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178 lines
4.6 KiB
Markdown
178 lines
4.6 KiB
Markdown
# 7400-Series Logic ICs Specification
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## 1. Overview
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The **7400-series** is a large family of **digital logic integrated circuits** originally implemented in **TTL (Transistor-Transistor Logic)** and later expanded to include **CMOS-compatible variants**. These devices provide fundamental building blocks such as gates, flip-flops, counters, multiplexers, decoders, and bus transceivers.
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7400-series ICs are widely used in **retrocomputing**, **6502/Z80 systems**, **glue logic**, and educational designs.
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---
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## 2. Logic Families
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| Family | Technology | Notes |
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| ------- | ----------------------- | ----------------------- |
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| 74xx | TTL | Original bipolar TTL |
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| 74LSxx | Low-power Schottky TTL | Faster, lower power |
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| 74HCTxx | CMOS (TTL-level inputs) | Ideal for mixed systems |
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| 74HCxx | CMOS | Wide voltage range |
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| 74ACTxx | Advanced CMOS TTL-level | Very fast |
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---
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## 3. Electrical Characteristics (Typical)
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| Parameter | TTL | CMOS |
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| ----------------- | ------- | ------------------- |
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| VCC | 5 V | 2-6 V (5 V typical) |
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| Input HIGH | ≥ 2.0 V | ≥ 0.7xVCC |
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| Input LOW | ≤ 0.8 V | ≤ 0.3xVCC |
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| Fan-out | ~10 | Very high |
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| Power consumption | Higher | Lower |
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---
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## 4. Standard Package Types
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| Package | Pins | Notes |
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| ------- | ---------- | ------------------- |
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| DIP | 14, 16, 20 | Breadboard-friendly |
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| SOIC | 14, 16, 20 | Surface-mount |
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| TSSOP | 14, 16 | Compact SMT |
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---
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## 5. Common Logic Categories
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### 5.1 Basic Logic Gates
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| IC | Function |
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| ---- | ----------------- |
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| 7400 | Quad 2-input NAND |
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| 7402 | Quad 2-input NOR |
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| 7404 | Hex inverter |
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| 7408 | Quad 2-input AND |
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| 7432 | Quad 2-input OR |
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| 7486 | Quad 2-input XOR |
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---
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### 5.2 Latches and Flip-Flops
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| IC | Function |
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| ----- | --------------------- |
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| 7474 | Dual D-type flip-flop |
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| 7473 | Dual JK flip-flop |
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| 7475 | Quad latch |
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| 74175 | Quad D-type FF |
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---
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### 5.3 Counters and Registers
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| IC | Function |
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| ----- | ------------------------------------- |
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| 74161 | Synchronous 4-bit counter |
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| 74163 | Synchronous binary counter |
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| 74193 | Up/down counter |
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| 74164 | Serial-in/parallel-out shift register |
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| 74165 | Parallel-in/serial-out shift register |
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---
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### 5.4 Decoders and Multiplexers
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| IC | Function |
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| ----- | ----------------------- |
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| 74138 | 3-to-8 decoder |
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| 74139 | Dual 2-to-4 decoder |
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| 74151 | 8-to-1 multiplexer |
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| 74157 | Quad 2-to-1 multiplexer |
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---
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### 5.5 Bus Interface and Glue Logic
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| IC | Function |
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| ----- | ----------------------------------- |
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| 74244 | Octal buffer / line driver |
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| 74245 | Octal bidirectional bus transceiver |
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| 74373 | Octal transparent latch |
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| 74574 | Octal D-type FF |
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---
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## 6. Pin Numbering Convention
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* DIP packages use **counter-clockwise numbering**
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* Pin 1 identified by notch or dot
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```text
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________
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1 °| |° 14
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2 °| |° 13
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3 °| |° 12
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4 °| |° 11
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5 °| |° 10
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6 °| |° 9
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7 °|________|° 8
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```
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---
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## 7. Power and Ground Pins
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| Package | VCC | GND |
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| ------- | --- | --- |
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| DIP-14 | 14 | 7 |
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| DIP-16 | 16 | 8 |
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| DIP-20 | 20 | 10 |
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---
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## 8. Timing Characteristics (General)
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| Parameter | TTL | CMOS |
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| ----------------- | ------- | -------- |
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| Propagation delay | 5-15 ns | 8-25 ns |
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| Max frequency | ~25 MHz | ~50+ MHz |
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---
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## 9. Interfacing Notes
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* TTL outputs reliably drive TTL inputs
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* CMOS inputs must not float
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* Use **74HCT** when interfacing CMOS with TTL signals
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* Decoupling capacitors (0.1 µF) required per IC
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---
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## 10. Typical Retrocomputer Applications
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* Address decoding
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* Chip-select generation
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* Bus buffering
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* Clock gating and control
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* State machines
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---
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## 11. Absolute Maximum Ratings (Summary)
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| Parameter | Rating |
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| ------------------- | --------------------- |
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| VCC | -0.5 V to +7.0 V |
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| Input voltage | -0.5 V to VCC + 0.5 V |
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| Storage temperature | -65 °C to +150 °C |
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---
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## 12. References
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* <https://www.ti.com/lit/ds/symlink/sn74ls00.pdf>
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* <https://archive.org/details/TTLCookBook>
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* <https://digilent.com/reference/test-and-measurement/analog-discovery-2/hardware-design-guide>
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---
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