MCIMX281AVM4B Freescale Semiconductor, MCIMX281AVM4B Datasheet - Page 903

• 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

HW_POWER_VDDIOCTRL, HW_POWER_VDDACTRL, and
HW_POWER_VDDDCTRL registers. Finally, set DCDC_XFER and clear
PWDN_5VBRNOUT in the HW_POWER_5VCTRL register. This sequence is important
because it is safe to disable the powerdown-on-unplug functionality of the device only after
the system is completely ready for a transition to battery power.
11.3.2.3 5-V Power and Battery Power
Battery charge can also be enabled to provide additional power efficiency when connected
to 5V. If the DC-DC switching converter is also enabled, the buck switching converters
will efficiently convert the battery voltage to the desired VDDA, VDDD, and VDDIO
voltages (instead of using the less efficient internal linear regulators).
11.3.3 Power-Up Sequence
The DC-DC converter controls the power-up and reset of the i.MX28. The power-up sequence
begins when the battery is connected to the BATT pin of the device (or a 5V source is
connected to the VDD5V pin). Either the BATT pin or VDD5V provides power to the
DC-DC startup circuitry, the crystal oscillator, and the real-time clock. This means that the
crystal oscillator can be running, if desired, whenever a battery is connected to BATT pin.
This feature allows the real-time clock to operate when the chip is in the off state. The
crystal oscillator/RTC is the only power drain on the battery in this state and consumes only
a very small amount of power. During this time, the VDDIO, VDDD and VDDA supplies
are held at ground. This is the off state that continues until the system power up begins.
Power-up can be started with one of several events:
When a power-up event has occurred, if VDD5V is valid, then the on-chip linear regulators
charge the VDDD, VDDA and VDDIO rails to their default voltages. If VDD5V is not
valid, then the DC-DC supplies the VDDD, VDDA, and VDDIO rails. When the voltage
rails have reached their target values, the digital logic reset is deasserted and the CPU begins
executing code. If the power supplies do not reach the target values by the time PSWITCH
is deasserted or 5V is removed, the system returns to the off state.
Freescale Semiconductor, Inc.
• PSWITCH pin >= minimum MID level PSWITCH for 100 ms
• VDD5V power pin > 4.25 V for 100 ms
• Real-time clock alarm wakeup
i.MX28 Applications Processor Reference Manual, Rev. 1, 2010
Chapter 11 Power Supply
903