Datasheet

189

7734Q–AVR–02/12

AT90PWM81/161

15. Voltage Reference and Temperature Sensor

15.1 Features

• Accurate voltage reference of 2.56V

• Internal temperature sensor

• Possibility for runtime compensation of temperature drift in both voltage reference and on-chip

oscillators

• Low power consumption

15.2 On Chip voltage Reference and Temperature sensor overview

A low power band-gap reference provides AT90PWM81/161 with an accurate On-chip Bandgap

voltage of 1.100V (Vbg).

Then when SW1 is off and SW2/SW3 is on, the bandgap voltage is multiplied and generates the

internal reference V

REF

of 2.56V. This reference voltage is used as reference for the ADC, the

DAC and can use a buffer with external decoupling capacitor (when SW0 is on) to enable excel-

lent noise performance with minimum power consumption as shown on Figure 15-1 on page

190.

The selection of the Voltage Reference for all the analog components (ADC, DAC, Compara-

tors) is done using the REFS1:0 bits in ADMUX register; see “ADMUX - ADC Multiplexer

For conditions using the Bandgap and the internal voltage reference, see “Bandgap and Internal

Voltage Reference Enable Signals and Start-up Time” on page 55.