for 0.05 – 6.0 GHz Higher Power Applications

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Rev 1.0

10

MASW-000822-12770T

RoHS

Compliant

Driver and SP2T Schematic with Positive and Negative Voltage

Notes for TTL Compatible Driver Functionality using +Vcc and –Vee.

1. The Mode Control defines the Type of TTL Logic. Grounding the Mode Control produces Inverting Logic:

TTL 0 ( Input ) = +V , + I ( Output ), and TTL 1 ( Input ) = -V, -I ( Output ).

Consequently Connecting the Mode Control to +5V , produces Non- Inverting Logic:

TTL 0 ( Input ) = -V , - I ( Output ), and TTL 1 ( Input ) = +V, +I ( Output ).

2. Open circuit output voltage ~ ( +Vcc-0.8V ) or( –Vee + 0.8V ). Diode Forward Voltage ,

∆Vd @ 50 mA ~ 1.0 V.

3. Rbias is used to build reverse D.C.voltage for the isolated , “ OFF “ , Series diode to Improve RF Linearity under High RF Signal.

Available Negative Bias Current = ( -Vee + ∆Vbe + ∆Vce + ∆Vd) / ( 75Ω + Rbias ) = ( -Vee + 0.3 V + 0.7+ 1.0 V ) / ( 75Ω + Rbias ). As example,

using –Vee = -12V for -50 mA bias current to forward Biased PIN Diode, Rbias = [ ( -12V + 2.0 V ) / - 0.05 A ] – 75Ω = 125 Ω.

In this example, using Rbias = 120 Ω ,Tx Bias Voltage ~ - [ (120 Ω*0.05A ) + 1.0 V ] ~ -7.0 V.

Using + Vcc = + 5V, the “ OFF “ Series Diode will have a Back Biased Voltage ~

| -6.0 V - ( 5 - 0.8 ) V | = | -10.2 V |.

4. The SP2T Switch can be operated from –Vee = -5V with slightly degraded Tx linearity.

RF State

TTL & D.C. Bias Conditions

Voltage at Common Anode

Rbias = 120Ω

- I bias = - 50 mA

Low Loss Tx-Ant &

Isolation Tx-Rx

TTL = 1

-12V @ -50mA ( Tx ), + 5V @ 0 mA ( Rx )

- 6.0 V

Low Loss Ant-Rx &

Isolation Rx-Tx

TTL = 0

-12V @ -50mA ( Rx ), + 5V @ 0 mA ( Tx )

- 6.0 V

D.C. Bias to RF Truth Table