MC145170D2

Clock Generators, PLLs, Frequency Synthesizers Overview

The MC145170D2 is a single-chip PLL frequency synthesizer designed for direct use in MF, HF, and VHF bands. It features fully programmable R and N counters, dual phase detectors with linear transfer functions, and BitGrabber registers for address-free random access via a 2-byte serial interface. The device operates on a supply voltage of 2.7 to 5.5 V with a maximum operating frequency of 185 MHz at 4.5 V minimum supply. It includes an improved power-on reset circuit, a patented jam-load feature for rapid counter initialization, and configurable output controls to minimize noise.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• BitGrabber registers enable random access to C, N, and R registers without address or steering bits.
• Dual phase/frequency detectors provide linear transfer functions with no dead zones.
• Patented jam-load feature initializes N and R counters simultaneously to reduce lock times.
• Configurable C register allows disabling unused outputs (fR, fV, LD, REFout) to minimize interference.

Clock Generators, PLLs, Frequency Synthesizers Applications

• MF, HF, and VHF band frequency synthesis
• Direct interface to Motorola SPI serial data ports
• Systems requiring robust power-on reset response to momentary supply interruptions

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the ordering suffix 'D' corresponds to the SOG-16 package as specified in the datasheet. Confirm the device variant is MC145170-2, which features the improved power-on reset circuit compared to the MC145170-1. Ensure the application environment supports the -40 to 85 °C operating temperature range and the 2.7 to 5.5 V supply voltage requirements.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select the MC145170D2 when a pin-for-pin compatible upgrade from the MC145170-1 is required with enhanced POR responsiveness. Choose this component if the design necessitates a 16-bit N counter (range 40–65,535) and a 15-bit R counter (range 5–32,767). Consider the SOG-16 package constraints and ensure the host microcontroller can support the required serial clock frequencies up to 4.0 MHz at 5.5 V.

Clock Generators, PLLs, Frequency Synthesizers Part Context

The MC145170D2 is part of the MC145170-2 family, manufactured by Motorola (now Freescale/NXP). It is functionally identical to the MC145170P2 (Plastic DIP) and MC145170DT2 (TSSOP-16), differing only in packaging. The device is a successor to the MC145170-1, offering a more robust power-on reset circuit at the cost of approximately 20 µA additional quiescent current.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

The MC145170-1 is a direct functional substitute but lacks the improved power-on reset circuit and has a lower minimum supply voltage of 2.5 V. The MC145170P2 and MC145170DT2 are pin-compatible alternatives with different package types (Plastic DIP and TSSOP-16, respectively).

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. This improvement results in approximately 20 µA additional supply current, though the maximum quiescent current specification remains unchanged at 100 µA.

What is the purpose of the BitGrabber registers?

The BitGrabber registers allow for random access to the C, N, and R registers without requiring address or steering bits. This enables tuning via a simple 2-byte serial transfer to the 16-bit N register, simplifying the programming interface.

How is the jam-load feature utilized?

The jam-load feature initializes both the N and R counters with their respective loaded values simultaneously when a new divide ratio is loaded. This reduces lock times and prevents erroneous data from being loaded into the counters during operation.