SN74S299DW Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
SN74S299DW is an 8-bit universal shift/storage register with bidirectional shifting and parallel I/O by Texas Instruments, in a 20-pin SOIC package. Key specs: 50 MHz max clock, 45 pF load capacitance, Schottky (74S) logic family, 0°C to 70°C commercial range. From $2.50, in stock with worldwide shipping.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 20
- Lifecycle
- OBSOLETE
- Datasheet
- SN74S299DW Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74S299DW?
- 8-bit bidirectional universal shift register with parallel-in/parallel-out for flexible data routing
- 50 MHz maximum clock frequency using Schottky (74S) logic for high-speed digital systems
- Hold mode preserves register contents without clock activity, reducing power toggling
- Three-state outputs enable direct bus connection and multiplexing across multiple register stages
- 20-pin SOIC package simplifies board layout for dense 8-bit datapath designs
What is SN74S299DW used for?
SN74S299DW is used in high-speed digital systems requiring 8-bit serial-to-parallel or parallel-to-serial data conversion, such as bus interface buffers, FIFO pre-stages, and serial communication controllers. Its bidirectional shift capability and hold mode make it suitable for temporary data storage and direction-switchable communication links in minicomputer and embedded processor designs. Operating at up to 50 MHz, it fits into time-division multiplexed data bus architectures in industrial controllers and legacy digital signal processing hardware.
What are the specifications of SN74S299DW?
| Pbfree Code | No |
| YTEOL | 0 |
| Additional Feature | HOLD MODE |
| Count Direction | BIDIRECTIONAL |
| Family | S |
| JESD-30 Code | R-PDSO-G20 |
| Load Capacitance (CL) | 45pF |
| Logic IC Type | PARALLEL IN PARALLEL OUT |
| Max Frequency@Nom-Sup | 50000000Hz |
| Number of Bits | 8 |
| Number of Functions | 1 |
| Output Characteristics | 3-STATE |
| Output Polarity | TRUE |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP20,.4 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Power Supply Current-Max (ICC) | 225mA |
| Propagation Delay (tpd) | 21ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.25V |
| Supply Voltage-Min (Vsup) | 4.75V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | TTL |
| Temperature Grade | COMMERCIAL |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | NOT SPECIFIED |
| Trigger Type | POSITIVE EDGE |
| fmax-Min | 50MHz |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.60 |
Where can I find the SN74S299DW datasheet?
SN74S299DW Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74S299DW?
Compatible alternatives and drop-in replacements for SN74S299DW:
Parallel In Parallel Out, S Series, 8-Bit, Bidirectional, True Output, TTL, PDSO20
Frequently Asked Questions
What is the maximum operating frequency of SN74S299DW and which logic family does it belong to?
SN74S299DW operates at a maximum clock frequency of 50 MHz and belongs to the 74S (Schottky TTL) logic family, which provides faster switching speeds than standard 74LS devices. At 50 MHz with a 45 pF load capacitance, the device supports high-throughput 8-bit serial-to-parallel conversion in bus interface and data pipeline applications.
How does the hold mode on SN74S299DW benefit system designs with intermittent data flow?
The hold mode on SN74S299DW preserves the current 8-bit register contents indefinitely without requiring clock pulses, reducing unnecessary switching activity and associated power dissipation. In bus arbitration circuits where data must be latched between bus cycles, hold mode eliminates the need for external D-latches, simplifying the design and reducing component count by combining storage and shift functions in one 20-pin SOIC device.
Can SN74S299DW be used to cascade 16-bit shift register chains and how is cascading achieved?
SN74S299DW can be cascaded by connecting the serial output pin (Q7 or Q0 depending on shift direction) of one device to the serial input of the next, forming 16-bit or wider shift register chains. The three-state outputs allow bus-sharing, and with synchronous parallel loading at 50 MHz, two cascaded SN74S299DW devices can serialize or deserialize 16-bit parallel data in 16 clock cycles, suitable for UART pre-processing or serial bus bridges.
What are the key differences between SN74S299DW and the slower SN74LS299 for a 10 MHz serial data interface?
SN74S299DW uses Schottky clamping to achieve a 50 MHz maximum clock versus 36 MHz for SN74LS299, and its propagation delay is typically 7 ns versus 14 ns for the LS version. For a 10 MHz serial interface, either device is adequate, but SN74S299DW provides 3x timing margin, reducing sensitivity to PCB trace capacitance up to 45 pF and supply noise in shared-bus environments where multiple 74S devices are switching simultaneously.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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