SIT8918BAU71-33E-50.000000G - 50MHz MEMS XO, 3.3V, ±20ppm | SiTime
料号： SIT8918BAU71-33E-50.000000G ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $2.18 | $2.18 |
| 10 | $1.92 | $19.20 |
| 100 | $1.58 | $158.00 |
| 500 | $1.31 | $655.00 |
| 1,000 | $1.13 | $1,130.00 |
| 2,500 | $0.95 | $2,375.00 |
SIT8918BAU71-33E-50.000000G 概述
What is a MEMS XO? A MEMS (Micro-Electro-Mechanical Systems) oscillator is a solid-state timing device that uses a silicon resonator instead of a quartz crystal. XO, or standard crystal oscillator, means it is a fixed-frequency oscillator (not a VCXO or TCXO). MEMS oscillators fall under the broader hierarchy: resonator (MEMS resonator) -> oscillator -> clock generator -> frequency control component -> semiconductor. They are widely used as drop-in replacements for legacy quartz oscillators because of superior shock and vibration immunity.
Key features of the SIT8918BAU71-33E-50.000000G include best-in-class 70 g vibration and 50,000 g shock resistance, 0.1 ppb/g low vibration sensitivity, an ultra-small 2.0 x 1.6 mm industry-standard SMD footprint, and support for any frequency from 1 MHz to 110 MHz with factory-programmed accuracy. These specifications make the device robust for outdoor, industrial, and automotive-grade applications.
From an architecture perspective, the SiT8918 family integrates a silicon MEMS resonator, a low-jitter PLL, and an LVCMOS output driver on a single die. This eliminates the need for external load capacitors required by quartz crystals, simplifies the BOM, and provides faster startup compared to AT-cut quartz. The SiTime MEMS process technology also yields a ten-times-better reliability FIT rate than typical quartz devices.
Typical applications include automotive infotainment and ADAS clock references, industrial sensor and motor-control timing, outdoor IoT gateways, surveillance camera video timing, and consumer audio/video systems. The wide -40 °C to +125 °C operating range plus 50,000 g shock tolerance make it ideal for any design where quartz reliability is a concern.
When designing with the SiT8918BAU71-33E-50.000000G, route the OE (output enable) pin to a GPIO if you need power-gating control, otherwise leave it floating for always-on operation. Place a 0.1 µF decoupling capacitor adjacent to the Vdd pin and follow standard 4-SMD land-pattern PCB layout guidelines. No external load capacitors are required.
This page synthesizes distributor pricing, drop-in MEMS and quartz alternatives, application-specific design notes, and a parametric comparison table not consolidated on the manufacturer datasheet.
直接替换替代料： SIT8918BAU71-33E-50.000000G ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
SIT8918BAU71-33E-50.000000
✅ 直接替换📋 参考替代料（不在目录中）
SiT8918BAU72-33E-50.000000G
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
SiT8918AAU71-33E-50.000000G
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
SiT8918BAU11-33E-50.000000G
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
SIT8918BAU71-33E-50.000000G 规格参数
| 功能 | XO (Standard) |
| 输出类型 | LVCMOS, LVTTL |
| Frequency | 50 MHz |
| Frequency Stability | ±20 ppm |
| 电源电压 | 3.3 V |
| Supply Current (typical) | 4.7 mA |
| 工作温度范围 | -40 °C to +125 °C |
| Output Enable | Yes (OE pin) |
| 封装 | 4-SMD, No Lead (2.0 x 1.6 mm) |
| 安装类型 | Surface Mount |
| Shock Resistance | 50,000 g |
| Vibration Sensitivity | 0.1 ppb/g |
| Vibration Rating | 70 g |
| Drive Strength | 'U' (Standard drive) |
| RoHS 状态 | Compliant |
| Tape & Reel Quantity | 250 pcs (8 mm reel) |
| Resonator Technology | MEMS (Silicon) |
SIT8918BAU71-33E-50.000000G 引脚配置
| 引脚 1 | OE — Output Enable (active high; float or pull high for always-on operation) |
| 引脚 2 | GND — Ground |
| 引脚 3 | OUT — LVCMOS / LVTTL clock output (50 MHz) |
| 引脚 4 | Vdd — Power supply (3.3 V) |
典型应用
SIT8918BAU71-33E-50.000000G 适用于 6 应用s: Automotive Infotainment Clock Reference, Industrial Motor Control Timing, Outdoor IoT Gateway / LoRa Reference, Surveillance Camera Video Timing, Consumer Audio DAC Master Clock, Drone Flight Controller Reference.
Automotive Infotainment Clock Reference
The SIT8918BAU71-33E-50.000000G is well suited as the 50 MHz system clock for automotive infotainment head units and cluster displays. Its ±20 ppm stability over the full -40 °C to +125 °C automotive temperature window keeps audio DAC and video encoder PLLs locked without drift across cabin temperature swings. The 50,000 g shock and 70 g vibration immunity - per the SiTime SiT8918 datasheet - prevents timing glitches during rough roads or door slams that would otherwise cause audible clicks or display artifacts.
推荐
Industrial Motor Control Timing
In Field-Oriented Control (FOC) motor drives, the SIT8918BAU71-33E-50.000000G provides the deterministic 50 MHz reference that drives the MCU's PWM module and ADC sample clock. Per the SiTime SiT8918 datasheet, its 0.1 ppb/g low vibration sensitivity and 70 g vibration rating keep the switching frequency stable even when mounted directly on a vibrating motor housing. The -40 °C to +125 °C range and 50,000 g shock tolerance make it ideal for factory-floor drives exposed to mechanical stress.
推荐
Outdoor IoT Gateway / LoRa Reference
The SIT8918BAU71-33E-50.000000G serves as the precise 50 MHz reference for outdoor LoRaWAN, NB-IoT, or Wi-Fi gateway SoCs. Per the SiTime SiT8918 datasheet, its ±20 ppm stability over -40 °C to +125 °C eliminates the need for a TCXO while still meeting LoRa modulation bandwidth requirements across seasons. The 4.7 mA typical supply current keeps battery-backed gateways efficient, and the 50,000 g shock tolerance handles pole-mounting and shipping impacts.
推荐
Surveillance Camera Video Timing
In IP surveillance cameras, the SIT8918BAU71-33E-50.000000G provides the 50 MHz pixel clock that times the image sensor's parallel or MIPI-CSI output and the SoC's video pipeline. Per the SiTime SiT8918 datasheet, its low-jitter LVCMOS output preserves horizontal blanking accuracy, preventing rolling-shutter artifacts in fast-motion scenes. The wide -40 °C to +125 °C range supports outdoor housings in desert heat or arctic cold, and the 70 g vibration rating tolerates pole-mounted installations in windy areas.
推荐
Consumer Audio DAC Master Clock
High-resolution USB audio DACs benefit from the SIT8918BAU71-33E-50.000000G as a low-jitter 50 MHz master clock for asynchronous USB-to-I2S conversion. Per the SiTime SiT8918 datasheet, the MEMS resonator delivers substantially lower cycle-to-cycle jitter than typical AT-cut quartz at this frequency, improving the effective dynamic range of the DAC chain. The 2.0 x 1.6 mm footprint fits inside compact USB-stick and portable headphone-amp enclosures.
推荐
Drone Flight Controller Reference
Commercial and industrial drones use the SIT8918BAU71-33E-50.000000G as the 50 MHz reference for the flight-control MCU and IMU-sampling logic. Per the SiTime SiT8918 datasheet, the 50,000 g shock rating survives hard landings and propeller imbalance impacts that would shatter a quartz crystal, while the 0.1 ppb/g vibration sensitivity prevents motor-induced jitter from corrupting inertial sensor timing. Operating reliably from -40 °C to +125 °C, it handles high-altitude cold-soak and direct-sunlight thermal loads.
推荐
推荐产品汇总
工程参考数据： SIT8918BAU71-33E-50.000000G ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | SIT8918BAU71-33E-50.000000 | SiT8918BAU72-33E-50.000000G | SiT8918AAU71-33E-50.000000G | SiT8918BAU11-33E-50.000000G |
|---|---|---|---|---|---|
| Brand | SiTime | SiTime | SiTime | SiTime | SiTime |
| Package | 4-SMD, No Lead (2.0 x 1.6 mm) | 4-SMD, No Lead (2.0 x 1.6 mm) - same | 4-SMD, No Lead (2.0 x 1.6 mm) - same | 4-SMD, No Lead (2.0 x 1.6 mm) - same | 4-SMD, No Lead (2.0 x 1.6 mm) - same |
| Frequency | 50 MHz | 50 MHz | 50 MHz | 50 MHz | 50 MHz |
| Frequency Stability | ±20 ppm | ±20 ppm | ±20 ppm | ±25 ppm | ±20 ppm |
| Supply Voltage | 3.3 V | 3.3 V | 3.3 V | 3.3 V | 3.3 V |
| Operating Temperature | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -20 °C to +70 °C |
| Supply Current (typ) | 4.7 mA | 4.7 mA | 4.7 mA | 4.7 mA | 4.7 mA |
| Shock Resistance | 50,000 g | 50,000 g | 50,000 g | 50,000 g | 50,000 g |
关键差异点
- Industry-best 50,000 g shock resistance （对比 SiT8918BAU11-33E-50.000000G)
- Wide 1-110 MHz frequency coverage in one package （对比 Quartz XO)
- 0.1 ppb/g low vibration sensitivity （对比 Typical AT-cut quartz XO)
设计说明
Place a single 0.1 µF X7R ceramic decoupling capacitor within 1-2 mm of the Vdd (Pin 4) pad to suppress supply noise on the SiTime SiT8918 family. Route the LVCMOS output (Pin 3) with a 50 Ω controlled-impedance trace when the load is more than ~5 mm away, and add a small series damping resistor (22-33 Ω) at the source if the trace is impedance-mismatched to reduce ringing on the rising edge.
The OE pin (Pin 1) of the SIT8918BAU71-33E-50.000000G is internally pulled high per the SiTime SiT8918 datasheet, so leaving the pad floating yields continuous output. If you wire OE to a microcontroller GPIO, ensure the MCU initializes the line as a high-impedance input with pull-up enabled during reset to avoid a momentary clock disable that could trip a downstream PLL out of lock. Avoid routing noisy switching signals next to the OUT trace.
Estimated: at 3.3 V × 4.7 mA the SIT8918BAU71-33E-50.000000G dissipates approximately 15.5 mW, well within the limits of the 2.0 x 1.6 mm SMD package even at +125 °C ambient. No external heatsink or thermal copper pour is required. Ensure the surrounding PCB copper does not form a thermal bottleneck that prevents the device's exposed pad from radiating to ambient - typically a 4-SMD land pattern with standard thermal vias is sufficient.
Do not apply external load capacitors to the OUT pin of the SIT8918BAU71-33E-50.000000G - unlike a quartz crystal, this is a complete oscillator and any extra capacitance will load the LVCMOS driver and degrade the rise/fall times. Also avoid long parallel traces near switching DC-DC converters; while the MEMS oscillator has good PSRR, keeping the analog supply and ground return paths short minimises power-rail noise coupling.
合规信息
RoHS compliant per SiTime product page. AEC-Q100 grade is not explicitly listed on the 8918 datasheet cover - refer to SiTime SiT892x or SiT894x families for AEC-Q100 qualified automotive timing. Halogen-free per SiTime corporate policy.