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Home > Products > Integrated Circuits (ICs) > Interface > Sensor and Detector Interfaces

Diodes Incorporated PT8A2648WEX

Name: PT8A2648WEX
Brand: Diodes Incorporated
SKU: PT8A2648WEX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PT8A2648WEX

Manufacturer:: Diodes Incorporated

Category:: Sensor and Detector Interfaces

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: PT8A2648WEX.pdf

Description:: RELAY DRIVER

Quantity:: RFQ Add To RFQ list

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Product details

Overview

PT8A2648WEX from Princeton Technology is a CMOS PIR sensor signal processor IC designed for automatic lighting control in 2-wire (triac) or 3-wire (relay) AC lamp applications. It integrates dual op-amps, zero-crossing detector, on-chip 3.6V regulator, adjustable timing oscillator (OSCD), and MODE-selectable ON/AUTO/OFF operation. Typical supply current is 120µA at 5V, with system oscillator frequency set to 16kHz via external RC network.

For engineers reviewing the PT8A2648WEX datasheet, PT8A2648WEX pinout, PT8A2648WEX application, or PT8A2648WEX equivalent, this device supports daylight-sensing via CDS input, auto-reset on ZC loss (>3s), 40-second warm-up, quick-install mode activation, and relay-level output drive (active-high) compatible with NPN transistor interface.

Technical Context

The PT8A2648WEX implements a two-stage analog signal chain: OP1 amplifies raw PIR sensor output, followed by OP2 configured as a window comparator with VTH=2.0V and VL=1.5V (typ). Trigger validation requires either one ≥340ms pulse, two pulses within 2s (one ≥160ms), or ≥3 pulses within 2s - all synchronized to AC zero-crossing (ZC) input.

Its digital control logic uses a 31.25Hz square-wave MODE output in AUTO mode, enables override via ZC toggling (twice within 3s), and delivers relay output with 125–200µs delay after ZC rising edge. The internal VEE regulator provides stable 3.6V ±0.36V to analog circuitry under 0.5–2mA load.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	5.0V typical; supports 4.75–6.0V range for robust AC line-derived supply designs
Quiescent Current	120µA typical; enables battery-backed or ultra-low-power wall-switch implementations
System Oscillator	16kHz typical (via 430kΩ/180pF); sets base timing resolution for motion detection window
Output Drive	Active-high RELAY output; sinks ≥15mA to drive external NPN transistor directly
CDS Input Threshold	V_H=3.3V / V_L=1.2V; 5s debounce ensures reliable day/night discrimination
ZC Detection	Schmitt-trigger input with V_H=2.9V / V_L=1.4V; synchronizes TRIAC/RELAY firing to AC zero-crossing
VEE Regulator	3.6V ±0.36V output; powers analog front-end independently of noisy VCC rail

Pinout & Package

PT8A2648WEX is housed in a 16-pin DIP package (JEDEC MS-001D/BB), 19.0mm × 6.4mm body, 2.54mm pitch.

Pin/Terminal	Circuit Role	Design Meaning
1, 9	GND	Signal and power reference ground for analog/digital sections
2	RELAY	Active-high open-drain output; drives base of external NPN transistor for relay control
3	OSCD	Timing oscillator I/O; connects to RC network (e.g., 2MΩ/104) to set lamp-on duration
4	OSCS	System oscillator I/O; sets 16kHz clock via 430kΩ/180pF for detection timing accuracy
5	ZC	Schmitt-trigger AC zero-crossing input; enables synchronized, EMI-robust switching
6	CDS	Daylight-sensing input; high = night mode enabled, debounced for 5s to reject transients
7	MODE	Tri-state control: VCC=ON, GND=OFF, open=AUTO; also outputs 31.25Hz square wave in AUTO
8	Vcc	Main power supply input (4.75–6.0V); powers digital logic and internal regulator
10	VEE	Regulated 3.6V analog supply output; powers op-amps and comparators independently
11–13	OP1P/OP1N/OP1O	First-stage op-amp: non-inverting/inverting inputs and output; gain set externally
14–16	OP2P/OP2N/OP2O	Second-stage op-amp: internal 1.8V reference on OP2P; forms window comparator with OP1O

Key Features

Feature	Design Value
Integrated Zero-Crossing Detector	Enables flicker-free, low-EMI AC lamp switching synchronized to line voltage
On-Chip 3.6V Regulator (VEE)	Isolates noise-sensitive analog circuitry from unregulated VCC supply rail
Adjustable Output Duration	Set via OSCD pin RC network (2kΩ–3MΩ range); supports 1000:1 timing ratio
Override Function via ZC Toggling	Two ZC transitions within 3s forces quick-install mode or ON/AUTO toggle without hardware change
40-Second Warm-Up Period	Prevents false triggers during amplifier settling; automatically resets if ZC signal lost >3s

Applications

Occupancy-Sensing Wall Switch

Energy-Efficient Outdoor Lighting

Use Scenario: Residential or commercial wall-mounted light switch that activates only when motion is detected at night.

IC Role / Device Role / Timing Role: PIR signal processor with CDS-based daylight rejection, ZC-synchronized relay drive, and MODE-configurable behavior.

Use Value: Eliminates standby power waste in unoccupied rooms; 120µA quiescent current extends battery life in wireless retrofit switches.

Use Scenario: Streetlight or security light controlled by passive infrared sensing in outdoor environments.

IC Role / Device Role / Timing Role: Core timing and logic controller interfacing PIR sensor, CDS photocell, and AC mains via triac or relay driver.

Use Value: Auto-reset on ZC loss prevents latch-up during grid instability; 40s warm-up avoids nuisance triggers during cold start.

Smart Building Corridor Lighting

Industrial Warehouse Motion Control

Use Scenario: Multi-zone corridor lighting where occupancy in any zone triggers local and adjacent fixtures.

IC Role / Device Role / Timing Role: Standalone PIR processor enabling retriggerable lamp-on duration via OSCD timing adjustment.

Use Value: Retrigger capability extends illumination during continuous movement; 31.25Hz MODE output supports system-level status monitoring.

Use Scenario: High-bay lighting in warehouses requiring robust motion detection under variable ambient light and temperature.

IC Role / Device Role / Timing Role: Dual-op-amp front-end with window comparator rejects vibration and thermal drift; ZC sync ensures safe AC switching.

Use Value: CDS debounce (5s) and trigger validation logic (≥3 pulses/2s) suppress false triggers from machinery vibration or HVAC airflow.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PIR signal processing applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
PT8A2646WEX	Same pinout and function but outputs COMPO (comparator output) instead of CDSO; lacks CDSO pin (pin 10)	Used where raw comparator output is needed for external logic or diagnostics, not CDS enable/disable control	Select PT8A2646WEX only if CDSO functionality is unnecessary and COMPO access is required at pin 10
AP3216C	Digital ambient light + proximity + IR sensor IC with I²C interface; no integrated ZC detection or relay drive	Requires external MCU for timing/logic; suited for smart lighting with ambient-aware dimming, not standalone AC switching	Choose AP3216C only in MCU-based systems needing multi-sensor fusion; not a drop-in replacement

Compared with PT8A2646WEX, PT8A2648WEX provides CDSO for direct CDS-enable control and retains full AUTO/OVERIDE functionality; versus AP3216C, it delivers complete AC-mains-ready lamp control without firmware or external timing components.

Availability

PT8A2648WEX is available at Aetrix Electronics and suitable for occupancy-sensing wall switches, energy-efficient outdoor lighting, and smart building corridor lighting requiring stable component supply across industrial production cycles.

Supply support for PT8A2648WEX 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

Princeton Technology Corporation is a Taiwan-based semiconductor company specializing in mixed-signal ASICs for consumer and industrial control applications.

The PT8A26xx series is a dedicated PIR sensor signal processor product line designed specifically for cost-sensitive, high-reliability AC-powered automatic lighting control systems.

FAQ

What is the function of the OSCD pin and how is output duration adjusted?

The OSCD pin is the timing oscillator input/output that connects to an external RC network (e.g., 2MΩ resistor + 104 capacitor) to set lamp-on duration. The chip measures the RC time constant to generate a programmable hold time; minimum resistor is 2kΩ and maximum is 3MΩ, enabling ~1000:1 adjustment range. Linearity is preserved when CD ≥103.

How does the CDS input interface with a photocell and what happens when it's inactive?

The CDS pin accepts a voltage divider with a cadmium sulfide (CDS) photocell; low input disables PIR detection (day mode), high input enables it (night mode). It features Schmitt-trigger input with 5-second debounce to reject transient light changes. If left unconnected, CDS is pulled high internally, defaulting to night-mode operation.

Can PT8A2648WEX drive a relay directly, or is external transistor buffering required?

PT8A2648WEX cannot drive a relay coil directly. Its RELAY pin is an active-high, open-drain output rated for ≥15mA sink current, intended to drive the base of an external NPN transistor (e.g., 9014) which then switches the relay coil. This architecture isolates the IC from inductive kickback and supports standard 5–12V relay modules.

What is the purpose of the RSTB pin and how does it affect power-on behavior?

The RSTB pin is an active-low reset input with internal pull-up. When left open, the chip performs a fixed 40-second warm-up before accepting PIR triggers. Adding an external capacitor (e.g., 104) to RSTB extends initial reset time, but this extension is ignored if ZC signal is lost >3s - in which case the chip always restarts a full 40s initialization regardless of RSTB configuration.

PT8A2648WEX Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Series:: -

Packaging:: Tape & Reel (TR)

Product Status:: Active

Programmable:: Not Verified

Type:: Infrared (IR)

Input Type:: CMOS

Output Type:: CMOS

Current - Supply:: 120 µA

Operating Temperature:: -20°C ~ 70°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

PT8A2648WEX FAQ

1.How can I place an order for PT8A2648WEX through Aetrix?

Please submit a Request for Quotation (RFQ) for PT8A2648WEX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for PT8A2648WEX reliable?

The price and inventory of PT8A2648WEX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PT8A2648WEX is usually 5 days.

3.What payment methods are accepted for PT8A2648WEX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PT8A2648WEX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PT8A2648WEX?

PT8A2648WEX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PT8A2648WEX order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for PT8A2648WEX?

For technical support, including PT8A2648WEX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PT8A2648WEX requirements.

6.How does Aetrix verify that PT8A2648WEX is sourced from the original manufacturer or authorized distributors?

All PT8A2648WEX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PT8A2648WEX meets industry standards.

7.What is the process for return or replacement of PT8A2648WEX?

All PT8A2648WEX units undergo pre-shipment inspection (PSI). If there is an issue with PT8A2648WEX, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The PT8A2648WEX part is unused and in its original packaging.

Return procedure for PT8A2648WEX:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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