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

 

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)	60	60	60	60
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	1.8	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	± 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.

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 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 2 Complementary programming (logic "0" is bit on) 7 Two SMA male RF connectors 10 One SMA male (J1) and one SMA female (J2) RF connector  62 ±15V Operation C38 30 dB attenuation range. Consult factory for impact on specifications. G09 Guaranteed to meet Environmental Ratings.  G12 RoHS 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.

The information contained in this data sheet is basic marketing information and does not contain any export controlled information.