RF Signal Path IDTF1200 IDTF19500 pages

IDTF1950
DATASHEET
7-bit 0.25 dB Digital Step Attenuator

150 MHz to 4000 MHz

FEATURES

GENERAL DESCRIPTION

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This document describes the specification for the
IDTF1950 Digital Step Attenuator. The F1950 is part of a
family of Glitch-FreeTM DSAs optimized for the demanding
requirements of communications Infrastructure. These
devices are offered in a compact 4x4 QFN package with
50 impedances for ease of integration into the radio
system.

COMPETITIVE ADVANTAGE
Digital step attenuators are used in Receivers and
Transmitters to provide gain control. The IDTF1950 is a
7-bit step attenuator optimized for these demanding
applications. The silicon design has very low insertion
loss and low distortion (+65 dBm IP3I.) The device has
pinpoint accuracy and settles to final attenuation value
within 400 nsec. Most importantly, the F1950 includes
IDT’s Glitch-FreeTM technology which results in less
than 0.6 dB of overshoot ringing during MSB transitions.
This is in stark contrast to competing DSAs that glitch as
much as 10 dB during MSB transitions (see p.10)

Glitch-FreeTM, < 0.6 dB transient overshoot
Spurious Free Design
3V to 5V supply
Attenuation Error < 0.3 dB @ 2 GHz
Low Insertion Loss < 1.3 dB @ 2 GHz
Excellent Linearity +65 dBm IP3I
Fast settling time, < 400 nsec
Class 2 JEDEC ESD (> 2kV HBM)
Serial & Parallel Interface 31.75 dB Range
4x4 mm Thin QFN 24 pin package

DEVICE BLOCK DIAGRAM

RF1

Lowest insertion loss for best SNR

RF2

Glitch-FreeTM when transitioning –
won’t damage PA or ADC
Extremely accurate with low distortion

TM
Glitch-FreeTM

APPLICATIONS
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Bias

DEC

SPI

Base Station 2G, 3G, 4G, TDD radiocards

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Repeaters and E911 systems

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Digital Pre-Distortion

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Point to Point Infrastructure

7
VMODE VDD

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WIMAX Receivers and Transmitters

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CLK DATA LE

Public Safety Infrastructure

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D[6:0]

Military Systems, JTRS radios

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RFID handheld and portable readers

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Cable Infrastructure

ORDERING INFORMATION
Omit IDT
prefix

PART# MATRIX
Part#

Freq range

Resolution
/ Range

F 1950

150 - 4000

0.25 / 31.75

Control

IL

Pinout

Parallel &
Serial

- 1 .3

PE

F1951

100 - 4000

0.50 / 31.5

Serial Only

-1.2

100 – 4000

0.50 / 15.5

Serial Only

-0.9

IDTF1950NBGI8

HITT

F1952

HITT

Glitch-FreeTM Digital Step Attenuator

Tape &
Reel

0.8 mm height
package

RF product Line

1

Green

Industrial
Temp range

Rev1 March 2012