MCIMX281AVM4B Freescale Semiconductor, MCIMX281AVM4B Datasheet - Page 13

• Manufacturer Part Number: MCIMX281AVM4B
• Description: IC MPU I.MX28 1.2 289MAPBGA
• Manufacturer: Freescale Semiconductor
• Series: i.MX28r

Specifications of MCIMX281AVM4B

• Core Processor: ARM9
• Core Size: 32-Bit
• Speed: 454MHz
• Connectivity: CAN, EBI/EMI, Ethernet, I²C, MMC, SmartCard, SPI, SSI, UART/USART, USB OTG
• Peripherals: DMA, I²S, LCD, POR, PWM, WDT
• Program Memory Size: 128KB (32K x 32)
• Program Memory Type: Mask ROM
• Ram Size: 32K x 32
• Voltage - Supply (vcc/vdd): 1.25 V ~ 5.25 V
• Data Converters: A/D 17x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 289-LFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of I /o: -
• Eeprom Size: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed

7
7.1
Freescale Semiconductor
•
•
•
•
•
•
•
•
•
Any external pull-up resistors should be placed close to the signal trace to minimize stubs and stray
capacitance as shown below.
USB
USB signal lines should be routed on top or bottom layers to allow for tight control of 90 ohm
differential impedance requirement.
Maintain parallelism between USB differential signals needed to achieve 90ohms differential
impedance between D+ and D- for the entire routed length. Slight deviations from this will
normally occur due to package, USB jack footprints, and routing to connector pins. The number
and length of the deviations should be kept to a minimum.
Use an impedance calculator to determine the trace width and spacing required for the specific
board stack up and material being used. This should also be verified with the PCB manufacturer
before routing is finalized.
Minimize the length of high-speed clock and periodic signal traces that run parallel to the USB
signal lines to minimize crosstalk. High speed and periodic signals should be kept at least 50 mils
away from USB D+/D-.
All other signals should be kept at least 20 mils away from the high-speed USB signal pairs to help
prevent crosstalk.
Stubs - Avoid creating unnecessary stubs by placing any component footprints over the path of the
D+/D- traces. If a stub is unavoidable in the design, no stub should be greater than 200 mils in
length.
Crossing a plane split - The USB data lines should never cross a power or ground plane split. This
causes unpredictable return path currents, which can cause signal quality failures as well as EMI
problems.
Failure to maintain parallelism – Failing to maintain parallelism will cause impedance
discontinuities that will directly affect signal quality. It also contributes to the trace-length
mismatch and will cause an increase in signal skew.
Common USB Routing Mistakes
i.MX28 Layout and Design Guidelines, Rev. 0
USB
13