accuracy constraints, battery status indication logic (LED/MOLLI), and validated alternatives for NiCd/NiMH charger designs requiring self-discharge compensation and trickle-charge duty-cycle control.

Technical Context

The 74LV4799D,118 implements time-based battery management using a synchronous CMOS architecture with a bistable power-on reset and Schmitt-triggered PWRS/DIS inputs. Its core timing engine combines an on-chip oscillator (externally tuned via RC/RD/RS pins and C1 capacitor), a 17-stage divider, and a 10-stage up/down counter to measure charge, discharge, and self-discharge durations independently.

Control logic interprets PWRS (power sense, 50 Hz–100 kHz AC/DC detection), DIS (discharge trigger), and SEL (LED mode select) to switch between five operational modes: charge, trickle charge, charge/discharge, discharge, and self-discharge - each with distinct counter direction, clock source, and EN/EN output states per Function Table 1.

Key Specifications

Pinout & Package

74LV4799D,118 is housed in a 16-pin plastic SO (Small Outline) package per SOT109-1, with 1.27 mm pitch, gull-wing leads, and JEDEC MS-012AC compliance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery timer applications.

Compared with 74LV4799D,118, MAX713 offers superior voltage-based termination but requires external components and lacks self-discharge compensation, while UC3906 delivers robust analog current control but omits the integrated counter-based timing, LED/MOLLI signaling, and scan-test diagnostics unique to the 74LV4799D,118.

Availability

74LV4799D,118 is available at Aetrix Electronics and suitable for rechargeable shaver charging, cordless telephone base station power management, and electric toothbrush battery maintenance requiring stable component supply across industrial and consumer OEM programs.

Supply support for 74LV4799D,118 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

NXP Semiconductors is a global semiconductor leader specializing in secure connectivity solutions, automotive radar, and power management ICs, with roots in Philips' pioneering analog and mixed-signal design heritage.

The 74LV4799D,118 belongs to NXP's legacy low-voltage logic and battery management portfolio, engineered explicitly for cost-sensitive, high-reliability NiCd/NiMH charger applications in consumer electronics where minimal external components and proven timing accuracy are critical.

FAQ

What is the primary function of the 74LV4799D,118 in battery charging systems?

The 74LV4799D,118 serves as a fully autonomous battery management timer for NiCd and NiMH chemistries. It measures charge, discharge, and self-discharge durations using an on-chip oscillator and counter, then controls external transistors via EN/EN outputs to execute full charge, trickle charge, and low-battery alert sequences without microcontroller intervention. Its design eliminates need for software-based timing in simple chargers.

How does the 74LV4799D,118 handle low-voltage startup with deeply discharged batteries?

The 74LV4799D,118 uses its Vin pin (pin 4) to bias external bipolar transistors during initial power-up, enabling reliable start-up even when VCC is below 0.9 V. The internal power-on reset (POR) activates below 0.25 V and releases above 0.65 V, ensuring the counter resets to zero and initiates a full charge cycle. Data retention is guaranteed down to 0.9 V, preventing state corruption during motor-induced supply dips.

Can the 74LV4799D,118 be used for lithium-ion battery charging?

No, the 74LV4799D,118 is not suitable for lithium-ion batteries. Its timing architecture, voltage thresholds, and termination logic (based on fixed time and MOLLI low-voltage alert) are specifically calibrated for NiCd/NiMH characteristics including voltage plateau behavior, self-discharge rates, and safe trickle-charge currents. Li-ion requires constant-current/constant-voltage regulation and precise voltage cutoffs not supported by the 74LV4799D,118.

What is the role of the SCAN and SCI pins on the 74LV4799D,118?

The SCAN (pin 14) and SCI (pin 15) pins enable boundary-scan test functionality. When SCAN is driven HIGH, the on-chip oscillator is disabled and the internal counter value is serially shifted out via the MOLLI/SCO pin (pin 6) synchronized to clocks applied to IOSC (pin 13). This allows non-invasive readout of remaining battery energy-49 clock pulses yield the full counter state-without halting normal charger operation.

How does the 74LV4799D,118 implement trickle charge mode?

In trickle charge mode, the 74LV4799D,118 alternates between RC-C1 and RS-C1 time constants-four RC periods followed by three RS periods-to generate a duty cycle that reduces average charge current. This dedicated control compensates for battery self-discharge regardless of original charge rate (e.g., 4-hour vs. 16-hour), maintaining optimal float voltage without overcharging. EN/EN outputs toggle accordingly to gate external transistors.