40600; 40601; 40602 dual gate FET's

RCA

40600

40601

40602

 

SILICON DUAL INSULATED-GATE FIELD-EFFECT TRANSISTORS

N-channel depletion types for VHF TV receiver applications

 

APPLICATIONS:

VHF TV Receiver:

• 40600 for RF amplifier applications

• 40601 for mixer applications

• 40602 for first-IF- amplifier applications

performance FEATURES

• superior cross modulation performance and greater dynamic dynamic range than bipolar or single-gate field-effect transistors.

• permits use of vacuum-tube biasing techniques

• excellent thermal stability

   

DEVICE FEATURES

extremely low feedback capacitance

C_rss = 0.02 pF typ.

• high power gain

MUG_U= 20 dB typ. for 40600

MAG = 35 dB typ. for 40602

MAGC= 14 dB typ. for 40601

 

RCA 40600, 40601, and 40602* are n-channel depletion type, dual-insulated-gate, field-effect transistors utilising the MOS construction. These devices have characteristics which make them highly desirable for RF-amplifier applications (40600), mixer applications (40601) and first-IF-amplifier applications (40602) in VHF TV receivers and other types of commercial equipment operating at frequencies up to approximately 250 MHz.

These transistors feature a series arrangement of two separate channels, each channel having an independent control gate. In amplifier applications the 40600 and 40602 with their wide dynamic range provide substantially better cross modulation performance than is obtainable with bipolar or single-gate field-effect transistors. In mixer applications the 40601 provides excellent isolation between the oscillator and RF signals because each of the two signal frequencies being mixed has its own control element. The wide dynamic range of the 40601 minimizes cross-modulation which is generally encountered in mixer stages.

Provision of two insulated gates also results in extremely low feedback capacitances (0.02 pF typ.), a feature which enables the 40600 and 40602 to provide high maximum usable power gains in unneutralized circuits - for example, 20 dB at 200 MHz typ. for the 40600, and 35 dB typ. at 44 MHz for the 40602. The gain of the RF and IF stages can be controlled by applying AGC voltage to gate No. 2 and AGC delay is easily obtained. Virtually no AGC power is required for full gain reduction.

Types 40600, 40601, and 40602 are hermetically sealed in metal JEDEC TO-72 packages.

* Formerly dev. types TA7149, TA7262, TA7189, respectively.

  

Maximum Ratings, Absolute Maximum Values at T_A =25°C :

DRAIN-TO-SOURCE VOLTAGE, V_DS ...0 to +20 V

GATE NO-1-TO-SOURCE VOLTAGE V_G1S:

Continuous (dc) ............ + 1 to -8 V

Peak AC .........................+20 to -8 V

GATE No-2-TO SOURCE VOLTAGE, V_G2S

Continuous (DC)................-8 to 40% of V_DS V

Peak AC ........................... -8 to +20 V

 

DRAIN-TO-GATE VOLTAGE, VDG1 or VDG2:...+20 V

DRAIN CURRENT, I_D (Pulsed,):

Pulse duration ≤ 20 ms, duty factor ≤ 0.15 ................ 50 mA

 

TRANSISTOR DISSIPATION P_T :

At ambient temperature up to 25°C :............400 mW

above 25°C : .....................derate linearly at 2.67 mW/°C

 

AMBIENT TEMPRATURE RANGE :

Storage and operating ............. -65 to +175 °C

LEAD TEMPERATURE (During soldering):

At distances > 1/32 " from at sealing surface for 10 seconds, max. 265 °C

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Above series of RCA Dual-Gate-MOSFETs has been amended by the types

40603    RF Amplifier in FM Receivers (up to 100 MHz)

- power gain (unneutralized) 24 dB typ. at 100 MHz
- noise figure 3 dB typ. at 100 MHz
- high forward transconductance 10.000 µmho typ.
- low feedback capacitance 0.03 pF max.

40604    Mixer in FM Receivers (up to 100 MHz)

- closely approximates ideal 'Square Law' mixer with consequent reduction of spurious responses
- high forward transconductance 10.000 µmho typ.
- 100 MHz conversion gain 23 dB typ.


All these devices of 4060x series, however, had been designed with unprotected gates.
Transistors were delivered with a rivet across all 4 connection leads that had to be
replaced by a thin shorting wire prior to installation into the circuitry. When soldered
to the circuit, the protection wire cold be removed.

Later on, MOSFETS were protected by a flat clamp that could be left connected to the device until soldered to the circuitry
 

To overcome these handling restrictions, a new series of Dual-Gate-MOSFETs
has been developed with gates protected against handling and in-circuit transients:

40673    400 MHz  RF Amplifier, Mixer and IF Amplifier

- low gate leakage currents  50nA max.
- high forward transconductance 12.000 µmho typ.
- high unneutralized RF power gain  18 dB typ. at 200 MHz
- low VHF noise figure 3.5 dB typ. at 200 MHz


40820    RF Amplifier for VHF-TV Tuners

- high forward transconductance 12.000 µmho typ.
- high RF power gain 17 dB typ. at 200 MHz
- low VHF noise figure 3.5 dB typ. at 200 MHz


40821    RF Mixer for VHF-TV Tuners

- high forward transconductance 12.000 µmho typ.
- 200 MHz conversion gain 11 dB min.


40822    RF Amplifier for FM Tuners

- high forward transconductance 12.000 µmho typ.


40823    RF Mixer for FM Tuners

- high forward transconductance 12.000 µmho typ.
- 100 MHz conversion gain 14 dB min.


40841    500 MHz General Purpose Economy Type

- high forward transconductance 12.000 µmho typ.
- high  power gain 32 dB typ. at 44 MHz


Data taken from 'RCA MOSFET Product Guide'  issued FEB.1971
For further details see RCA Application Notes ST-3703 and AN-4018

 

F.H.

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Dual gate MOSFETs were also produced by General Instruments, as the one at right in the picture above. Until the early seventies, volume productions of unprotected types were also ran in their Italian plant of Giugliano, near Naples. They were supplied with pins shorted by metal springs.

Nevertheless, these devices were quite expensive and could be easily damaged by improper handling or even by unexpected glitches on the power supply. In many applications a couple of JFETs, series connected, did the same job with higher reliability and at lower price.

Emilio Ciardiello
 

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