Manual

CRD5376

26 DS612RD2

The PLL on CRD5376 uses a voltage controlled crystal oscillator (VCXO) to minimize jitter, and has a sin-

gle gate phase/frequency detector and clock divider to minimize size and power.

2.3.4 RS-485 Telemetry

By default, CRD5376 communicates with the PC evaluation software through the microcontroller USB

port. Additional hardware is designed onto CRD5376 to use the microcontroller I2C

port as a low-level

local telemetry, but it is provided for custom programming convenience only and is not directly supported

by the CRD5376 PC evaluation software or microcontroller firmware.

Telemetry signals enter CRD5376 through RS-485 transceivers, which are differential current mode

transceivers that can reliably drive long distance communication. Data passes through the RS-485 trans-

ceivers to the microcontroller I2C interface and the clock and synchronization inputs.

Specification Value

Oscillator - Citizen 32.768 MHz VCXO CSX750VBEL32.768MTR

Surface Mount Package Type Leadless 6-Pin, 5x7 mm

Supply Voltage, Current 3.3 V, 11 mA

Frequency Stability, Pullability ± 50 ppm, ± 90 ppm

Startup Time 4 ms

Specification Value

Phase Detector - TI LittleLogic XOR SN74LVC1G86DBVR

Surface Mount Package Type SOT23-5

Supply Voltage, Current

3.3 V, 10 µA

Specification Value

Loop Filter Integrator - Linear Tech Op-Amp LT1783IS5

Surface Mount Package Type SOT23-5

Supply Voltage, Current

3.3 V, 375 µA

Specification Value

Clock Divider - TI LittleLogic D-Flop SN74LVC2G74DCTR

Surface Mount Package Type SSOP8-199

Supply Voltage, Current

3.3 V, 10 µA

Specification Value

RS-485 Transceiver - Linear Tech LTC1480IS8

Surface Mount Package Type SOIC-8, 5mm x 6mm

Supply Voltage, Quiescent Current

3.3V, 600 µA

Maximum Data Rate 2.5 Mbps

Transmitter Delay, Receiver Delay 25 - 80 ns, 30 - 200 ns

Transmitter Current, Full Termination (60 Ω)

25 mA

Transmitter Current, Half Termination (120 Ω)

13 mA