mc12061p Freescale Semiconductor, Inc, mc12061p Datasheet - Page 6

• Manufacturer Part Number: mc12061p
• Description: Crystal Oscillator
• Manufacturer: Freescale Semiconductor, Inc

oscillator with AGC and two translators (NO TAG). Buffered
complementary sine wave outputs are available from the
oscillator section. The translators convert these sine wave
outputs to levels compatible with MECL and/or TTL.
it is necessary or desirable to adjust the crystal frequency, a
reactive element can be inserted in series with the crystal —
an inductor to lower the frequency or a capacitor to raise it.
When such an adjustment is necessary, it is recommended
that the crystal be specified slightly lower in frequency and a
series trimmer capacitor be added to bring the oscillator back
on frequency. As the oscillator frequency is changed from the
natural resonance of the crystal, more and more dependence
is placed on the external reactance, and temperature drift of
the trimming components then affects overall oscillator
performance.
supply — either +5.0 Vdc or –5.2 Vdc. Although each
translator has separate V CC and V EE supply pins, the
circuit is NOT designed to operate from both voltage levels
at the same time. The separate V EE pin from the TTL
translator helps minimize transient disturbance. If neither
translator is being used, all unused pins (9 thru 16) should
be connected to V EE (pin 8). With the translators not
powered, supply current drain is typically reduced from 42
mA to 23 mA for the MC12061.
Frequency Stability
given device type number) will vary somewhat when used
with a given test setup. However, the variation should be
within approximately 0.001% from unit to unit.
the crystal, which is held at 25 C) are small — about – 0.08
ppm/ C for MC12061 operating at 8.0 MHz (see NO TAG).
Signal Characteristics
typically range from 800 mV p-p (no load) to 500 mV p-p
(120 ohm ac load). Approximately 500 mV p-p can be
provided across 50 ohms by slightly increasing the dc
current in the output buffer by the addition of an external
resistor (680 ohms) from pin 2 or 3 to ground, as shown in
Figure 9. Frequency drift is typically less than 0.0003%
when going from a high-impedance load (1 megohm, 15
pF) to the 50 ohm load of Figure 9. The dc voltage level at
pin 2 or 3 is nominally 3.5 Vdc with V CC = +5.0 Vdc.
crystal as well as circuit dependent. The largest harmonic
(third) will usually be at least 15 dB down from the
fundamental. The harmonic content is approximately load
independent except that the higher harmonic levels
6
The MC12061 consists of three basic sections: an
Series mode crystals should be used with the oscillator. If
The MC12061 is designed to operate from a single
Output frequency of different oscillator circuits (of a
Frequency variations with temperature (independent of
The sine wave outputs at either pin 2 or pin 3 will
Harmonic distortion content in the sine wave outputs is
OPERATING CHARACTERISTICS
MC12061
(greater than the fifth) are increased when the MECL
translator is being driven.
to five gates, as defined in NO TAG, and the TTL output (pin
10) will drive up to ten gates, as defined in NO TAG.
Noise Characteristics
circuit of NO TAG, with operation at or 9.0 MHz, indicates
the following characteristics:
1. Noise floor (200 kHz from oscillator center frequency) is
2. Close-in noise (100 Hz from oscillator center frequency)
+10
Typically, the MECL outputs (pins 12 and 13) will drive up
Noise level evaluation of the sine wave outputs using the
–10
–20
–30
approximately –122 dB when referenced to a 1.0 Hz
bandwidth. Noise floor is not sensitive to load
conditions and/or translator operation.
is approximately –88 dB when referenced to a 1.0 Hz
bandwidth.
Figure 8. Frequency Variation Due to Temperature
* See text under signal characteristics.
0
–55
Figure 9. Driving Low Impedance Loads
7
6
0.1 µF
–25
1
+5.0 V
5
0.1 µF
T A , AMBIENT TEMPERATURE ( )
0
0.1 µF
MOTOROLA RF/IF DEVICE DATA
4
8
25
MC12061
2 or 3
50
680
0.1 µF
V CC = +5.0 Vdc
T crystal = 25 C
MC12061
75
50
100
125