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NXP Semiconductors N74F521N,602
- Part No.:
- N74F521N,602
- Manufacturer:
- NXP Semiconductors
- Category:
- Comparators
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
N74F521N,602.pdf
- Description:
- IC COMPARATOR IDENTITY 8B 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,124
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Product details
Overview
N74F521N,602 from Philips Semiconductors is an 8-bit identity comparator IC that performs bit-for-bit equality comparison between two parallel 8-bit words, delivering a low-active QA=B output in 7.0 ns typical propagation delay at 5 V, with 24 mA typical supply current, and designed for commercial-temperature (0°C to +70°C) logic systems requiring fast word matching.
For engineers reviewing the N74F521N,602 datasheet, N74F521N,602 pinout, N74F521N,602 application, or N74F521N,602 equivalent, key selection criteria include its active-low expandable enable (IA=B), TTL-compatible input/output levels, 20-pin DIP package, and ripple/parallel expansion capability for multi-word comparisons.
Technical Context
The N74F521N,602 implements combinational logic using F-series bipolar TTL technology to compare A0–A7 and B0–B7 inputs synchronously, asserting QA=B low only when all eight bit pairs match and IA=B is low. Its propagation delay splits into two paths: 3.0–7.0 ns (IA=B → QA=B) and 3.5–9.5 ns (An/Bn → QA=B), both specified under CL = 50 pF and RL = 500 Ω.
It supports hierarchical word-length expansion via cascading: the QA=B output of one device drives the IA=B input of the next, enabling 16-, 24-, or wider-bit comparisons without external gating. The device draws 24–36 mA total supply current across VCC = 4.5–5.5 V and operates within standard 74F logic voltage thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 8-bit identity comparator with active-low QA=B output and active-low expandable enable (IA=B) |
| Propagation Delay (IA=B → QA=B) | 3.0–7.0 ns typical/max - determines minimum time between enable assertion and match detection |
| Propagation Delay (An/Bn → QA=B) | 3.5–9.5 ns typical/max - defines worst-case latency for input change to output response |
| Supply Voltage Range | 4.5–5.5 V - compatible with standard 5 V TTL bus systems and tolerant of ±10% rail variation |
| Output Drive Capability | 20 mA sink (IOL), 1 mA source (IOH) - sufficient to drive 33–50 Ω transmission lines or fan-out to 5–10 74F loads |
| Input Loading | 1.0 FAST unit load per input (20 µA high / 0.6 mA low) - ensures predictable fan-out and timing across mixed 74F logic families |
Pinout & Package
Package: 20-pin plastic dual in-line package (DIP), SOT146-1 footprint, 300-mil width, through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | IA=B | Active-low expansion input / enable - must be low to activate comparison; connects to QA=B of upstream stage |
| 2–9 | A0–A7 | Word A data inputs - bit 0 (LSB) to bit 7 (MSB); TTL-compatible voltage thresholds |
| 3–10 | B0–B7 | Word B data inputs - bit 0 (LSB) to bit 7 (MSB); electrically identical to A-side inputs |
| 10 | GND | Ground reference - common return for all signals and power |
| 11 | VCC | +5 V supply - powers internal TTL circuitry; decoupling capacitor required near pin |
| 19 | QA=B | Active-low identity output - goes low only when IA=B = L and A0–A7 ≡ B0–B7 |
Key Features
| Feature | Design Value |
|---|---|
| 8-bit parallel comparison | Performs full-word equality check in single clock cycle - eliminates need for sequential XOR/AND logic trees |
| Expandable architecture | Supports ripple or parallel expansion to arbitrary word lengths using QA=B → IA=B chaining |
| 7.0 ns typical propagation delay | Enables operation in high-speed address/data bus matching applications up to ~100 MHz effective rate |
| TTL-compatible I/O | Direct interface with 74F, 74LS, and 74AS logic families without level-shifting or buffering |
Applications
| Memory Address Decoding | CPU Bus Arbitration |
|---|---|
Use Scenario: Matching CPU address bus against peripheral chip-select ranges in 8-bit microcontroller systems. IC Role / Device Role / Timing Role: Identity comparator verifying exact 8-bit address segment equality to assert chip-select enable. Use Value: Reduces decode latency to ≤7 ns and eliminates combinatorial logic gates, improving timing margin and board density. | Use Scenario: Resolving bus master contention by comparing arbitration ID fields during multi-master cycles. IC Role / Device Role / Timing Role: Fast word-match detector generating grant signal only when requesting and granted IDs match. Use Value: Enables deterministic, sub-10 ns arbitration resolution without software intervention or state-machine overhead. |
| Digital Test Equipment | Legacy Protocol Analyzers |
Use Scenario: Capturing specific 8-bit instruction opcodes or data patterns in real-time logic analyzers. IC Role / Device Role / Timing Role: Hardware trigger generator detecting exact byte matches on parallel data buses. Use Value: Provides deterministic, zero-software-latency triggering independent of processor clock domain or firmware delays. | Use Scenario: Validating frame synchronization bytes (e.g., HDLC flag 0x7E) in serial-to-parallel converted streams. IC Role / Device Role / Timing Role: Parallel pattern recognizer identifying known sync markers in buffered parallel data lanes. Use Value: Enables reliable, jitter-immune frame boundary detection at full bus throughput without microcontroller polling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar identity comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F521N | Identical logic function, pinout, and AC/DC specs; manufactured by Texas Instruments under second-source agreement | No functional difference; validated drop-in replacement in all 74F-based designs | Select when TI-sourced supply chain assurance or dual-sourcing strategy is required |
| 74ACT521PC | Advanced CMOS version: 5 V tolerant, 3.3 V compatible, 6.5 ns max tPD, lower ICC (4 mA typ), but requires VIH ≥ 3.5 V | Not directly interchangeable due to higher VIH threshold and different noise margins; needs level adaptation in 74F systems | Choose for new low-power, mixed-voltage designs where 74F compatibility is not mandatory |
Compared with SN74F521N and 74ACT521PC, the N74F521N,602 offers guaranteed 74F-family timing and loading behavior in legacy TTL environments, while SN74F521N provides sourcing flexibility and 74ACT521PC enables power reduction at the cost of voltage-level redesign.
Availability
N74F521N,602 is available at Aetrix Electronics and suitable for memory decoding, bus arbitration, digital test equipment, and legacy protocol analyzers requiring stable component supply and long-term obsolescence management.
Supply support for N74F521N,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
Philips Semiconductors (now NXP Semiconductors) was a leading European semiconductor manufacturer specializing in logic, analog, and RF components for industrial, automotive, and consumer electronics.
The 74F logic family-including the N74F521N,602-was engineered for high-speed, low-noise TTL-compatible operation in commercial-grade computing and control systems of the 1980s–1990s.
FAQ
What is the primary function of the N74F521N,602?
The N74F521N,602 is an 8-bit identity comparator that outputs a low signal on QA=B only when all corresponding bits of inputs A0–A7 and B0–B7 match exactly and the IA=B enable input is low. It is used for fast parallel word equality detection in digital systems, with propagation delays as low as 3.0 ns for the enable path. This function is implemented in fixed TTL logic and does not require configuration or programming.
Does the N74F521N,602 support expansion beyond 8 bits?
Yes, the N74F521N,602 supports expansion to any word length via its IA=B input and QA=B output. Cascading multiple devices allows 16-bit, 24-bit, or wider comparisons: the QA=B output of one stage connects to the IA=B input of the next. Both ripple and parallel expansion topologies are supported, as documented in the Philips application diagram SF00277. This capability is intrinsic to the N74F521N,602's logic architecture.
What are the absolute maximum ratings for the N74F521N,602?
The N74F521N,602 has an absolute maximum VCC of –0.5 V to +7.0 V, input voltage range of –0.5 V to +7.0 V, output short-circuit current limit of –60 to –150 mA, and operating temperature range of 0°C to +70°C. Exceeding these values-even briefly-may cause permanent damage. These limits are defined per IEC 134 and are distinct from recommended operating conditions, which specify VCC = 4.5–5.5 V and Tamb = 0–70°C for reliable N74F521N,602 operation.
Can the N74F521N,602 be used with 3.3 V logic systems?
No, the N74F521N,602 is a 5 V-only TTL device and is not 3.3 V compatible. Its input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and output drive characteristics are optimized for 5 V operation. Driving it from 3.3 V sources may result in marginal or non-functional VIH recognition, and connecting its 5 V outputs to 3.3 V–tolerant inputs risks overvoltage damage. For 3.3 V systems, consider the 74ACT521 or level-shifting solutions instead of the N74F521N,602.
What package type is used for the N74F521N,602?
The N74F521N,602 uses a 20-pin plastic dual in-line package (DIP), designated SOT146-1, with 300-mil body width and through-hole leads. This package is industry-standard for legacy 74F logic and supports manual soldering, socketing, and prototyping. It is distinct from the SO20 (SOT163-1) surface-mount variant, and the N74F521N,602 specifically denotes the DIP version per Philips ordering information.
N74F521N,602 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74F
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- 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-DIP
- Mounting Type:
- Through Hole
N74F521N,602 FAQ
1.How can I place an order for N74F521N,602 through Aetrix?
Please submit a Request for Quotation (RFQ) for N74F521N,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 N74F521N,602 reliable?
The price and inventory of N74F521N,602 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for N74F521N,602 is usually 5 days.
3.What payment methods are accepted for N74F521N,602?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for N74F521N,602 transactions.
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4.How is shipping managed for N74F521N,602?
N74F521N,602 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your N74F521N,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 N74F521N,602?
For technical support, including N74F521N,602 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your N74F521N,602 requirements.
6.How does Aetrix verify that N74F521N,602 is sourced from the original manufacturer or authorized distributors?
All N74F521N,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 N74F521N,602 meets industry standards.
7.What is the process for return or replacement of N74F521N,602?
All N74F521N,602 units undergo pre-shipment inspection (PSI). If there is an issue with N74F521N,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 N74F521N,602 part is unused and in its original packaging.
Return procedure for N74F521N,602:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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