MC145170DT2

Clock Generators, PLLs, Frequency Synthesizers Overview

The MC145170DT2 is a single-chip PLL frequency synthesizer in a TSSOP-16 package, designed for direct use in MF, HF, and VHF bands. It features fully programmable R (1–32,767) and N (40–65,535) counters with a BitGrabber serial interface requiring no address bits. The device operates on a 2.7 V to 5.5 V supply, drawing up to 5.8 mA at 185 MHz. It includes dual phase detectors with linear transfer functions, an internal oscillator circuit, and a robust power-on reset mechanism.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• BitGrabber registers enable random access via simple 2-byte serial transfers without steering bits.
• Jam-load feature initializes N and R counters simultaneously to reduce lock times.
• Dual phase detectors provide linear transfer functions with no dead zones.
• Configurable C register allows disabling unused outputs to minimize noise.

Clock Generators, PLLs, Frequency Synthesizers Applications

• MF, HF, and VHF band frequency synthesis
• Direct interface to Motorola SPI serial data ports
• Systems requiring low-noise reference output generation

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the DT suffix corresponds to the TSSOP-16 package and check RoHS compliance status, as original documentation indicates non-compliance. Confirm the specific revision (MC145170-2) for the improved power-on reset circuit characteristics before integration.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this component when designing synthesizers for frequencies up to 185 MHz with a 5.5 V maximum supply. Ensure the application can accommodate the 2.7 V minimum operating voltage and that the serial interface timing requirements (setup/hold times) are met by the host controller.

Clock Generators, PLLs, Frequency Synthesizers Part Context

This part is the MC145170-2 variant, which is pin-for-pin compatible with the MC145170-1 but features a more robust power-on reset circuit. It draws approximately 20 µA additional quiescent current compared to the previous version while maintaining the same maximum specification limits.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

The MC145170-1 is a functional predecessor with identical pinouts but lacks the enhanced POR circuit. No other direct substitutes are documented in the provided source material.

Clock Generators, PLLs, Frequency Synthesizers FAQ

How does the MC145170-2 differ from the MC145170-1?

The MC145170-2 has a more robust power-on reset circuit that is more responsive to momentary power supply interruptions, drawing approximately 20 µA more supply current than the MC145170-1.

What is the purpose of the jam-load feature?

The jam-load feature initializes both the N and R counters with their respective values simultaneously when a new divide ratio is loaded, reducing lock times and preventing erroneous data loading.

Can the MC145170-2 operate with DC coupling to the OSCin pin?

Yes, DC coupling is permitted if the external signal swings rail-to-rail. In this case, OSCout must be left unconnected, and no external feedback resistor is required.