Motorola MC1648L, MC1648P, MC1648D, MC1648FN Datasheet

MOTOROLA

SEMICONDUCTOR TECHNICAL DATA

Voltage	Controlled	Oscillator		MC1648
Consider	MC12148 for
		New Designs
The MC1648 requires an external parallel tank circuit consisting of the				VOLTAGE
inductor (L) and capacitor (C). For Maximum Performance QL ≥ 100 at
Frequency of Operation.				CONTROLLED

A varactor diode may be incorporated into the tank circuit to provide a

voltage variable input for the oscillator (VCO). The MC1648 was OSCILLATOR designed for use in the Motorola Phase±Locked Loop shown in Figure 9.

This device may also be used in many other applications requiring a fixed or variable frequency clock source of high spectral purity. (See Figure 2)

The MC1648 may be operated from a +5.0Vdc supply or a ±5.2Vdc supply, depending upon system requirements.

NOTE: The MC1648 is NOT useable as a crystal oscillator.

Pinout: 14±Lead Package (Top View)

L SUFFIX

VCC

NC

TANK

NC

BIAS

NC

VEE

14±LEAD CERAMIC PACKAGE

CASE 632±08

14

13

12

11

10

9

8

Not Recommended for New Designs

		1	2	3	4	5	6	7
		VCC NC		OUT	NC	AGC	NC	VEE			P SUFFIX
											14±LEAD PLASTIC PACKAGE
		Pin assignment is for Dual±in±Line Package.									CASE 646±06
	For PLCC pin assignment, see the MC1648 Non±Standard Pin Conversion Table below.
	MC1648 NON±STANDARD PIN CONVERSION DATA										D SUFFIX
											8±PIN PLASTIC SOIC PACKAGE
	Package	TANK	VCC	VCC	OUT	AGC		VEE	VEE	BIAS
											CASE 751±05
	8 D	1	2	3	4		5	6	7	8
	14 L,P	12	14	1	3		5	7	8	10
	20FN	18	20	2	4		8	10	12	14
	*NOTE ± All unused pins are not connected.										FN SUFFIX
	Supply Voltage			GND Pins				Supply Pins			20±LEAD PLCC PACKAGE
											CASE 775±02
	+5.0Vdc				7,8				1,14
	±5.2Vdc				1,14				7,8

LOGIC DIAGRAM

BIAS POINT 10	3
TANK 12	OUTPUT
	5
	AGC

•Input Capacitance = 6.0pF (TYP)

•Maximum Series Resistance for L (External Inductance) = 50Ω (TYP)

•Power Dissipation = 150mW (TYP)/Pkg (+5.0Vdc Supply)

•Maximum Output Frequency = 225MHz (TYP)

VCC1 = Pin 1

VCC2 = Pin 14

VEE = Pin 7

1/97

Motorola, Inc. 1997

1

REV 2

MC1648
				VCC2		VCC1
				14		1
			Q9			Q1
					Q3	Q2
						3
						OUTPUT
					Q4
Q11	Q10		Q7	Q6
					D1
					Q5
		D2	Q8
	7	10	12	8	5
	VEE1	BIAS	TANK	VEE	AGC
		POINT

Figure 1. Circuit Schematic

TEST VOLTAGE/CURRENT VALUES

	@ Test		(Volts)		mAdc
	Temperature
		VIHmax	VILmin	VCC	IL
		MC1648
	±30°C	+2.0	+1.5	+5.0	±5.0
	+25°C
		+1.85	+1.35	+5.0	±5.0
	+85°C
		+1.7	+1.2	+5.0	±5.0

Note: SOIC ªDº package guaranteed ±30°C to +70°C only

ELECTRICAL CHARACTERISTICS (Supply Voltage = +5.0V)

±30°C

+25°C

+85°C

Symbol

Characteristic

Min

Max

Min

Max

Min

Max

Unit

Condition

IE

Power Supply Drain Current

±

±

±

41

±

±

mAdc

Inputs and outputs open

VOH

Logic ª1º Output Voltage

3.955

4.185

4.04

4.25

4.11

4.36

Vdc

VILmin to Pin 12, IL @ Pin 3

VOL

Logic ª0º Output Voltage

3.16

3.4

3.2

3.43

3.22

3.475

Vdc

VIHmax to Pin 12, IL @ Pin 3

VBIAS1

Bias Voltage

1.6

1.9

1.45

1.75

1.3

1.6

Vdc

VILmin to Pin 12

Min

Typ

Max

Min

Typ

Max

Min

Typ

Max

Unit

Condition

VP±P

Peak±to±Peak Tank Voltage

±

±

±

±

400

±

±

±

±

mV

See Figure 3

Vdc

Output Duty Cycle

±

±

±

±

50

±

±

±

±

%

fmax2

Oscillation Frequency

±

225

±

200

225

±

±

225

±

MHz

1. This measurement guarantees the dc potential at the bias point for purposes of incorporating a varactor tuning diode at this point.

2. Frequency variation over temperature is a direct function of the C/

Temperature and L/

Temperature.

MOTOROLA

2

HIPERCOMM

BR1334 Ð Rev 4

				MC1648
L: Micro Metal torroid #T20±22, 8 turns #30 Enameled Copper wire.				L=40nH
C = 3.0±35pF				C=10pF
				+5.0Vdc
			0.1μF	10μF
		14	1
		10
			1200*
0.1μF	L	C	3
				SIGNAL
		12		UNDER
			5	TEST
B.W. = 10 kHz
			0.1μF
Center Frequency = 100 MHz
Scan Width = 50 kHz/div
Vertical Scale = 10 dB/div

*The 1200 ohm resistor and the scope termination impedance constitute a 25:1 attenuator probe. Coax shall be CT±075±50 or equivalent.

Figure 2. Spectral Purity of Signal Output for 200MHz Testing

TEST VOLTAGE/CURRENT VALUES

	@ Test		(Volts)		mAdc
	Temperature
		VIHmax	VILmin	VEE	IL
		MC1648
	±30°C	±3.2	±3.7	±5.2	±5.0
	+25°C
		±3.35	±3.85	±5.2	±5.0
	+85°C
		±3.5	±4.0	±5.2	±5.0

Note: SOIC ªDº package guaranteed ±30°C to +70°C only

ELECTRICAL CHARACTERISTICS (Supply Voltage = ±5.2V)

±30°C

+25°C

+85°C

Symbol

Characteristic

Min

Max

Min

Max

Min

Max

Unit

Condition

IE

Power Supply Drain Current

±

±

±

41

±

±

mAdc

Inputs and outputs open

VOH

Logic ª1º Output Voltage

±1.045

±0.815

±0.96

±0.75

±0.89

±0.64

Vdc

VILmin to Pin 12, IL @ Pin 3

VOL

Logic ª0º Output Voltage

±1.89

±1.65

±1.85

±1.62

±1.83

±1.575

Vdc

VIHmax to Pin 12, IL @ Pin 3

VBIAS1

Bias Voltage

±3.6

±3.3

±3.75

±3.45

±3.9

±3.6

Vdc

VILmin to Pin 12

Min

Typ

Max

Min

Typ

Max

Min

Typ

Max

Unit

Condition

VP±P

Peak±to±Peak Tank Voltage

±

±

±

±

400

±

±

±

±

mV

See Figure 3

Vdc

Output Duty Cycle

±

±

±

±

50

±

±

±

±

%

fmax2

Oscillation Frequency

±

225

±

200

225

±

±

225

±

MHz

1. This measurement guarantees the dc potential at the bias point for purposes of incorporating a varactor tuning diode at this point.

2. Frequency variation over temperature is a direct function of the C/

Temperature and L/

Temperature.

HIPERCOMM	3	MOTOROLA
BR1334 Ð Rev 4

MC1648

			VCC
				***	**
	10	1	14
				3	1200
0.1μF	L	C
	12	7	8	5	0.1μF
	0.1μF		***	0.1μF	QL ≥ 100
	*		VEE

*Use high impedance probe (>1.0 Megohm must be used).

**The 1200 ohm resistor and the scope termination impedance constitute a 25:1 attenuator probe. Coax shall be CT±070±50 or equivalent.

***Bypass only that supply opposite ground.

VP±P

50%

	ta	PRF = 1.0MHz	ta
	tb	Duty Cycle (Vdc) ±
			tb

Figure 3. Test Circuit and Waveforms

OPERATING CHARACTERISTICS

Figure 1 illustrates the circuit schematic for the MC1648. 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.

VEE (≈1.4V for positive supply operation).

When the MC1648 is used with a constant dc voltage to the varactor diode, the output frequency will vary slightly because of internal noise. This variation is plotted versus operating frequency in Figure 5.

In order to maintain the high Q of 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. Q2 and Q3, in conjunction with output transistor Q1, provides a highly buffered output which produces a square wave. Transistors Q9 and Q11 provide the bias drive for the oscillator and output buffer. Figure 2 indicates the high spectral purity of the oscillator output (pin 3).

When operating the oscillator in the voltage controlled mode (Figure 4), it should be noted that the cathode of the

varactor diode (D) should be biased at least ª2º V above BE

		10
	0.1μF	L		3
	D			Output
	Vin	12
	C1			5
		QL ≥	100	C2

Figure 4. The MC1648 Operating in the

Voltage Controlled Mode

(Hz)	100
DEVIATION, RMS		VCC = 5 Vdc
	10
f, FREQUENCY
	1
	1	10	100
		f, OPERATING FREQUENCY (MHz)

Oscillator Tank Components

(Circuit of Figure 4)

f		L
MHz	D	μH
1.0±10	MV2115	100
10±60	MV2115	2.3
60±100	MV2106	0.15

Signal Generator

20kHz above MC1648 Frequency

300mV

HP608 or Equiv

10mV

20kHz

MC1648

Attenuator

Product

BW=1.0kHz Frequency

Voltmeter RMS

Under Test

MC1648

Detector

Meter HP5210A or Equiv

HP3400A or Equiv

Frequency (f)

Frequency Deviation + (HP5210A output voltage) (Full Scale Frequency) 1.0Volt

Figure 5. Noise Deviation Test Circuit and Waveform

MOTOROLA	4	HIPERCOMM
		BR1334 Ð Rev 4