Application Notes for Microwave Attenuators
The Digitally Controlled Model 3499 Millimeter Wave Attenuator provides greater than octave-band performance and wide programming flexibility in a compact rugged package.
The Model 3499 is an integrated assembly of a balanced PIN diode attenuator and a driver circuit consisting of a PROM, a D/A converter and a current-to-voltage converter, as shown in Figure 1. This arrangement provides a high degree of accuracy and repeatability and also preserves the inherent monotonicity of the attenuator.
The Model 3499 offers attenuation range of 50dB and 60 dB repectively, 0.03 dB resolution and switching speed of no more than 500 nanoseconds. It is available with either a strobe/latch or a non-linear current or voltage controlled attenuation capability.

- Frequency range: 18-40 GHz
- 60 dB attenuation range
- 500 nanosecond switching speed
- 11 Bit binary programming
- Guaranteed monotonicity
- Absorptive
PERFORMANCE CHARACTERISTICS
| MODEL | FREQUENCY RANGE (GHz) | MAX INSERTION LOSS (dB) | MAX VSWR | FLATNESS (± dB) AT MEAN ATTENUATION LEVELS UP TO | ||||
| 10dB | 20dB | 40dB | 50dB | 60dB | ||||
| 3499 | 18 – 26.5 | 4.1 | 2.2 | 1.3 | 2.2 | 3.4 | 4.0 | N/A |
| >26.5 – 36 | 4.6 | |||||||
| >36 – 40 | 5.2 | |||||||
| 3499-60 | 18 – 26.5 | 4.3 | 2.2 | 1.3 | 2.2 | 3.4 | 4.0 | 5.0 |
| >26.5 – 36 | 4.9 | |||||||
| >36 – 40 | 5.8 | |||||||
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DIMENSIONS AND WEIGHT
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| Weight: 5 oz. (142 gr) approx.
Dimensions are stated in inches (mm). Tolerances, |
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NOTES (1) The Model 3499 attenuator is an 11-bit digital attenuator. 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, when operated as an 8-bit unit, the Model 3499 would have Pin 15, Pin 1 and Pin 2 connected to ground. All other parameters remain unchanged. |
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