IQCM-140

OCXO Specification

ISSUE 3; November 2020

Outline (mm)

Workflow Diagram

Description

A GPS disciplined Oven Controlled Crystal Oscillator (OCXO)

with a 1PPS input, 1PPS output and 10MHz output.

Key Feature - Holdover Stability Options:

● 80µs/24hrs, ΔT=±5°C, 24hrs holdover after turn on 3 days

and lock 2 days. Time to maintain ±1.5µs: 3-4hrs typical.

● 20µs/24hrs, ΔT=±5°C, 24hrs holdover after turn on and lock

7 days. Time to maintain ±1.5µs: 6-7hrs typical.

● 80µs/24hrs, ΔT=±5°C, 24hrs holdover after turn on and lock

2hrs. Time to maintain ±1.5µs: 3-4hrs typical.

Working States (Reference Drawing):

Run1: Fast track. Adjust the OCXO 10MHz output frequency

quickly to track the GPS.

Run2: Slow track. Adjust the OCXO 10MHz output frequency

slowly when phase error is in the defined range.

Holdover: No GPS input present; an algorithm enables

adaptive modelling of the frequency stability of an OCXO with

reference to the GPS timing signal.

Free Run: Clock module powered up with no GPS input.

Frequency Parameters

Frequency

10.0MHz

Frequency Stability

±5.00ppb

Frequency Stability: TA varied across the operating

temperature range, measurement referenced to frequency

observed with fref=(fmax+fmin)/2, Vs=3.3V, load=15pF and

temperature variable speed less than 2°C/min.

Short Term Stability (temperature stable, no EMI/EMC or other

interference, tested after power for 1hr ref. to 25°C; 1s):

±0.1ppb max

Accuracy (24hrs average when locked to 1PPS after power on

2 days): ±10ppt max

Warm Up (TA=25°C and Vs=3.3V constant, measurement

referenced to 10MHz, after power on 5mins with GPS lock):

±1ppm max

Ageing (constant measurement referenced to frequency

observed with TA=25°C, Vs=3.3V and after 30 days of

operation):

±3ppb max per day

±0.5ppm max per year

Printed on 25 Nov 20 10:56 using Model Data Sheet V1.2700

Page 1 of 4

Sales Office Contact Details:

USA: +1.760.318.2824

France: 0800 901 383

UK: +44 (0)1460 270200

Germany: 0800 1808 443

Email: info@iqdfrequencyproducts.com

Web: www.iqdfrequencyproducts.com

IQCM-140

OCXO Specification

Electrical Parameters

3.3V ±5%

Supply Voltage

State Input (Pin 1):

Lock (<5mA load): 2.4V min

Holdover (<5mA load): 0.4V max

Supply Voltage AC Ripple (10Hz to 1MHz, Pin 2): 50mV pk-pk

max

1PPS Input (Pin 4):

Waveform: HCMOS

Output High VoH: 2.4V min

Output Low VoL: 0.4V max

Pulse Width: 10μs min

Serial Interface (Pins 5 and 6, serial protocol 9600-8-N-1):

Rx high level Input Voltage: 2.4V min

Rx low level Input Voltage: 0.4V max

Tx high-level Output Voltage: 2.4V min

Tx low-level Output Voltage: 0.4V max

Current Consumption:

Warm Up: 1A max

Steady State (@ 25°C): 600mA max

Note: All pins should not be subjected to a voltage greater

3.6V. If subjected to a higher voltage the processor will be

damaged and the unit will not work correctly.

Operating Temperature Ranges

-40 to 85°C

Output Details

Output Compatibility HCMOS

1PPS Output (Pin 7):

Waveform: HCMOS

Output High VoH: 2.4V min

Output Low VoL: 0.4V max

Pulse Width: 10µs min

Accuracy (24hrs average when locked to 1PPS after power on

2 days): ±200ns max

10MHz HCMOS Output (synchronised with 1PPS input, Pin 8):

Output High VoH (<5mA load): 2.7V min

Output Low VoL (<5mA load): 0.4V max

Rise/Fall Time (ref 15pF load): 10ns max

Duty Cycle (ref 15pF load): 45/55% max

Noise Parameters

Phase Noise (typ) on 10MHz RF Output Signal (Pin 8):

-100dBc/Hz @ 10Hz

-130dBc/Hz @ 100Hz

-148dBc/Hz @ 1kHz

-150dBc/Hz @ 10kHz

-150dBc/Hz @ 100kHz

-150dBc/Hz @ 1MHz

Phase Noise (max) on 10MHz RF Output Signal (pin 8):

-90dBc/Hz @ 10Hz

-120dBc/Hz @ 100Hz

-143dBc/Hz @ 1kHz

-145dBc/Hz @ 10kHz

-145dBc/Hz @ 100kHz

-145dBc/Hz @ 1MHz