IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
GENERAL DESCRIPTION
FEATURES
The IDTF2255 is a low insertion loss Voltage Variable
RF Attenuator (VVA) designed for a multitude of
wireless and other RF applications. This device covers
a broad frequency range from 1MHz to 3000MHz. In
addition to providing low insertion loss, the IDTF2255
provides excellent linearity performance over its entire
voltage control and attenuation range.
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The F2255 uses a single positive supply voltage of
3.15V to 5.25V. Other features include the VMODE pin
allowing either positive or negative voltage control
slope vs attenuation and multi-directional operation
meaning the RF input can be applied to either RF1 or
RF2 pins. Control voltage ranges from 0V to 3.6V
using either positive or negative control voltage slope.
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COMPETITIVE ADVANTAGE
Low Insertion Loss: 1.1dB @ 500MHz
Typical / Min IIP3: 60dBm / 46dBm
Typical / Min IIP2: 98dBm / 74dBm
33dB Attenuation Range
Bi-directional RF ports
+36dBm Input P1dB compression
VMODE pin allows either positive or negative
control response
Linear-in-dB attenuation characteristic
Supply voltage: 3.15V to 5.25V
VCTRL range: 0V to 3.6V using 5V supply
+105°C max operating temperature
3x3, 16-pin QFN package
DEVICE BLOCK DIAGRAM
IDTF2255 provides extremely low insertion loss and
superb IP3, IP2, Return Loss and Slope Linearity across
the control range. Comparing to competitive VVAs this
device is better as follows:
Operation down to 1MHz
Insertion Loss @ 500MHz: 1.1dB
Maximum Attenuation Slope: 33dB/Volt
Minimum Output IP3: 35dBm
Minimum Input IP2: 74dBm
High Operating Temperature: +105°C
ORDERING INFORMATION
APPLICATIONS
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Omit IDT
prefix
Base Station 2G, 3G, 4G,
Portable Wireless
Repeaters and E911 systems
Digital Pre-Distortion
Point to Point Infrastructure
Public Safety Infrastructure
Satellite Receivers and Modems
WIMAX Receivers and Transmitters
Military Radios covering HF, VHF, UHF
RFID handheld and portable readers
Cable Infrastructure
Wireless LAN
Test / ATE Equipment
Voltage Variable RF Attenuator
Tape &
Reel
0.9 mm height
package
IDTF2255NLGK8
Green
RF product Line
PART# MATRIX
1
IIP3
Part#
RF Freq Range
(MHz)
Insertion Loss
(dB)
(dBm)
Pinout
Compatibility
F2250
50 - 6000
1.4 (at 2GHz)
+65
RFMD
F2255
1 - 3000
1.1 (at 500MHz)
+60
F2258
50 - 6000
1.4 (at 2GHz)
+65
Hittite
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
ABSOLUTE MAXIMUM RATINGS
Parameter / Condition
VDD to GND
VMODE to GND
VCTRL to GND
VDD = 0V to 5.25V
RF1, RF2 to GND
RF1 or RF2 Input Power applied for 24 hours maximum
(VDD applied @ 2GHz and Tc=+85°C)
RF1 or RF2 Continuous Operating Power
Maximum Junction Temperature
Storage Temperature Range
Lead Temperature (soldering, 10s)
ESD Voltage– HBM (Per ESD STM5.1-2007)
ESD Voltage – CDM (Per ESD STM5.3.1-2009)
Symbol
VDD
VMODE
VCTRL
VRF
Min
-0.3
-0.3
-0.3
-0.3
Max
5.5
Minimum ( VDD, 3.9 )
Minimum ( VDD, 4.0 )
0.3
Units
V
V
V
V
PMAX24
30
dBm
PMAX_OP
TJMAX
TST
TLEAD
VESDHBM
VESDCDM
See Figure 1
+150
+150
+260
Class 2
Class C3
dBm
°C
°C
°C
-65
FIGURE 1: MAXIMUM OPERATING RF INPUT POWERS VS. RF FREQUENCY
Stresses above those listed above may cause permanent damage to the device. Functional operation of the device at
these or any other conditions above those indicated in the operational section of this specification is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
PACKAGE THERMAL AND MOISTURE CHARACTERISTICS
ΘJA (Junction – Ambient)
ΘJC (Junction – Case) The Case is defined as the exposed paddle
Moisture Sensitivity Rating (Per J-STD-020)
Voltage Variable RF Attenuator
2
80.6°C/W
5.1°C/W
MSL 1
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
IDTF2255 OPERATING CONDITIONS
Parameter
Operating Freq Range
Supply Voltage
Symbol
VIH
VMODE Logic
Condition
FRF
VDD
VDD > 3.9V
VDD = 3.15 to 3.9V
VIL
VCTRL Range
VCTRL
Supply Current
Logic Current
ICTRL Current
RF Operating Power
VDD = 3.9V to 5.25V
VDD = 3.15V to 3.9V
IMODE
ICTRL
Typ
1
3.15
1.17
1.17
0
0
0
0.801
-1.0
-1.0
IDD
3
Min
1.15
PMAXCW
RF1 Port Impedance
ZRF1
50
RF2 Port Impedance
Operating Temperature
Range
ZRF2
50
TCASE
Exposed Paddle
Temperature
-40
Max
Units
3000
5.25
3.62
VDD -0.3V
0.63
3.6
VDD-0.3
MHz
V
1.50
24
10
mA
µA
µA
See
Figure 1
dBm
V
V
Ω
+105
°C
Operating Conditions Notes:
1 – Items in min/max columns in bold italics are Guaranteed by Test.
2 – Items in min/max columns that are not bold/italics are Guaranteed by Design Characterization.
3 – Refer to the Maximum Operating RF Input Power vs. RF Frequency curves in Figure 1.
Voltage Variable RF Attenuator
3
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
IDTF2255 SPECIFICATIONS
Refer to EVKit / Applications Circuit, VDD = +3.3V, TC = +25°C, signals applied to RF1 input, FRF = 500MHz, minimum
attenuation, PIN = 0dBm for small signal parameters, +20dBm for single tone linearity tests, +20dBm per tone for
two tone tests, two tone delta frequency = 80MHz, PCB board traces and connector losses are de-embedded unless
otherwise noted. Refer to Typical Operating Curves for performance over entire frequency band.
Parameter
Insertion Loss, IL
Maximum attenuation
Symbol
AMIN
AMAX
Φ∆MAX
Insertion Phase ∆
Φ∆MID
Input 1dB Compression3
S11
Minimum RF2 Return Loss
over control voltage range
S22
Input IP3
Input IP3 over Attenuation
Minimum Output IP3
IIP3
IIP3ATTEN
OIP3MIN
Minimum Input IP2
Input IH2
Input IH3
Settling Time
Min
Typ
Max
Units
1.7 1
33
1.1
34.6
dB
dB
At 36dB attenuation
relative to Insertion Loss
At 18dB attenuation
relative to Insertion Loss
27
deg
8
P1dB
Minimum RF1 Return Loss
over control voltage range
Input IP2
Condition
Minimum Attenuation
IIP2
IIP2MIN
HD2
HD3
TSETTL0.1dB
20MHz
500MHz
2000MHz
3000MHz
20MHz
500MHz
2000MHz
3000MHz
All attenuation settings
Maximum attenuation
PIN + IM2dBC,
IM2 term is F1+F2
All attenuation settings
PIN + H2dBc
PIN + (H3dBc/2)
Any 1dB step in the 0dB
to 33dB control range
50% VCTRL to RF settled to
within ± 0.1dB
442
36
23
22
23
30
23
22
23
24
60
46
35
dBm
dB
dB
dBm
98
dBm
74
82
49
dBm
dBm
dBm
15
µSec
Specification Notes:
1 – Items in min/max columns in bold italics are Guaranteed by Test
2 – Items in min/max columns that are not bold/italics are Guaranteed by Design Characterization.
3 – The input 1dB compression point is a linearity figure of merit. Refer to Absolute Maximum Ratings section
along with Figure 1 for the maximum RF input power vs. RF frequency.
Voltage Variable RF Attenuator
4
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CURVES
Unless otherwise noted, the following conditions apply:
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•
VDD = +3.3V or +5.0V
TC = +25ºC
VMODE = 0V
RF trace and connector losses are de-embedded for S-parameters
Pin = 0dBm for all small signal tests
Pin = +20dBm for single tone linearity tests (RF1 port driven)
Pin = +20dBm/tone for two tone linearity tests (RF1 port driven)
Two tone frequency spacing = 80MHz
Voltage Variable RF Attenuator
5
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS [S2P BROADBAND PERFORMANCE] (-1-)
Attenuation vs. VCTRL
Attenuation vs. Frequency
25C /
25C /
25C /
25C /
25C /
25C /
25C /
25C /
25C /
Attenuation (dB)
-5
-10
-15
-20
0
10MHz
50MHz
100MHz
250MHz
500MHz
900MHz
1200MHz
1900MHz
2700MHz
-5
Attenuation (dB)
0
-25
-30
-35
-10
-15
-20
-25
-30
-35
25C / 0.0V
25C / 1.2V
25C / 1.8V
-40
25C / 1.0V
25C / 1.6V
25C / 2.8V
-45
-40
0.0
0.4
0.8
1.2
1.6
2.0
2.4
0
2.8
500
1000
Min. & Max. Attenuation vs. Frequency
4
-16
-40C / 0.0V
25C / 0.0V
105C / 0.0V
-40C / 2.8V
25C / 2.8V
105C / 2.8V
-4
-24
-6
-32
-8
0
500
1000
1500
2000
2500
2500
3000
-40C / 11MHz
-40C / 251MHz
-40C / 900MHz
105C / 11MHz
105C / 251MHz
105C / 900MHz
3
2
1
0
-1
-2
-3
-40
3000
0.0
0.4
0.8
1.2
1.6
2.0
2.4
VCTRL (V)
Frequency (MHz)
Voltage Variable RF Attenuator
2000
Attenuation Delta to 25C vs. VCTRL
-8
Attenuation Error (dB)
0
-2
1500
Frequency (MHz)
VCTRL (Volts)
Attenuation (dB)
25C / 0.8V
25C / 1.4V
25C / 2.2V
6
REV O, July 2015
2.8
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CURVES [S2P vs. VCTRL] (-2-)
Attenuation vs. VCTRL
Attenuation Slope vs. VCTRL
25C
Attenuation (dB)
-5
40
4MHz
25C
15MHz
Attenuation Slope (dB/V)
0
60MHz
-10
200MHz
600MHz
-15
1200MHz
-20
2100MHz
-25
-30
-35
-40
35
30
25
20
15
4MHz
60MHz
600MHz
2100MHz
10
5
0
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
0.6
0.8
1.0
1.2
VCTRL (V)
1.6
1.8
2.0
2.2
RF2 Return Loss vs. VCTRL
0
0
-10
25C
15MHz
200MHz
1200MHz
4MHz
60MHz
600MHz
2100MHz
-5
RF2 Return Loss (dB)
4MHz
60MHz
600MHz
2100MHz
-5
RF1 Return Loss (dB)
1.4
VCTRL (V)
RF1 Return Loss vs. VCTRL
-15
-20
-25
-30
-35
-10
25C
15MHz
200MHz
1200MHz
-15
-20
-25
-30
-35
-40
-40
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
0.0
0.4
0.8
1.2
VCTRL (V)
4MHz
15MHz
60MHz
200MHz
600MHz
1200MHz
2100MHz
70
60
50
40
110
(positive phase = electrically shorter)
30
25C
20
10
0
0.0
0.4
0.8
1.2
1.6
2.0
2.4
4MHz
200MHz
2100MHz
90
2.4
2.8
15MHz
600MHz
60MHz
1200MHz
25C
70
50
30
10
-10
0.6
2.8
0.8
1.0
1.2
1.4
1.6
1.8
2.0
VCTRL (V)
VCTRL (V)
Voltage Variable RF Attenuator
2.0
Insertion Phase Slope vs. VCTRL
Insertion Phase Slope (deg/V)
80
1.6
VCTRL (V)
Insertion Phase ∆ vs. VCTRL
Insertion Phase ∆ (deg)
15MHz
200MHz
1200MHz
7
REV O, July 2015
2.2
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS [S2P VS. VCTRL & TEMPERATURE] (-3-)
Attenuation Response vs. VCTRL
0
45
-10
-15
-20
Attenuation Slope (dB/V)
-40C / 15MHz
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
-5
Attenuation (dB)
Attenuation Slope vs. VCTRL
-25
-30
-35
-40
-40C / 15MHz
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
40
35
30
25
20
15
10
5
0
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8
VCTRL (V)
VCTRL (V)
RF1 Return Loss vs. VCTRL
RF2 Return Loss vs. VCTRL
0
-10
-15
-20
-25
-30
-35
-10
-15
-20
-25
-30
-35
-40
-40
0.0
0.4
0.8
1.2
1.6
2.0
2.4
0.0
2.8
30
Insertion Phase Slope (deg/V)
40
1.2
1.6
80
-40C / 15MHz
(positive phase = electrically shorter)
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
50
0.8
2.0
2.4
2.8
Insertion Phase Slope vs. VCTRL
Insertion Phase ∆ vs. VCTRL
60
0.4
VCTRL (V)
VCTRL (V)
Insertion Phase ∆ (deg)
-40C / 15MHz
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
-5
RF2 Return Loss (dB)
-5
RF1 Return Loss (dB)
0
-40C / 15MHz
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
20
10
-40C / 15MHz
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
70
60
50
40
30
20
10
0
0
0.0
0.4
0.8
1.2
1.6
2.0
2.4
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8
2.8
VCTRL (V)
VCTRL (V)
Voltage Variable RF Attenuator
8
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS [S2P VS. ATTENUATION & TEMPERATURE] (-4-)
RF1 Return Loss vs. Attenuation
RF1 Return Loss vs. Attenuation
0
RF1 Return Loss (dB)
-5
-10
4MHz
60MHz
600MHz
2100MHz
0
25C / 15MHz
25C / 200MHz
25C / 1200MHz
-40C / 15MHz
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
-5
RF1 Return Loss (dB)
25C /
25C /
25C /
25C /
-15
-20
-25
-30
-10
-15
-20
-25
-30
-35
-35
-40
-40
0
4
8
12
16
20
24
28
32
0
36
4
8
RF2 Return Loss vs. Attenuation
-10
-40C / 15MHz
-40C / 1200MHz
25C / 500MHz
105C / 15MHz
105C / 1200MHz
-5
-15
-20
-25
-30
28
32
36
-10
-40C / 500MHz
25C / 15MHz
25C / 1200MHz
105C / 500MHz
-15
-20
-25
-30
-35
-35
-40
-40
0
4
8
12
16
20
24
28
32
0
36
4
8
Insertion Phase ∆ vs. Attenuation
80
25C / 15MHz
60
25C / 60MHz
25C / 200MHz
50
25C / 600MHz
25C / 1200MHz
40
20
24
28
32
36
28
32
36
60
Insertion Phase ∆ (deg)
70
16
Insertion Phase ∆ vs. Attenuation
(positive phase = electrically shorter)
25C / 4MHz
12
Attenuation (dB)
Attenuation (dB)
Insertion Phase ∆ (deg)
24
0
25C / 15MHz
25C / 200MHz
25C / 1200MHz
RF2 Return Loss (dB)
RF2 Return Loss (dB)
-5
20
RF2 Return Loss vs. Attenuation
0
4MHz
60MHz
600MHz
2100MHz
16
Attenuation (dB)
Attenuation (dB)
25C /
25C /
25C /
25C /
12
25C / 2100MHz
30
20
10
-40C / 15MHz
-40C / 500MHz
-40C / 1200MHz
25C / 15MHz
25C / 500MHz
25C / 1200MHz
105C / 15MHz
105C / 500MHz
105C / 1200MHz
50
40
30
20
10
0
0
0
4
8
12
16
20
24
28
32
0
36
Voltage Variable RF Attenuator
4
8
12
16
20
24
Attenuation (dB)
Attenuation (dB)
9
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS [S2P VS. FREQUENCY] (-5-)
Min. & Max. Attenuation vs. Frequency
Min. & Max. Attenuation Slope vs. Frequency
-8
-2
-16
-40C / 0.0V
25C / 0.0V
105C / 0.0V
-40C / 2.8V
25C / 2.8V
105C / 2.8V
-4
40
Min/Max ATTN slope (dB/V)
Attenuation (dB)
0
-24
-6
-32
-8
0
500
1000
1500
2000
30
25
20
15
max slope
10
min slope
5
0
-40
3000
2500
VCTRL varied from 0.8V to 1.7V
35
0
500
1000
-5
-10
-15
-20
-40C
25C
105C
-35
3000
0
-5
-10
-15
-20
-40C
-25
25C
-30
105C
-35
-40
-40
0
500
1000
1500
2000
2500
0
3000
500
1000
1500
2000
2500
3000
Frequency (MHz)
Frequency (MHz)
Gain Compression vs. Frequency
Max. Insertion Phase ∆ vs. Frequency
1
70
(positive phase = electrically shorter)
Gain Compression (dB)
Max Insertion Phase ∆ (deg)
2500
Worst-Case RF2 Return Loss vs. Frequency
0
RF2 Worstcase Return Loss (dB)
RF1 WorstCase Return Loss (dB)
Worst-Case RF1 Return Loss vs. Frequency
-30
2000
Frequency (MHz)
Frequency (MHz)
-25
1500
60
50
40
30
-40C
25C
20
105C
10
0
0.5
1MHz
125MHz
250MHz
500MHz
1000MHz
2700MHz
0
-0.5
-1
-1.5
-2
0
500
1000
1500
2000
2500
3000
10
Voltage Variable RF Attenuator
14
18
22
26
30
34
RF Input Power (dBm)
Frequency (MHz)
10
REV O, July 2015
38
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS [S2P @ LOW FREQUENCY, GROUP DELAY] (-6-)
Low-Frequency Attenuation vs. VCTRL
0
0
-5
-5
-10
-10
Attenuation (dB)
Attenuation (dB)
Min. & Max. Attenuation vs. Low Frequency
0.0V
-15
-20
2.8V
-25
-30
1.0MHz
3.0MHz
7.0MHz
-15
10.0MHz
50.0MHz
-20
100.0MHz
-25
-30
-35
-35
-40
-40
-45
-45
0
10
20
30
40
50
60
70
80
90
100
0.0
0.4
0.8
Frequency (MHz)
0
0
-15
2.0
2.4
-20
-25
-30
-35
-10
-15
-20
-25
-30
-35
-40
-40
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
0.0
VCTRL (V)
0.4
0.8
1.2
1.6
2.0
2.4
VCTRL (V)
Group Delay vs. Frequency
200
Group Delay (picosec)
2.8
0.5MHz
1.0MHz
3.0MHz
7.0MHz
10.0MHz
50.0MHz
100.0MHz
-5
RF2 Return Loss (dB)
-10
1.6
Low-Frequency RF2 Return Loss vs. VCTRL
0.5MHz
1.0MHz
3.0MHz
7.0MHz
10.0MHz
50.0MHz
100.0MHz
-5
1.2
VCTRL (V)
Low-Frequency RF1 Return Loss vs. VCTRL
RF1 Return Loss (dB)
0.5MHz
25C
-40C / 0.8V
-40C / 1.8V
150
25C / 0.8V
25C / 1.8V
100
105C / 0.8V
105C / 1.8V
50
0
-50
-100
0
500
1000
1500
2000
2500
3000
Frequency (MHz)
Voltage Variable RF Attenuator
11
REV O, July 2015
2.8
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS 500MHZ, VDD=3.3V [IP3, IP2, IH2, IH3 VS. VCTRL, VMODE] (-7-)
Output IP3 vs. VCTRL
Input IP3 vs. VCTRL
80
80
70
Output IP3 (dBm)
Input IP3 (dBm)
70
60
50
-40C / Vmode = 0V
25C / Vmode = 0V
105C / Vmode = 0V
-40C / Vmode = 3V
25C / Vmode = 3V
105C / Vmode = 3V
40
30
60
50
40
30
-40C / Vmode = 0V
25C / Vmode = 0V
105C / Vmode = 0V
-40C / Vmode = 3V
25C / Vmode = 3V
105C / Vmode = 3V
20
10
0
20
0
0.4
0.8
1.2
1.6
2
2.4
0
2.8
0.4
0.8
120
110
110
Output IP2 (dBm)
Input IP2 (dBm)
120
100
90
80
-40C / Vmode = 3V
25C / Vmode = 3V
105C / Vmode = 3V
-40C / Vmode = 0V
25C / Vmode = 0V
105C / Vmode = 0V
70
60
50
0.8
1.2
1.6
2
2.4
70
60
-40C / Vmode = 0V
25C / Vmode = 0V
105C / Vmode = 0V
-40C / Vmode = 3V
25C / Vmode = 3V
105C / Vmode = 3V
50
30
0
0.4
0.8
80
120
70
IH3 (dBm)
IH2 (dBm)
130
110
100
90
-40C / Vmode = 0V
25C / Vmode = 0V
105C / Vmode = 0V
-40C / Vmode = 3V
25C / Vmode = 3V
105C / Vmode = 3V
70
60
50
1.2
1.6
2
2.4
2.8
2
2.4
60
50
-40C / Vmode = 0V
25C / Vmode = 0V
105C / Vmode = 0V
-40C / Vmode = 3V
25C / Vmode = 3V
105C / Vmode = 3V
40
30
20
10
0
2.8
0.4
0.8
1.2
1.6
2
2.4
2.8
VCTRL (V)
VCTRL (V)
Voltage Variable RF Attenuator
1.6
3rd Harm Input Intercept Point vs. VCTRL
90
80
1.2
VCTRL (V)
140
0.8
2.8
80
2.8
2nd Harm Input Intercept Point vs. VCTRL
0.4
2.4
90
VCTRL (V)
0
2
100
40
40
0.4
1.6
Output IP2 vs. VCTRL
Input IP2 vs. VCTRL
0
1.2
VCTRL (V)
VCTRL (V)
12
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS 500MHZ, VDD=3.3V [IP3, IP2, IH2, IH3 VS. VCTRL, RF1/RF2 DRIVEN] (-8-)
Output IP3 vs. VCTRL
80
70
70
60
Output IP3 (dBm)
Input IP3 (dBm)
Input IP3 vs. VCTRL
60
50
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
40
30
20
0
0.4
0.8
1.2
1.6
2
2.4
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
50
40
30
20
10
0
2.8
0.4
0.8
VCTRL (V)
120
110
110
Output IP2 (dBm)
Input IP2 (dBm)
120
100
90
80
70
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
60
50
40
0.4
0.8
1.2
1.6
2
2.4
100
90
70
60
50
30
0
2.8
0.4
0.8
120
80
110
70
100
90
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
70
60
50
1.2
1.6
2
2.4
2.8
2
2.4
60
50
40
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
30
20
10
0
2.8
0.4
0.8
1.2
1.6
2
2.4
2.8
VCTRL (V)
VCTRL (V)
Voltage Variable RF Attenuator
1.6
3rd Harm Input Intercept Point vs. VCTRL
90
80
1.2
VCTRL (V)
IH3 (dBm)
IH2 (dBm)
2.8
80
130
0.8
2.4
40
2nd Harm Input Intercept Point vs. VCTRL
0.4
2
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
VCTRL (V)
0
1.6
Output IP2 vs. VCTRL
Input IP2 vs. VCTRL
0
1.2
VCTRL (V)
13
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS 500MHZ, VDD=3.3V [IP3, IP2, IH2, IH3 VS. ATTENUATION] (-9-)
Input IP3 vs. Attenuation
Output IP3 vs. Attenuation
80
80
70
70
Output IP3 (dBm)
Input IP3 (dBm)
-40C
60
50
40
-40C
25C
30
25C
105C
60
50
40
30
20
105C
20
10
0
4
8
12
16
20
24
28
32
36
0
4
8
Attenuation (dB)
Input IP2 vs. Attenuation
16
20
24
28
32
36
Output IP2 vs. Attenuation
120
120
110
110
25C
100
100
105C
Output IP2 (dBm)
Input IP2 (dBm)
12
Attenuation (dB)
90
80
70
60
-40C
50
25C
-40C
90
80
70
60
50
40
105C
30
40
0
4
8
12
16
20
24
28
32
0
36
4
8
2nd Harm Input Intercept Point vs. Attenuation
16
20
24
28
32
36
3rd Harm Input Intercept Point vs. Attenuation
140
90
130
80
120
70
IH3 (dBm)
IH2 (dBm)
12
Attenuation (dB)
Attenuation (dB)
110
100
90
60
50
40
80
-40C
30
70
25C
20
-40C
25C
105C
105C
60
10
0
4
8
12
16
20
24
28
32
36
0
Voltage Variable RF Attenuator
4
8
12
16
20
24
28
32
36
Attenuation (dB)
Attenuation (dB)
14
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
TYPICAL OPERATING CONDITIONS 500MHZ, VDD=3.3V [IP3, IP2, IH2, IH3 VS. VCTRL, RF1/RF2 DRIVEN] (-10-)
Output IP3 vs. Attenuation
80
70
70
60
Output IP3 (dBm)
Input IP3 (dBm)
Input IP3 vs. Attenuation
60
50
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
40
30
20
0
4
8
12
16
20
24
28
32
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
50
40
30
20
10
0
36
4
8
Attenuation (dB)
120
110
110
100
90
80
70
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
60
50
40
4
8
12
16
20
24
28
32
100
90
50
30
0
36
4
8
IH3 (dBm)
IH2 (dBm)
70
100
90
80
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
60
50
20
24
16
20
24
28
32
36
3rd Harm Input Intercept Point vs. Attenuation
110
70
12
Attenuation (dB)
80
28
32
60
50
40
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
30
20
10
0
36
4
8
12
16
20
24
28
32
Attenuation (dB)
Attenuation(dB)
Voltage Variable RF Attenuator
36
60
120
16
32
70
90
12
28
80
130
8
24
40
2nd Harm Input Intercept Point vs. Attenuation
4
20
-40C / RF1 Driven
25C / RF1 Driven
105C / RF1 Driven
-40C / RF2 Driven
25C / RF2 Driven
105C / RF2 Driven
Attenuation (dB)
0
16
Output IP2 vs. Attenuation
120
Output IP2 (dBm)
Input IP2 (dBm)
Input IP2 vs. Attenuation
0
12
Attenuation (dB)
15
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36
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
PACKAGE DRAWING (3X3 16 PIN)
Voltage Variable RF Attenuator
16
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
GND
15
14
NC
VDD
16
VCTRL
VMODE
PINOUT & BLOCK DIAGRAM
13
1
12
GND
Control
NC
2
11
NC
RF1
3
10
RF2
NC
4
9
NC
Voltage Variable RF Attenuator
17
RTN
7
8
RTN
6
GND
5
RTN
E.P.
REV O, July 2015
IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
PIN DESCRIPTION
Pin
Name
Function
1, 7, 12
GND
2, 4, 9, 11, 13
NC
3
RF1
5, 6, 8
RTN
10
RF2
14
VCTRL
15
VDD
16
VMODE
Ground these pins as close to the device as possible.
No internal connection. IDT recommends connecting these pins
to GND.
RF Port 1. Matched to 50 ohms. Must use an external AC
coupling capacitor as close to the device as possible. For low
frequency operation increase the capacitor value to result in a
low reactance at the frequency of interest.
Attenuator Ground Return. Each of these pins require a capacitor
to GND to provide an RF return path. Placed as close to the
device as possible.
RF Port 2. Matched to 50 ohms. Must use an external AC
coupling capacitor as close to the device as possible. For low
frequency operation increase the capacitor value to result in a
low reactance at the frequency of interest.
Attenuator control voltage. Apply a voltage in the range as
specified in the Operating Conditions Table. See application
section for details about VCTRL.
Power supply input. Bypass to GND with capacitors close as
possible to pin.
Attenuator slope control. Set to logic LOW to enable negative
attenuation slope. Set to logic HIGH to enable positive
attenuation slope.
Exposed Pad. Internally connected to GND. Solder this exposed
pad to a PCB pad that uses multiple ground vias to achieve the
specified RF performance.
— EP
Voltage Variable RF Attenuator
18
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
APPLICATIONS INFORMATION
Default Start-up
VMODE must be tied to either GND or Logic High. If the VCTRL pin is left floating, the part will power up in the
minimum attenuation state when VMODE = GND, or the maximum attenuation state when VMODE = High.
VCTRL
The VCTRl pin is used to control the attenuation of the F2255. With VMODE set to a logic low (high), this places
the device in a negative (positive) slope mode where increasing (decreasing) the VCTRL voltage produces an
increasing (a decreasing) attenuation from min attenuation (max attenuation) to max attenuation (min
attenuation) respectively. See the Operating Conditions Table for the allowed control voltage range and its
dependence on VDD. The VCTRl pin has an on-chip pullup ESD diode so VDD should be applied before VCTRl is
applied. If this sequencing is not possible, then resistor R2 should be set for 1kΩ to limit the current into the
VCTRl pin.
VMODE
The VMODE pin is used to set the attenuation vs. VCTRl slope. With VMODE set to logic low (high) this will set the
attenuation slope to be negative (positive). A negative (positive) slope is defined as increasing (decreasing)
attenuation with increasing (decreasing) VCTRl voltage. The EVKIT provides an on-board jumper to manually
set the VMODE. Install a jumper on header J2 from VMODE (pin2) to GND (pin3) to set the device for a negative
slope. For a positive slope install the J2 jumper from VMODE (pin2) to VHI (pin1). For proper operation one of
the above noted jumper positions must be selected.
RF1 and RF2 Ports
The F2255 is a bi-directional device thus allowing RF1 or RF2 to be used as the RF input. As displayed in the
Typical Operating Conditions curves, RF1 shows enhanced linearity when used as the RF input. VDD must be
applied prior to the application of RF power to ensure reliability. DC blocking capacitors are required on the
RF pins and should be set to a value that results in a low reactance over the frequency range of interest.
Power Supplies
The supply pin should be bypassed with external capacitors to minimize noise and fast transients. Supply noise
can degrade noise figure and fast transients can trigger ESD clamps and cause them to fail. Supply voltage
change or transients should have a slew rate smaller than 1V/20uS. In addition, all control pins should remain
at 0V (+/-0.3V) while the supply voltage ramps or while it returns to zero.
Voltage Variable RF Attenuator
19
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
Control Pin Interface
If control signal integrity is a concern and clean signals cannot be guaranteed due to overshoot, undershoot,
ringing, etc., the following circuit at the input of control pins 14 and 16 is recommended as shown below.
Voltage Variable RF Attenuator
20
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
EVKIT / APPLICATIONS CIRCUIT
Voltage Variable RF Attenuator
21
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
EVKIT PICTURE / LAYOUT (TOP VIEW)
Voltage Variable RF Attenuator
22
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
EVKIT PICTURE / LAYOUT (BOTTOM VIEW)
Voltage Variable RF Attenuator
23
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IDTF2255NLGK
Datasheet
Voltage Variable RF Attenuator
1MHz to 3000MHz
EVKIT BOM
TOP MARKINGS
Voltage Variable RF Attenuator
24
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