the rf mosfet line
nchannel enhancementmode designed for power amplifier applications in industrial, commercial and amateur radio equipment to 175 mhz. ? superior high order imd ? specified 50 volts, 30 mhz characteristics output power = 30 watts power gain = 18 db (typ) efficiency = 40% (typ) ? imd (d3) (30 w pep) e 35 db (typ) ? imd (d11) (30 w pep) e 60 db (typ) ? 100% tested for load mismatch at all phase angles with 30:1 vswr ? lower reverse transfer capacitance (3.0 pf typical) maximum ratings rating symbol value unit drainsource voltage v dss 120 vdc draingate voltage v dgo 120 vdc gatesource voltage v gs 40 vdc drain current e continuous i d 6.0 adc total device dissipation @ t c = 25 c derate above 25 c p d 115 0.66 watts w/ c storage temperature range t stg 65 to +150 c operating junction temperature t j 200 c thermal characteristics characteristic symbol max unit thermal resistance, junction to case r q jc 1.52 c/w note caution mos devices are susceptible to damage from electrostatic charge. reasonable precautions in handling and packaging mos devices should be observed.
30 w, to 175 mhz nchannel mos linear rf power fet case 21107, style 2 d g s order this document by mrf 14 8 / d semiconductor technica l d a t a 1 replaces mrf148/d
electrical characteristics (t c = 25 c unless otherwise noted.) characteristic symbol min typ max unit off characteristics drainsource breakdown voltage (v gs = 0, i d = 10 ma) v (br)dss 125 e e vdc zero gate voltage drain current (v ds = 50 v, v gs = 0) i dss e e 1.0 madc gatebody leakage current (v gs = 20 v, v ds = 0) i gss e e 100 nadc on characteristics gate threshold voltage (v ds = 10 v, i d = 10 ma) v gs(th) 1.0 2.5 5.0 vdc drainsource onvoltage (v gs = 10 v, i d = 2.5 a) v ds(on) 1.0 3.0 5.0 vdc forward transconductance (v ds = 10 v, i d = 2.5 a) g fs 0.8 1.2 e mhos dynamic characteristics input capacitance (v ds = 50 v, v gs = 0, f = 1.0 mhz) c iss e 62 e pf output capacitance (v ds = 50 v, v gs = 0, f = 1.0 mhz) c oss e 35 e pf reverse transfer capacitance (v ds = 50 v, v gs = 0, f = 1.0 mhz) c rss e 3.0 e pf functional tests (ssb) common source amplifier power gain (30 mhz) (v dd = 50 v, p out = 30 w (pep), i dq = 100 ma) (175 mhz) g ps e e 18 15 e e db drain efficiency (30 w pep) (v dd = 50 v, f = 30 mhz, i dq = 100 ma) (30 w cw) h e e 40 50 e e % intermodulation distortion (v dd = 50 v, p out = 30 w (pep), f = 30; 30.001 mhz, i dq = 100 ma) imd (d3) imd (d11) e e 35 60 e e db load mismatch (v dd = 50 v, p out = 30 w (pep), f = 30; 30.001 mhz, i dq = 100 ma, vswr 30:1 at all phase angles) y no degradation in output power class a performance intermodulation distortion (1) and power gain (v dd = 50 v, p out = 10 w (pep), f1 = 30 mhz, f2 = 30.001 mhz, i dq = 1.0 a) g ps imd (d3) imd (d9 13) e e e 20 50 70 e e e db note: 1. to milstd1311 version a, test method 2204b, two tone, reference each tone. figure 1. 2.0 to 50 mhz broadband test circuit c1, c2, c3, c4, c5, c6 e 0.1 m f ceramic chip or equivalent c7 e 10 m f, 100 v electrolytic c8 e 100 pf dipped mica l1 e vk200 20/4b ferrite choke or equivalent (3.0 m h) l2 e ferrite bead(s), 2.0 m h r1, r2 e 200 w , 1/2 w carbon r3 e 4.7 w , 1/2 w carbon r4 e 470 w , 1.0 w carbon t1 e 4:1 impedance transformer t2 e 1:2 impedance transformer rf output rf input bias 010 v 50 v + c1 + c4 c5 c6 c7 c2 c3 r1 r3 t1 t2 dut l1 l2 r4 c8 r2 + 2 replaces mrf148/d
figure 2. power gain versus frequency figure 3. output power versus input power figure 4. imd versus p out figure 5. common source unity gain frequency versus drain current figure 6. 150 mhz test circuit c1 e 91 pf unelco type mcm 01/010 c2, c4 e 0.1 m f erie red cap c3 e allen bradley 680 pf feed thru c5 e 1.0 m f, 50 vdc electrolytic c6 e 15 pf unelco type j101 c7 e 24 pf unelco type mcm 01/010 l1 e 2 turns #18 awg, 5/16 id l2 e 4 turns #18 awg, 5/16 id r1 e 1.0 ohm, 1/4 w carbon r2 e 2000 ohm, 1/4 w carbon rfc1 e vk200 21/4b t1 e 4:1 transformer, 1.75 subminiature t1 e coaxial cable t1 e 4:1 impedance ratio t1 e transformer, line t1 e impedance = 25 w + bias + 50 vdc rf output rf input c3 c2 r2 r1 c1 t1 dut l2 c4 rfc1 l1 c6 c7 50 w 12.5 w c5 power gain (db) f, frequency (mhz) 25 20 15 10 5 0 2 5 10 20 20050 100 v dd = 50 v i dq = 100 ma p out = 30 w (pep) p out , output power (watts) p in , input power (watts) 60 40 0 0 0 0.5 1 1.5 2 2.5 20 60 40 20 150 mhz 30 mhz v dd = 50 v 40 v v dd = 50 v 40 v i dq = 100 ma i dq = 100 ma imd, intermodulation distortion (db) p out , output power (watts pep) 30 40 50 30 40 50 010203040 d 5 d 3 d 3 d 5 v dd = 50 v, i dq = 100 ma, tone separation 1 khz 150 mhz 30 mhz 2000 1000 0 01234 i d , drain current (amps) v ds = 15 v f t , unity gain frequency (mhz) v ds = 30 v 06 v + 3 replaces mrf148/d
figure 7. gate voltage versus drain current figure 8. dc safe operating area (soa) figure 9. impedance coordinates e 50 ohm characteristic impedance 2 1 0 0246810 v gs , gatesource voltage (volts) 135 79 v ds = 10 v g fs = 1.2 mho i ds , drain current (amps) 10 7 3 2 5 1 0.7 0.5 0.3 0.2 0.1 0.2 0.4 v ds , drainsource voltage (volts) t c = 25 c i d , drain current (amps) 0.7 1 2 4 7 10 20 40 70 100 200 150 50 30 7.0 4.0 f = 2.0 mhz 175 f = 2.0 mhz z ol * z in v dd = 50 v i dq = 100 ma p out = 30 w pep gate shunted by 100 w 15 175 z ol * = conjugate of the optimum load impedance z ol * = into which the device output operates at a z ol * = given output power, voltage and frequency. 4 replaces mrf148/d
rf power mosfet considerations mosfet capacitances the physical structure of a mosfet results in capacitors between the terminals. the metal oxide gate structure determines the capacitors from gatetodrain (c gd ), and gatetosource (c gs ). the pn junction formed during the fabrication of the rf mosfet results in a junction capaci- tance from draintosource (c ds ). these capacitances are characterized as input (c iss ), output (c oss ) and reverse transfer (c rss ) capacitances on data sheets. the relationships between the interterminal capaci- tances and those given on data sheets are shown below. the c iss can be specified in two ways: 1. drain shorted to source and positive voltage at the gate. 2. positive voltage of the drain in respect to source and zero volts at the gate. in the latter case the numbers are lower. however, neither method represents the actual operat- ing conditions in rf applications. c gd gate source c gs drain c ds c iss = c gd + c gs c oss = c gd + c ds c rss = c gd linearity and gain characteristics in addition to the typical imd and power gain data presented, figure 5 may give the designer additional informa- tion on the capabilities of this device. the graph represents the small signal unity current gain frequency at a given drain current level. this is equivalent to f t for bipolar transistors. since this test is performed at a fast sweep speed, heating of the device does not occur. thus, in normal use, the higher temperatures may degrade these characteristics to some extent. drain characteristics one figure of merit for a fet is its static resistance in the fullon condition. this onresistance, v ds(on) , occurs in the linear region of the output characteristic and is specified under specific test conditions for gatesource voltage and drain current. for mosfets, v ds(on) has a positive temperature coefficient and constitutes an important design consideration at high temperatures, because it contributes to the power dissipation within the device. gate characteristics the gate of the rf mosfet is a polysilicon material, and is electrically isolated from the source by a layer of oxide. the input resistance is very high e on the order of 10 9 ohms e resulting in a leakage current of a few nanoamperes. gate control is achieved by applying a positive voltage slightly in excess of the gatetosource threshold voltage, v gs(th) . gate voltage rating e never exceed the gate voltage rating. exceeding the rated v gs can result in permanent damage to the oxide layer in the gate region. gate termination e the gates of these devices are essentially capacitors. circuits that leave the gate opencir- cuited or floating should be avoided. these conditions can result in turnon of the devices due to voltage buildup on the input capacitor due to leakage currents or pickup. gate protection e these devices do not have an internal monolithic zener diode from gatetosource. if gate protection is required, an external zener diode is recommended. equivalent transistor parameter terminology collector drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . emitter source. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . base gate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v (br)ces v (br)dss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v cbo v dgo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i c i d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i ces i dss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i ebo i gss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v be(on) v gs(th) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v ce(sat) v ds(on) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c ib c iss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c ob c oss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . h fe g fs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . r ce(sat) = v ce(sat) i c r ds(on) = v ds(on) i d 5 replaces mrf148/d
package dimensions case 21107 issue n notes: 1. dimensioning and tolerancing per ansi y14.5m, 1982. 2. controlling dimension: inch. a u m m q r b 1 4 32 d k e seating plane c j h s dim min max min max millimetersinches a 0.960 0.990 24.39 25.14 b 0.370 0.390 9.40 9.90 c 0.229 0.281 5.82 7.13 d 0.215 0.235 5.47 5.96 e 0.085 0.105 2.16 2.66 h 0.150 0.108 3.81 4.57 j 0.004 0.006 0.11 0.15 k 0.395 0.405 10.04 10.28 m 40 50 40 50 q 0.113 0.130 2.88 3.30 r 0.245 0.255 6.23 6.47 s 0.790 0.810 20.07 20.57 u 0.720 0.730 18.29 18.54 style 2: pin 1. source 2. gate 3. source 4. drain 6 specifications subject to change without notice. n north america: tel. (800) 366 - 2266, fax (800) 618 - 8883 n asia/pacific: tel.+ 81 - 44 - 844 - 8296 , fax + 81 - 44 - 844 - 8298 n europe: tel. +44 (1344) 869 595, fax+44 (1344) 300 020 visit www.macom.com for additional data sheets and product information. replaces mrf148/d
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