TOC Control Devices LIMITER DIODES DESCRIPTION APPLICATIONS The GC4700 series diodes are specially processed PIN diodes designed for use in passive or active limiters at frequencies through Ku band. A diode limiter is a power-sensitive variable attenuator that uses the non-linear properties of the diode to provide an impedance mismatch when sufficient amounts of RF power are incident on the device. The output power is reduced to a level that will not overdrive a receiver, burn out a mixer, etc. For varying input power levels in excess of the diode’s threshold level, the limiter’s output power tends to remain constant. Twelve categories of devices are offered for flexibility in design of low (lower Vb, fastest turn-on time), medium and high (highest Vb, slowest turn-on time) power limiters. λ 4 DC BLOCK INPUT DC BLOCK COARSE (HIGH POWER) LIMITER DIODE DC RETURN A passive limiter is one in which the limiter diodes are “turned on” by the RF signal itself. An active limiter is one in which the limiter diodes are “turned on” primarily by an external bias current typically supplied by a Schottky detector diode which senses the incident signal. CLEAN UP OUTPUT (FAST) LIMITER DIODE Since limiter diodes are not designed to dissipate large amounts of power, the limiter must reflect or divert the excess incident power back to the source or to another load (i.e. via a circulator, hybrid coupler, etc.). Limiter diodes may be used in wave guides, coax, microstrip, stripline or other media. Single or cascaded devices may be used, depending on power levels. BASIC TWO-DIODE LIMITER CHIP ELECTRICAL PARAMETERS: TA = 25°C MODEL NUMBER GC4701 GC4702 GC4711 GC4712 GC4713 GC4721 GC4722 GC4723 GC4731 GC4732 GC4741 GC4742 TYPICAL VB CJO CJ6 MIN (VOLTS) TYP MAX IR = 10µA (pF) (pF) 20 20 45 45 45 120 120 120 15 15 30 30 0.20 0.50 0.20 0.50 0.70 0.20 0.60 0.80 0.12 0.20 0.12 0.20 0.15 0.30 0.15 0.30 0.50 0.15 0.30 0.50 0.10 0.15 0.10 0.15 RS @10 mA (Ohms) 1.5 1.2 1.5 1.2 1.0 1.5 1.0 0.5 2.0 1.5 2.0 1.5 TYPICAL TYPICAL TL θP 1 (nS) (°C/W) 5 10 10 15 20 50 50 100 5 5 7 7 20 12 15 10 6 1.2 0.5 0.3 30 20 20 15 MAXIMUM THERMAL 2 RESISTANCE (°C/W) 100 80 80 60 40 40 20 15 120 80 100 70 1) Pulse length 1 microsecond. 2) As measure in style 30 package. SEMICONDUCTOR OPERATION 75 Technology Drive Lowell, MA 01851 Tel: 978-442-5600 Fax: 978-937-3748 83 TOC Control Devices LIMITER DIODES TYPICAL LIMITER PERFORMANCE RATINGS: TA = 25°C MAXIMUM TYPICAL MODEL PEAK LEAKAGE NUMBER PIN Pout @1.µS (dBm) GC4701 GC4702 GC4711 GC4712 GC4713 GC4721 GC4722 GC4723 GC4731 GC4732 GC4741 GC4742 TYPICAL INSERTION LOSS (dBm) (dB) +10 +10 +15 +15 +15 +20 +20 +20 +7 +7 +12 +12 0.1 0.2 0.1 0.2 0.2 0.1 0.2 0.2 0.1 0.1 0.1 0.1 (dBm) +50 +53 +53 +56 +59 +60 +63 +66 +47 +50 +47 +50 MAXIMUM TYPICAL THRESHOLD +22 +24 +27 +29 +31 +39 +41 +44 +19 +22 +24 +27 CW POWER (Watts) 2 3 3 4 5 5 10 15 2 3 3 4 Notes: 1. Available in standard case styles 30, 35, 42 AND 45. When ordering specify the desired case style by adding its number as a suffix to the basic part number. Some other case styles are available on request. TYPICAL PERFORMANCE +9 LEAKAGE POWER ABOVE 1.0GHz (dB) POWER OUT (mw) 10,000 1 72 C4 G +1000 0dB 10dB 20dB 30dB 41 +100 47 01, 47 THRESHOLD GC +8 +7 +6 GC4721 +5 +4 +3 +2 +1 GC4701, 4741 0 +10 2 4 6 8 10 12 FREQUENCY (GHz) +1.0 +10 +20 +30 +40 +50 +60 PEAK POWER INPUT (dBm) RATINGS Maximum Leakage Current: 0.5µA at 80% of minimum rated breakdown Operating Temperature: 55°C to +150°C SEMICONDUCTOR OPERATION 75 Technology Drive Lowell, MA 01851 Tel: 978-442-5600 Fax: 978-937-3748 84 14 16 18