QCCN Phase Locked Loops (PLL) & Frequency Synthesis Circuits 278

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Part	Manufacturer	Other IC type	Temperature Grade	No. of Terminals	Package Code	Package Shape	Surface Mount	Package Body Material	Maximum Supply Current (Isup)	No. of Functions	Technology	Screening Level	Terminal Form	Nominal Supply Voltage (Vsup)	Power Supplies (V)	Package Style (Meter)	Package Equivalence Code	Sub-Category	Terminal Pitch	Maximum Operating Temperature	Minimum Operating Temperature	Terminal Finish	Terminal Position	JESD-30 Code	Moisture Sensitivity Level (MSL)	Maximum Supply Voltage (Vsup)	Maximum Seated Height	Width (mm)	Qualification	Minimum Supply Voltage (Vsup)	Additional Features	JESD-609 Code	Maximum Time At Peak Reflow Temperature (s)	Peak Reflow Temperature (C)	Length
HMC833LP6GETR	Analog Devices	PHASE LOCKED LOOP	INDUSTRIAL	40	QCCN	SQUARE	YES	PLASTIC/EPOXY	100 mA				NO LEAD		3.3,5	CHIP CARRIER	LCC40,.24SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N40	1				Not Qualified			e3	30	260
LMX2531LQX2820E/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	36	QCCN	SQUARE	YES	PLASTIC/EPOXY	52 mA		BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC36,.25SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N36	3				Not Qualified			e3	30	260
ADF4159CCPZ	Analog Devices	PHASE DETECTOR	AUTOMOTIVE	24	QCCN	SQUARE	YES	PLASTIC/EPOXY	40 mA		BICMOS		NO LEAD		1.8,3/3.3	CHIP CARRIER	LCC24,.16SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	125 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N24	3				Not Qualified			e3		260
ADF4159CCPZ-RL7	Analog Devices	PHASE DETECTOR	AUTOMOTIVE	24	QCCN	SQUARE	YES	PLASTIC/EPOXY	40 mA		BICMOS		NO LEAD		1.8,3/3.3	CHIP CARRIER	LCC24,.16SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	125 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N24	3				Not Qualified			e3		260
HMC703LP4ETR	Analog Devices	PHASE LOCKED LOOP	INDUSTRIAL	24	QCCN	SQUARE	YES	PLASTIC/EPOXY	95 mA				NO LEAD		3.3,5	CHIP CARRIER	LCC24,.16SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N24	1				Not Qualified			e3	30	260
CD-700-EAT-KANN-50M0000000	Microchip Technology	PHASE LOCKED LOOP	COMMERCIAL	16	QCCN	RECTANGULAR	YES	CERAMIC, METAL-SEALED COFIRED	63 mA	1			NO LEAD	3.3 V		CHIP CARRIER	LCC16,.2X.3,40		1.02 mm	70 Cel	0 Cel	GOLD OVER NICKEL	QUAD	R-CQCC-N16	1	3.63 V	2.13 mm	5.08 mm		2.97 V		e4	40	260	7.49 mm
HMC821LP6CETR	Analog Devices	PHASE LOCKED LOOP	INDUSTRIAL	40	QCCN	SQUARE	YES	PLASTIC/EPOXY			BICMOS		NO LEAD		3.3,5	CHIP CARRIER	LCC40,.24SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N40					Not Qualified				NOT SPECIFIED	NOT SPECIFIED
ADF4159WCCPZ	Analog Devices	PHASE DETECTOR	AUTOMOTIVE	24	QCCN	SQUARE	YES	PLASTIC/EPOXY	40 mA		BICMOS	AEC-Q100	NO LEAD		1.8,3/3.3	CHIP CARRIER	LCC24,.16SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	125 Cel	-40 Cel		QUAD	S-PQCC-N24					Not Qualified				NOT SPECIFIED	NOT SPECIFIED
SKY72310-11	Skyworks Solutions	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	SQUARE	YES	UNSPECIFIED		1			NO LEAD	3 V		CHIP CARRIER, VERY THIN PROFILE	LCC24,.16SQ,20		.5 mm	85 Cel	-40 Cel		QUAD	S-XQCC-N24		3.3 V	.85 mm	4 mm		2.7 V			NOT SPECIFIED	NOT SPECIFIED	4 mm
CD-700-LAC-GCB-16M3840000	Microchip Technology	PHASE LOCKED LOOP	COMMERCIAL	16	QCCN	RECTANGULAR	YES	CERAMIC, METAL-SEALED COFIRED		1			NO LEAD	3.3 V		CHIP CARRIER	LCC16,.2X.3,40		1.02 mm	70 Cel	0 Cel		QUAD	R-CQCC-N16		3.63 V	2.13 mm	5.08 mm		2.97 V					7.49 mm
UC2635L	Texas Instruments	PLL FREQUENCY SYNTHESIZER	OTHER	20	QCCN	SQUARE	YES	CERAMIC, METAL-SEALED COFIRED		1	BIPOLAR		NO LEAD	12 V		CHIP CARRIER			1.27 mm	85 Cel	-25 Cel		QUAD	S-CQCC-N20		15 V	2.54 mm	8.89 mm	Not Qualified	8 V	MOTION CONTROL APPLICATIONS				8.89 mm
LM2316SLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1	BICMOS		NO LEAD	3 V		CHIP CARRIER			.5 mm	85 Cel	-40 Cel		QUAD	S-XQCC-N16		5.5 V	1.1 mm	3.5 mm		2.3 V					3.5 mm
TRF376122IRHAR	Texas Instruments		INDUSTRIAL	40	QCCN	SQUARE	YES	PLASTIC/EPOXY					NO LEAD	5 V	5	CHIP CARRIER	LCC40,.24SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N40					Not Qualified
UC1635L	Texas Instruments	PLL FREQUENCY SYNTHESIZER	MILITARY	20	QCCN	SQUARE	YES	CERAMIC, METAL-SEALED COFIRED		1	BIPOLAR		NO LEAD	12 V	12	CHIP CARRIER	LDCC20,.4SQ	PLL or Frequency Synthesis Circuits	1.27 mm	125 Cel	-55 Cel		QUAD	S-CQCC-N20		15 V	2.54 mm	8.89 mm	Not Qualified	8 V	MOTION CONTROL APPLICATIONS		NOT SPECIFIED	NOT SPECIFIED	8.89 mm
TRF376115IRHAR	Texas Instruments		INDUSTRIAL	40	QCCN	SQUARE	YES	PLASTIC/EPOXY					NO LEAD	5 V	5	CHIP CARRIER	LCC40,.24SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N40					Not Qualified
LMX1601SLB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1	BICMOS		NO LEAD	3 V		CHIP CARRIER			.5 mm	85 Cel	-40 Cel		QUAD	S-XQCC-N16		3.6 V	1.1 mm	3.5 mm	Not Qualified	2.7 V	DUAL MODULUS PRESCALER: (MAIN) 16/17 (AUX) 8/9				3.5 mm
LMX3305SLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	OTHER	24	QCCN	RECTANGULAR	YES	UNSPECIFIED		1	CMOS		NO LEAD	3 V	3/3.3	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-30 Cel	TIN LEAD	QUAD	R-XQCC-N24		3.6 V	1.1 mm	3.5 mm	Not Qualified	2.7 V		e0			4.5 mm
UC1635L/883B	Texas Instruments	PLL FREQUENCY SYNTHESIZER	MILITARY	20	QCCN	SQUARE	YES	CERAMIC, METAL-SEALED COFIRED		1	BIPOLAR	MIL-STD-883	NO LEAD	12 V		CHIP CARRIER			1.27 mm	125 Cel	-55 Cel		QUAD	S-CQCC-N20		15 V	2.54 mm	8.89 mm	Not Qualified	8 V	MOTION CONTROL APPLICATIONS				8.89 mm
LMX1602SLB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1	BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC16,.14SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	TIN LEAD	QUAD	S-XQCC-N16		3.6 V	1.1 mm	3.5 mm	Not Qualified	2.7 V	DUAL MODULUS PRESCALER: (MAIN) 16/17 (AUX) 16/17	e0			3.5 mm
TRF376119IRHAR	Texas Instruments		INDUSTRIAL	40	QCCN	SQUARE	YES	PLASTIC/EPOXY					NO LEAD	5 V	5	CHIP CARRIER	LCC40,.24SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N40					Not Qualified
LM2326SLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1	BICMOS		NO LEAD	3 V		CHIP CARRIER			.5 mm	85 Cel	-40 Cel		QUAD	S-XQCC-N16		5.5 V	1.1 mm	3.5 mm		2.3 V					3.5 mm
TRF376117IRHAR	Texas Instruments		INDUSTRIAL	40	QCCN	SQUARE	YES	PLASTIC/EPOXY					NO LEAD	5 V	5	CHIP CARRIER	LCC40,.24SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N40					Not Qualified
TRF376121IRHAR	Texas Instruments		INDUSTRIAL	40	QCCN	SQUARE	YES	PLASTIC/EPOXY					NO LEAD	5 V	5	CHIP CARRIER	LCC40,.24SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N40					Not Qualified
LMX1600SLB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1	BICMOS		NO LEAD	3 V		CHIP CARRIER			.5 mm	85 Cel	-40 Cel		QUAD	S-XQCC-N16		3.6 V	1.1 mm	3.5 mm	Not Qualified	2.7 V	DUAL MODULUS PRESCALER: (MAIN) 32/33 (AUX) 8/9				3.5 mm
UC3635L	Texas Instruments	PLL FREQUENCY SYNTHESIZER	COMMERCIAL	20	QCCN	SQUARE	YES	CERAMIC, METAL-SEALED COFIRED		1	BIPOLAR		NO LEAD	12 V		CHIP CARRIER			1.27 mm	70 Cel	0 Cel		QUAD	S-CQCC-N20		15 V	2.54 mm	8.89 mm	Not Qualified	8 V	MOTION CONTROL APPLICATIONS				8.89 mm
LMX2330LSLDX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	20	QCCN	SQUARE	YES	PLASTIC/EPOXY	6.6 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC20,.14SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N20					Not Qualified
LMX2354SLB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	SQUARE	YES	UNSPECIFIED	8.5 mA	1	BICMOS		NO LEAD	3 V	3/5	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	TIN LEAD	QUAD	S-XQCC-N24		5.5 V	1.2 mm	3.5 mm	Not Qualified	2.7 V	SELECTABLE PRESCALER OF 16/17 OR 20/21 AND 8/9 OR 12/13	e0			4.5 mm
LMX2531LQX2265E/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	36	QCCN	SQUARE	YES	PLASTIC/EPOXY	49 mA		BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC36,.25SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N36	3				Not Qualified			e3	30	260
LMX2306SLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1	BICMOS		NO LEAD	3 V		CHIP CARRIER			.5 mm	85 Cel	-40 Cel		QUAD	S-XQCC-N16	2	5.5 V	1.1 mm	3.5 mm		2.3 V				235	3.5 mm
LMX2331LSLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	RECTANGULAR	YES	PLASTIC/EPOXY	5.4 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	R-PQCC-N24					Not Qualified
LMX2486SQX/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	SQUARE	YES	PLASTIC/EPOXY			CMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC24,.16SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N24	3				Not Qualified			e3	30	260
LMX2331LSLDX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	20	QCCN	SQUARE	YES	PLASTIC/EPOXY	5.4 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC20,.14SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N20	1				Not Qualified				30	260
LMX2332LSLDX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	20	QCCN	SQUARE	YES	PLASTIC/EPOXY	4.1 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC20,.14SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	S-PQCC-N20					Not Qualified
LMX2531LQX1312E/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	36	QCCN	SQUARE	YES	PLASTIC/EPOXY	49 mA		BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC36,.25SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N36	3				Not Qualified			e3	30	260
LMX2487SQX/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	SQUARE	YES	PLASTIC/EPOXY			CMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC24,.16SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N24	3				Not Qualified			e3	30	260
LMX2531LQX2080E/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	36	QCCN	SQUARE	YES	PLASTIC/EPOXY	46 mA		BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC36,.25SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N36	3				Not Qualified			e3	30	260
LMX2531LQX1415E/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	36	QCCN	SQUARE	YES	PLASTIC/EPOXY	46 mA		BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC36,.25SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N36	3				Not Qualified			e3	30	260
LMX2332LSLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	RECTANGULAR	YES	PLASTIC/EPOXY	4.1 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	R-PQCC-N24					Not Qualified
LMX2350SLB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	RECTANGULAR	YES	PLASTIC/EPOXY	8.75 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	R-PQCC-N24					Not Qualified				NOT SPECIFIED	NOT SPECIFIED
LMX2336USLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	RECTANGULAR	YES	UNSPECIFIED		1			NO LEAD	3 V		CHIP CARRIER			.5 mm	85 Cel	-40 Cel		QUAD	R-XQCC-N24		5.5 V	1.1 mm	3.5 mm		2.7 V					4.5 mm
LMX2335USLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1			NO LEAD	3 V		CHIP CARRIER			.5 mm	85 Cel	-40 Cel		QUAD	S-XQCC-N16		5.5 V	1.1 mm	3.5 mm		2.7 V					3.5 mm
LMX2487ESQE/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	SQUARE	YES	PLASTIC/EPOXY					NO LEAD	3 V	3	CHIP CARRIER	LCC24,.16SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N24	3				Not Qualified			e3	30	260
LMX2324SLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	16	QCCN	SQUARE	YES	UNSPECIFIED		1	BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC16,.14SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	TIN LEAD	QUAD	S-XQCC-N16		5.5 V	1.1 mm	3.5 mm	Not Qualified	2.7 V	DUAL MODULUS PRESCALER: 32/33	e0			3.5 mm
LMX2531LQX1146E/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	36	QCCN	SQUARE	YES	PLASTIC/EPOXY	49 mA		BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC36,.25SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N36	3				Not Qualified			e3	30	260
LMX2330LSLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	RECTANGULAR	YES	PLASTIC/EPOXY	6.6 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	R-PQCC-N24					Not Qualified
LMX2531LQX1500E/NOPB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	36	QCCN	SQUARE	YES	PLASTIC/EPOXY	46 mA		BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC36,.25SQ,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	MATTE TIN	QUAD	S-PQCC-N36	3				Not Qualified			e3	30	260
LMX2352SLB	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	RECTANGULAR	YES	PLASTIC/EPOXY	6 mA		BICMOS		NO LEAD		3/5	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel		QUAD	R-PQCC-N24					Not Qualified				NOT SPECIFIED	NOT SPECIFIED
LMX2332USLBX	Texas Instruments	PLL FREQUENCY SYNTHESIZER	INDUSTRIAL	24	QCCN	RECTANGULAR	YES	PLASTIC/EPOXY	3.3 mA	1	BICMOS		NO LEAD	3 V	3	CHIP CARRIER	LCC24,.17X.14,20	PLL or Frequency Synthesis Circuits	.5 mm	85 Cel	-40 Cel	TIN LEAD	QUAD	R-PQCC-N24		5.5 V	1.1 mm	3.5 mm	Not Qualified	2.7 V	DUAL MODULUS PRESCALER (RF): 64/65 OR 128/129 AND DUAL MODULUS PRESCALER (IF): 8/9 OR 16/17	e0			4.5 mm

Phase Locked Loops (PLL) & Frequency Synthesis Circuits

Phase Locked Loops (PLL) and Frequency Synthesis Circuits are electronic circuits used to generate and control stable and precise frequencies for use in various applications, such as communication systems, signal processing, and instrumentation.

A PLL is a feedback system that compares the phase of an input signal to the phase of a reference signal and adjusts the output frequency to match the reference frequency. The basic components of a PLL include a phase detector, a low-pass filter, a voltage-controlled oscillator (VCO), and a frequency divider. The phase detector compares the phase of the input and reference signals and generates an error signal that is filtered and used to adjust the frequency of the VCO. The output of the VCO is divided by a frequency divider to generate the output frequency. PLLs are commonly used for frequency synthesis, clock recovery, and phase modulation/demodulation.

Frequency synthesis circuits are electronic circuits used to generate precise and stable frequencies by combining multiple signals with different frequencies. These circuits use various techniques, such as direct digital synthesis (DDS), fractional-N synthesis, and frequency mixing to generate frequencies. DDS is a technique that uses a digital signal generator to generate a waveform with a specific frequency, phase, and amplitude. Fractional-N synthesis is a technique that uses a PLL to generate a frequency that is a fraction of the reference frequency. Frequency mixing is a technique that combines two signals with different frequencies to generate a signal with a frequency equal to the difference between the two frequencies.

PLLs and frequency synthesis circuits are critical components in many electronic systems that require precise and stable frequencies. These circuits are used in communication systems, signal processing, instrumentation, and other applications where accurate frequency generation and control is required.