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RFFC2071/2072

DS140110

7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical

support, contact RFMD at (+1) 336-678-5570 or customerservice@rfmd.com.

Multi-Slice Mode

The Multi-Slice mode of operation allows up to four chips to be controlled from a common serial bus. The device address pins

(15 and 16) ADD1 and ADD2 are used to set the address of each part.

On power up, and after a reset, the devices ignore the address pins ADD1 and ADD2 and any data presented to the serial bus

will be programmed into all the devices. However, once the ADDR bit in the SDI_CTRL register is set, each device then adopts

an address according to the state of the address pins on the device.

General Purpose Outputs

The general purpose outputs (GPOs) can be controlled via the GPO register and will depend on the state of MODE since they

can be set in different states corresponding to either mixer path 1 or 2. For example, the GPOs can be used to drive LEDs or to

control external circuitry such as switches or low power LNAs.

Each GPO pin can supply approximately 20mA load current. The output voltage of the GPO high state will drop with increased

current drive by approximately 25mV/mA. Similarly the output voltage of the GPO low state will rise with increased current,

again by approximately 25mV/mA.

External Modulation

The RFFC2071 and RFFC2072 fractional-N synthesizer can be used to modulate the frequency of the VCO. There are two dedi-

cated registers, EXT_MOD and FMOD, which can be used to configure the device as a modulator. It is possible to modulate the

VCO in two ways:

1.Binary FSK

The MODSETUP bits in the EXT_MOD register are set to 11. GPO3 is then configured as an input and used to control the signal

frequency. The frequency deviation is set by the MODSTEP and MODULATION bits in the EXT_MOD and FMOD registers respec-

tively.

The modulation frequency is calculated according to the following formula:

2.Continuous Modulation

The MODSETUP bits in the EXT_MOD register are set to 01. The frequency deviation is set by the MODSTEP and MODULATION

bits in the EXT_MOD and FMOD registers respectively. The VCO frequency is then changed by writing a new value into the MOD-

Slice2

(0)

Slice2

(1)

Slice2

(2)

Slice2

(3)

A1 A2

ENX

SDATA

SCLK

Vdd

Vdd

Vdd

Vdd

A1 A2

A1 A2

A1 A2

2

PD

MODULATION

 2

16





=