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Texas Instruments SN74ABT7820-15PH
- Part No.:
- SN74ABT7820-15PH
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 80-BQFP
- Datasheet:
-
SN74ABT7820-15PH.pdf
- Description:
- IC FIFO ASYNC 512X18X2 80QFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,675
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Product details
Overview
SN74ABT7820-15PH from Texas Instruments is a strobed bidirectional first-in, first-out (FIFO) memory IC with two independent 512 × 18-bit FIFO buffers operating in opposite directions, supporting up to 67 MHz clock rates, 12 ns access time at 50-pF load, and programmable almost-full/almost-empty flags. It serves as a high-speed data flow controller in bus arbitration and protocol bridging applications between asynchronous subsystems.
For engineers reviewing the SN74ABT7820-15PH datasheet, SN74ABT7820-15PH pinout, SN74ABT7820-15PH application, or SN74ABT7820-15PH equivalent, key selection considerations include dual-FIFO depth and directionality, strobe-synchronized read/write timing, programmable flag offsets, 80-pin PH package compatibility, and 5-V operation with BiCMOS drive strength.
Technical Context
The SN74ABT7820-15PH integrates two physically separate 512 × 18-bit FIFOs with independent load clocks (LDCKA/LDCKB), unload clocks (UNCKA/UNCKB), and reset controls (RSTA/RSTB). Each FIFO supports real-time bypass via SAB/SBA select logic and transceiver isolation via GAB/GBA enables.
Flag generation is fully configurable: AF/AEA and AF/AEB support programmable almost-empty (X) and almost-full (Y) thresholds (default 128), while FULLA/FULLB, EMPTYA/EMPTYB, and HFA/HFB provide fixed-depth status signals. All timing parameters are specified for 5-V supply and 0°C to 70°C operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| FIFO Depth × Width × Count | 512 × 18 × 2 - Dual independent buffers enable simultaneous A→B and B→A data staging without contention. |
| Max Clock Frequency | 67 MHz - Supports high-throughput data transfer in backplane and interface bridging systems. |
| Access Time | 12 ns @ 50-pF load - Enables sub-15-ns cycle times for synchronous burst transfers. |
| Supply Voltage | 4.5 V to 5.5 V - Compatible with standard 5-V TTL/CMOS logic families and industrial power rails. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial and industrial embedded control environments. |
| Programmable Flag Offsets | X/Y = 0–255 (default 128) - Allows fine-grained buffer level monitoring for adaptive flow control. |
| Output Drive Strength | IOL = 24 mA, IOH = –12 mA - Drives heavy capacitive loads and multiple TTL inputs directly. |
Pinout & Package
SN74ABT7820-15PH uses an 80-pin plastic quad flat (PH) package with 0.65-mm lead pitch and exposed thermal pad. Pin numbering follows top-view orientation with corner pin 1 marked.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Port-A bidirectional data bus | 18-bit parallel interface for side-A real-time or FIFO-stored data transfer. |
| B0–B17 | Port-B bidirectional data bus | 18-bit parallel interface for side-B real-time or FIFO-stored data transfer. |
| LDCKA / LDCKB | FIFO A/B write strobe input | Low-to-high transition writes data into respective FIFO when FULL flag is active. |
| UNCKA / UNCKB | FIFO A/B read strobe input | Low-to-high transition reads data from respective FIFO when EMPTY flag is inactive. |
| RSTA / RSTB | FIFO A/B asynchronous reset | Active-low signal clears all FIFO contents and initializes flags (FULL=H, EMPTY=L, AF=H, HF=L). |
| PENA / PENB | FIFO A/B program enable | Enables latching of A0–A7/B0–B7 as X/Y offset values for AF/AEA/AF/AEB during reset initialization. |
| SAB / SBA | Port-B/A read source select | Selects real-time (low) or FIFO output (high) for corresponding port's read path. |
| GAB / GBA | Port-B/A output enable | High enables transceiver drivers; low places outputs in high-impedance state for bus sharing. |
| AF/AEA / AF/AEB | Programmable almost-full/almost-empty flag | Open-drain output asserted high when FIFO contains ≤X words or ≥(512−Y) words. |
| EMPTYA / EMPTYB | FIFO empty status | Active-low signal indicates zero valid words stored; initialized low after reset. |
| FULLA / FULLB | FIFO full status | Active-low signal indicates 512 words stored; initialized high after reset. |
| HFA / HFB | Half-full status | Active-high signal indicates ≥256 words stored; initialized low after reset. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent FIFO architecture | Enables concurrent bidirectional buffering-e.g., A→B streaming while B→A command response-without shared resource conflict. |
| Strobed load/unload control | Separate LDCK/UNCK inputs decouple write and read timing, allowing precise synchronization with external controllers. |
| Configurable almost-full/almost-empty thresholds | Per-FIFO X/Y programming via PENA/PENB + LDCKA/LDCKB allows custom flow-control trigger points for latency-sensitive protocols. |
| Real-time bypass capability | SAB/SBA select logic routes data directly between ports without FIFO delay, supporting transparent mode for low-latency paths. |
| BiCMOS output drivers | Delivers 24-mA sink current and fast edge rates compatible with legacy TTL loads and mixed-voltage backplanes. |
Applications
| Telecom Line Card Data Buffering | Industrial PLC Backplane Interface |
|---|---|
Use Scenario: Buffering packetized voice/data between TDM framer and packet-switching ASIC on a carrier-grade line card. IC Role / Device Role / Timing Role: Dual-FIFO acts as elastic store to absorb clock domain skew between 8 kHz TDM and variable-rate Ethernet MAC layers. Use Value: 512-word depth accommodates worst-case jitter accumulation; programmable AF flags trigger DMA before overflow, ensuring zero packet loss. |
Use Scenario: Interfacing fieldbus master (Modbus TCP) with legacy RS-485 slave network via isolated backplane. IC Role / Device Role / Timing Role: SN74ABT7820-15PH bridges asynchronous protocol stacks by decoupling master polling rate from slave response latency. Use Value: Real-time bypass mode enables immediate echo-back for diagnostics; FIFO mode absorbs bursty sensor data during network congestion. |
| Test Equipment Pattern Generator | Medical Imaging Data Pipeline |
Use Scenario: Staging high-speed digital stimulus patterns from FPGA sequencer to DUT interface with precise timing alignment. IC Role / Device Role / Timing Role: Acts as deterministic delay line and pattern repeater using LDCK/UNCK edge-triggered control. Use Value: 12 ns access time ensures sub-cycle timing resolution; half-full flag provides ready signal for continuous pattern streaming. |
Use Scenario: Aggregating parallel ADC streams from CT scanner detector modules into unified frame buffer before compression. IC Role / Device Role / Timing Role: Dual FIFOs separately buffer X- and Y-axis scan data, enabling synchronized readout despite minor channel skew. Use Value: Independent reset (RSTA/RSTB) allows per-channel calibration flush; AF flags prevent pipeline stall during dynamic range shifts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT72V251L15PF | 3.3-V LVDS interface, 512 × 18 depth, 15-ns access, no real-time bypass or SAB/SBA logic. | Designed for low-power, high-speed serial links-not direct replacement for 5-V parallel bus management. | Choose IDT72V251L15PF only if migrating to 3.3-V LVDS infrastructure and eliminating real-time pass-through requirements. |
| SN74ACT7820-15PH | Same pinout and function but ACT-series CMOS (not ABT BiCMOS); lower drive (24 mA sink only), no 50-pF 12-ns guarantee. | Compatible in static logic designs but unsuitable for driving long traces or multiple TTL loads at 67 MHz. | SN74ACT7820-15PH may be substituted where fanout and trace length are limited, but verify timing margins under actual load. |
Compared with IDT72V251L15PF and SN74ACT7820-15PH, SN74ABT7820-15PH uniquely delivers 5-V BiCMOS drive strength, real-time bypass capability, and guaranteed 12-ns access at 50-pF load-making it irreplaceable in legacy 5-V bus arbitration and mixed-signal test equipment.
Availability
SN74ABT7820-15PH is available at Aetrix Electronics and suitable for telecom line cards, industrial PLC backplanes, automated test equipment, and medical imaging data pipelines requiring stable component supply across extended production lifecycles.
Supply support for SN74ABT7820-15PH 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 specializing in analog, embedded processing, and logic solutions, with decades of heritage in high-reliability interface and memory products.
The SN74ABT7820-15PH belongs to TI's Widebus™ family of advanced bus-interface devices, engineered specifically for robust, high-speed parallel data buffering in industrial, telecom, and test instrumentation systems.
FAQ
What is the maximum clock frequency supported by the SN74ABT7820-15PH?
The SN74ABT7820-15PH supports a maximum clock frequency of 67 MHz for both LDCKA/LDCKB and UNCKA/UNCKB inputs under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C). This rating is validated with 50-pF load and accounts for setup/hold timing margins per the SCAS206D datasheet.
Does the SN74ABT7820-15PH support real-time data pass-through without FIFO storage?
Yes, the SN74ABT7820-15PH supports real-time pass-through via its SAB and SBA control inputs. When SAB = L, B0–B17 outputs reflect A0–A17 inputs directly; when SBA = L, A0–A17 outputs reflect B0–B17 inputs-bypassing both FIFOs entirely. This mode eliminates storage latency for time-critical signals.
How are the almost-full/almost-empty flag thresholds programmed on the SN74ABT7820-15PH?
The SN74ABT7820-15PH programs AF/AEA and AF/AEB thresholds using PENA/PENB and LDCKA/LDCKB. After reset, asserting PENA low during LDCKA↑ latches A0–A7 as the almost-empty (X) value; a second LDCKA↑ pulse (with PENA still low) latches A0–A7 as the almost-full (Y) value. Default is X = Y = 128 if PENA remains high.
What is the function of the GAB and GBA pins on the SN74ABT7820-15PH?
GAB and GBA are output-enable controls for the B-port and A-port transceivers, respectively. When GAB = H, B0–B17 drivers are enabled; when GAB = L, they enter high-impedance state. Similarly, GBA = H enables A0–A17 drivers. These pins allow bus sharing and prevent contention during multi-drop configurations.
Is the SN74ABT7820-15PH compatible with 3.3-V logic interfaces?
No, the SN74ABT7820-15PH is specified for 4.5 V to 5.5 V operation only and is not 3.3-V tolerant. Its VIH minimum is 2.0 V and VIL maximum is 0.8 V, but input thresholds and output drive levels are optimized for 5-V TTL/CMOS systems. Interfacing with 3.3-V logic requires level-shifting circuitry.
SN74ABT7820-15PH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 80-BQFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Size:
- 18K (512 x 18 x 2)
- Function:
- Asynchronous
- Data Rate:
- 67MHz
- Access Time:
- 12ns
- Voltage - Supply:
- 4.5 V ~ 5.5 V
- Current - Supply (Max):
- 95mA
- Bus Directional:
- Bi-Directional
- Expansion Type:
- -
- Programmable Flags Support:
- Yes
- Retransmit Capability:
- No
- FWFT Support:
- No
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 80-QFP (14x20)
SN74ABT7820-15PH FAQ
1.How can I place an order for SN74ABT7820-15PH through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT7820-15PH 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 SN74ABT7820-15PH reliable?
The price and inventory of SN74ABT7820-15PH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT7820-15PH is usually 5 days.
3.What payment methods are accepted for SN74ABT7820-15PH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ABT7820-15PH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ABT7820-15PH?
SN74ABT7820-15PH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT7820-15PH 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 SN74ABT7820-15PH?
For technical support, including SN74ABT7820-15PH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT7820-15PH requirements.
6.How does Aetrix verify that SN74ABT7820-15PH is sourced from the original manufacturer or authorized distributors?
All SN74ABT7820-15PH 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 SN74ABT7820-15PH meets industry standards.
7.What is the process for return or replacement of SN74ABT7820-15PH?
All SN74ABT7820-15PH units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT7820-15PH, 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 SN74ABT7820-15PH part is unused and in its original packaging.
Return procedure for SN74ABT7820-15PH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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