CD74HC374 - Octal D Flip-Flop, 3-State, 2-6V | Texas Instruments
部品番号: CD74HC374 ✓ 生産中| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.56 | $5.60 |
| 100 | $0.44 | $44.00 |
| 500 | $0.37 | $185.00 |
| 1,000 | $0.3 | $300.00 |
CD74HC374 概要
An octal D-type flip-flop is a sequential logic IC containing eight independent D flip-flops that share a common clock and output-enable control. It belongs to the 74HC (High-speed CMOS) logic family, which combines LSTTL-compatible speed with the low static power consumption of CMOS technology, sitting within the broader hierarchy of digital logic ICs > flip-flops > edge-triggered registers.
Key features include positive-edge-triggered data capture on the LOW-to-HIGH clock (CP) transition, 3-state outputs controlled by an active-low output enable (OE) that is independent of register operation, a typical propagation delay of 15 ns at 5V, and a maximum clock frequency of 30 MHz. The silicon-gate CMOS process provides high noise immunity and very low quiescent current compared with bipolar LSTTL equivalents.
Architecturally, data present on the D inputs is stored on each rising clock edge, while OE=HIGH forces all Q outputs into a high-impedance state without disturbing the stored register contents. This enables bus multiplexing, shared data buses, and bidirectional data flow in microprocessor and memory systems. The device works in both 3.3V and 5V logic systems thanks to its wide supply range.
Typical applications include microprocessor address and data latching, I/O port expansion, bus interfacing, register files, and synchronization stages in DSP and communication interfaces. Designers should keep the clock clean and glitch-free, control OE to avoid bus contention, and place 100 nF decoupling capacitors close to the VCC pin. According to TI datasheet SCHS183A, unused inputs must never be left floating.
This page synthesizes distributor pricing, drop-in alternatives, pinout data, and practical design notes not found in the manufacturer datasheet alone.
ドロップイン代替品: CD74HC374 — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
クイック比較ツール — 並列比較する代替部品を選択:
CD74HCT374E
✅ ドロップイン📋 参考代替品（カタログ未掲載）
SN74HC374N
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MC74HC374AN
✅ ドロップイン📋 参考代替品（カタログ未掲載）
TC74HC374AP
✅ ドロップイン📋 参考代替品（カタログ未掲載）
74HC374N
✅ ドロップイン📋 参考代替品（カタログ未掲載）
CD74HC374 最大定格＆電気的特性
| 機能 | Octal D-type flip-flop, positive-edge triggered |
| Logic Family | 74HC (High-Speed CMOS) |
| Supply Voltage Range | 2 V to 6 V |
| 出力タイプ | 3-State |
| Output Drive Capability | 15 LSTTL loads |
| Typical Propagation Delay | 15 ns at 5 V |
| 最大クロック周波数 | 30 MHz |
| Clock Trigger | LOW-to-HIGH (rising) edge |
| Output Enable | OE, active-low, independent of register |
| Package Options | PDIP-20 (N), SOIC-20 (DW), TSSOP-20 (PW) |
| 実装タイプ | Through Hole (PDIP) / Surface Mount (SOIC, TSSOP) |
| Technology | Silicon-gate CMOS |
| Number of Bits | 8 |
| Datasheet Document | SCHS183A (original Harris/TI datasheet) |
CD74HC374 ピン構成
| ピン 1 | OE — Output enable, active-low (HIGH = outputs Hi-Z) |
| ピン 2 | D1 — Data input, flip-flop 1 |
| ピン 3 | D2 — Data input, flip-flop 2 |
| ピン 4 | D3 — Data input, flip-flop 3 |
| ピン 5 | D4 — Data input, flip-flop 4 |
| ピン 6 | D5 — Data input, flip-flop 5 |
| ピン 7 | D6 — Data input, flip-flop 6 |
| ピン 8 | D7 — Data input, flip-flop 7 |
| ピン 9 | D8 — Data input, flip-flop 8 |
| ピン 10 | GND — Ground |
| ピン 11 | CP — Clock input, positive-edge triggered |
| ピン 12 | Q8 — 3-state output, flip-flop 8 |
| ピン 13 | Q7 — 3-state output, flip-flop 7 |
| ピン 14 | Q6 — 3-state output, flip-flop 6 |
| ピン 15 | Q5 — 3-state output, flip-flop 5 |
| ピン 16 | Q4 — 3-state output, flip-flop 4 |
| ピン 17 | Q3 — 3-state output, flip-flop 3 |
| ピン 18 | Q2 — 3-state output, flip-flop 2 |
| ピン 19 | Q1 — 3-state output, flip-flop 1 |
| ピン 20 | VCC — Positive supply, 2 V to 6 V |
主な用途
CD74HC374 の用途: 6 件s: Microprocessor Address and Data Latching, I/O Port Expansion, Shared Data Bus Interfacing, Register Files and Pipeline Staging, Synchronization of Asynchronous Signals, Industrial Control and Legacy Equipment Maintenance.
Microprocessor Address and Data Latching
The CD74HC374 is a classic choice for demultiplexing address/data buses on 8-bit and 16-bit microprocessors. Its eight positive-edge-triggered flip-flops capture a full byte on a single ALE or strobe rising edge, and the 15 ns typical propagation delay at 5V keeps latch-to-valid-address latency small relative to bus cycle times. The 3-state outputs let the latched address share a trace with other bus masters, since OE=HIGH isolates the register without disturbing its contents. Designers should route CP from a clean, edges-only source, since the HC374 captures whatever is on D inputs at the clock instant. With a 30 MHz maximum clock at 5V, the part comfortably supports classic embedded bus speeds while drawing near-zero static current from the silicon-gate CMOS process.
おすすめ
I/O Port Expansion
When a microcontroller runs out of parallel I/O, the CD74HC374 provides eight additional latched outputs from just a clock, data-bus, and OE connection. Because outputs drive up to 15 LSTTL loads each, they can directly drive relays drivers, LED indicators, or ribbon-cable signals without external buffering in most designs. The 2V to 6V supply range allows use on both 3.3V and 5V controllers, and the tri-state outputs permit several CD74HC374 devices to time-share one output bus, selected one at a time via their OE lines. A practical pattern is to decode OE from address lines using a CD74HC138 so each register occupies a unique I/O location. Keep 100 nF decoupling per device and never leave unused D inputs floating, per TI datasheet SCHS183A.
おすすめ
Shared Data Bus Interfacing
The CD74HC374 excels in multi-source bus architectures where several registers must drive a common data path. Its asynchronous OE control is independent of the register clock, so one register can hold data on the bus for many cycles while others are updated off-line - a key requirement for DMA-style arbitration and backplane systems. Outputs sink and source enough current for 15 LSTTL loads, so a bus of moderate length works without line drivers. Designers must enforce a one-hot OE scheme and insert a dead time between disabling one register and enabling the next to avoid bus contention; the HC374 has no built-in contention protection. At 5V the 30 MHz register ceiling supports fast backplane clocks, while the high-impedance third state minimizes loading when the register is deselected.
おすすめ
Register Files and Pipeline Staging
In discrete pipeline designs, DSP glue logic, and small register files, the CD74HC374 serves as an 8-bit pipeline stage that retimes data with a system clock. Rising-edge triggering gives deterministic one-clock latency, and the typical 15 ns clock-to-output delay at 5V defines the per-stage timing budget for multi-stage pipelines. Multiple devices clocked in parallel form 16-, 24-, or 32-bit registers, since all parts capture simultaneously on the shared CP edge. The 3-state outputs allow pipelined data to be multiplexed onto a shared result bus during the following cycle. For clock distribution, keep trace lengths matched across cascaded registers to avoid skew-induced sampling errors, and decouple each device locally because simultaneous switching of eight outputs produces noticeable ground bounce in DIP packages.
おすすめ
Synchronization of Asynchronous Signals
The CD74HC374 can act as a bank of eight independent single-bit synchronizers for slowly changing asynchronous status signals, capturing all eight inputs on one clock edge to present a coherent status snapshot to a processor. This avoids the incoherence that occurs when individual bits are sampled at slightly different times. The HC-family CMOS inputs draw essentially zero DC current, so status signals from high-impedance sources are not loaded. For truly asynchronous single-bit signals, engineers should still evaluate metastability - the 74HC374 is not marketed as a dedicated metastability-hardened synchronizer, so for fast asynchronous inputs consider two-stage synchronization or a dedicated synchronizer part. Within its 30 MHz clock capability, however, it is an efficient way to snapshot parallel status buses at 5V or 3.3V.
おすすめ
Industrial Control and Legacy Equipment Maintenance
In PLC-style I/O panels, motor-control latch banks, and maintenance of legacy industrial equipment, the CD74HC374 remains a workhorse because it is active, inexpensive, and available in through-hole PDIP-20 for easy prototyping and field replacement. Its wide 2V to 6V range tolerates supply sag common in industrial 5V rails, and CMOS noise immunity helps in electrically noisy factory environments. Eight latched outputs can hold actuator states indefinitely between update cycles, and OE allows a supervisory controller to tri-state all outputs during startup or fault conditions for safe-state handover. Because many second sources (onsemi, Toshiba, NXP) exist in the 74HC374 family, long-term maintainability is excellent. Follow TI guidance: tie unused inputs to VCC or GND, and add 100 nF local decoupling per device.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: CD74HC374 — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | CD74HCT374E | SN74HC374N | MC74HC374AN | TC74HC374AP | 74HC374N |
|---|---|---|---|---|---|---|
| Package | PDIP-20 (N) / SOIC-20 (DW) / TSSOP-20 (PW) | PDIP-20 (N) - same footprint | PDIP-20 (N) - same footprint | PDIP-20 - same footprint | PDIP-20 - same footprint | PDIP-20 - same footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | onsemi | Toshiba | NXP Semiconductors |
| Supply Voltage Range | 2 V to 6 V | 4.5 V to 5.5 V (HCT family) | 2 V to 6 V | 2 V to 6 V | 2 V to 6 V | 2 V to 6 V |
| Input Threshold | CMOS (~50% VCC) | TTL (~1.4 V) | CMOS (~50% VCC) | CMOS (~50% VCC) | CMOS (~50% VCC) | CMOS (~50% VCC) |
| 3-State Outputs | Yes, active-low OE (pin 1) | Yes, active-low OE (pin 1) | Yes, active-low OE (pin 1) | Yes, active-low OE (pin 1) | Yes, active-low OE (pin 1) | Yes, active-low OE (pin 1) |
| Clock Trigger | Positive edge (rising) | Positive edge (rising) | Positive edge (rising) | Positive edge (rising) | Positive edge (rising) | Positive edge (rising) |
| Drop-in Compatibility | Reference part | Pin-to-pin, HCT input levels | Pin-to-pin, near-identical | Pin-to-pin, cross-brand | Pin-to-pin, cross-brand | Pin-to-pin, cross-brand |
主な差別化要因
- Wide 2V to 6V supply range （vs CD74HCT374E)
- High fan-out of 15 LSTTL loads per output （vs MC74HC374AN)
- Through-hole PDIP-20 availability （vs 74HC374N)
設計ノート
Place a 100 nF ceramic decoupling capacitor within a few millimeters of the VCC pin (pin 20) to GND (pin 10). Because all eight outputs can switch simultaneously on one clock edge, ground bounce in through-hole DIP packages can be significant at 5V; a local decoupling capacitor plus a solid ground path is essential. For SOIC-20 and TSSOP-20 versions, add a small bulk capacitor (4.7-10 uF) per group of registers on shared supply rails.
Never leave unused D inputs floating. Per TI datasheet SCHS183A, HC-family CMOS inputs must be tied to VCC or GND - floating inputs can drift to the threshold region, causing oscillation, excess current draw, and uncontrolled register states. Similarly, OE must be actively driven, not left open: a floating OE can permit bus contention when two registers drive the same line. Enforce a one-hot OE decode with dead time between enable transitions.
The clock (CP, pin 11) must have fast, clean edges; the 74HC374 captures the D inputs at the rising-edge threshold, so slow or glitchy clock edges cause metastable or erroneous captures. Route the clock away from the D input lines, and if the clock source is more than a few centimeters away, add a Schmitt-trigger buffer (e.g., SN74LVC1G17) to restore edge rates. De-rate the 30 MHz clock ceiling when operating below 5V, since fMAX scales with VCC.
Estimated: HC-family static supply current is typically in the microamp range, but dynamic current scales with clock frequency and load capacitance - each output driving ~50 pF at 5V and 10 MHz adds roughly I = C*V*f = 50pF*5V*10MHz = 2.5 mA per output, so eight heavily loaded outputs can draw tens of milliamps. Budget supply current accordingly and verify against the datasheet's dynamic characteristics at your actual VCC and frequency.
コンプライアンス情報
Compliance data was not present in the provided verified web data. Consult the TI product page (ti.com/product/CD74HC374) for current RoHS/REACH status per package suffix.
