AT91SAM7S128 ATMEL [ATMEL Corporation], AT91SAM7S128 Datasheet - Page 11

• Manufacturer Part Number: AT91SAM7S128
• Manufacturer: ATMEL [ATMEL Corporation]

6. Power Considerations
6.1
6.2
6.3
6175BS–ATARM–04-Nov-05
Power Supplies
Power Consumption
Voltage Regulator
The AT91SAM7S Series has six types of power supply pins and integrates a voltage regulator,
allowing the device to be supplied with only one voltage. The six power supply pin types are:
During startup, core supply voltage (VDDCORE) slope must be superior or equal to
6V/ms.
No separate ground pins are provided for the different power supplies. Only GND pins are pro-
vided and should be connected as shortly as possible to the system ground plane.
In order to decrease current consumption, if the voltage regulator and the ADC are not used,
VDDIN, ADVREF, AD4, AD5, AD6 and AD7 should be connected to GND. In this case VDDOUT
should be left unconnected.
The AT91SAM7S Series 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 brown-out detector is
activated, 20 µA static current is added.
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 AT91SAM7S Series 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 25 µA
static current and draws 1 mA of output current.
Adequate output supply decoupling is mandatory for VDDOUT to reduce ripple and avoid oscil-
lations. 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
• VDDIN pin. It powers the voltage regulator and the ADC; voltage ranges from 3.0V to 3.6V,
• 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
• VDDFLASH pin. It powers a part of the Flash and is required for the Flash to operate
• VDDCORE pins. They power the logic of the device; voltage ranges from 1.65V to 1.95V,
• VDDPLL pin. It powers the oscillator and the PLL. It can be connected directly to the
3.3V nominal.
supported. Ranges from 3.0V to 3.6V, 3.3V nominal or from 1.65V to 1.95V, 1.8V nominal.
Note that supplying less than 3.0V to VDDIO prevents any use of the USB transceivers.
correctly; voltage ranges from 3.0V to 3.6V, 3.3V nominal.
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.
VDDOUT pin.
AT91SAM7S Series Summary
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