AT91SAM7S32-AI ATMEL [ATMEL Corporation], AT91SAM7S32-AI Datasheet - Page 8

• Manufacturer Part Number: AT91SAM7S32-AI
• Description: AT91 ARM Thumb-based Microcontrollers
• Manufacturer: ATMEL [ATMEL Corporation]

Power Considerations
Power Supplies
Power Consumption
Voltage Regulator
8
AT91SAM7S32 Preliminary
The AT91SAM7S32 has six types of power supply pins and integrates a voltage regula-
tor, allowing the device to be supplied with only one voltage. The six power supply pin
types are:
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•
•
•
•
•
No separate ground pins are provided for the different power supplies. Only GND pins
are provided and should be connected as shortly as possible to the system ground
plane.
The AT91SAM7S32 has a static current of less than 60 µA on VDDCORE at 25°C,
including the RC oscillator, the voltage regulator and the power-on reset when the
brownout detector is deactivated. Activating the brownout detector adds 20 µA static
current.
The dynamic power consumption on VDDCORE is less than 50 mA at full speed when
running out of the Flash. Under the same conditions, the power consumption on
VDDFLASH does not exceed 10 mA.
The AT91SAM7S32 embeds a voltage regulator that is managed by the System
Controller.
In Normal Mode, the voltage regulator consumes less than 100 µA static current and
draws 100 mA of output current.
The voltage regulator also has a Low-power Mode. In this mode, it consumes less than
20 µA static current and draws 1 mA of output current.
Adequate output supply decoupling is mandatory for VDDOUT to reduce ripple and
avoid oscillations. The best way to achieve this is to use two capacitors in parallel: one
external 470 pF (or 1 nF) NPO capacitor must be connected between VDDOUT and
GND as close to the chip as possible. One external 2.2 µF (or 3.3 µF) X7R capacitor
must be connected between VDDOUT and GND.
Adequate input supply decoupling is mandatory for VDDIN in order to improve startup
stability and reduce source voltage drop. The input decoupling capacitor should be
placed close to the chip. For example, two capacitors can be used in parallel: 100 nF
NPO and 4.7 µF X7R.
VDDIN pin. It powers the voltage regulator; voltage ranges from 3.0V to 3.6V, 3.3V
nominal. If the voltage regulator is not used, VDDIN should be connected to GND.
VDDOUT pin. It is the output of the 1.8V voltage regulator.
VDDIO pin. It powers the I/O lines and the USB transceivers; dual voltage range is
supported. Ranges from 3.0V to 3.6V, 3.3V nominal.
VDDFLASH pin. It powers a part of the Flash and is required for the Flash to
operate correctly; voltage ranges from 3.0V to 3.6V, 3.3V nominal.
VDDCORE pins. They power the logic of the device; voltage ranges from 1.65V to
1.95V, 1.8V typical. It can be connected to the VDDOUT pin with decoupling
capacitor. VDDCORE is required for the device, including its embedded Flash, to
operate correctly.
VDDPLL pin. It powers the oscillator and the PLL. It can be connected directly to the
VDDOUT pin.
6071A–ATARM–28-Oct-04