TCXO Oscillators

TCXO’s (Temperature Compensated Crystal Oscillators) are used in designs that need better temperature stability than what can be offered by XO’s or VCXO oscillators. TCXO Oscillators can achieve stability of less than 1ppm as opposed to a typical crystal of 30ppm.

A wide range of temperature stabilities options are available in TCXO’s, from 5ppm to 50ppb. TCXO oscillators vary in size from the smallest 2.0 x 1.6mm to larger sizes and even TH devices used in military applications.

The key factor to consider when selecting a TCXO is the temperature range over which it operates. -20°C to 70°C is common with -40°C to 85°C a premium especially at tight tolerances.


How do TCXO’s work?


TCXO Oscillators use a compensation network that senses the change in frequency over temperature and creates a near inverse curve. This is used to pull the TCXO back to the nominal frequency. The remaining error we see is the stated stability, e.g. 1ppm over -20°C to 70°C meaning the error from nominal should be no larger over that temperature range.

One of the first types of TCXO compensation was &147direct compensation&148; these devices used a network of components to alter the capacitive load on the crystal to shift the frequency as it naturally changed with temperature. The other type is called the "indirect method", in early models this saw the use of thermistors again that created a temperature dependent voltage. This was used to drive a varactor who’s changing capacitance changed the crystal frequency

Today we see the use of an IC to change the voltage to the varactor, and testing in small temperature steps to confirm the correction (due to differences in the crystal curve). These types are referred to as analog TCXO’s.which are recommended for GPS/GNSS clocking applications; due to small shifts of frequency per °C change they help keep the GPS loop locked as temperature changes.

Digitally controlled TCXOs are also available and these tend to fall into the smaller packages and more cost-effective solutions. These oscillators use internal ADC’s (analog to digital converters) monitoring the temperature but follow the temperature change in digital steps related to the ADC value.
These types are unsuitable for GNSS solutions due to the frequency jumps over temperature.


VCTCXO - Voltage Controlled Temperature Compensated Oscillator


VCTCXO Oscillators have the same features as the TCXO with the added functionality of a voltage controlled function to allow precision tuning of the output frequency. The VCTCXO differentiate themselves by having a VC pad (voltage control) in the oscillator. This input requires an analog voltage that works to control the varactor inside and is normally part of an external PLL that controls the VCTCXO frequency.


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Description Price Output Frequency Frequency Stability Load Capacitance Package Type Output Level Minimum Operating Temperature Maximum Operating Temperature Height Dimensions Oscillator Type
RS庫存編號 103-9918
製造零件編號DS3232SN#
BrandMaxim
HK$64.52
毎管:36 個
單位
32.768 kHz ±3.5ppm - SOIC CMOS -40 °C +85 °C 2.35mm 13 x 7.6 x 2.35mm TCXO
RS庫存編號 709-9369
製造零件編號R0053-T-036-3
BrandTAITIEN
HK$23.60
單位
13 MHz ±2.5ppm - SMD Clipped Sinewave -30 °C +85 °C 1.2mm 5 x 3.2 x 1.2mm TCXO
RS庫存編號 732-7589
製造零件編號DS3232SN#
BrandMaxim
HK$73.85
單位
32.768 kHz ±3.5ppm - SOIC CMOS -40 °C +85 °C 2.35mm 13 x 7.6 x 2.35mm TCXO
RS庫存編號 144-2373
BrandRS PRO
HK$238.01
單位
24.57 MHz ±0.028ppm - SMD HCMOS, TTL -40 °C +85 °C 2mm 7 x 5 x 2mm TCXO
RS庫存編號 894-9714
製造零件編號LFTVXO063787Bulk
BrandIQD
HK$325.76
單位
10 → 50 MHz ±0.14ppm - SMD HCMOS -40 °C +85 °C 2mm 5 x 3.2 x 2mm TCXO
RS庫存編號 144-2363
BrandRS PRO
HK$33.975
/個 (每包:2個)
單位
26 MHz ±1.5ppm - SMD Clipped Sinewave -40 °C +85 °C 0.85mm 2 x 1.6 x 0.85mm TCXO
RS庫存編號 894-9697
製造零件編號LFTCXO063783Bulk
BrandIQD
HK$413.36
單位
10 → 50 MHz ±0.14ppm - SMD Clipped Sinewave -40 °C +85 °C 2mm 5 x 3.2 x 2mm TCXO
RS庫存編號 146-1286
製造零件編號DS32KHZS#
BrandMaxim
HK$52.71
毎管:46 個
單位
32.768 kHz 7.5ppm 15.5pF SOIC Squarewave 0 °C +70 °C 2.35mm 10.5 x 7.6 x 2.35mm TCXO
RS庫存編號 103-9919
製造零件編號DS32KHZSN#
BrandMaxim
HK$68.71
毎管:46 個
單位
32.768 kHz ±7.5ppm - SOIC CMOS -40 °C +85 °C 2.35mm 10.5 x 7.6 x 2.35mm TCXO
RS庫存編號 148-5683
製造零件編號LFTVXO009915
BrandIQD
HK$143.16
單位
16.384 MHz ±0.5ppm 15pF SMD HCMOS -40 °C +85 °C 2mm 7 x 5 x 2mm TCXO
RS庫存編號 709-9259
製造零件編號TCETCLSANF-10.0MHz
BrandTAITIEN
HK$29.50
單位
10 MHz ±2ppm - SMD Clipped Sinewave -40 °C +85 °C 2mm 7 x 5 x 2mm TCXO
RS庫存編號 894-9644
製造零件編號LFTCXO063715Bulk
BrandIQD
HK$307.37
單位
10 → 50 MHz ±0.28ppm - SMD Clipped Sinewave -40 °C +85 °C 2.4mm 7 x 5 x 2.4mm TCXO
RS庫存編號 709-9379
製造零件編號R0053-T-040-3
BrandTAITIEN
HK$23.60
單位
20 MHz ±0.5ppm - SMD Clipped Sinewave -30 °C +85 °C 1.2mm 5 x 3.2 x 1.2mm TCXO
RS庫存編號 144-2365
BrandRS PRO
HK$33.975
/個 (每包:2個)
單位
40 MHz ±1.5ppm - SMD Clipped Sinewave -40 °C +85 °C 0.85mm 2 x 1.6 x 0.85mm TCXO
RS庫存編號 709-9408
製造零件編號R0053-T-048-3
BrandTAITIEN
HK$19.40
單位
16.368 MHz ±0.5ppm - SMD Clipped Sinewave -30 °C +85 °C 1mm 3.2 x 2.5 x 1mm TCXO
RS庫存編號 144-2354
BrandRS PRO
HK$39.41
/個 (每包:2個)
單位
10 MHz - - SMD CMOS -20 °C +70 °C 0.95mm 2.5 x 2 x 0.95mm TCXO
全新
RS庫存編號 189-7191
製造零件編號DS32KHZS#
BrandMaxim
HK$62.336
毎管:46 個
單位
32.768 kHz 7.5ppm - SOIC Squarewave 0 °C +70 °C 2.35mm 10.5 x 7.6 x 2.35mm TCXO
RS庫存編號 709-9420
製造零件編號R0053-T-054-3
BrandTAITIEN
HK$19.40
單位
26 MHz ±0.5ppm 10pF SMD Clipped Sinewave -30 °C +85 °C 1mm 3.2 x 2.5 x 1mm TCXO
RS庫存編號 478-9038
製造零件編號LFTVXO009905
BrandIQD
HK$103.23
單位
16.384 MHz ±0.9ppm 15pF 7x5mm SMD HCMOS -20 °C +70 °C 2mm 7 x 5 x 2mm TCXO
全新
RS庫存編號 189-7183
製造零件編號DS3232SN#
BrandMaxim
HK$73.218
毎管:36 個
單位
32.768 kHz ±3.5ppm - SOIC CMOS -40 °C +85 °C 2.35mm 13 x 7.6 x 2.35mm TCXO