16 Phase Locked Loops (PLL) & Frequency Synthesis Circuits 2,400+

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Part RoHS Manufacturer Other IC type Temperature Grade No. of Terminals Package Code Package Shape Surface Mount Total Dose (V) Package Body Material Maximum Supply Current (Isup) No. of Functions Technology Screening Level Nominal Bandwidth Terminal Form Maximum Negative Supply Voltage (Vsup) Nominal Negative Supply Voltage (Vsup) Nominal Supply Voltage (Vsup) Power Supplies (V) Maximum Output Frequency 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 Minimum Negative Supply Voltage (Vsup) JESD-609 Code Maximum Time At Peak Reflow Temperature (s) Peak Reflow Temperature (C) Length

TSA5512T

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

COMMERCIAL EXTENDED

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

50 mA

1

BIPOLAR

GULL WING

5 V

5

SMALL OUTLINE

SOP16,.25

PLL or Frequency Synthesis Circuits

1.27 mm

80 Cel

-10 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

Not Qualified

4.5 V

e4

9.9 mm

933656140602

NXP Semiconductors

PHASE LOCKED LOOP

COMMERCIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

BIPOLAR

GULL WING

5 V

SMALL OUTLINE

1.27 mm

70 Cel

0 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1.93 mm

3.9 mm

Not Qualified

e4

9.9 mm

933656140623

NXP Semiconductors

PHASE LOCKED LOOP

COMMERCIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

BIPOLAR

GULL WING

5 V

SMALL OUTLINE

1.27 mm

70 Cel

0 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1.93 mm

3.9 mm

Not Qualified

e4

9.9 mm

UMA1021AM/C1

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

OTHER

16

LSSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

BICMOS

GULL WING

3 V

SMALL OUTLINE, LOW PROFILE, SHRINK PITCH

.65 mm

85 Cel

-30 Cel

DUAL

R-PDSO-G16

5.5 V

1.5 mm

4.4 mm

Not Qualified

2.7 V

5.2 mm

MC12210D

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

16 mA

1

BIPOLAR

GULL WING

3 V

SMALL OUTLINE

SOP16,.23

1.27 mm

85 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

2.7 V

9.9 mm

MC12181D

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

5.5 mA

1

BIPOLAR

GULL WING

3 V

SMALL OUTLINE

SOP16,.25

1.27 mm

85 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

2.7 V

9.9 mm

74HC4046AT

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

6 V

1.75 mm

3.9 mm

Not Qualified

2 V

9.9 mm

74HCT7046ADB

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

85 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

Not Qualified

4.5 V

74HCT4046AD-T

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1

5.5 V

1.75 mm

3.81 mm

Not Qualified

4.5 V

WITH THREE PHASE COMPARATORS

e4

9.9 mm

74HCT4046AN

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

5

IN-LINE

DIP16,.3

PLL or Frequency Synthesis Circuits

2.54 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDIP-T16

5.5 V

4.06 mm

7.62 mm

Not Qualified

4.5 V

WITH THREE PHASE COMPARATORS

e4

19.09 mm

74HCT7046ADB-T

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

85 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

Not Qualified

4.5 V

74HC4046N

NXP Semiconductors

INDUSTRIAL

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

CMOS

THROUGH-HOLE

2/6

IN-LINE

DIP16,.3

PLL or Frequency Synthesis Circuits

2.54 mm

85 Cel

-40 Cel

Tin/Lead (Sn/Pb)

DUAL

R-PDIP-T16

Not Qualified

e0

74HC4046AD-T

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

Nickel/Palladium/Gold (Ni/Pd/Au)

DUAL

R-PDSO-G16

1

6 V

1.75 mm

3.81 mm

Not Qualified

3 V

WITH THREE PHASE COMPARATORS

e4

30

260

9.9 mm

74HCT7046APW-T

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

85 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

Not Qualified

4.5 V

74HCT9046AN,699

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

5

IN-LINE

DIP16,.3

PLL or Frequency Synthesis Circuits

2.54 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDIP-T16

5.5 V

4.7 mm

7.62 mm

Not Qualified

4.5 V

e4

30

260

21.6 mm

74HC7046AT-T

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

6 V

1.75 mm

3.9 mm

Not Qualified

2 V

9.9 mm

74HCT4046ATD

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

Not Qualified

4.5 V

9.9 mm

74HC7046ADB,112

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

2/6

SMALL OUTLINE, SHRINK PITCH

SSOP16,.3

PLL or Frequency Synthesis Circuits

.65 mm

85 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1

6 V

2 mm

5.3 mm

Not Qualified

2 V

e4

6.2 mm

74HCT7046AN

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

5

IN-LINE

DIP16,.3

PLL or Frequency Synthesis Circuits

2.54 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDIP-T16

5.5 V

4.7 mm

7.62 mm

Not Qualified

4.5 V

WITH TWO PHASE COMPARATORS

e4

21.6 mm

74HCT9046AT-T

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

Not Qualified

4.5 V

WITH TWO PHASE COMPARATORS

9.9 mm

74HC7046ADB-T

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE, SHRINK PITCH

.65 mm

85 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1

6 V

2 mm

5.3 mm

Not Qualified

2 V

e4

6.2 mm

74HC4046APW

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

TSSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

2/6

SMALL OUTLINE, THIN PROFILE, SHRINK PITCH

TSSOP16,.25

PLL or Frequency Synthesis Circuits

.65 mm

125 Cel

-40 Cel

Nickel/Palladium/Gold (Ni/Pd/Au)

DUAL

R-PDSO-G16

1

6 V

1.1 mm

4.4 mm

Not Qualified

2 V

e4

30

260

5 mm

74HC7046AD,118

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

2/6

SMALL OUTLINE

SOP16,.25

PLL or Frequency Synthesis Circuits

1.27 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1

6 V

Not Qualified

3 V

WITH TWO PHASE COMPARATORS

e4

74HCT4046AT

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

Not Qualified

4.5 V

9.9 mm

74HCT7046AD,112

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

5

SMALL OUTLINE

SOP16,.25

PLL or Frequency Synthesis Circuits

1.27 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1

5.5 V

Not Qualified

4.5 V

WITH TWO PHASE COMPARATORS

e4

74HC4046ADB

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

SSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

2/6

SMALL OUTLINE, SHRINK PITCH

SSOP16,.3

PLL or Frequency Synthesis Circuits

.65 mm

125 Cel

-40 Cel

Nickel/Palladium/Gold (Ni/Pd/Au)

DUAL

R-PDSO-G16

1

6 V

2 mm

5.3 mm

Not Qualified

2 V

e4

30

260

6.2 mm

74HCT9046ADB-T

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

Not Qualified

4.5 V

74HCT7046ATD

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

Not Qualified

4.5 V

9.9 mm

MC145170P2

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

INDUSTRIAL

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

THROUGH-HOLE

IN-LINE

2.54 mm

85 Cel

-40 Cel

DUAL

R-PDIP-T16

5.5 V

4.4 mm

7.62 mm

2.7 V

19.175 mm

74HC7046APW

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

85 Cel

-40 Cel

DUAL

R-PDSO-G16

6 V

Not Qualified

2 V

74HCT4046APW

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

TSSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE, THIN PROFILE, SHRINK PITCH

.65 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.2 mm

4.4 mm

Not Qualified

4.5 V

5 mm

HEF4046BPN

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

THROUGH-HOLE

IN-LINE

2.54 mm

85 Cel

-40 Cel

TIN

DUAL

R-PDIP-T16

15 V

4.7 mm

7.62 mm

Not Qualified

3 V

e3

21.6 mm

74HCT4046APW-T

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

TSSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE, THIN PROFILE, SHRINK PITCH

.65 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.2 mm

4.4 mm

Not Qualified

4.5 V

5 mm

74HC4046ADB-T

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

SSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE, SHRINK PITCH

.65 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1

6 V

2 mm

5.3 mm

Not Qualified

2 V

e4

6.2 mm

MC145170DT2

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

INDUSTRIAL

16

TSSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

4.5 V

3/5

SMALL OUTLINE, THIN PROFILE, SHRINK PITCH

TSSOP16,.25

PLL or Frequency Synthesis Circuits

.65 mm

85 Cel

-40 Cel

Tin/Lead (Sn/Pb)

DUAL

R-PDSO-G16

3

5.5 V

1.2 mm

4.4 mm

Not Qualified

2.7 V

e0

30

240

5 mm

74HC4046ATD

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

6 V

1.75 mm

3.9 mm

Not Qualified

2 V

9.9 mm

74HC7046AD

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

2/6

SMALL OUTLINE

SOP16,.25

PLL or Frequency Synthesis Circuits

1.27 mm

125 Cel

-40 Cel

Nickel/Palladium/Gold (Ni/Pd/Au)

DUAL

R-PDSO-G16

1

6 V

Not Qualified

3 V

WITH TWO PHASE COMPARATORS

e4

30

260

74HCT4046AN,112

NXP Semiconductors

PLL FREQUENCY SYNTHESIZER

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

5

IN-LINE

DIP16,.3

PLL or Frequency Synthesis Circuits

2.54 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDIP-T16

5.5 V

4.06 mm

7.62 mm

Not Qualified

4.5 V

WITH THREE PHASE COMPARATORS

e4

19.09 mm

74HCT4046AP

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

IN-LINE

2.54 mm

125 Cel

-40 Cel

DUAL

R-PDIP-T16

5.5 V

4.7 mm

7.62 mm

Not Qualified

4.5 V

74HCT7046AN,112

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

5

IN-LINE

DIP16,.3

PLL or Frequency Synthesis Circuits

2.54 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDIP-T16

5.5 V

4.7 mm

7.62 mm

Not Qualified

4.5 V

WITH TWO PHASE COMPARATORS

e4

21.6 mm

HEF4046BT-T

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

85 Cel

-40 Cel

DUAL

R-PDSO-G16

15 V

1.75 mm

3.9 mm

Not Qualified

3 V

WITH TWO PHASE COMPARATORS

9.9 mm

74HCT9046AN,112

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

5

IN-LINE

DIP16,.3

PLL or Frequency Synthesis Circuits

2.54 mm

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDIP-T16

5.5 V

4.7 mm

7.62 mm

Not Qualified

4.5 V

e4

21.6 mm

74HCT4046ATD-T

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

1.27 mm

125 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

1.75 mm

3.9 mm

Not Qualified

4.5 V

9.9 mm

74HC4046AP

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

DIP

RECTANGULAR

NO

PLASTIC/EPOXY

1

CMOS

THROUGH-HOLE

5 V

IN-LINE

2.54 mm

125 Cel

-40 Cel

DUAL

R-PDIP-T16

6 V

4.7 mm

7.62 mm

Not Qualified

2 V

74HC7046AD-T

NXP Semiconductors

PHASE LOCKED LOOP

AUTOMOTIVE

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

125 Cel

-40 Cel

NICKEL PALLADIUM GOLD

DUAL

R-PDSO-G16

1

6 V

Not Qualified

3 V

WITH TWO PHASE COMPARATORS

e4

74HCT7046APW

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

SMALL OUTLINE

85 Cel

-40 Cel

DUAL

R-PDSO-G16

5.5 V

Not Qualified

4.5 V

74HC7046ADB

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

SSOP

RECTANGULAR

YES

PLASTIC/EPOXY

1

CMOS

GULL WING

5 V

2/6

SMALL OUTLINE, SHRINK PITCH

SSOP16,.3

PLL or Frequency Synthesis Circuits

.65 mm

85 Cel

-40 Cel

Nickel/Palladium/Gold (Ni/Pd/Au)

DUAL

R-PDSO-G16

1

6 V

2 mm

5.3 mm

Not Qualified

2 V

e4

30

260

6.2 mm

HEF4046BDF

NXP Semiconductors

PHASE LOCKED LOOP

INDUSTRIAL

16

DIP

RECTANGULAR

NO

CERAMIC, GLASS-SEALED

1

THROUGH-HOLE

IN-LINE

2.54 mm

85 Cel

-40 Cel

DUAL

R-GDIP-T16

15 V

5.08 mm

7.62 mm

Not Qualified

3 V

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.