LTC6952

Demonstration circuit 2664A is a VCO Rider Board with Loop Filter that supports the popular 0.5" × 0.5" VCO package footprint.

The DC2664A expedites evaluation of Phase-Locked Loop (PLL) devices requiring an external Voltage Controlled Oscillator (VCO). Without the DC2664A, each VCO and PLL combination requires a unique loop filter design, resulting in several PLL demo board modifications to evaluate each VCO. These board modifications are time consuming and often result in damage to either the PLL or the VCO.

The DC2664A integrates the VCO and loop filter allowing these unique designs to reside on multiple DC2664As. The DC2664A RFOUT and VTUNE SMA connections allow the user to quickly evaluate a PLL with multiple VCOs without risk of damage from multiple board modifications.

VCOs are notoriously sensitive to power supply noise and spurs. The DC2664A resolves the concern of locating a low noise and low spurious lab supply by powering the VCO with an onboard ultralow noise and ultrahigh PSRR LDO, the LT3042. A second LT3042 LDO is available on the DC2664A to power an active loop filter. Both LDOs are powered from a single supply, simplifying the number of lab supplies required to evaluate a VCO and PLL combination.

The DC2664A was designed to mate directly with the LTC6955 (DC2611A) and LTC6952 (DC2609A) demo boards.

Demonstration circuit 2609A features the LTC6952, an Ultralow Jitter, 4.5GHz PLL with 11 Outputs and JESD204B Support.

By default, the DC2609A is powered from two supplies. The 9V-12V supply input powers the onboard reference and VCO circuitry, along with the LTC6952 5V supply pin. The 4V-6V supply input powers the LTC6952 3.3V supply pins. A reduced power option is provided that allows the LTC6952’s output supply pins to connect to an LTC Silent Switcher^® and the LTC6952 input supply pins to connect to a low noise LDO.

All differential inputs and six of the differential outputs are populated with 0.5” spaced SMA connectors. These outputs are AC-coupled with 50Ω transmission lines making them suitable to drive 50Ω impedance instruments. The remaining five differential outputs are terminated with 100Ω.

The LTC6952’s EZSync^™ and SYSREF request functions are made available via the LTC6952 SPI interface or the EZS_SRQ SMA/turret connectors. The DC2609A, DC2610A, and DC2611A SMA placement was designed for ease of connection for all multi-part synchronization and SYSREF request modes.

The V_TUNE and VCO SMAs can mate directly with the DC2664A VCO rider board. This options allows for a quick method to evaluate multiple VCOs.

A DC2026 USB serial controller board is used for SPI communication with the LTC6952, controlled by the supplied LTC6952Wizard^™ software.

Demonstration circuit 2430A is a Linduino^® SPI 1:8 Expander Shield. The DC2430A shield routes SPI and I²C signals from one DC2026 to one of eight selectable QuikEval^™ connector sites. When a DC2430A QuikEval connector site is selected, an LED will illuminate next to the active site. 

Linduino One controller board (commonly referred to as Linduino or DC2026C) is Analog Device's Arduino compatible system for developing and distributing firmware libraries and example code for Linear Technology’s integrated circuits. The code is designed to be highly portable to other microcontroller platforms, and is written in C using as few processor specific functions as possible. LTSketchbook is the entire code base that holds sketches to talk to Analog Devices’s integrated circuits using Linduino. It allows you to test out the code directly, using the standard demo board for the particular IC.

The Linduino One board is compatible with the Arduino Uno, using the Atmel ATMEGA328 processor. This board features a 14-pin “QuikEval” connector that can be plugged into nearly 100 daughter boards for various Analog Devices parts, including Analog to Digital converters, Digital to Analog Converters, high-voltage power monitors, temperature measurement devices, RF synthesizers, battery stack monitors, and more.

An LTM2884 USB Isolator breaks the ground connection to the PC, allowing projects to operate at a differentground potential than the computer that is controlling it. Contact linduino@analog.com or check our EngineerZone forum for any questions. For a list of frequently asked questions, please visit our FAQ.

The Linduino board ships with firmware that allows it to communicate with the QuikEval program, which provides all of the GUIs for compatible demo boards. Installing QuikEval is also the recommended way to install the correct USB drivers for the Linduino One board. To modify the code, and to load programs into the Linduino, download the Arduino IDE LTSketchbook.