MC145170DT2R2

Clock Generators, PLLs, Frequency Synthesizers Overview

The MC145170DT2R2 is a single-chip PLL frequency synthesizer designed for direct usage in MF, HF, and VHF bands. It features fully programmable R and N counters, an amplifier at the fin pin, and on-chip support for external crystals. The device utilizes patented BitGrabber registers for random access without address bits, allowing tuning via a 2-byte serial transfer to the 16-bit N register. Operating voltage ranges from 2.7 to 5.5 V, with maximum operating frequencies of 185 MHz at 4.5 V supply and 100 MHz at 3.0 V supply. Quiescent supply current is limited to 100 µA.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Patented BitGrabber registers enable random access to C, N, and R registers without address or steering bits.
• Jam-load feature initializes N and R counters simultaneously to reduce lock times and prevent erroneous data loading.
• Dual phase detectors (single- and double-ended) with linear transfer functions eliminate dead zones.
• Configuration register allows disabling unused outputs to minimize noise and interference.

Clock Generators, PLLs, Frequency Synthesizers Applications

• MF, HF, and VHF band frequency synthesis
• Direct interface to Motorola SPI serial data ports
• Spectrum analyzer local oscillator circuits

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the DT2 suffix corresponds to the TSSOP-16 package and R2 tape-and-reel orientation. Confirm the device variant is MC145170-2, which includes an improved power-on reset circuit compared to the -1 version. Ensure the ordering information matches the specific temperature range and package requirements for the design.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this component when a robust POR circuit is required for momentary power interruptions. The MC145170-2 draws approximately 20 µA more quiescent current than the -1 version but maintains the same 100 µA maximum limit. Choose based on the need for direct SPI interfacing and the ability to program divide ratios up to 65,535 for the N counter.

Clock Generators, PLLs, Frequency Synthesizers Part Context

The MC145170DT2R2 is part of the MC145170 family, specifically the -2 variant. It is pin-for-pin compatible with the MC145170-1 but offers enhanced power-on reset responsiveness. The device contains 4,800 active transistors and is manufactured using CMOS technology. It supports both bit-oriented and byte-oriented serial programming formats.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

The MC145170-1 is a direct functional replacement with identical pinout but lacks the improved POR circuit. No other cross-model substitutes are documented in the provided datasheet.

Clock Generators, PLLs, Frequency Synthesizers FAQ

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

The MC145170-2 features a more robust power-on reset (POR) circuit that is more responsive to momentary power supply interruptions. It draws approximately 20 µA additional supply current but maintains the same 100 µA maximum quiescent current specification.

What is the purpose of the jam-load feature?

The jam-load feature ensures that whenever a new divide ratio is loaded into the N register, both the N and R counters are initialized with their respective values and begin counting down together. This reduces lock times and prevents erroneous data from being loaded into the counters.

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

Yes, DC coupling can be used if the external signal swings virtually rail-to-rail (VDD to VSS). In this case, no external feedback resistor is needed, and OSCout must be left unconnected. For frequencies below 1 MHz, DC coupling is required.