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Frequently asked questions

Industrial UART General FAQ

Q What is your Impact series?
A A single product in our Impact series has the following features so that it may be used in multiple operating applications and environments:
  • 3.3V and 5V operation
  • Intel and Motorola selectable interface
  • Industrial temperature range of -40oC to +85oC
  • Low-power CMOS technology
  • Deeper FIFOs (16 to 256 bytes)
Q Which products fall under the category of Impact Line?
A All SC28Lxxx parts.
Q What is the definition of Bus Access Time?
A Bus Access Time = Read pulse (TRD) + Read delay (TDY).
Q How do you determine the external capacitor values for the crystal?
A The values for the external capacitors CL1 and CL2 depend on the crystal manufacturer's requirements. The load capacitance (CL) can be determined as follows: CL = (C1*C2)/(C1+C2). For example if C1 and C2 are 28pF, then CL value will be 14pF. Note that the values for C1 and C2 should include the internal capacitances CP1 and CP2.
Q What is the moisture sensitivity level for a given chip/package?
A General moisture sensitivity levels can be found on our Moisture Sensitivity Level webpage and also in our Packaging Handbook Chapter 7. We also have specific MSL data available on our website for specific products/packages. Additional package testing and certification information can also be found in our Packaging Handbook.
Q How do you choose the non-integer number for the divisor n?
A If n = 26.3, then 26 is chosen and the baud rate error is (26.3-26) / 26.3 = 1.14%. If n = 26.7, then 27 is chosen and the baud rate error is (27-26.7) / 26.7 = 1.12%.
Q What is the voltage range of SC28Lxxx parts?
A They operate in the voltage range of 3.3V to 5V +/-10% over the industrial temperature range (-40oC to +85oC).
Q What crystals are recommended for use with the SC28L92?
A Crystals with 500uW drive level are recommended. Below are some sources for the crystal:
  1. SARONIX 3.6864Mhz HC-18/U
  2. U.S CRYSTAL SIG36864-HC18
Q What is the maximum baud rate for your industrial UARTs?
A 1Mbps to 3.125Mbps.
Q What is the deepest available FIFO in an industrial UART?
A Our SC28L202 dual UART has 256-byte FIFOs for each receiver/transmitter.
Q What are the functional features of industrial UARTs?
A
All of our industrial UARTs have the following:
  • Independent transmit and receive baud rates
  • Independent transmitter and receiver enable/disable
  • Programmable interrupt priority
  • Programmable interrupt vector format
  • Transmitter and receiver software reset
  • Receiver watchdog timer
  • Receiver time-out mode
  • IACKN and DACKN signal pins
Q What are the FIT and MTBF numbers for the SC26C92C1A?
A MTBF is 8814 years, FIT is 13 failures/1 billion device hours.

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