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Texas Instruments SN74AS109AD
- Part No.:
- SN74AS109AD
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AS109AD.pdf
- Description:
- IC FF JK TYPE DUAL 1BIT 16SOIC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SN74AS109AD from Texas Instruments is a dual J-K positive-edge-triggered flip-flop IC operating at 0°C to 70°C, supporting 105 MHz maximum clock frequency, 17 mA typical ICC supply current, and 20 mA low-level output drive. It implements asynchronous preset/clear and supports toggle and D-type configurations in digital control, state-machine, and clock-synchronized logic circuits.
For engineers reviewing the SN74AS109AD datasheet, SN74AS109AD pinout, SN74AS109AD application, or SN74AS109AD equivalent, this page delivers verified functional identity, SOIC-16 package mapping, timing parameters (tsu = 5.5 ns, tPLH = 2.5 ns), and validated alternative options for synchronous logic design and legacy TTL system upgrades.
Technical Context
The SN74AS109AD integrates two independent edge-triggered J-K flip-flops with active-low asynchronous PRE and CLR inputs, enabling immediate state override regardless of clock phase. Each section features separate J, K, CLK, PRE, CLR, Q, and Q̅ terminals, with propagation delays referenced to CLK↑ transitions and defined setup/hold timing relative to data stability windows.
It uses advanced Schottky-clamped bipolar (AS) technology to achieve higher speed than ALS variants while maintaining TTL-compatible voltage thresholds (VIH = 2 V, VIL = 0.8 V) and drive capability (IOL = 20 mA, IOH = −2 mA). The device operates strictly within 4.5–5.5 V supply range and is not 3.3-V tolerant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74AS - Advanced Schottky TTL, ensuring 105 MHz operation with controlled power-speed tradeoff |
| Max Clock Frequency | 105 MHz - Enables high-speed synchronous logic in counters, shift registers, and pipeline stages |
| Supply Voltage Range | 4.5 V to 5.5 V - Requires regulated 5-V rail; no 3.3-V or mixed-voltage operation support |
| Output Drive (IOL / IOH) | 20 mA / −2 mA - Sufficient to directly drive multiple TTL inputs or small LED loads without buffering |
| Setup Time (tsu) | 5.5 ns - Defines minimum data stability window before CLK↑ for reliable state capture |
| Propagation Delay (tPLH) | 2.5 ns (min) to 9 ns (max) - Critical for timing closure in multi-stage sequential logic paths |
| Operating Temperature | 0°C to 70°C - Commercial-grade rating; not suitable for extended industrial or automotive ambient ranges |
Pinout & Package
SN74AS109AD is housed in a 16-pin SOIC (D) package per JEDEC MS-012, 7.5 mm body width, 1.75 mm max height, with 1.27 mm lead pitch and gull-wing leads. Pin 1 is marked by a beveled corner or notch on the package top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1CLR | Active-low asynchronous clear for first flip-flop; forces Q = L, Q̅ = H when asserted |
| 2 | 1J | Data input J for first flip-flop; controls set behavior on next CLK↑ when PRE/CLR inactive |
| 3 | 1K | Data input K for first flip-flop; controls reset behavior on next CLK↑ when PRE/CLR inactive |
| 4 | 1CLK | Positive-edge-triggered clock input for first flip-flop; samples J/K on rising transition |
| 5 | 1PRE | Active-low asynchronous preset for first flip-flop; forces Q = H, Q̅ = L when asserted |
| 6 | 1Q | True output of first flip-flop; reflects stored state after CLK↑ and hold-time completion |
| 7 | 1Q̅ | Inverted output of first flip-flop; complementary to 1Q, usable for feedback or differential signaling |
| 8 | GND | Ground reference for all internal circuitry and I/O; must be low-impedance connection |
| 9 | VCC | +5 V supply input; bypassing with 0.1 µF ceramic capacitor near pin is mandatory for noise immunity |
| 10 | 2Q̅ | Inverted output of second flip-flop; electrically isolated from first section |
| 11 | 2PRE | Active-low asynchronous preset for second flip-flop; independent of first section's PRE |
| 12 | 2CLK | Positive-edge-triggered clock input for second flip-flop; may share CLK with first or use separate source |
| 13 | 2K | Data input K for second flip-flop; functionally identical to 1K but electrically isolated |
| 14 | 2J | Data input J for second flip-flop; functionally identical to 1J but electrically isolated |
| 15 | 2CLR | Active-low asynchronous clear for second flip-flop; independent of first section's CLR |
| 16 | 2Q | True output of second flip-flop; fully decoupled from first section's outputs |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent J-K flip-flops | Enables compact implementation of two-bit state elements without inter-section coupling or shared timing constraints |
| Asynchronous preset and clear | Allows immediate initialization or forced reset independent of clock timing-critical for power-up sequencing and fault recovery |
| Positive-edge clock triggering | Ensures deterministic sampling aligned to rising clock edges, simplifying timing analysis in synchronous systems |
| Toggle and D-type configuration support | Permits re-use as divide-by-2 counter (J=K=H) or transparent latch (J=K tied), reducing BOM count in mixed-function designs |
| TTL-compatible input/output levels | Guarantees interoperability with legacy 74xx, 74LS, and 74ALS logic families without level-shifting circuitry |
Applications
| Industrial Control Sequencing | Digital Test Equipment |
|---|---|
|
Use Scenario: Implementing step-indexed state machines in PLC I/O modules where deterministic timing and fail-safe reset are required. IC Role / Device Role / Timing Role: SN74AS109AD serves as the core register element in a 4-state sequence controller, with PRE/CLR driven by watchdog timeout signals. Use Value: 105 MHz clock tolerance allows oversampling of sensor inputs at 25 MHz while maintaining margin for temperature drift and supply variation. |
Use Scenario: Building programmable pattern generators in automated test equipment requiring precise pulse-width and edge alignment. IC Role / Device Role / Timing Role: SN74AS109AD provides synchronized clock division and signal inversion for generating complementary test waveforms. Use Value: 2.5 ns tPLH min enables sub-10 ns edge placement resolution, meeting IEEE 1149.1 boundary-scan stimulus timing requirements. |
| Legacy System Upgrades | Communications Protocol Logic |
|
Use Scenario: Replacing aging 74LS109 or 74ALS109 in field-deployed instrumentation where speed and reliability have degraded. IC Role / Device Role / Timing Role: SN74AS109AD acts as drop-in functional replacement with identical pinout and enhanced AC performance. Use Value: 3× higher fmax than 74ALS109A (105 vs 34 MHz) extends system lifetime without PCB redesign or firmware changes. |
Use Scenario: Managing framing synchronization in UART-to-parallel converters used in embedded modem interfaces. IC Role / Device Role / Timing Role: SN74AS109AD latches start/stop bit detection flags and generates handshake strobes for data transfer. Use Value: 20 mA IOL drives parallel bus lines directly, eliminating external buffers and reducing component count in space-constrained modems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual J-K flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS109AD | Lower max clock (34 MHz), lower ICC (4 mA), slower propagation (16 ns tPLH max), same SOIC-16 pinout | Suitable for cost-sensitive, lower-speed legacy replacements where timing margin is ample | Select SN74ALS109AD only if system clock ≤ 25 MHz and power budget < 5 mA per device is critical |
| SN74HC109DR | CMOS family, 3.3/5-V tolerant, 30 MHz max fclock, 4 µA ICC, different voltage thresholds (VIH = 3.15 V @ 5 V) | Required for mixed-voltage systems or ultra-low-power battery operation; not TTL-compatible | Choose SN74HC109DR only when migrating to CMOS logic families or adding 3.3-V interface capability |
Compared with SN74ALS109AD, the SN74AS109AD delivers 3× higher speed and stronger drive at higher power; versus SN74HC109DR, it ensures direct TTL interoperability but requires strict 5-V supply and consumes >400× more static current.
Availability
SN74AS109AD is available at Aetrix Electronics and suitable for industrial control sequencing, digital test equipment, legacy system upgrades, and communications protocol logic requiring stable component supply across long-lifecycle programs.
Supply support for SN74AS109AD 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 with broad industrial, automotive, and communications reach.
The SN74AS109AD belongs to TI's 74AS logic family, engineered for high-speed TTL-compatible digital systems where propagation delay, fanout, and noise immunity outweigh ultra-low-power requirements.
FAQ
What is the maximum clock frequency supported by the SN74AS109AD?
The SN74AS109AD supports a maximum clock frequency of 105 MHz under recommended operating conditions (VCC = 4.5–5.5 V, CL = 50 pF, TA = 0°C to 70°C). This value is characterized-not production-tested per MIL-STD-883-but confirmed in TI's SDAS198B datasheet switching characteristics table for SN74AS109A devices in SOIC packages.
Does the SN74AS109AD support 3.3-V operation?
No, the SN74AS109AD does not support 3.3-V operation. Its absolute maximum supply voltage is 7 V, but recommended operation is strictly 4.5–5.5 V. Input thresholds (VIH = 2 V, VIL = 0.8 V) and output drive are specified only for 5-V TTL compatibility; applying 3.3 V to VCC risks undefined logic states and unreliable switching.
Can the SN74AS109AD be used as a D-type flip-flop?
Yes, the SN74AS109AD can function as a D-type flip-flop by connecting the J and K inputs of each section together. When J = K, the flip-flop toggles only if both are high; tying them to the same data line causes Q to follow D on the next CLK↑, replicating D-type behavior without external gates.
What is the purpose of the PRE and CLR pins on the SN74AS109AD?
The PRE (pin 5 and 11) and CLR (pins 1 and 15) are active-low asynchronous control inputs. When asserted (LOW), they force the corresponding Q output HIGH or LOW respectively-immediately overriding clock and data inputs. This enables hardware-initiated reset or preset during power-up, error recovery, or system initialization sequences.
Is the SN74AS109AD pin-compatible with the SN74ALS109AD?
Yes, the SN74AS109AD is pin-compatible with the SN74ALS109AD in the same SOIC-16 (D) package. Both share identical pin numbering, terminal functions, and mechanical footprint, allowing direct substitution where higher speed and drive strength are acceptable trade-offs for increased power consumption.
SN74AS109AD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Set(Preset) and Reset
- Type:
- JK Type
- Output Type:
- Complementary
- Number of Elements:
- 2
- Number of Bits per Element:
- 1
- Clock Frequency:
- 105 MHz
- Max Propagation Delay @ V, Max CL:
- 9ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 2mA, 20mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 17 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74AS109AD FAQ
1.How can I place an order for SN74AS109AD through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS109AD 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 SN74AS109AD reliable?
The price and inventory of SN74AS109AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS109AD is usually 5 days.
3.What payment methods are accepted for SN74AS109AD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS109AD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS109AD?
SN74AS109AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS109AD 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 SN74AS109AD?
For technical support, including SN74AS109AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS109AD requirements.
6.How does Aetrix verify that SN74AS109AD is sourced from the original manufacturer or authorized distributors?
All SN74AS109AD 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 SN74AS109AD meets industry standards.
7.What is the process for return or replacement of SN74AS109AD?
All SN74AS109AD units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS109AD, 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 SN74AS109AD part is unused and in its original packaging.
Return procedure for SN74AS109AD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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