74HCT9046AD datasheet(6/40 Pages) PHILIPS

No de pièce	74HCT9046AD

Description	PLL with bandgap controlled VCO

Download	40 Pages

Scroll/Zoom	100%

Fabricant	PHILIPS [NXP Semiconductors]

Site Internet	http://www.nxp.com

Logo

6 / 40 page

1999 Jan 11

6

Philips Semiconductors

Product speciﬁcation

PLL with bandgap controlled VCO

74HCT9046A

FUNCTIONAL DESCRIPTION

The 74HCT9046A is a

phase-locked-loop circuit that

comprises a linear VCO and two

different phase comparators (PC1

and PC2) with a common signal input

amplifier and a common comparator

input (see Fig.4). The signal input can

be directly coupled to large voltage

signals (CMOS level), or indirectly

coupled (with a series capacitor) to

small voltage signals. A self-bias

input circuit keeps small voltage

signals within the linear region of the

input amplifiers. With a passive

low-pass filter, the '9046A' forms a

second-order loop PLL.

The principle of this

phase-locked-loop is based on the

familiar HCT4046A. However extra

features are built in, allowing very

high performance phase-locked-loop

applications. This is done, at the

expense of PC3, which is skipped in

this HCT9046A. The PC2 is equipped

with a current source output stage

here. Further a bandgap is applied for

all internal references, allowing a

small centre frequency tolerance. The

details are summed up in the next

section called: “Differences with

respect to the familiar HCT4046A”.

If one is familiar with the HCT4046A

already, it will do to read this section

only.

DIFFERENCES WITH RESPECT TO

THE FAMILIAR HCT4046A

• A centre frequency tolerance of

maximum

±10%.

• The on board bandgap sets the

internal references resulting in a

minimal frequency shift at supply

voltage variations and temperature

variations.

• The value of the frequency offset is

determined by an internal

reference voltage of 2.5 V instead

of VCC − 0.7 V. In this way the offset

frequency will not shift over the

supply voltage range.

• A current switch charge pump

output on PC2 allows a virtually

ideal performance of PC2. The gain

of PC2 is independent of the

voltage across the low-pass filter.

Further a passive low-pass filter in

the loop achieves an active

performance now. The influence of

the parasitic capacitance of the

PC2 output plays no role here,

resulting in a true correspondence

of the output correction pulse and

the phase difference even up to

phase differences as small as a few

nanoseconds.

• Because of its linear performance

without dead zone, higher

impedance values for the filter,

hence lower C-values, can now be

chosen. Correct operation will not

be influenced by parasitic

capacitances as in the instance

with voltage source output of the

4046A.

• No PC3 on pin 15 but instead a

resistor connected to GND, which

sets the load/unload currents of the

charge pump (PC2).

• Extra GND pin at pin 1 to allow an

excellent FM demodulator

performance even at 10 MHz and

higher.

• Combined function of pin 2. If

pin 15 is connected to VCC (no bias

resistor Rb) pin 2 has its familiar

function viz. output of PC1. If at

pin 15 a resistor (Rb) is connected

to GND it is assumed that PC2 has

been chosen as phase comparator.

Connection of Rb is sensed by

internal circuitry and this changes

the function of pin 2 into a lock

detect output (PCPOUT) with the

same characteristics as PCPOUT of

pin 1 of the well known

74HCT4046A.

• The inhibit function differs. For the

HCT4046A a HIGH level at the

inhibit input (INH) disables the VCO

and demodulator, while a LOW

level turns both on. For the

74HCT9046A a HIGH level on the

inhibit input disables the whole

circuit to minimize standby power

consumption.

VCO

The VCO requires one external

capacitor C1 (between C1A and C1B)

and one external resistor R1

(between R1 and GND) or two

external resistors R1 and R2

(between R1 and GND, and R2 and

GND). Resistor R1 and capacitor C1

determine the frequency range of the

VCO. Resistor R2 enables the VCO

to have a frequency offset if required

(see Fig.5).

The high input impedance of the VCO

simplifies the design of the low-pass

filters by giving the designer a wide

choice of resistor/capacitor ranges. In

order not to load the low-pass filter, a

demodulator output of the VCO input

voltage is provided at pin 10

(DEMOUT). The DEMOUT voltage

equals that of the VCO input. If

DEMOUT is used, a load resistor (Rs)

should be connected from pin 10 to

GND; if unused, DEMOUT should be

left open. The VCO output (VCOOUT)

can be connected directly to the

comparator input (COMPIN), or

connected via a frequency-divider.

The VCO output signal has a duty

factor of 50% (maximum expected

deviation 1%), if the VCO input is held

at a constant DC level. A LOW level at

the inhibit input (INH) enables the

VCO and demodulator, while a HIGH

level turns both off to minimize

standby power consumption.

Numéro de pièce similaire - 74HCT9046AD

Fabricant	No de pièce	Fiches technique	Description
NXP Semiconductors	74HCT9046AD	230Kb / 43P	PLL with band gap controlled VCO Rev. 06-15 September 2009
Nexperia B.V. All right...	74HCT9046AD	667Kb / 36P	PLL with band gap controlled VCO Rev. 9 - 20 March 2020

More results

Description similaire - 74HCT9046AD

Fabricant	No de pièce	Fiches technique	Description
NXP Semiconductors	74HCT9046A	230Kb / 43P	PLL with band gap controlled VCO Rev. 06-15 September 2009
Nexperia B.V. All right...	74HCT9046A	667Kb / 36P	PLL with band gap controlled VCO Rev. 9 - 20 March 2020
Texas Instruments	TRF3761	443Kb / 18P	[Old version datasheet] INTEGER-N PLL WITH INTEGRATED VCO
Texas Instruments	TRF3762	1Mb / 33P	[Old version datasheet] INTEGER-N PLL WITH INTEGRATED VCO
Analog Devices	HMC837LP6CE	777Kb / 12P	FRACTIONAL-N PLL WITH INTEGRATED VCO
Semtech Corporation	SX1781	460Kb / 16P	PLL Frequency Synthesizer with Integrated VCO
Semtech Corporation	ACS1790T	1Mb / 48P	PLL Frequency Synthesizer with Integrated VCO
Analog Devices	HMC807LP6CE	1Mb / 14P	FRACTIONAL-N PLL WITH INTEGRATED VCO
	HMC828LP6CE	676Kb / 10P	FRACTIONAL-N PLL WITH INTEGRATED VCO
	HMC836LP6CE	680Kb / 10P	FRACTIONAL-N PLL WITH INTEGRATED VCO

More results

74HCT9046AD Fiches technique(PDF) 6 Page - NXP Semiconductors

74HCT9046AD Fiches technique(HTML) 6 Page - NXP Semiconductors

Numéro de pièce similaire - 74HCT9046AD

Description similaire - 74HCT9046AD

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Fiches technique Télécharger

Lien URL