74FCT38075SCMGI8 - 1:5 LVCMOS Clock Buffer, 50fs Jitter | Renesas
MPN： 74FCT38075SCMGI8 ✓ 啟用中74FCT38075SCMGI8 概覽
A clock buffer is a fanout device that takes one reference clock and replicates it across multiple outputs while preserving timing integrity. Buffers such as the 74FCT38075S sit between a clock source (crystal oscillator, PLL, or FPGA) and downstream loads (DACs, ADCs, FPGAs, SerDes, microcontrollers). They are essential in mixed-signal and high-speed digital systems where skew, jitter, and noise directly limit bit-error-rate, ADC SNR, and image-sensor frame-to-frame consistency. Within the broader taxonomy, the 74FCT38075S belongs to the family of clock-tree buffers -> timing ICs -> clock & timing -> integrated circuits.
Key features include <50 fs RMS additive phase jitter, 50 ps output-to-output skew, LVCMOS-compatible 1.8 V/2.5 V/3.3 V outputs, and an internal input hysteresis that rejects coupled noise on the input trace. The exposed-pad DFN package minimises thermal resistance and provides a low-impedance ground return, preserving edge fidelity even at 200 MHz switching rates. The "I8" suffix indicates tape-and-reel packaging for high-volume assembly.
The device uses a low-skew differential-to-LVCMOS receiver with matched output tree, achieving sub-50 fs RMS additive jitter at 156.25 MHz output. This makes it suitable for cleaning up jitter-sensitive SerDes reference clocks without contributing measurable degradation of the link budget.
Typical applications include networking switches and routers, telecom base-station timing, FPGA fanout, ADC/DAC reference distribution, and precision test-and-measurement backplanes. The DFN footprint also suits space-constrained designs such as industrial sensor modules and high-channel-count data-acquisition boards.
When designing with this part, place a 0.01 µF decoupling capacitor as close as possible between VDD (pin 2) and GND (pin 4), match trace lengths across all five outputs, and consider 33 Ω series termination if any output trace runs more than 25 mm.
This page synthesises distributor pricing, drop-in alternatives, and practical PCB layout guidance not found in the manufacturer datasheet, with cross-references to JEDEC-standard MSL-1 moisture sensitivity classification.
直接替換替代品，適用於 74FCT38075SCMGI8 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： 74FCT38075SCMGI8 （相同外形與佔位） — 差異在於 Function, MSL Level, Number of Outputs, Package, Supply Voltage (VDD).
74FCT38075SCMGI
✅ 直接替換📋 參考替代品（不在目錄中）
74FCT38075SCM
✅ 直接替換📋 參考替代品（不在目錄中）
74FCT38075SCMGI8
✅ 直接替換聯絡詢價
查看資料表 →74FCT38075SCMG
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
74FCT38075SCMI8
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
74FCT38075SCMGI8 規格
| 功能 | 1:5 LVCMOS Clock Buffer |
| 輸出數量 | 5 |
| Output Skew (typ) | 50 ps |
| Additive Phase Jitter (RMS) | <50 fs (12 kHz to 20 MHz) |
| Maximum Input Frequency | 200 MHz |
| Supply Voltage (VDD) | 1.8 V to 3.3 V |
| Logic Level | LVCMOS |
| Input Type | LVCMOS with hysteresis |
| 輸出類型 | LVCMOS |
| 封裝 | 8-pin DFN (UFDFN) with exposed pad |
| 安裝類型 | Surface Mount |
| 工作溫度 | -40°C to +85°C (industrial) |
| RoHS 狀態 | Compliant |
| MSL 等級 | 1 (per JEDEC J-STD-020) |
| Packaging | Tape & Reel (I8 suffix) |
74FCT38075SCMGI8 腳位配置
| 腳位 1 | CLKIN — LVCMOS clock input |
| 腳位 2 | VDD — Supply voltage, 1.8 V to 3.3 V |
| 腳位 3 | CLKOUT0 — LVCMOS clock output 0 |
| 腳位 4 | GND — Ground |
| 腳位 5 | CLKOUT1 — LVCMOS clock output 1 |
| 腳位 6 | CLKOUT2 — LVCMOS clock output 2 |
| 腳位 7 | CLKOUT3 — LVCMOS clock output 3 |
| 腳位 8 | CLKOUT4 — LVCMOS clock output 4 |
典型應用
74FCT38075SCMGI8 適用於 6 應用s: Networking Switch and Router Clock Distribution, FPGA Clock Fanout for Multi-Channel Data Acquisition, Telecom Base Station Timing Reference Distribution, Precision Test and Measurement Backplane, Medical Imaging and Diagnostic Equipment, Industrial Sensor and Motor Control Backplanes.
Networking Switch and Router Clock Distribution
The 74FCT38075SCMGI8 distributes a single low-jitter 156.25 MHz or 161.13 MHz reference clock from a primary oscillator or PLL to multiple PHY, SerDes, and switch ASIC clock inputs across a networking line card. Its <50 fs RMS additive phase jitter preserves the link budget of 10 GbE, 25 GbE, and emerging 100 GbE SerDes channels, where each additional femtosecond of jitter directly degrades eye-mask margin. The 50 ps output-to-output skew ensures deterministic phase relationships between transmit and receive paths, simplifying MAC-to-PHY timing closure. Housed in the 2 mm × 2 mm DFN package, the buffer fits within tight switch-fabric PCB layouts where board area is at a premium. Operating from 1.8 V to 3.3 V, it interfaces directly with modern switch ASICs running at 0.9 V core but 1.8 V I/O clock domains without level shifting.
推薦
FPGA Clock Fanout for Multi-Channel Data Acquisition
Multi-channel data-acquisition systems route a shared sampling clock to several FPGAs, each driving multiple ADC channels. The 74FCT38075SCMGI8 takes one reference clock from a TCXO or OCXO and produces five LVCMOS outputs with 50 ps matched skew, ensuring that every FPGA samples its ADCs simultaneously across the chassis. The sub-50 fs additive jitter contribution is negligible compared to the inherent aperture uncertainty of high-precision ADCs, so the buffer does not degrade ENOB. The wide 1.8 V to 3.3 V supply range allows direct connection to Lattice, AMD, or Altera FPGAs without level translation. The 8-pin DFN exposed pad provides the thermal dissipation required for continuous 200 MHz switching across five outputs.
推薦
Telecom Base Station Timing Reference Distribution
In 4G LTE and 5G NR base stations, a GPS-disciplined OCXO or rubidium reference generates a stable 10 MHz to 122.88 MHz clock that must be fanned out to multiple radio units, baseband processors, and timing cards. The 74FCT38075SCMGI8 preserves the OCXO's phase noise floor thanks to its <50 fs additive jitter, ensuring that the base station meets the 3GPP time-error requirement of less than 100 ns RMS over the air interface. The wide industrial temperature range of -40°C to +85°C handles outdoor base-station cabinet environments, and the LVCMOS compatibility at 1.8 V, 2.5 V, and 3.3 V rails accommodates the mixed voltage domains of modern SoCs and FPGAs in the radio chain. The 2 mm × 2 mm DFN footprint keeps the timing tree compact on space-constrained radio cards.
推薦
Precision Test and Measurement Backplane
ATE and bench-instrument backplanes must distribute a single high-purity sampling clock to multiple measurement channels with deterministic phase alignment. The 74FCT38075SCMGI8 with its 50 ps output skew allows each measurement slot to see the same reference phase within the instrument's calibration window, simplifying cross-channel correlation. The sub-50 fs additive jitter means the buffer introduces far less timing noise than the jitter of most bench-digitiser apertures, preserving measurement integrity. Operating from 1.8 V to 3.3 V, it directly drives modern FPGA-based instruments such as PXIe cards. The DFN exposed pad also serves as a low-impedance ground, which is critical for rejecting the common-mode noise present on long backplane traces.
推薦
Medical Imaging and Diagnostic Equipment
Ultrasound, MRI, and CT imaging systems use a common sampling clock to drive beamformer channels, ADC banks, and image-reconstruction FPGAs. The 74FCT38075SCMGI8 fans the master reference to five LVCMOS loads with matched 50 ps skew, ensuring that all receive channels digitise the returning echo in phase. The sub-50 fs additive jitter is critical for diagnostic image resolution because clock jitter translates directly into positional uncertainty in beam-formed ultrasound images. The industrial -40°C to +85°C temperature grade and JEDEC MSL-1 rating support long product lifecycles required for FDA-cleared medical devices. The wide supply range allows integration into battery-backed mobile cart designs as well as fixed imaging-room installations.
推薦
Industrial Sensor and Motor Control Backplanes
Multi-axis motor drives and industrial robotics controllers require a deterministic reference clock shared across several control FPGAs and DSPs. The 74FCT38075SCMGI8 distributes the master PWM reference with matched 50 ps skew, ensuring simultaneous switching events across the six-step or field-oriented control loops. The sub-50 fs additive jitter preserves the timing margin needed for high-resolution PWM at 16-bit duty-cycle accuracy at 100 kHz switching rates. The wide 1.8 V to 3.3 V supply range allows direct interface with modern DSP controllers without level shifting. The exposed-pad DFN package handles the thermal load of continuous 200 MHz operation in enclosed industrial cabinets with limited airflow.
推薦
推薦產品摘要
工程參考資料，適用於 74FCT38075SCMGI8 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | 74FCT38075SCMGI | 74FCT38075SCM | 553SCMGI8 |
|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Package | 8-pin DFN (UFDFN) | 8-pin DFN (UFDFN) - same | 8-pin SOIC - different footprint | 8-pin DFN - same |
| Function | 1:5 LVCMOS Clock Buffer | 1:5 LVCMOS Clock Buffer | 1:5 LVCMOS Clock Buffer | 1:5 LVCMOS Clock Buffer |
| Additive Phase Jitter (RMS) | <50 fs | <50 fs | <50 fs | 50 fs class |
| Supply Voltage | 1.8 V to 3.3 V | 1.8 V to 3.3 V | 1.8 V to 3.3 V | 1.8 V to 3.3 V |
| Logic Level | LVCMOS | LVCMOS | LVCMOS | LVCMOS |
| RoHS | Compliant | Compliant | Compliant | Compliant |
| Packaging | Tape & Reel (I8) | Tube (I) | Tube | Tape & Reel |
主要差異化特點
- Best-in-class sub-50 fs additive jitter preserves SerDes eye margin (對比Generic 1:5 LVCMOS buffer (e.g., 74LVCH1G34-class discrete buffers))
- Wide 1.8 V to 3.3 V supply range without level shifters (對比74FCT38075S family variants that require 3.3 V only)
- Compact 2 mm × 2 mm DFN footprint with exposed thermal pad (對比74FCT38075SCM in 8-pin SOIC)
- JEDEC MSL-1 rating eliminates moisture bake-out step (對比MSL-3 rated clock buffers from competing vendors)
設計說明
Estimated: at VDD = 3.3 V the 74FCT38075SCMGI8 draws approximately 25 mA total, so dissipation is about 83 mW. Place a 0.01 µF decoupling capacitor within 2 mm of VDD (pin 2) and GND (pin 4) on the top layer, with a 1 µF bulk capacitor on the same supply rail close to the IC. The exposed pad must be soldered to a continuous ground pour, which doubles as the thermal dissipation path and a low-impedance return for the 200 MHz edges.
To achieve the rated 50 ps output-to-output skew, all five CLKOUT traces must be length-matched to within 5 mm of each other and to the CLKIN trace length. Use 50 Ω microstrip or stripline with a 33 Ω series source termination if any output trace exceeds 25 mm. Keep CLKIN away from switching power lines and route it on an inner layer with adjacent ground reference for best noise immunity.
Do not leave the exposed pad unsoldered - doing so raises junction temperature by 30°C and degrades jitter performance. Avoid driving more than 5 pF per output without the recommended 33 Ω series resistor, since capacitive loads increase edge rate and degrade additive jitter. Also ensure VDD rises monotonically at power-up; if the input clock is present before VDD, the device may latch up or exhibit metastable outputs.
The 74FCT38075SCMGI8 LVCMOS outputs have sub-nanosecond rise times that can couple into adjacent traces through the dielectric. Maintain at least 3W spacing between clock traces and signal traces (W = trace width to ground), and use a continuous reference ground plane below the clock routing layer. For multi-layer boards, route clocks between two ground planes using stripline.
合規資訊
RoHS and REACH compliant per Renesas product page; lead-free and halogen-free per datasheet. JEDEC MSL-1 per J-STD-020. Not AEC-Q100 qualified; for automotive applications consult Renesas automotive-grade portfolio.
