MC13109A

19

MOTOROLA RF/IF DEVICE DATA

Figure 17. Circuit Blocks Powered During Power Saving Modes

Circuit Blocks

Active

Rx

Standby

Inactive

“PLL Vref” Regulated Voltage

X

X

X1

X1

MPU Interface

X

X

X

X

2nd LO Oscillator

X

X

X

MPU Clock Output

X

X

X

RF Receiver

X

X

1st LO VCO

X

X

Rx PLL

X

X

Carrier Detect

X

X

Data Amp

X

X

Low Battery Detect

X

X

Tx PLL

X

Rx Audio Path

X

Tx Audio Path

X

NOTE: 1. In Standby and Inactive Modes, “PLL Vref” remains powered but is not regulated. It will fluctuate with VCC.

Inactive Mode Operation and Hardware Interrupt

In some handset applications it may be desirable to power

down all circuitry including the microprocessor (MPU). First

put the MC13109A into the Inactive mode, which turns off the

MPU Clock Output (see Figure 18), and then disable the

microprocessor. In order to give the MPU adequate time to

power down, the MPU Clock output remains active for a

minimum of one reference counter cycle (about 200

µs) after

the command is given to switch into the “Inactive” mode. An

external timing circuit should be used to initiate the turn–on

sequence. The “CD Out” pin has a dual function. In the Active

and Rx modes it performs the carrier detect function. In the

Standby and Inactive modes the carrier detect circuit is

disabled and the “CD Out” pin is in a “High” state due to the

external pull–up resistor. In the Inactive mode the “CD Out”

pin is the input for the hardware interrupt function. When the

“CD Out” pin is pulled “low” by the external timing circuit, the

MC13109A switches from the Inactive to the Interrupt mode

thereby turning on the MPU Clock Output. The MPU can then

resume control of the combo IC. The “CD Out” pin must

remain low until the MPU changes the operating mode from

Interrupt to Standby, Active or Rx modes.

Figure 18. Hardware Interrupt Operation

Mode

EN

CD Out/Hardware Interrupt

MPU Clock Out

CD Out Low

Delay after MPU selects Inactive Mode to when CD turns off

CD Turns Off

External Timer

Pulls Pin Low

MPU Initiates

Mode Change

Timer Output

Disabled

MPU Initiates

Inactive Mode

“MPU Clock Out” remains active for a minimum of one count of reference

counter after “CD Out/Hardware Interrupt” pin goes high

Active/Rx

Inactive

Interrupt

Standby/Rx/Active