My Inquiry
My Account
Texas Instruments SN74ALS1640AN
- Part No.:
- SN74ALS1640AN
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS1640AN.pdf
- Description:
- IC OCT BUS XCVR TRI-ST 20-DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,931
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74ALS1640AN from Texas Instruments is an octal bus transceiver with 3-state outputs, inverting logic, and bidirectional data flow between A and B buses. It operates at 4.5–5.5 V, supports 0°C to 70°C ambient, delivers ±15 mA output drive, and achieves propagation delays as low as 2 ns (tPHL). It is used in legacy industrial backplane and parallel bus isolation systems.
For engineers reviewing the SN74ALS1640AN datasheet, SN74ALS1640AN pinout, SN74ALS1640AN application, or SN74ALS1640AN equivalent, key selection criteria include direction-control (DIR) and output-enable (OE) timing behavior, 3-state isolation integrity, inverting signal path compatibility, and PDIP-20 package thermal performance under sustained bus loading.
Technical Context
The SN74ALS1640AN implements asynchronous bidirectional data transfer using a single DIR input to select A→B or B→A direction, and OE to enable/disable all outputs simultaneously. Its inverting logic means A1–A8 and B1–B8 signals are inverted during transmission - critical for matching legacy bus inversion schemes.
It features TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2 V), guaranteed 3-state off-leakage (< ±0.1 mA), and switching characteristics characterized at CL = 50 pF with R1/R2 = 500 Ω. Propagation delay (tPLH/tPHL) ranges from 2–15 ns, and enable/disable times (tPZH/tPZL) span 2–25 ns across temperature and voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL/ALS logic rails without level-shifting. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade industrial control and instrumentation environments. |
| Output Drive | IOH = –15 mA / IOL = 16 mA - sufficient to drive eight TTL loads or terminate short stubs on parallel buses. |
| Propagation Delay | tPHL = 2–10 ns, tPLH = 4–15 ns - enables reliable operation up to ~50 MHz bus toggle rates in point-to-point configurations. |
| 3-State Enable Time | tPZH = 2–12 ns, tPZL = 5–13 ns - ensures fast bus release to prevent contention during multi-master arbitration. |
| Input Thresholds | VIH = 2 V, VIL = 0.8 V - matches standard ALS/TTL logic families, eliminating need for external biasing. |
| Quiescent Current | ICC = 18–32 mA at VCC = 5.5 V - reflects typical active-state power for octal transceivers in legacy 5-V systems. |
Pinout & Package
SN74ALS1640AN uses a 20-pin plastic DIP (N package), 300-mil width, with through-hole mounting and standard pin spacing. Thermal resistance θJA = 67°C/W enables operation at full load without forced airflow in enclosed enclosures.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control input: LOW enables B→A transfer; HIGH enables A→B transfer. |
| 2 | A1 | Inverting input/output terminal for A-bus bit 1 - connects to upstream data source or latch. |
| 3–9 | A2–A8 | Inverting A-bus I/O terminals - collectively form 8-bit inverting data path toward A-side system. |
| 10 | GND | Ground reference for all internal logic and output stages - must be low-impedance connection. |
| 11–18 | B1–B8 | Inverting B-bus I/O terminals - provide mirrored 8-bit inverting path toward B-side peripheral or memory. |
| 19 | OE | Active-low output enable: LOW enables transceiver; HIGH forces all A/B pins into high-impedance state. |
| 20 | VCC | Positive supply rail (4.5–5.5 V) - requires local 0.1 µF ceramic decoupling adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting bidirectional logic | Ensures signal polarity alignment with legacy bus architectures requiring inverted handshake or data paths. |
| True 3-state isolation | Guaranteed off-state leakage < ±0.1 mA prevents bus contention when multiple transceivers share A or B lines. |
| ALS family compatibility | Matches SN74ALS640B timing and drive strength - allows drop-in replacement in existing ALS-based designs. |
| Low propagation skew | Max tPHL–tPLH delta ≤ 8 ns across all 8 channels - maintains byte-level timing integrity in parallel transfers. |
| Robust input overvoltage tolerance | Withstands VI = 7 V on control inputs and 5.5 V on I/O ports - protects against transient coupling in noisy industrial settings. |
Applications
| Industrial Backplane Interface | Legacy Parallel Printer Port |
|---|---|
|
Use Scenario: Isolating CPU address/data bus from expansion slot peripherals in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional octal buffer with DIR-controlled flow direction and OE-gated 3-state isolation during bus arbitration. Use Value: Enables safe hot-swap of modules by guaranteeing high-Z state on both buses when OE is asserted, preventing short-circuits. |
Use Scenario: Interfacing microcontroller GPIO to Centronics-style parallel printer port with inverted strobe/data protocol. IC Role / Device Role / Timing Role: Inverting transceiver translating MCU-native logic levels to printer-required inverted data and handshaking signals. Use Value: Eliminates discrete inverters by embedding inversion in the data path, reducing component count and board space. |
| EPROM Programming Adapter | Test Equipment Bus Extender |
|
Use Scenario: Connecting PC LPT port to EPROM programmer PCB requiring inverted address latching and data loading. IC Role / Device Role / Timing Role: Direction-controlled inverter enabling PC-driven programming pulses and device-readback data capture via same bus lines. Use Value: Supports bidirectional communication over shared 8-bit bus without external direction logic or multiplexers. |
Use Scenario: Extending IEEE-488 (GPIB) controller bus to remote test fixtures with long cable runs and signal degradation. IC Role / Device Role / Timing Role: Signal repeater buffering and isolating GPIB data lines while preserving timing margins and noise immunity. Use Value: Maintains setup/hold timing integrity across extended traces by driving capacitive loads with 16 mA sink/source capability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS1645AN | Noninverting logic; otherwise identical pinout, timing, and electrical specs. | Used where bus polarity must be preserved end-to-end (e.g., direct CPU-to-peripheral connections without inversion). | Select SN74ALS1645AN only when system-level signal polarity mandates noninverted data path. |
| SN74LS245N | Noninverting; higher ICC (40 mA typ); slower tPLH (17 ns max); no guaranteed 3-state leakage spec. | Suitable for cost-sensitive, lower-speed legacy systems where ALS speed and leakage control are not required. | Choose SN74LS245N only if design tolerates +2 ns delay penalty and higher static power; verify 3-state leakage in context. |
Compared with SN74ALS1640AN, SN74ALS1645AN provides identical performance with noninverting logic-ideal for polarity-critical paths-while SN74LS245N offers broader availability but sacrifices speed, leakage control, and ALS-family consistency.
Availability
SN74ALS1640AN is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy parallel printer ports, and EPROM programming adapters requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS1640AN 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74ALS1640AN belongs to TI's ALS (Advanced Low-Power Schottky) logic family, engineered for high-speed, low-power 5-V TTL-compatible systems where propagation delay and power efficiency were critical trade-offs.
FAQ
What is the logic polarity of SN74ALS1640AN?
The SN74ALS1640AN implements inverting logic: data appearing at A1–A8 is inverted when transmitted to B1–B8, and vice versa. This is intrinsic to its internal gate structure and confirmed in the function table and logic diagrams of the SDAS246B datasheet. The SN74ALS1640AN differs from the noninverting SN74ALS1645AN solely in this polarity characteristic - all other timing, electrical, and packaging specifications remain identical.
Does SN74ALS1640AN support 3.3-V operation?
No, SN74ALS1640AN is specified only for 4.5 V to 5.5 V supply operation per the recommended operating conditions table. Its input thresholds (VIH = 2 V, VIL = 0.8 V) and output drive levels (VOH ≥ 2.4 V at IOH = –3 mA) are optimized for 5-V TTL/ALS systems. Applying 3.3 V to VCC violates minimum supply requirements and will result in undefined logic states, excessive ICC variation, and potential failure to meet timing specs.
What is the maximum capacitive load SN74ALS1640AN can drive reliably?
The SN74ALS1640AN switching characteristics are characterized at CL = 50 pF, and its output drive (IOL = 16 mA, IOH = –15 mA) supports heavier loads than typical 50-pF test conditions. However, propagation delay increases linearly with load capacitance - tPLH rises from 4 ns (CL = 50 pF) to ~12 ns at CL = 100 pF. For reliable operation beyond 50 pF, layout must minimize trace length and avoid stubs; SN74ALS1640AN remains functional up to ~100 pF with verified timing margin.
Is SN74ALS1640AN pin-compatible with SN74LS245N?
Yes, SN74ALS1640AN and SN74LS245N share identical 20-pin PDIP (N) package geometry and pin assignments - including DIR, OE, A1–A8, B1–B8, VCC, and GND locations. However, SN74ALS1640AN is inverting while SN74LS245N is noninverting, so direct substitution requires verification of system-level polarity requirements and timing compliance under actual load conditions.
What is the thermal performance of SN74ALS1640AN in its N package?
The SN74ALS1640AN in the PDIP (N) package has a specified thermal resistance θJA = 67°C/W. At maximum rated ICC = 32 mA and VCC = 5.5 V, power dissipation is ~176 mW, resulting in a junction-to-ambient rise of ~11.8°C above ambient. This allows continuous operation at full load in still-air environments up to 70°C ambient without heatsinking - consistent with its commercial temperature grade rating.
SN74ALS1640AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74ALS1640AN FAQ
1.How can I place an order for SN74ALS1640AN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS1640AN 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 SN74ALS1640AN reliable?
The price and inventory of SN74ALS1640AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS1640AN is usually 5 days.
3.What payment methods are accepted for SN74ALS1640AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS1640AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS1640AN?
SN74ALS1640AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS1640AN 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 SN74ALS1640AN?
For technical support, including SN74ALS1640AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS1640AN requirements.
6.How does Aetrix verify that SN74ALS1640AN is sourced from the original manufacturer or authorized distributors?
All SN74ALS1640AN 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 SN74ALS1640AN meets industry standards.
7.What is the process for return or replacement of SN74ALS1640AN?
All SN74ALS1640AN units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS1640AN, 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 SN74ALS1640AN part is unused and in its original packaging.
Return procedure for SN74ALS1640AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ALS1640AN 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 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…
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…
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…
