Organize and Share your Electronics the way you want. Sign-Up for a free account now. It takes only 30 seconds!

PLL & PLLVCO Serial Programming Interface (SPI) Mode Selection Design Considerations

PLL & PLLVCO Serial Programming Interface (SPI) Mode Selection Design Considerations

This application note discusses best practices for use of the Serial Port Interface (SPI) Mode selection feature of Hittite’s PLL and PLLVCO product lines. In this note, we will refer to them all, simply as the PLL/VCOs.

The PLL/VCO devices covered in this document support two different serial interface modes or protocols: Open Mode and HMC Mode.

The serial interface mode selection occurs after power-up and Power-On-Reset (POR) in the PLL/VCO. The PLL/VCO is reset and ready for mode selection after an internal Power-On-Reset occurs, automatically about 450 µsec after the PLL/VCO digital supply rises past half of its nominal value. The mode selection is then determined by the first occurrence of a rising edge on either the SCK (Open Mode) or SEN (HMC Mode) after the POR event.

Once the mode is selected on the initial bus transaction, the mode cannot be changed without powering down the power supply. Activity on the SPI lines prior to POR is ignored assuming both MPU and the PLL/VCO are powered up at the same time.

It should be noted that circuits with VCO subsystems, such as the RF PLLVCOs have a second POR circuit in the VCO subsystem on the VCC2 supply. The POR in the VCO subsystem does not affect mode selection but it does affect proper operation of the VCO and has certain conditions for minimum rise time, and maximum voltage on start up. It is typically recommended to be less than 1 msec rise time and less than 150mV on startup.

Read more Here







 

More Articles to Read

Peeqo is a desktop bot that communicates through GIFs
Peeqo is a desktop bot that communicates through GIFs
Using a Programmable Input Multiplier to Minimize Integer Boundary Spurs
Using a Programmable Input Multiplier to Minimize Integer Boundary Spurs
Serial seven segment LED display shield
Serial seven segment LED display shield
G-code controlled drawing plotter
G-code controlled drawing plotter
An Arduino round word clock
An Arduino round word clock
The Sandwich-o-Matic will make your lunch automatically
The Sandwich-o-Matic will make your lunch automatically
Scalar Network Analyser Jr
Scalar Network Analyser Jr
An Arduino-controlled automated whiskey distillery
An Arduino-controlled automated whiskey distillery
The Rex800 looks like a dinosaur Terminator
The Rex800 looks like a dinosaur Terminator
Home Environment Monitor
Home Environment Monitor
Understanding the Operation of the Frequency Synthesizer in Maxim’s RF Transceivers
Understanding the Operation of the Frequency Synthesizer in Maxim’s RF Transceivers
App note: EPIC: Electro-Pyrotechnic Initiator Chip Resistor
App note: EPIC: Electro-Pyrotechnic Initiator Chip Resistor
Noisy ESP8266
Noisy ESP8266
App note: Noise analysis for high-speed op amps
App note: Noise analysis for high-speed op amps
Skill Sunday: Arrays
Skill Sunday: Arrays
App note: Infrared remote control implementation with MSP430FR4xx
App note: Infrared remote control implementation with MSP430FR4xx
Gesture Controlled Smart Home
Gesture Controlled Smart Home
Design for a Wideband, Differential Transimpedance DAC Output
Design for a Wideband, Differential Transimpedance DAC Output
Wrist thrusters let you fly through the water effortlessly
Wrist thrusters let you fly through the water effortlessly
Bertan/Spellman 225-20R HV power supply teardown
Bertan/Spellman 225-20R HV power supply teardown

Top


Shares