Philips HEF4750VU, HEF4750VDB, HEF4750VD, HEC4750VDB Datasheet

DATA SH EET

Product speciﬁcation File under Integrated Circuits, IC04

January 1995

INTEGRATED CIRCUITS

HEF4750V LSI

Frequency synthesizer

For a complete data sheet, please also download:

•The IC04 LOCMOS HE4000B Logic Family Specifications HEF, HEC

•The IC04 LOCMOS HE4000B Logic Package Outlines/Information HEF, HEC

January 1995 2

Philips Semiconductors Product speciﬁcation

Frequency synthesizer

HEF4750V

LSI

DESCRIPTION

The HEF4750V frequency synthesizer is one of a pair of LOCMOS devices, primarily intended for use in high-performance frequency synthesizers, e.g. in all communication, instrumentation, television and broadcast applications. A combination of analogue and digital techniques results in an integrated circuit that enables high performance. The complementary device is the universal divider type HEF4751V.

Together with a standard prescaler, the two LOCMOS integrated circuits offer low-cost single loop synthesizers with full professional performance. Salient features offered (in combination with HEF4751V) are:

• Wide choice of reference frequency using a single crystal.

• High-performance phase comparator  low phase noise  low spurii.

• System operation to > 1 GHz.

• Typical 15 MHz input at 10 V.

• Flexible programming:

frequency offsets ROM compatible fractional channel capability.

• Programme range 6

⁄2 decades, including up to

3 decades of prescaler control.

• Division range extension by cascading.

• Built-in phase modulator.

• Fast lock feature.

• Out-of-lock indication.

• Low power dissipation and high noise immunity.

APPLICATION INFORMATION

Some examples of applications for the HEF4750V in combination with the HEF4751V are:

• VHF/UHF mobile radios.

• HF s.s.b. transceivers.

• Airborne and marine communications and navaids.

• Broadcast transmitters.

• High quality radio and television receivers.

• High performance citizens band equipment.

• Signal generators.

SUPPLY VOLTAGE

RATING RECOMMENDED OPERATING

−0,5 to +15 9,5 to 10,5 V

January 1995 3

Philips Semiconductors Product speciﬁcation

Frequency synthesizer

HEF4750V

LSI

HEF4750VD(F): 28-lead DIL; ceramic (cerdip)

(SOT135)

( ): Package Designator North America

Fig.1 Pinning diagram.

PINNING

R phase comparator input, reference V phase comparator input STB strobe input TCA timing capacitor C

TCB timing capacitor C

TCC timing capacitor C

TRA biasing pin (resistor R

)

analogue phase comparator output

digital phase comparator output MOD phase modulation input OL out-of-lock indication OSC reference oscillator/buffer input XTAL reference oscillator/buffer output A

to A

programming inputs/programmable divider NS

, NS1programming inputs, prescaler

OUT reference divider output

January 1995 4

Philips Semiconductors Product speciﬁcation

Frequency synthesizer

HEF4750V

LSI

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Fig.2 Block diagram comprising five basic functions: phase comparator 1 (PC1), phase comparator 2 (PC2), phase modulator, reference

oscillator and reference divider. These functions are described separately.

N.B. PC1= analogue output; PC2= 3-state output.

January 1995 5

Philips Semiconductors Product speciﬁcation

Frequency synthesizer

HEF4750V

LSI

FUNCTIONAL DESCRIPTION Phase comparator 1

Phase comparator 1 (PC1) is built around a SAMPLE and HOLD circuit. A negative-going transition at the V-input causes the hold capacitor (C

) to be discharged and after a specified delay, caused by the Phase Modulator by means of an internal V’ pulse, it produces a positive-going ramp. A negative-going transition at the R-input terminates

the ramp. Capacitor C

holds the voltage that the ramp has attained. Via an internal sampling switch this voltage is transferred to CCand in turn buffered and made available at output PC1.

If the ramp terminates before an R-input is present, an internal end of ramp (EOR) signal is produced.

These actions are illustrated in Fig.3.

The resultant phase characteristic is shown in Fig.4.

Fig.3 Waveforms associated with PC1.

January 1995 6

Philips Semiconductors Product speciﬁcation

Frequency synthesizer

HEF4750V

LSI

Fig.4 Phase characteristic of PC1.

PC1 is designed to have a high gain, typically 3200 V/cycle (at 12,5 kHz). This enables a low noise performance.

Phase comparator 2

Phase comparator 2 (PC2) has a wide range, which enables faster lock times to be achieved than otherwise would be possible. It has a linear ± 360° phase range, which corresponds to a gain of typically 5 V/cycle.

This digital phase comparator has three stable states:

• reset state,

• V’ leads R state,

• R leads V’ state.

Conversion from one state to another takes place according to the state diagram of Fig.5.

Fig.5 State diagram of PC2.

Output PC2produces positive or negative-going pulses with variable width; they depend on the phase relationship of R and V’. The average output voltage is a linear function of the phase difference. Output PC2remains in the high impedance OFF-state in the region in which PC1 operates. The resultant phase characteristic is shown in Fig.6.

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