Matched Broadband RF VGA

400MHz to 2700MHz

Glitch-Free

9

Rev 3, April 2015

IDTF0480NBGI

Datasheet

The SPI interface should be built up by an 8-bit word (defined as MOSI) where 5 bits are used for attenuation setting

per the example shown below. BOLD indicates bits used for programming the attenuator; data bits 2 through 6.

D7

(MSB)

D6

D5

D4

D3

D2

D1

D0

(LSB)

ATTENUATION

SETTING

x

Low

Low

Low

Low

Low

x

x

insertion loss

x

Low

Low

Low

Low

High

x

x

1 dB

x

Low

Low

Low

High

Low

x

x

2 dB

x

Low

Low

High

Low

Low

x

x

4 dB

x

Low

High

Low

Low

Low

x

x

8 dB

x

High

Low

Low

Low

Low

x

x

16 dB

x

High

Low

High

High

Low

x

x

22 dB

x

High

Low

High

High

High

x

x

23 dB (max)

x

High

High

Low

Low

Low

x

x

23 dB (max)

x

High

High

Low

Low

High

x

x

23 dB (max)

x

High

High

Low

High

Low

x

x

23 dB (max)

x

High

High

Low

High

High

x

x

23 dB (max)

x

High

High

High

Low

Low

x

x

23 dB (max)

x

High

High

High

Low

High

x

x

23 dB (max)

x

High

High

High

High

Low

x

x

23 dB (max)

x

High

High

High

High

High

x

x

23 dB (max)

PARAMETER

LEVEL

FUNCTION

STBY

0 Volts or

Open Circuit

Power On

+5 Volts

Power Off

* Startup/Power on requirements:

SPI shall be left on during Standby mode. When the circuit is initially powered up (+5V applied on pin 12/13), the

default VGA setting should be minimum gain (max attenuation setting). If the attenuator is programmed in Standby

mode, the programmed setting will be active when the device is taken out of Standby mode.

PARAMETER

LEVEL

FUNCTION

LogicCTL

3.3 Volts or

open Circuit

3.3V logic

0 Volts

1.8V logic