ADF5904ACPZ-RL7 Datasheet ADF5904WCCPZ, ADF5904ACPZ, ADF5904WCCPZ-RL7 | P13-P15

ADF5904 Data Sheet

Rev. A | Page 12 of 15

DB31 DB30

DB29 DB28

DB27

DB26

DB25

DB24

DB23

DB22

DB21

DB20

DB19

DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10

DB9

DB8 DB7

DB6

DB5 DB4

DB3

DB2

DB1

DB0

CS2 CS1 CS0 0 0 0 0 0

CONTROL

BITS

0 0

0

0 0

0

1 0 1 0 0 1 0 0 1 0

C2(0)

C1(1)1

RESERVED

CHANNEL

SELECT

REGISTER 1 (R1)

12885-019

CS2

CS1

CS0 CHANNEL SELECT

NONE

CHANNEL 1

CHANNEL 2

CHANNEL 3

CHANNEL 4

LO

RESERVED

0

1

0

1

0

1

0

1

0

1

0

1

0

1

Figure 19. Register 1

DB31 DB30

DB29 DB28 DB27 DB26 DB25 DB24 DB23 DB22 DB21

DB20 DB19 DB18

DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9

DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

0

0 0 0 0 0 0 0 0

CONTROL

BITS

0

0 0 0 0

1 0 0 TC4 TC3 TC2 TC1 TC0 0

0 0 0 0 0 0 1 C2(1) C1(0)

REGISTER 2 (R2)

RESERVED

5-BIT

CHANNEL TEST SELECT

RESERVED

CHANNEL TEST SELECT

NONE SELECTED

TEMPERATURE SENSOR TO ATEST

RESERVED

REGISTER 0 READBACK

REGISTER 1 CHANNEL 1 READBACK

REGISTER 1 CHANNEL 2 READBACK

REGISTER 1 CHANNEL 3 READBACK

REGISTER 1 CHANNEL 4 READBACK

REGISTER 1 LO READBACK

REGISTER 2 READBACK

RESERVED

TC4 TC3 TC1

TC0

TC2

0

1

0

-

1

0

1

0

1

0

1

0

1

x

0

1

-

1

0

1

0

1

x

0

-

1

0

1

x

0

-

1

0

1

0

1

12855-020

Figure 20. Register 2

REGISTER 1

Register 1 Control Bits

With Bits[C2:C1] set to 01, Register R1 is programmed.

Register 1 contains the internal controls for the four RF channels

and the LO path. During the initialization sequence, the default

conditions are loaded. See Step 3 to Step 7 in Table 6.

REGISTER 2

Register 2 Control Bits

With Bits[C2:C1] set to 10, Register R2 is programmed. Figure 20

shows the input data format for programming this register.

5-Bit Channel Test Select

Bits[DB14:DB10] control the ADF5904 test modes. These bits

allow access to the temperature sensor on the ATEST pin and

the register readback on the DOUT pin. See Figure 20 for the

truth table.

Data Sheet ADF5904

Rev. A | Page 13 of 15

INITIALIZATION SEQUENCE

After powering up the device, administer the initialization

sequence in Table 6 to set the register with the code to configure

the device.

Table 6. Initialization Sequence

Step Register Hex Code Description

1 R3 0x00000003 Reserved

2 R2 0x00020406 Temperature sensor to ATEST

3 R1 0x20001499 Configure Channel 1

4 R1 0x40001499 Configure Channel 2

5 R1 0x60001499 Configure Channel 3

6 R1 0x80001499 Configure Channel 4

7 R1 0xA0000019 Configure LO

8 R0 0x80007CA0 Power up

TEMPERATURE SENSOR

The on-chip temperature sensor of the ADF5904 is accessed on

the ATEST pin. The temperature sensor operates over the full

operating temperature range of −40°C to +105°C. To improve

accuracy, conduct a one-point calibration at room temperature

and store the result in the external memory. Convert the ATEST

voltage to temperature by using the following equation:

Temperature (°C) = (V

ATEST

− V

OFF

)/V

GAIN

where:

V

ATEST

is the voltage on the ATEST pin.

V

OFF

is the offset voltage and it is 1.212 V.

V

GAIN

is the voltage gain and it is 4.072e

−3

.

ADF5904 Data Sheet

Rev. A | Page 14 of 15

APPLICATION INFORMATION

APPLICATION OF THE ADF5904 IN FMCW RADAR

Figure 21 shows the application of the ADF5904 in a frequency

modulated continuous wave (FMCW) radar system.

In the FMCW radar system, the ADF4159 generates the

sawtooth or triangle ramps necessary for this type of radar to

operate.

The ADF4159 controls the VTUNE pin on the transceiver (Tx)

monolithic microwave integrated circuit (MMIC) and thus the

frequency of the voltage controlled oscillator (VCO) and the Tx

output signal on TXOUT1 or TXOUT2. The LO signal from the

Tx MMIC is fed to the LO input on the ADF5904.

The ADF5904 downconverts the signal from the four receiver

antennas to baseband with the LO signal from the Tx MMIC.

The downconverted baseband signals from the four receiver

channels on the ADF5904 are fed to the ADAR7251 4-channel,

continuous time (CT), sigma-delta (Σ-Δ) analog-to-digital

converter (ADC).

A digital signal processor (DSP) follows the ADC to handle the

target information processing.

TX_MMIC

ADF5904

ADF4159

TXOUT1

TXOUT2

RX3_RF

RX2_RF

RX1_RF

RX4_RF

LO_IN

LO_OUT

RF

IN

A

RF

IN

B

AUX

ADAR7251DSP RX BASEBAND

VTUNECP

LOOP

FILTER

12885-021

Figure 21. FMCW Radar with ADF5904

ADF5904ACPZ-RL7

ADF5904ACPZ-RL7

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