Typical characteristics, F, where c, Load capacitance, v – Rainbow Electronics AT90LS4433 User Manual

Page 101

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101

AT90S/LS4433

1042G–AVR–09/02

Typical
Characteristics

The following charts show typical behavior. These figures are not tested during manu-
facturing. All current consumption measurements are performed with all I/O pins
configured as inputs and with internal pull-ups enabled. A sine wave generator with rail-
to-rail output is used as clock source.

The power consumption in Power-down mode is independent of clock selection.

The current consumption is a function of several factors, such as: operating voltage,
operating frequency, loading of I/O pins, switching rate of I/O pins, code executed and
ambient temperature. The dominating factors are operating voltage and frequency.

The current drawn from capacitive loaded pins may be estimated (for one pin) as
C

L

• V

CC

• f, where C

L

= load capacitance, V

CC

= operating voltage and f = average

switching frequency of I/O pin.

The parts are characterized at frequencies higher than test limits. Parts are not guaran-
teed to function properly at frequencies higher than the ordering code indicates.

The difference between current consumption in Power-down mode with Watchdog
Timer enabled and Power-down mode with Watchdog Timer disabled represents the dif-
ferential current drawn by the Watchdog Timer.

The difference between Power-down mode with Brown-out Detector enabled and
Power-down mode with Watchdog Timer disabled represents the differential current
drawn by the Brown-out Detector.

Figure 70. Active Supply Current vs. Frequency

0

5

10

15

20

25

30

35

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

ACTIVE SUPPLY CURRENT vs. FREQUENCY

T

A

= 25˚C

V

CC

= 6V

V

CC

= 5.5V

V

CC

= 5V

V

CC

= 4.5V

V

CC

= 4V

V

CC

= 3.6V

V

CC

= 3.3V

V

CC

= 3.0V

V

CC

= 2.7V

Frequency (MHz)

I

CC

(mA)

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