SP8858
1·5GHz Professional Synthesiser
Supersedes March 1997 version, DS3843 - 3.0
DS3843 - 4.1 July 1998
The SP8858 is a single chip synthesiser intended for PLL
signal synthesis applications up to 1.5GHz and includes a
dual modulus prescaler (4N/N11), programmable A, M and
R dividers, digital phase detector, charge pump and lock
detect circuits.
The SP8858 is a development of the SP8853 synthesiser
with low residual phase noise, increased dynamic range
above 1GHz and an improved high gain phase detector
design that eliminates the dead-band.
The low prescaler modulus, programmable to either 16/17
or 8/9, together with the 15-bit M counter and 13-bit reference
counter make this device ideal for a diverse range of high
performance applications.
The nominal phase detector gain is set by a reference
current into pin 24 and the gain can be varied over a 4:1 range
when the device is programmed. The dividers, the phase
detector sense, the prescaler modulus and the data buffer
control logic are also programmable using the three wire
serial interface. An alternative 22-bit control word for the A
and M dividers and phase detector gain can be stored so
allowing fast frequency hopping and bandwidth switching by
simply toggling the logic level on pin 13 (F1/F2). In addition,
the A counter of the ‘active’ buffer can be programmed with
only 6 bits, allowing fast hopping to adjacent channels.
A simple exclusive - or lock detect circuit is also provided,
thesensitivityofwhichisdeterminedbyanexternalcapacitor.
4
3
2
1
28 27 26
5
25
24
23
22
21
20
19
F
*
CP OUTPUT
RPD
REF
6
POWER DOWN
7
V
V
4
4
1
V
3
CC
EE
8
GROUND
XTAL 1
XTAL2
SP8858
CC
CC
9
V
10
11
RF INPUT
RF INPUT
V
2
EE
12 13 14 15 16 17 18
HC28
FEATURES
4
3
2
1
28 27 26
■ Low Residual Phase Noise (see Reference 1)
■ Operation to 1·5GHz over Full Temperature Range
■ High Input Sensitivity
5
25
F
*
REF
CP OUTPUT
RPD
6
24
23
22
21
20
19
POWER DOWN
7
V
V
4
4
1
EE
V
3
CC
■ Improved Linear Digital Phase Detector
■ Programmable Charge Pump Current: 10µA to 2 mA
■ On-chip 416/17 or 48/9 Dual Modulus Prescaler
■ Three-wire Serial Data Interface
■ 13-bit Reference Counter
8
SP8858
CC
CC
GROUND
XTAL 1
XTAL2
9
V
10
11
RF INPUT
RF INPUT
V
2
EE
12 13 14 15 16 17 18
■ 15-bit M Counter
■ Stores an Alternative Programming Word
■ Facility to Program A counter Only
■ Power Saving Standby Mode
HP28
Fig. 1 Pin connections (top view)
ABSOLUTE MAXIMUM RATINGS
ORDERING INFORMATION
Supply voltage
20·3V to 17V
265°C to 1150°C
255°C to 1125°C
2·5V p-p
Storage temperature
Operating temperature
Prescaler input voltage
SP8858 IG HCAR 240°C to 185°C (Industrial grade)
SP8858 MG HCAR 255°C to 1125°C (Military grade)
SP8858 IG HPAS 240°C to 185°C (Industrial grade)
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