Product Specification

SP4306

Page 7 of 10

Evaluation Kit

The Digital Attenuator Evaluation Kit board was

designed to ease customer evaluation of the

SP4306 DSA.

J9 is used in conjunction with the supplied DC

cable to supply VDD, GND, and –VDD. If use of

the internal negative voltage generator is desired,

then connect –VDD (black banana plug) to

ground. If an external –VDD is desired, then apply

-3V.

J1 should be connected to the LPT1 port of a PC

with the supplied control cable. The evaluation

software is written to operate the DSA in serial

mode, so switch 7 (P/S) on the DIP switch SW1

should be ON with all other switches off. Using the

software, enable or disable each attenuation

setting to the desired combined attenuation. The

software automatically programs the DSA each

time an attenuation state is enabled or disabled.

To evaluate the power up options, first disconnect

the control cable from the evaluation board. The

control cable must be removed to prevent the PC

port from biasing the control pins.

During power up with P/S=1 high and LE=0 or P/

S=0 low and LE=1, the default power-up signal

attenuation is set to the value present on the five

control bits on the five parallel data inputs (C1 to

C16). This allows any one of the 32 attenuation

settings to be specified as the power-up state.

During power up with P/S=0 high and LE=0, the

control bits are automatically set to one of four

possible values presented through the PUP

interface. These four values are selected by the

two power-up control bits, PUP1 and PUP2, as

shown in the Table 6.

Pin 20 is open and can be connected to any bias.

Resistor on Pin 1 & 3

A 10 k

Ω resistor on the inputs to pins 1 & 3

(Figure 16) will eliminate package resonance

between the RF input pin and the two digital

inputs. Specified attenuation error versus

frequency performance is dependent upon this

condition.

Figure 15. Evaluation Board Layout

Figure 16. Evaluation Board Schematic

Note: Resistors on pins 1 and 3 are required and should be placed as

close to the part as possible to avoid package resonance and

meet error specifications over frequency.

10 kohm

Z=50 Ohm

PS

J5

SMA

1

10kohm

J4

SMA

1

DATA

C2

C1

CLK

VCC

C16

LE

Z=50 Ohm

U1

QFN4X4

1

2

3

4

5

11

12

13

14

15

C16

RFin

DATA

CLK

LE

GND

VNEG

PS

RFout

C8

C8

100 pF

C4

Tel: +86-23-62808818

Fax: +86-23-62805284

www.sipatsaw.com / sawmkt@sipat.com