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NXP Semiconductors N74F521D,602
- Part No.:
- N74F521D,602
- Manufacturer:
- NXP Semiconductors
- Category:
- Comparators
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
N74F521D,602.pdf
- Description:
- IC COMPARATOR IDENTITY 8BIT 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,559
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Product details
Overview
N74F521D,602 from NXP Semiconductors (formerly Philips) is an 8-bit identity comparator IC with active-Low QA=B output, 7.0 ns typical propagation delay, 24 mA typical supply current, and TTL-compatible 5 V operation. It performs bit-for-bit comparison of two 8-bit words and supports parallel or ripple expansion for wider word lengths in address decoding and data validation circuits.
For engineers reviewing the N74F521D,602 datasheet, N74F521D,602 pinout, N74F521D,602 application, or N74F521D,602 equivalent, key selection considerations include its expandable architecture, active-Low enable/expand input (IA=B), guaranteed 0–70°C commercial temperature range, and compatibility with standard 74F logic families in high-speed digital systems.
Technical Context
The N74F521D,602 implements a combinatorial identity comparison function using fast TTL circuitry, delivering match detection within 7.0 ns (typical) from any input change to QA=B assertion. Its IA=B terminal serves dual purpose: as expansion input for cascading multiple comparators and as active-Low enable-asserting QA=B only when IA=B is Low and A[0:7] = B[0:7].
Designed for synchronous digital systems, it operates strictly at VCC = 4.5–5.5 V with VIH ≥ 2.0 V and VIL ≤ 0.8 V, supporting fan-out of up to 50 loads in Low state (20 mA sink capability). Output QA=B is open-collector compatible but internally driven as totem-pole with VOH ≥ 2.7 V and VOL ≤ 0.50 V under specified load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 8-bit identity comparator with active-Low QA=B output |
| Propagation Delay | 7.0 ns typical (A/B or IA=B to QA=B), enabling sub-10 ns match detection |
| Supply Voltage | 4.5–5.5 V - compatible with standard 5 V TTL bus systems |
| Supply Current | 24 mA typical total ICC - defines power budget per unit in dense logic arrays |
| Output Drive | 20 mA sink (IOL), 1 mA source (IOH) - supports direct LED drive or wired-AND expansion |
| Operating Temp | 0°C to +70°C - validated for commercial-grade embedded control and instrumentation |
| Input Loading | 1.0 FAST unit load per input (20 µA High / 0.6 mA Low) - ensures predictable fan-out in mixed-F family designs |
Pinout & Package
Package: Plastic small outline (SO20), 20-lead, 7.5 mm body width (SOT163-1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | IA=B | Active-Low expansion/enable input; must be Low to activate comparison and allow QA=B assertion |
| 2–9, 11–18 | A0–A7, B0–B7 | Two independent 8-bit parallel word inputs; paired as A0/B0 through A7/B7 for bit-wise matching |
| 10 | GND | Ground reference for all internal logic and I/O |
| 19 | QA=B | Active-Low identity output; goes Low only when IA=B is Low AND all eight A/B bit pairs match |
| 20 | VCC | +5 V power supply connection; decoupling required per high-speed TTL practice |
Key Features
| Feature | Design Value |
|---|---|
| Expandable architecture | Supports unlimited word-length comparison via cascaded IA=B/QA=B connections in parallel or ripple mode |
| High-speed match detection | 7.0 ns typical propagation delay enables use in 100+ MHz clock domain boundary checks |
| Dual-role IA=B input | Eliminates need for external gating logic by combining enable and expansion functions in one pin |
| TTL-compatible I/O | Meets 74F voltage thresholds and loading specs - interoperable with legacy 74LS/74AS/74F systems without level shifting |
| Robust DC output drive | 20 mA sink capability allows direct interface to LEDs, relays, or downstream TTL inputs without buffers |
Applications
| Memory Address Decoding | Bus Arbitration Logic |
|---|---|
Use Scenario: Detecting exact match between CPU address bus and peripheral chip select range in 16-bit or wider memory maps. IC Role / Device Role / Timing Role: Identity comparator verifying A[0:7] = B[0:7] as part of multi-stage decode tree with expanded IA=B chaining. Use Value: Enables precise 8-bit window recognition with <7 ns latency, reducing address setup overhead in wait-state-free systems. | Use Scenario: Resolving simultaneous bus request signals from multiple DMA controllers or peripherals sharing a common data bus. IC Role / Device Role / Timing Role: Comparing priority-encoded request IDs against grant ID to assert dedicated acknowledge lines. Use Value: Provides deterministic, race-free arbitration decision within one TTL propagation delay, eliminating metastability in synchronous bus grants. |
| Data Integrity Verification | Instruction Fetch Validation |
Use Scenario: Validating checksum or CRC residue bytes against expected values during firmware boot or configuration loading. IC Role / Device Role / Timing Role: Performing real-time byte-equality check on incoming serial or parallel data streams before storage or execution. Use Value: Delivers immediate pass/fail indication with no software overhead, supporting fail-fast diagnostics in safety-critical boot sequences. | Use Scenario: Confirming instruction opcode or immediate operand matches expected pattern prior to ALU dispatch in microcoded control units. IC Role / Device Role / Timing Role: Acting as early-stage filter in pipeline decode stage to gate invalid or privileged instructions. Use Value: Reduces pipeline stalls by rejecting illegal opcodes in hardware, improving average instruction throughput in fixed-function controllers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar identity comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F521N | Dual-in-line package (DIP20, SOT146-1); identical AC/DC specs and pinout | Preferred for through-hole prototyping or legacy board rework where SOIC footprint is incompatible | Select SN74F521N when manual soldering, socket-based testing, or PCB layout constraints require DIP form factor |
| 74ACT521SCX | Advanced CMOS (ACT) family; 3.3 V tolerant inputs, 4.5–5.5 V supply, 6.5 ns max tPD, lower ICC (~4 mA) | Better noise immunity and reduced power in mixed-voltage systems; not drop-in due to different input threshold specs | Choose 74ACT521SCX for new 5 V designs requiring lower static power or improved noise margin over legacy 74F |
Compared with SN74F521N and 74ACT521SCX, the N74F521D,602 offers identical logic functionality and timing in a space-saving SO20 package, making it optimal for high-density commercial-grade boards where thermal and layout efficiency outweigh DIP serviceability needs.
Availability
N74F521D,602 is available at Aetrix Electronics and suitable for memory address decoding, bus arbitration logic, and data integrity verification requiring stable component supply across industrial control, test equipment, and legacy system repair programs.
Supply support for N74F521D,602 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
NXP Semiconductors is a global semiconductor company formed from the spin-off of Philips' semiconductor division, specializing in secure connectivity solutions and high-performance analog/digital ICs.
The 74F logic family-including N74F521D,602-was engineered for high-speed commercial applications demanding sub-10 ns propagation delays and robust TTL interoperability in computing, instrumentation, and communications infrastructure.
FAQ
What is the operating voltage range for N74F521D,602?
The N74F521D,602 operates over VCC = 4.5 V to 5.5 V, with recommended nominal supply at 5.0 V ±10%. This range ensures compatibility with standard TTL bus systems while maintaining guaranteed timing and logic thresholds across the full 0°C to +70°C commercial temperature range. The N74F521D,602 does not support 3.3 V or mixed-voltage operation.
How does the IA=B pin function in N74F521D,602?
The IA=B pin on the N74F521D,602 serves as both an active-Low enable and expansion input: comparison is only performed and QA=B can only go Low when IA=B is driven Low. When cascading multiple N74F521D,602 devices, upstream QA=B drives downstream IA=B to build wider comparators. The N74F521D,602 requires no external pull-up or pull-down on IA=B for basic operation.
Is N74F521D,602 pin-compatible with other 74F-series comparators?
Yes - the N74F521D,602 shares identical pinout and logic behavior with SN74F521N (DIP20) and other second-source 74F521 variants. All use the same 20-pin arrangement: IA=B at Pin 1, A0–A7/B0–B7 interleaved across Pins 2–9 and 11–18, GND at Pin 10, QA=B at Pin 19, and VCC at Pin 20. This allows direct SOIC-to-DIP substitution where package permits.
What is the maximum fan-out capability of N74F521D,602 outputs?
The QA=B output of the N74F521D,602 supports up to 50 FAST unit loads in the Low state (20 mA sink) and 33 loads in the High state (1 mA source), per Philips' definition of 1 FAST unit = 20 µA High / 0.6 mA Low. This enables direct driving of multiple 74F inputs without buffering. The N74F521D,602 input pins each present exactly 1.0 FAST load.
Can N74F521D,602 be used in extended temperature applications?
No - the N74F521D,602 is qualified only for the commercial temperature range (0°C to +70°C), as stated in its Philips specification document dated May 15, 1990. It lacks characterization or guarantee for industrial (–40°C to +85°C) or automotive temperature grades. For extended-range use, designers must select alternatives such as 74ACT521 or custom-qualified variants - the N74F521D,602 is not rated beyond its published 0–70°C spec.
N74F521D,602 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74F
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Identity Comparator
- Number of Bits:
- 8
- Output:
- Active Low
- Output Function:
- A=B
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Output High, Low:
- 1mA, 20mA
- Max Propagation Delay @ V, Max CL:
- 9.5ns @ 5V, 50pF
- Current - Quiescent (Iq):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 20-SO
- Mounting Type:
- Surface Mount
N74F521D,602 FAQ
1.How can I place an order for N74F521D,602 through Aetrix?
Please submit a Request for Quotation (RFQ) for N74F521D,602 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 N74F521D,602 reliable?
The price and inventory of N74F521D,602 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for N74F521D,602 is usually 5 days.
3.What payment methods are accepted for N74F521D,602?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for N74F521D,602 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for N74F521D,602?
N74F521D,602 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your N74F521D,602 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 N74F521D,602?
For technical support, including N74F521D,602 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your N74F521D,602 requirements.
6.How does Aetrix verify that N74F521D,602 is sourced from the original manufacturer or authorized distributors?
All N74F521D,602 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 N74F521D,602 meets industry standards.
7.What is the process for return or replacement of N74F521D,602?
All N74F521D,602 units undergo pre-shipment inspection (PSI). If there is an issue with N74F521D,602, 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 N74F521D,602 part is unused and in its original packaging.
Return procedure for N74F521D,602:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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