Maxim Integrated Products introduces the DS4M-XO series of crystal oscillators, which supports frequency operation from 100MHz to 300MHz and provides frequency margining in a 5.0mm x 3.2mm package. The industry’s first crystal oscillators to provide frequency margining at levels of ±5%, the DS4M-XO series facilitates frequency-margin testing in production environments through simple logic control, thereby eliminating the need for signal generators and nonstandard oscillator frequencies. The DS4M-XO series of crystal oscillators provides simple frequency-margining control for use in production environments. These crystal oscillators save 55% board space, while providing frequency outputs from 100MHz to 300MHz and low-noise performance over the entire -40°C to +85°C extended temperature range. To enable high-frequency operation, these devices integrate a high-frequency, low-noise PLL circuit, which is designed using Maxim’s proprietary SiGe process. The DS4M-XO series is ideal for PCI, PCI Express II, InfiniBand, and Ethernet applications. The ease of use, small size, and high performance of these crystal oscillators make them ideal for use in space-constrained Ethernet, InfiniBand, PCI™, and PCI Express® II applications.

The DS4M125/DS4M133/DS4M200 are margining clock oscillators with LVPECL or LVDS outputs. They are designed to fit in a 5mm x 3.2mm ceramic package with an AT-cut fundamental-mode crystal to form a complete clock oscillator. These XOs are manufactured using fundamental AT-cut crystal technology with no overtone, and they integrate a low-noise, PLL-based oscillator designed using Maxim’s proprietary SiGe process. This design ensures jitter performance of less than 1psRMS (12kHz to 20MHz) over the -40°C to +85°C extended temperature range. The DS4M125/DS4M133/DS4M200 are available with either an LVPECL or LVDS output. The output can be disabled by pulling the OE pin low. When disabled, both OUTP and OUTN levels of the LVPECL driver go to the LVPECL bias voltage, while the output of the LVDS driver is a logical one. The OE input is an active-high logic signal and has an internal 100kΩ pullup resistor. When OE is in a logic-high state, the OUTP and OUTN outputs are enabled. These crystal oscillators are highly competitive against both SAW-based and third-overtone crystal oscillator designs. The DS4M-XO devices provide exceptional long-term aging characteristics (< ±7ppm), good stability over temperature (< ±50ppm), low phase-jitter performance (< 1psRMS), and smaller packaging (5mm x 3.2mm versus 5mm x 7mm). Moreover, these XOs provide frequency margining, which is not currently provided by SAW-based or third-overtone oscillator designs.

Frequency margining is a circuit operation to change the output frequency to 5% higher or 5% lower than the nominal frequency. Frequency margining is accomplished through the margining select pin, MS. This three-state input pin accepts a three-level voltage signal to control the output frequency. In a low-level state, the output frequency is set to the nominal frequency. Standard frequencies for the DS4M-XO series of margining XOs include 125MHz (DS4M125), 133MHz (DS4M133), and 200MHz (DS4M200). For frequencies not listed above, customers should contact the factory for availability and lead-times. The DS4M-XO devices are available in a space-saving, 5.0mm x 3.2mm x 1.49mm, 10-pin LCCC surface-mount package. Prices start at $7.39 (1000-up, FOB USA). Samples are available to speed designs.

Key Features

• Frequency Margining: ±5%
• Nominal Clock Output Frequencies: 125MHz, 133.33MHz, and 200MHz
• Jitter < 0.9ps RMS from 12kHz to 20MHz
• LVPECL or LVDS Output
• 3.3V Operating Voltage
• Operating Temperature Range: -40°C to +85°C
• Supply Current: < 100mA at 3.3V
• Excellent Power-Supply Noise Rejection
• 5mm x 3.2mm Ceramic LCCC Package
• Output Enable/Disable

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