AT77C104BCH08YV Atmel, AT77C104BCH08YV Datasheet - Page 34

• Manufacturer Part Number: AT77C104BCH08YV
• Manufacturer: Atmel

Specifications of AT77C104BCH08YV

• Lead Free Status / Rohs Status: Compliant

16. Power Management
16.1
16.2
16.3
16.3.1
16.3.2
16.4
16.4.1
16.4.2
34
Sleep Mode (<10 µA)
Standby Mode (<10 µA Providing SPI Bus not Accessed)
Acquisition Mode Current Consumption
Navigation and Click Modes Current Consumption
AT77C104B
Static Current Consumption
Dynamic Current Consumption
Static Current Consumption
Dynamic Current Consumption
Reset high
Power consumption can be reduced in several ways:
When the SPI bus is not used, only the analog part of the circuit consumes power at around 4
mA.
When the clock is running, the digital sections also consume current. With a 30 pF load at 16
MHz, the power consumption is approximately 4.5 mA on the V
The SPI bus’ consumption is very low in click and navigation modes, the majority of the con-
sumption being generated by the analog part of the circuit. Therefore, the static and dynamic
consumption is almost the same.
With a 30 pF load at maximum clock frequency, the current consumption in click mode is almost
300 µA on pins V
navigation mode is approximately 1.5 mA.
Note:
• By switching off the FingerChip sensor
• By programming a standby mode by writing 00001xx in the MODCTRL register (STANDBY
mode set and oscillator stopped.) Bit b6 (HEAT) of the HEATCTRL register must be turned to
‘0’ when programming standby mode
We advise use of the interrupt capabilities (IRQ signal or Interrupts register) so as to limit the
host’s overall current consumption. The host can, from time to time, check the IRQ or Interrupt
register. A strategy for very low power consumption is to use the click mode only as a wake-up.
The click mode is only 300 µA, and once a click is detected the host can turn on the navigation
mode as well.
DD
. With a 30 pF load at maximum clock frequency, the current consumption in
DD
pins.
5347F–BIOM–3/08