Frequency Synthesiser with resettable counters
NJ88C22
Frequency Synthesiser with resettable counters
DS2439 - 2.2
The NJ88C22 is a synthesiser circuit fabricated on ...
Description
NJ88C22
Frequency Synthesiser with resettable counters
DS2439 - 2.2
The NJ88C22 is a synthesiser circuit fabricated on the GPS CMOS process and is capable of achieving high sideband attenuation and low noise performance. It contains a reference oscillator, 11-bit programmable reference divider, digital and sample-and-hold comparators, 10-bit programmable ‘M’ counter, 7-bit programmable ‘A’ counter and the necessary control and latch circuitry for accepting and latching the input data. Data is presented serially under external control from a suitable microprocessor. Although 28 bits of data are initially required to program all counters, subsequent updating can be abbreviated to 17 bits, when only the ‘A’ and ‘M’ counters require changing. The NJ88C22 is intended to be used in conjunction with a two-modulus prescaler such as the SP8715 series to produce a universal binary coded synthesiser for up to 1100MHz operation.
PDA PDB LD FIN VSS VDD OSC IN OSC OUT
1 2 3 4
16 15 14 13
CH RB MC PDA PDB NC ENABLE LD FIN CLOCK VSS DATA VDD NC NC OSC IN CAP 1 2 3 4 5 6 7 8 9 18 17 16 15 NJ88C22 14 13 12 11 10 CH RB MC CAP ENABLE CLOCK DATA NC OSC OUT
NJ88C22
5 6 7 8 12 11 10
9
DG16, DP16 FEATURES s Low Power Consumption
MP18
Fig.1 Pin connections - top view (not to scale)
s s s s
High Performance Sample and Hold Phase Detector Serial Input with Fast Update Feature >20MHz Input Frequency Fast Lock-up Time ABSOLUTE MAXIMUM RATINGS
Supply voltage, VDD2VSS: Input voltage Open drain ...
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