My Inquiry
My Account
STMicroelectronics M74HC623B1R
- Part No.:
- M74HC623B1R
- Manufacturer:
- STMicroelectronics
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
M74HC623B1R.pdf
- Description:
- IC TXRX NON-INVERT 6V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,074
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
M74HC623B1R from STMicroelectronics is an octal bus transceiver with non-inverting 3-state outputs, designed for bidirectional asynchronous data exchange between two 8-bit buses. It features dual direction controls (GAB/GBA), symmetrical output drive (±6 mA), 10 ns typical propagation delay at 6 V, and operates across 2–6 V supply range. Used in legacy industrial control backplanes and modular I/O expansion systems where bus isolation and state retention are required.
For engineers reviewing the M74HC623B1R datasheet, M74HC623B1R pinout, M74HC623B1R application, or M74HC623B1R equivalent, key selection criteria include bidirectional enable timing (tPZL/tPLZ ≤ 22 ns at 6 V), high noise immunity (VNIH/VNIL = 28% VCC min), and compatibility with 74-series logic families in DIP-20 packaging.
Technical Context
The M74HC623B1R implements a dual-control transceiver architecture: GAB enables A→B transmission while GBA enables B→A, and simultaneous low on both inputs places all 16 I/Os in high-impedance isolation. When both enables are active, internal feedback reinforces bus states, enabling transparent data latching without external storage.
Its silicon gate CMOS process delivers rail-to-rail input thresholds (VIH = 3.15 V @ 4.5 V VCC), low quiescent current (ICC = 4 µA max at 25°C), and robust ESD protection on all pins. Propagation delays are balanced (tPLH ≅ tPHL) and load-independent within specified CL = 50 pF conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 6 V - supports mixed-voltage system interfacing and battery-backed operation down to 2 V. |
| tPD (Typ.) | 10 ns at VCC = 6 V - enables reliable 50 MHz bus handshaking in synchronous designs. |
| IOL / IOH | ±6 mA min - drives standard TTL loads and multiple 74HC inputs without fanout limitation. |
| VNIH / VNIL | 28% VCC min - rejects >1.2 V noise spikes on 4.5 V buses, critical in electrically noisy PLC racks. |
| ICC (Max) | 4 µA at TA = 25°C - enables always-on monitoring circuits with sub-µA standby power budget. |
| Operating Temp | −55°C to +125°C - qualified for extended-temperature industrial automation and avionics subsystems. |
Pinout & Package
Packaged in plastic DIP-20 (0.300" wide), with 2.54 mm lead pitch and through-hole mounting. Pin 10 = GND, Pin 20 = VCC, dual enable inputs at Pins 1 (GBA) and 19 (GAB), 8 bidirectional data lines each on A-side (Pins 2–9) and B-side (Pins 11–18).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | GBA / GAB | Active-low direction controls: GAB = L enables A→B; GBA = L enables B→A; both L = high-Z isolation. |
| 2–9 | A1–A8 | Bidirectional data terminals for Bus A; internally reinforced when both enables active. |
| 11–18 | B1–B8 | Bidirectional data terminals for Bus B; mirror behavior of A-side under same control logic. |
| 10 | GND | Reference ground for all I/O and supply return; decoupling capacitor must be placed adjacent. |
| 20 | VCC | Positive supply input; requires local 100 nF ceramic bypass between Pin 20 and Pin 10. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent direction control | Enables asymmetric bus arbitration - e.g., A→B only during write cycles, B→A only during read cycles. |
| Simultaneous enable latching | Both GAB and GBA low maintains last valid A/B bus states without external latch or clock. |
| Symmetrical output drive strength | IOH = IOL = 6 mA min ensures matched rise/fall times and eliminates skew-induced setup violations. |
| High noise immunity | VNIH = VNIL = 28% VCC minimizes false triggering in 24 V DC fieldbus environments with inductive switching noise. |
Applications
| Industrial Backplane Interfacing | Modular I/O Expansion |
|---|---|
Use Scenario: Connecting CPU module to isolated peripheral slots in DIN-rail mounted PLC chassis. IC Role / Device Role / Timing Role: Bidirectional data bridge between main bus and slot-specific address/data lines with cycle-by-cycle direction control. Use Value: Eliminates need for separate drivers and direction logic, reducing slot PCB area by 35% and enabling hot-swap-safe isolation. | Use Scenario: Adding analog input or digital output modules to programmable logic controllers via standardized mezzanine connectors. IC Role / Device Role / Timing Role: Level-shifting and bus-separation transceiver between controller-side 3.3 V logic and module-side 5 V sensor/actuator interfaces. Use Value: Supports mixed-voltage operation across 2–6 V range and provides 125°C thermal margin for enclosed cabinet deployments. |
| Legacy System Bus Extension | Test Equipment Signal Routing |
Use Scenario: Extending aging 8-bit microcontroller address/data buses to add memory-mapped peripherals without redesigning core logic. IC Role / Device Role / Timing Role: Non-inverting transceiver preserving signal polarity while adding bus loading isolation and direction gating. Use Value: Maintains full 50 MHz timing margin (tPD = 10 ns typ.) and avoids signal inversion errors in firmware-compatible upgrades. | Use Scenario: Reconfigurable signal path switching in automated test equipment (ATE) mainframes with shared resource buses. IC Role / Device Role / Timing Role: Controlled bus isolation element allowing dynamic routing of stimulus/response signals between instrument cards and DUT interface. Use Value: High-impedance disable time (tPLZ = 15 ns typ. at 6 V) enables sub-20 ns channel reconfiguration for high-throughput parametric testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC623N | Same logic function and pinout; TI version rated for −40°C to +85°C only (vs. −55°C to +125°C). | Lacks extended temperature qualification; unsuitable for aerospace or under-hood automotive use. | Select when operating ambient stays within commercial range and TI supply chain preference applies. |
| 74VHC623N | Higher speed (tPD = 5.5 ns typ. at 5 V); lower drive (±8 mA); VCC range 2–5.5 V only. | Narrower voltage window limits compatibility with 6 V legacy systems and battery-backed rails. | Choose for new designs prioritizing speed over voltage flexibility and extended temp support. |
Compared with SN74HC623N and 74VHC623N, M74HC623B1R uniquely combines military-grade temperature range, 6 V operation, and proven reliability in long-lifecycle industrial installations - making it the preferred choice for systems requiring 15+ year component availability and thermal resilience.
Availability
M74HC623B1R is available at Aetrix Electronics and suitable for industrial backplane interfacing, modular I/O expansion, and legacy system bus extension requiring stable component supply and long-term obsolescence management.
Supply support for M74HC623B1R 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power discrete solutions with vertical manufacturing capability.
M74HC623B1R belongs to the M74HC high-speed CMOS logic family, engineered for drop-in replacement of legacy 74LS devices while delivering lower power, higher noise immunity, and extended temperature operation in industrial control systems.
FAQ
What is the maximum capacitive load this transceiver can drive reliably?
The M74HC623B1R is characterized for CL = 50 pF in AC specs, with tPLH/tPHL up to 22 ns at 6 V. Driving >100 pF increases propagation delay nonlinearly and may cause timing violations; for >75 pF loads, add series termination or reduce clock rate below 25 MHz.
Can both GAB and GBA be held low continuously in a system?
Yes - holding both GAB and GBA low places all 16 I/Os in high-impedance mode, fully isolating the A and B buses. This is safe indefinitely and is used for system reset, power-down, or fault containment without damaging the device or connected circuitry.
Does this part support live insertion or hot-swap operation?
No - M74HC623B1R lacks hot-swap protection circuitry such as slew-rate limiting or undervoltage lockout. Applying VCC before GND or inserting into a live backplane risks latch-up due to input diode conduction; use only in cold-plug or powered-backplane systems.
Is there a surface-mount alternative with identical functionality and pinout?
Yes - M74HC623M1R in SO-20 package shares identical logic, timing, and pin mapping. Its mechanical dimensions differ (12.6 × 7.6 mm vs. DIP-20's 25.4 × 7.1 mm), but PCB layout adaptation is straightforward using standard footprint conversion guidelines.
M74HC623B1R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74HC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-DIP
M74HC623B1R FAQ
1.How can I place an order for M74HC623B1R through Aetrix?
Please submit a Request for Quotation (RFQ) for M74HC623B1R 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 M74HC623B1R reliable?
The price and inventory of M74HC623B1R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M74HC623B1R is usually 5 days.
3.What payment methods are accepted for M74HC623B1R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M74HC623B1R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M74HC623B1R?
M74HC623B1R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M74HC623B1R 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 M74HC623B1R?
For technical support, including M74HC623B1R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M74HC623B1R requirements.
6.How does Aetrix verify that M74HC623B1R is sourced from the original manufacturer or authorized distributors?
All M74HC623B1R 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 M74HC623B1R meets industry standards.
7.What is the process for return or replacement of M74HC623B1R?
All M74HC623B1R units undergo pre-shipment inspection (PSI). If there is an issue with M74HC623B1R, 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 M74HC623B1R part is unused and in its original packaging.
Return procedure for M74HC623B1R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M74HC623B1R Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
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.
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…
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…
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…
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 …
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…
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…
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…
