My Inquiry
My Account
Texas Instruments SN74LS670N
- Part No.:
- SN74LS670N
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74LS670N.pdf
- Description:
- IC REGISTER FILE 1 X 1:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:556
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74LS670N from Texas Instruments is a 4×4 TTL register file IC with three-state outputs, used as a compact, synchronous data storage element in bus-oriented digital systems. It provides 16 bits of storage (four 4-bit words), addressable via two select lines, with independent read/write control and output enable-enabling bidirectional data flow on shared buses in legacy microprocessor support circuits.
For engineers reviewing the SN74LS670N datasheet, SN74LS670N pinout, SN74LS670N application, or SN74LS670N equivalent, this device is commonly evaluated for retro-computing system restoration, educational logic design labs, and industrial controller memory expansion where discrete register-file architecture and TTL-level compatibility are required.
Technical Context
The SN74LS670N implements a fully synchronous 4-word × 4-bit register file using bipolar TTL circuitry, with separate write-enable (WE) and output-enable (OE) controls. Data is written on the rising edge of WE when address lines A0/A1 select a word, and read data appears at three-state outputs only when OE is active low.
It operates strictly within the 74LS family voltage and timing constraints: VCC = 4.75–5.25 V, tPD ≤ 35 ns (max), and supports fan-out of 20 LS-TTL loads. No internal clock signal is required-the device responds directly to control line transitions, making it suitable for asynchronous bus arbitration and handshaking protocols.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 4×4 register file with independent word select, write enable, and three-state output control |
| Logic Family | 74LS TTL - compatible with standard LS-TTL input thresholds and drive capability |
| Supply Voltage | 4.75 V to 5.25 V - requires regulated +5 V rail; not tolerant of undervoltage or overvoltage |
| Propagation Delay | ≤35 ns (max) from WE or OE to valid output - defines maximum bus cycle rate in synchronous systems |
| Output Drive | Three-state, active-low OE - enables direct connection to shared data buses without external bus transceivers |
| Operating Temperature | 0 °C to +70 °C - commercial-grade rating; not rated for extended industrial or military temperature ranges |
| Package | 16-pin plastic dual in-line package (PDIP-N) - through-hole mountable, RoHS-compliant lead finish |
Pinout & Package
SN74LS670N is housed in a 16-pin PDIP (N) package with 0.3-inch body width and standard DIP pin spacing. Pin 1 is located at the top-left corner, identified by a notch or dot marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | Address bit 0 | Selects one of four 4-bit words (00, 01, 10, 11) with A1; determines which register is accessed |
| 2 (A1) | Address bit 1 | MSB of 2-bit address; used with A0 to decode word selection |
| 3 (I0) | Data input 0 | LSB of 4-bit parallel input bus; latched into selected register on WE high-to-low transition |
| 4 (I1) | Data input 1 | Second bit of 4-bit input; driven during write cycles only |
| 5 (I2) | Data input 2 | Third bit of 4-bit input; no effect unless WE is asserted |
| 6 (I3) | Data input 3 | MSB of 4-bit input; must be stable before WE activation |
| 7 (GND) | Ground reference | Signal and power return path; must be low-impedance for TTL noise margin compliance |
| 8 (O3) | Data output 3 | MSB of 4-bit three-state output; high-impedance when OE = high |
| 9 (O2) | Data output 2 | Third bit of output bus; driven only when OE = low and selected word is read |
| 10 (O1) | Data output 1 | Second bit of output bus; reflects contents of addressed register when enabled |
| 11 (O0) | Data output 0 | LSB of output bus; synchronized to OE assertion, not clocked |
| 12 (WE) | Write enable | Active-high control; latches I0–I3 into selected register on rising edge (not edge-triggered per datasheet) |
| 13 (OE) | Output enable | Active-low control; enables O0–O3 drivers only when low; otherwise high-impedance |
| 14 (VCC) | Power supply | +5 V DC supply; requires local 0.1 µF ceramic bypass capacitor near pin |
| 15 (NC) | No connect | Internally unconnected pin; must remain floating or tied to GND/VCC per board layout best practice |
| 16 (NC) | No connect | Internally unconnected pin; no electrical function; avoid routing signals beneath |
Key Features
| Feature | Design Value |
|---|---|
| Four independent 4-bit registers | Enables compact storage of 16 bits with minimal chip count-replaces multiple 74LS170/173 configurations |
| Three-state outputs with separate OE | Allows direct connection to multi-master data buses without external bus buffers or direction control logic |
| Asynchronous address decoding | A0/A1 select word immediately; no clock required-simplifies timing in non-synchronous control planes |
| Standard 74LS DC and AC characteristics | Guaranteed interoperability with existing 74LS-based systems including fan-out, voltage thresholds, and noise margins |
| Through-hole PDIP packaging | Supports prototyping, repair, and legacy manufacturing with manual soldering and socket compatibility |
Applications
| Microprocessor Bus Interface | Educational Logic Labs |
|---|---|
Use Scenario: Interfacing an 8-bit CPU (e.g., Z80 or 6502) to a small local register file for temporary operand storage without using main RAM. IC Role / Device Role / Timing Role: Acts as a dedicated, fast-access scratchpad memory mapped into I/O space via address decoding logic. Use Value: Reduces memory access latency versus RAM; eliminates need for external latch + tri-state buffer combinations. |
Use Scenario: Teaching combinational and sequential logic concepts in undergraduate digital design courses using breadboard-based TTL systems. IC Role / Device Role / Timing Role: Demonstrates addressable storage, bus sharing, and control signal interaction (WE/OE) in real hardware. Use Value: Provides observable, debuggable register behavior with LEDs and switches-no firmware or toolchain required. |
| Retrocomputing System Restoration | Industrial Controller Data Buffering |
Use Scenario: Replacing failed or obsolete register files in vintage minicomputer peripherals or arcade game PCBs (e.g., early 1980s vector displays). IC Role / Device Role / Timing Role: Exact form-fit-function replacement for original SN74LS670N in legacy schematics with identical pinout and timing. Use Value: Maintains original system timing integrity and avoids redesign of critical timing-critical paths. |
Use Scenario: Storing configuration parameters or sensor calibration values in programmable logic controllers where EEPROM write endurance is limited. IC Role / Device Role / Timing Role: Volatile but fast-access storage node controlled by PLC firmware via discrete I/O lines. Use Value: Enables rapid parameter updates during runtime without EEPROM wear or latency penalties. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar register-file applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS170N | 4×4 register file with open-collector outputs (not three-state); requires external pull-ups | Lacks true bus-driving capability; unsuitable for direct bus connection without additional components | Choose only if legacy board uses open-collector bus architecture and pull-up resistors are already present |
| SN74LS670NSR | Same logic function and timing, but in 16-pin SOP (NS) surface-mount package | Requires rework or new PCB layout; incompatible with through-hole sockets or hand-soldered repairs | Prefer for new SMT designs needing same functionality with smaller footprint and tape-and-reel automation |
Compared with SN74LS170N and SN74LS670NSR, the SN74LS670N uniquely combines three-state bus driving, through-hole PDIP packaging, and guaranteed 74LS timing-making it the only drop-in replacement for legacy through-hole register-file implementations requiring zero layout change.
Availability
SN74LS670N is available at Aetrix Electronics and suitable for retrocomputing restoration, educational lab kits, and industrial controller upgrades requiring stable component supply across long product lifecycles.
Supply support for SN74LS670N 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic products with broad industrial and educational reach.
The SN74LS670N belongs to TI's classic 74LS logic family, designed in the 1970s for reliable, low-power TTL-based digital system building blocks-targeting computer peripherals, test equipment, and teaching platforms.
FAQ
What is the function of the SN74LS670N in a digital system?
The SN74LS670N functions as a 4×4 register file-storing 16 bits across four independent 4-bit words. It accepts a 2-bit address (A0/A1) to select a word, latches data on its four inputs (I0–I3) when write enable (WE) is asserted, and drives the selected word onto its three-state outputs (O0–O3) when output enable (OE) is active low. This makes the SN74LS670N ideal for compact, bus-shared temporary storage in TTL-based systems without requiring a clock signal.
Does the SN74LS670N require a clock signal to operate?
No, the SN74LS670N does not require a clock signal. It is an asynchronous register file: data is written on the rising edge of the WE signal, and outputs respond directly to the OE signal. Address selection (A0/A1) is combinatorial-no timing relationship to WE or OE is specified beyond setup/hold requirements. This distinguishes the SN74LS670N from synchronous RAM or register-based devices and simplifies integration into non-clocked control logic.
Can the SN74LS670N be used as a direct replacement for SN74LS170N?
No-the SN74LS670N is not a direct replacement for SN74LS170N due to fundamental output architecture differences. The SN74LS170N has open-collector outputs requiring external pull-up resistors, while the SN74LS670N features true three-state outputs with active-low OE. Swapping them without modifying pull-up networks and control logic will result in incorrect bus behavior or contention. Use SN74LS670N only where three-state drive is explicitly supported in the target design.
What is the operating temperature range of the SN74LS670N?
The SN74LS670N is rated for commercial operation from 0 °C to +70 °C. It is not qualified for extended temperature ranges such as −40 °C to +85 °C (industrial) or −55 °C to +125 °C (military). Designs intended for harsh environments must verify thermal derating, consider alternative temperature-qualified variants like SN54LS670J, or implement external thermal management to stay within the SN74LS670N's specified limits.
Is the SN74LS670N RoHS compliant?
Yes, the SN74LS670N is RoHS compliant, with NIPDAU (nickel/palladium/gold) lead finish and full compliance documentation available from Texas Instruments. Its PDIP (N) package meets EU RoHS Directive 2011/65/EU requirements, including restrictions on lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE. Note that earlier non-RoHS versions (e.g., SNJ54LS670J) use SNPB (tin-lead) finish and are not compliant.
SN74LS670N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Register File
- Circuit:
- 1 x 1:1
- Independent Circuits:
- 4
- Current - Output High, Low:
- 2.6mA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
SN74LS670N FAQ
1.How can I place an order for SN74LS670N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS670N 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 SN74LS670N reliable?
The price and inventory of SN74LS670N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS670N is usually 5 days.
3.What payment methods are accepted for SN74LS670N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS670N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS670N?
SN74LS670N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS670N 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 SN74LS670N?
For technical support, including SN74LS670N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS670N requirements.
6.How does Aetrix verify that SN74LS670N is sourced from the original manufacturer or authorized distributors?
All SN74LS670N 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 SN74LS670N meets industry standards.
7.What is the process for return or replacement of SN74LS670N?
All SN74LS670N units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS670N, 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 SN74LS670N part is unused and in its original packaging.
Return procedure for SN74LS670N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74LS670N Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
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…
