10

LT1394

TEMPERATURE (

°C)

0

0

–10

–20

–30

–40

–50

–60

–70

30

50

1394 F06

10

20

40

60

70

COMPENSATED

≈ 0.05ppm/°C

UNCOMPENSATED

(VARACTOR CORRECTION

DISABLED) –1ppm/

°C

Figure 6. Figure 5’s Compensated vs Uncompensated

Temperature Dependence. First Order Compensation

Reduces Oscillator Drift to 0.05ppm/

°C

A2

1/2 LT1126

–

+

5V

5V

200pF

OUTPUT

1394 F07

+INPUT

–INPUT

–5V

–5V

1

µF

1

µF

200pF

2k

1k

1k

2k

10k

10k

200

Ω

A1

LM733

A = 100

LT1394

A3

1/2 LT1126

–

+

Figure 7. Parallel Preamplified Paths Allow 18ns Comparator

Response to 500

µV Overdrive

Figure 5. Temperature-Compensated 10MHz Crystal Oscillator.

Temperature-Dependent Varactor Bias Reduces Drift by 20:1

1394 F05

–

+

LT1394

A1

LT1077

50k

5V

10M

390

Ω

0.01

µF

1

µF

0.068

µF

10mV/

°C

10MHz

0.05ppm/

°C

XTAL AT-CUT, 35

° 25′ ANGLE

* 1% FILM RESISTOR

LM134

5V

FREQ SET

LT1004-1.2

BAT-85

10MHz

1M*

1M*

5.8M*

MV-209

VARACTOR

DIODE

2M

2k

0.01

µF

1

µF

2M

2k

4.7k

100k

1M

470k*

10k*

226

Ω*