NXP Semiconductors MC14578P

Overview

MC14578P from Freescale Semiconductor is a CMOS micro-power analog building block integrating a high-impedance comparator, voltage follower, and four enhancement-mode MOSFETs for configurable output stages. It operates from 3.5 V to 14 V, draws only 10 μA quiescent current at 25°C, and features ±1 pA input leakage (DIP package) - designed specifically for UL217/UL268-compliant line-powered smoke detectors.

For engineers reviewing the MC14578P datasheet, MC14578P pinout, MC14578P application, or MC14578P equivalent, this device requires a 3.9 MΩ bias resistor and supports threshold detection, low-battery sensing, and CO detector interfacing with validated input offset voltage (±50 mV), common-mode range (0.7 V to VDD–1.5 V), and ESD protection on all pins.

Technical Context

The MC14578P integrates three functional blocks: a rail-to-rail comparator with ±50 mV offset and 0.5 V/9.5 V output swing at 30 μA load; a unity-gain voltage follower buffering the non-inverting input with ±100 mV offset; and four independent MOSFETs usable as open-drain or totem-pole outputs, each with on-chip static-protection diodes limiting output voltage to VSS–VDD.

Its architecture targets ultra-low-power sensor interface applications: the IN+ pin exhibits ±1 pA leakage (DIP), Cin = 5 pF, and requires short PCB traces due to >10¹² Ω input impedance; all inputs must be tied to VSS or VDD when unused, and Rbias must be externally connected from Pin 13 to VDD per specification.

Key Specifications

Pinout & Package

MC14578P is housed in an 16-lead plastic DIP (Case 648-08), 0.300" wide body, with 2.54 mm lead pitch and standard through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar comparator-plus-driver applications.

Compared with LM393DR2G and TLV3701CDR, the MC14578P uniquely combines comparator, follower, and four switchable MOSFETs in one UL-targeted package - reducing bill-of-materials, board space, and certification effort for smoke and gas detection systems.

Availability

MC14578P is available at Aetrix Electronics and suitable for line-powered smoke detectors, low-battery monitoring circuits, and CO detector interfaces requiring stable component supply across industrial and safety-critical production programs.

Supply support for MC14578P 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 was a global semiconductor company specializing in embedded processing, analog, and sensor solutions before its acquisition by NXP Semiconductors in 2015.

The MC14578P belongs to Freescale's legacy analog sensor interface product line, engineered specifically for UL-listed fire and life safety equipment with emphasis on micro-power operation and integrated signal conditioning.

FAQ

What is the required external component for MC14578P operation?

The MC14578P requires a single 3.9 MΩ ±10% resistor connected from Pin 14 (Rbias) to VDD. This resistor establishes the internal bias current necessary for proper comparator and MOSFET operation. Omitting or misvaluing this resistor will prevent correct functionality - especially in smoke detector applications where UL217 compliance depends on validated biasing.

Can MC14578P drive LEDs or relays directly?

Yes, MC14578P can drive LEDs or small relays directly via its integrated MOSFET outputs (OUT A, OUT B, OUT C1, OUT C2), each rated for ±25 mA continuous current. The on-chip static-protection diodes require that output voltages remain between VSS and VDD - so external flyback diodes are unnecessary for inductive loads within this voltage constraint.

Is MC14578P still manufactured and supported?

The MC14578P is a legacy Freescale part archived in 2009 and no longer in active production. However, Aetrix Electronics maintains verified inventory with full traceability and offers lifecycle availability coordination - including obsolescence forecasting and cross-reference support for ongoing smoke detector manufacturing and repair programs.

How does the voltage follower in MC14578P improve sensor interface accuracy?

The voltage follower in MC14578P buffers the IN+ pin with unity gain and ±100 mV offset, isolating high-impedance sensor sources (e.g., ionization chambers or moisture probes) from loading effects. This preserves signal fidelity in applications where input currents below 1 pA would otherwise cause measurable voltage drop across source impedances exceeding 100 MΩ.

What are the pin 9 and pin 11 (NC) connections for MC14578P?

Pins 9 and 11 of the MC14578P are designated No Connection (NC) - they are not bonded internally and must remain unconnected on the PCB. Neither pin should be tied to VDD, VSS, or any other net; doing so may compromise device reliability or violate UL217 layout requirements for isolation-critical safety circuits.