Cirrus Logic CRD5376 - Manual (Page 26)

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