Multi-Octave Attenuators

Application Notes for Microwave Attenuators

The 346C Series is a family of Non-reflective PIN diode attenuators, each programmable to 60 dB in attenuation steps as low as 0.06 dB, and covering the frequency range from 0.5 GHz to 18 GHz in four overlapping multi-octave bands.

Each model in the Series comprises of an integrated assembly of a dual (current-controlled) PIN diode attenuator, and a driver circuit consisting of a D/A converter and a voltage-to-current converter. (See Figure 1 below)

The RF circuit consists of two wide-band, T-pad attenuator sections in tandem. The levels of series and shunt currents required to maintain a bilateral match at all attenuation levels are provided by the driver.

This arrangement assures monotonicity over the operating band at all levels of attenuation and for any programmed attenuation step.

Frequency range: 0.5 GHz-18GHz in four overlapping ranges
Attenuation range: 60 dB
Programming: 10-Bit binary
LSB: 0.06 dB
Monotonicity: guaranteed

346C series multi-octave 10 bit digital PIN diode attenuator

PERFORMANCE CHARACTERISTICS

CHARACTERISTIC

MODEL
3460C*

MODEL
3461C

MODEL
3462C*

MODEL
3468C

Frequency Range (GHz)

0.5-4

0.5-8

2-8

2-18

Mean Attenuation Range (dB)

Insertion Loss (dB) (max)

2.5

2.5 (0.5-4 GHz)
3.2 (4-8 GHz)

3.2

4.5

VSWR (max)

1.8

2.0

Flatness up to          20 dB
40 dB
60 dB

± 0.5 dB
± 0.75 dB
± 1.0 dB

± 0.75 dB
± 1.0 dB
± 1.5 dB

± 1.0 dB
± 1.25 dB
± 3.0 dB

*Special-order product. Consult factory before ordering.

Accuracy of Attenuation
0 to 20 dB………………………………………..	± 1.0 dB
20 to 40 dB………………………………………	± 1.5 dB
40 to 60 dB………………………………………	± 2.0 dB
Monotonicity……………………………………..	Guaranteed
Phase Shift………………………………………..	See Application Notes
Temperature Coefficient………………………	± 0.02 dB/ °C
Power Handling Capability
Without Performance
Degradation…………………………………….	Up to 50 mW cw or peak (see figure 3)
Survival Power ………………………………..	2 W average or peak, from -65°C to +25°C (see figure 4 for higher temperatures).
Switching Time
ON Time…………………………………………	1.0 µsec. max.
OFF Time……………………………………….	0.5 µsec. max.
Programming……………………………………	Positive true binary. For complementary code, specify Option 2. To interface with other logic families, please contact factory.

Minimum Attenuation Step

0.06 dB⁽¹⁾

Logic Input

Logic “0” (Bit OFF) …………..

-0.3 to +0.8V

Logic”1″ (Bit ON) ……………..

+2.0 to +5.0V

Input Current …………………..

10 µA max.

Nominal Control Voltage Characteristics

Range……………………………

0 to 3 mA

Transfer Function……………..

20 dB / mA

Input Impedance………………

3 kohm

Power Supply Requirements…

+12V ±5%, 90 mA
-12V ±5%, 60 mA

Power Supply Rejection……..

Less than 0.1 dB / volt change in either supply

NOTE 1

The Series 346C attenuators are 10-bit digital attenuators. In order to use this device with a lesser number of bits (lower resolution), the user may simply ground the logic pins for the lowest order unused bits. For example, a Series 346C unit operated as an 8-bit unit would have Pin 15 and Pin 3 connected to ground. All other parameters remain unchanged.

series 346C maximum peak and average operating power without performance degradation model 346C attenuator survival power derating factor

OPTION (G09) ENVIRONMENTAL RATINGS

ENVIRONMENTAL CONDITIONS for SWITCHED BIT ATTENUATORS – WITH OPTION G09
Operating Temperature	-54ºC to +110ºC
Storage Temperature	-65ºC to +125ºC
Humidity	Per MIL-STD 202F, Method 103B, Cond. B (96 Hours at 95% R.H)
Shock	Per MIL-STD 202F, Method 213B, Cond. B (75g/6mSec)
Altitude	Per MIL-STD 202F, Method 105C, Cond. B (50,000 ft.)
Vibration	Per MIL-STD 202F, Method 204D, Cond. B (0.06′ double amplitude or 15G – which ever is less)
Thermal Shock	Per MIL-STD 202F, Method 107D, Cond. A (5 Cycles)

DIMENSIONS AND WEIGHT

Series 346C attenuator dimensions and weight diagram
SERIES 346C
Wt: 3 oz. (85 gm) approx.

Dimensions are stated in inches (mm).

Tolerances,
unless otherwise indicated: .XX ±.02; .XXX ±.008

AVAILABLE OPTIONS

Option No.

Description

Complementary programming
(logic “0” is bit on)

Two SMA male RF connectors

One SMA male (J1) and one SMA female (J2) RF connector

±15V Operation

C38

30 dB attenuation range. Consult factory for impact on specifications.

G09

Guaranteed to meet Environmental Ratings.

G12

RoHS & REACH Compliant

G18

REACH Compliant

Z06

1 to 18 GHz operation. I.L 4.8dB max. (Model 3468C)

ACCESSORY FURNISHED

Mating power/logic connector

PIN NO.

J3 PIN FUNCTIONS⁽¹⁾⁽⁴⁾

     1
     2
     3
     4
     5
     6
     7
     8
     9
     10
     11
     12
     13
     14
     15

     GND⁽²⁾
     Analog INPUT⁽³⁾
     0.13 dB
     GND
     0.25 dB
     0.5 dB
     1dB
     2dB
     4dB
     8dB
     16dB
     32 dB(MSB)
     +V
     -V
     0.06 dB(LSB)

NOTES

(1) All unused logic inputs must be grounded.
(2) For normal programming control Pin 1 must be grounded or at logic “0” . Application of logic “1” to Pin 1 overrides the digital input and sets the unit to Insertion loss. For units with complementary programming (Option 2), the application of a logic “1” to Pin 1 sets the unit to high isolation (60 dB or greater).
(3) Pin 2 is available to (a) monitor the D/A converter output, (b) apply a modulation signal from a current source, or (c) apply an independent analog signal for turn-on, turn-off or vernier attenuation levels. If not used as described in (a), (b) or (c). Pin 2 must be open.
(4) The Series 346C attenuators are 10-bit digital attenuators. In order to use this device with a lesser number of bits (lower resolution), the user may simply ground the logic pins for the lowest order unused bits. For example, a Series 346C unit operated as an 8-bit unit would have Pin 15 and Pin 3 connected to ground. All other parameters remain unchanged.

346C Series Multi-Octave 10 Bit Digital PIN Diode Attenuators

PERFORMANCE CHARACTERISTICS

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