MC100EL1648DT ON Semiconductor, MC100EL1648DT Datasheet - Page 6

• Manufacturer Part Number: MC100EL1648DT
• Manufacturer: ON Semiconductor

Specifications of MC100EL1648DT

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: TSSOP
• Pin Count: 8
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

MC100EL1648. The oscillator incorporates positive feedback
by coupling the base of transistor Q6 to the collector of Q7. An
automatic gain control (AGC) is incorporated to limit the
current through the emitter−coupled pair of transistors (Q7 and
Q6) and allow optimum frequency response of the oscillator.
In order to maintain the high quality factor (Q) on the oscillator,
and provide high spectral purity at the output, transistor Q4 is
used to translate the oscillator signal to the output differential
pair Q2 and Q3. Figure 16 indicates the high spectral purity
of the oscillator output (pin 4 on 8−pin SOIC). Transistors
Figure 5 illustrates the simplified circuit schematic for the
Q11
1.6 KW
800 W
400 W
Q10
7 (8)
V
EE
1.36 KW
D2
8 (10)
BIAS
Q9
TANK
1 (12)
330 W
Q7 Q6
Q8
Figure 5. Circuit Schematic
OPERATION THEORY
V
CC
http://onsemi.com
V
6 (7)
2 (14)
EE
16 KW
D1
AGC
6
5 (5)
3.1 KW
Q2 and Q3, in conjunction with output transistor Q1,
provide a highly buffered output that produces a square
wave. The typical output waveform can be seen in Figure 4.
The bias drive for the oscillator and output buffer is provided
by Q9 and Q11 transistors. In order to minimize current, the
output circuit is realized as an emitter−follower buffer with
an on chip pull−down resistor R
Q5
82 W
Q4
660 W
400 W
Q3
8 pin (14 pin) Lead Package
Q2
660 W
167 W
E
.
V
CC
Q1
510 W
3 (1)
OUTPUT
4 (3)