Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Clock/Timing > Programmable Timers and Oscillators

Texas Instruments NE556D

Name: NE556D
Brand: Texas Instruments
SKU: NE556D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: NE556D

Manufacturer:: Texas Instruments

Category:: Programmable Timers and Oscillators

Package:: 14-SOIC (0.154", 3.90mm Width)

Datasheet:: NE556D.pdf

Description:: IC OSC TIMER DUAL 100KHZ 14-SOIC

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:875

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

NE556D from Texas Instruments is a dual precision timer IC containing two independent NE555-compatible timing circuits in a single 14-pin SOIC package, operating from 4.5 V to 16 V supply, delivering ±200 mA output drive per channel, and supporting astable/monostable operation for timing intervals from microseconds to hours.

For engineers reviewing the NE556D datasheet, NE556D pinout, NE556D application, or NE556D equivalent, this page delivers verified electrical specs, validated dual-timer functional behavior, confirmed SOIC-14 package mapping, and real-world design context for pulse-width modulation, missing-pulse detection, sequential timing, and industrial control circuits.

Technical Context

The NE556D implements two fully independent 555-style timers sharing only VCC and GND. Each timer features dual comparators (trigger at ~⅓ VCC, threshold at ~⅔ VCC), an SR latch, push-pull output stage, and open-collector discharge switch - enabling precise RC-based timing with active reset override.

Timing stability is maintained via supply-independent thresholds and charge/discharge paths controlled by external RA/RB/CT networks. The CONT pin allows dynamic modulation of internal reference voltages, supporting pulse-width and pulse-position modulation without external op-amps or DACs.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply voltage	4.5 V to 16 V - supports standard TTL/CMOS logic rails and battery-backed industrial supplies without regulation.
Output current	±200 mA per channel - directly drives relays, LEDs, small solenoids, or logic inputs without external buffers.
Timing range	Microseconds to hours - determined solely by external R and C values; no internal oscillator limits.
Operating temperature	0°C to +70°C - qualified for commercial-grade embedded systems and consumer electronics environments.
Package	SOIC-14 (D) - surface-mount compatible with automated assembly; 91.4°C/W junction-to-ambient thermal resistance.
Reset function	Active-low asynchronous reset on Pins 4 & 10 - forces output low and DISCH low independently of TRIG/THRES states.
Control voltage input	CONT pins (3 & 11) - modulates internal comparator thresholds to enable analog-controlled timing variation.

Pinout & Package

NE556D is housed in a 14-pin Small Outline Integrated Circuit (SOIC) package with standard 1.27 mm pitch and 8.65 mm × 3.91 mm body dimensions. Pin 1 is marked by a beveled corner or notch orientation.

Pin/Terminal	Circuit Role	Design Meaning
1, 13	DISCH	Open-collector discharge switch - sinks timing capacitor current to GND when output is low.
2, 12	THRES	Threshold input - resets latch when voltage exceeds ~⅔ VCC; sets end of timing interval.
3, 11	CONT	Control voltage input - overrides internal voltage divider to adjust trigger/threshold levels dynamically.
4, 10	RESET	Asynchronous active-low reset - forces output low and DISCH low regardless of other inputs.
5, 9	OUT	High-current output - sources/sinks up to 200 mA; TTL-compatible logic level with defined VOL/VOH.
6, 8	TRIG	Trigger input - sets latch when voltage falls below ~⅓ VCC; initiates timing interval.
7	GND	Ground reference - common return path for both timers and power supply.
14	VCC	Positive supply - powers both timers; decoupling capacitor required at pin for stable operation.

Key Features

Feature	Design Value
Dual independent timers	Two fully isolated 555-style timing circuits share only VCC/GND - eliminates cross-talk and enables synchronized or staggered operation.
TTL-compatible output drive	±200 mA sourcing/sinking capability - eliminates need for external driver transistors in relay, LED, or logic interface applications.
Active pullup/pulldown	Push-pull output stage ensures fast rise/fall times (100–300 ns) and robust noise immunity without external pull resistors.
Modulatable timing references	CONT pin adjusts internal comparator thresholds - enables analog-controlled PWM, PPM, and voltage-controlled oscillation.
Asynchronous reset	Dedicated RESET inputs per timer - allows deterministic restart of timing cycles independent of RC network state.

Applications

Missing-Pulse Detection	Pulse-Width Modulation
Use Scenario: Monitoring serial data streams or encoder outputs where absence of expected pulses indicates fault or stall. IC Role / Device Role / Timing Role: NE556D configured as monostable one-shot per channel - first timer triggers on incoming pulse, second timer detects timeout if no subsequent pulse arrives. Use Value: Detects gaps as short as 10 µs using RC network; dual-timer integration reduces board space versus discrete 555 solutions.	Use Scenario: Generating variable-duty-cycle signals for motor speed control or LED brightness adjustment using analog control voltage. IC Role / Device Role / Timing Role: NE556D operated in monostable mode with CONT pin driven by DAC or potentiometer - modulates threshold level to vary output pulse width. Use Value: Achieves 10–90% duty cycle range over 1–4 V control input; avoids microcontroller firmware overhead for basic analog dimming.
Sequential Timing	Industrial Control Timer
Use Scenario: Implementing multi-stage process timers in PLC-like logic - e.g., delay start → run → cooldown → shutdown. IC Role / Device Role / Timing Role: NE556D's two timers cascaded - output of Timer 1 triggers Timer 2, with independent RC networks setting each stage duration. Use Value: Enables precise, repeatable multi-step sequences with <150 ppm/°C temperature coefficient and <0.5%/V supply sensitivity.	Use Scenario: Providing reliable time-delay functions in HVAC controllers, pump sequencers, or safety interlocks requiring fail-safe timing. IC Role / Device Role / Timing Role: NE556D used in astable mode to generate clock signal for watchdog circuits, or monostable mode for power-on delay/reset hold-off. Use Value: Operates across full 0°C to +70°C range with guaranteed 200 mA output drive - sustains load activation under worst-case ambient conditions.

Missing-Pulse Detection

Pulse-Width Modulation

Use Scenario: Monitoring serial data streams or encoder outputs where absence of expected pulses indicates fault or stall.

IC Role / Device Role / Timing Role: NE556D configured as monostable one-shot per channel - first timer triggers on incoming pulse, second timer detects timeout if no subsequent pulse arrives.

Use Value: Detects gaps as short as 10 µs using RC network; dual-timer integration reduces board space versus discrete 555 solutions.

Use Scenario: Generating variable-duty-cycle signals for motor speed control or LED brightness adjustment using analog control voltage.

IC Role / Device Role / Timing Role: NE556D operated in monostable mode with CONT pin driven by DAC or potentiometer - modulates threshold level to vary output pulse width.

Use Value: Achieves 10–90% duty cycle range over 1–4 V control input; avoids microcontroller firmware overhead for basic analog dimming.

Sequential Timing

Industrial Control Timer

Use Scenario: Implementing multi-stage process timers in PLC-like logic - e.g., delay start → run → cooldown → shutdown.

IC Role / Device Role / Timing Role: NE556D's two timers cascaded - output of Timer 1 triggers Timer 2, with independent RC networks setting each stage duration.

Use Value: Enables precise, repeatable multi-step sequences with <150 ppm/°C temperature coefficient and <0.5%/V supply sensitivity.

Use Scenario: Providing reliable time-delay functions in HVAC controllers, pump sequencers, or safety interlocks requiring fail-safe timing.

IC Role / Device Role / Timing Role: NE556D used in astable mode to generate clock signal for watchdog circuits, or monostable mode for power-on delay/reset hold-off.

Use Value: Operates across full 0°C to +70°C range with guaranteed 200 mA output drive - sustains load activation under worst-case ambient conditions.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
NE556DR	Same die, identical electrical specs, same SOIC-14 package - differs only in tape-and-reel packaging (2500 pcs vs. NE556D's obsolete status).	No functional difference; suitable for new designs requiring volume production and automated placement.	Select NE556DR for new designs - it is the active, recommended replacement for NE556D with identical performance and pinout.
LM556CN	Functional equivalent dual timer but with wider supply range (2 V to 16 V), higher ESD rating (±2 kV HBM), and PDIP-14 only packaging.	Preferred where lower-voltage operation (<4.5 V) or through-hole assembly is required; not drop-in for SOIC footprint.	Choose LM556CN only if PDIP-14 is acceptable and supply voltage may dip below 4.5 V - otherwise NE556DR is superior for SMT designs.

Compared with NE556D, NE556DR offers identical timing accuracy, output drive, and thermal performance in the same SOIC-14 package but with active manufacturing support and tape-and-reel delivery; LM556CN provides broader supply tolerance and higher ESD robustness but requires PCB layout change due to PDIP-14 footprint.

Availability

NE556D is available at Aetrix Electronics and suitable for industrial controls, pulse-shaping circuits, and missing-pulse detectors requiring stable component supply and long-term obsolescence management.

Supply support for NE556D 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and digital signal technologies with over 50 years of precision timing innovation.

The NE556D belongs to TI's legacy precision timer family designed for robust, low-cost, RC-based timing in commercial-grade instrumentation, industrial automation, and consumer electronics.

FAQ

What is the maximum timing interval achievable with the NE556D?

The NE556D supports timing intervals from microseconds to hours - limited only by external resistor and capacitor values. With typical RC combinations (e.g., 10 MΩ and 100 µF), intervals exceeding 1000 seconds are achievable. The device does not impose internal upper bounds; however, leakage currents and capacitor tolerance become dominant error sources beyond ~10⁴ seconds.

Can the NE556D operate from a 3.3 V supply?

No - the NE556D requires a minimum supply voltage of 4.5 V per its Recommended Operating Conditions. Operation below 4.5 V risks unreliable comparator switching, undefined output states, and failure to meet specified timing accuracy. For 3.3 V systems, consider the TLC556 LinCMOS™ dual timer, which supports 2 V to 16 V operation.

Is the NE556D pin-compatible with the NE555?

No - the NE556D contains two complete 555-style timers in one package and uses a 14-pin SOIC layout, whereas the NE555 is a single timer in an 8-pin package. However, each half of the NE556D (Pins 1–8 or 7–14) mirrors the NE555 pinout: TRIG, THRES, CONT, RESET, GND, DISCH, VCC, OUT - enabling direct substitution per timer when routed accordingly.

What is the purpose of the CONT pin on the NE556D?

The CONT pin (Pins 3 and 11) connects to the internal voltage divider node that sets the trigger (~⅓ VCC) and threshold (~⅔ VCC) reference levels. Applying an external voltage to CONT directly modulates these thresholds - enabling analog control of timing intervals, pulse width, or frequency without changing RC components. Bypassing CONT to ground with a 10 nF capacitor improves noise immunity.

Does the NE556D require external pull-up resistors on its RESET pins?

Yes - when RESET functionality is used, TI recommends a pull-up resistor (e.g., 10 kΩ) from each RESET pin (4 and 10) to VCC to prevent floating inputs and false triggering. If RESET is unused, the pin must be tied directly to VCC - not left open - to ensure predictable operation and avoid increased supply current or erratic output behavior in the NE556D.

NE556D Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 14-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Obsolete

Type:: 555 Type, Timer/Oscillator (Dual)

Count:: -

Frequency:: 100kHz

Voltage - Supply:: 4.5V ~ 16V

Current - Supply:: 20 mA

Operating Temperature:: 0°C ~ 70°C

Supplier Device Package:: 14-SOIC

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

NE556D FAQ

1.How can I place an order for NE556D through Aetrix?

Please submit a Request for Quotation (RFQ) for NE556D 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 NE556D reliable?

The price and inventory of NE556D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NE556D is usually 5 days.

3.What payment methods are accepted for NE556D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NE556D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for NE556D?

NE556D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your NE556D 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 NE556D?

For technical support, including NE556D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NE556D requirements.

6.How does Aetrix verify that NE556D is sourced from the original manufacturer or authorized distributors?

All NE556D 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 NE556D meets industry standards.

7.What is the process for return or replacement of NE556D?

All NE556D units undergo pre-shipment inspection (PSI). If there is an issue with NE556D, 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 NE556D part is unused and in its original packaging.

Return procedure for NE556D:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…