F2912

F2912, Rev 3, 04/01/2016

21

High Reliability SP2T RF Switch

Default Start-up

Control pins include no internal pull-down resistors to logic LOW or pull-up resistors to logic HIGH. Upon

start-up, all control pins should be set to logic LOW (0) thereby enabling 2 pin switch control, opening both

RF1 and RF2 paths, and setting logic control voltage to 3.3 V (see above tables for LOW logic states).

Power Supplies

A common VCC power supply should be used for all pins requiring DC power. All supply pins should be

bypassed with external capacitors to minimize noise and fast transients. Supply noise can degrade noise figure

and fast transients can trigger ESD clamps and cause them to fail. Supply voltage change or transients should

have a slew rate smaller than 1 V / 20 uS. In addition, all control pins should remain at 0 V (+/-0.3 V) while

the supply voltage ramps or while it returns to zero.

Control Pin Interface

If control signal integrity is a concern and clean signals cannot be guaranteed due to overshoot, undershoot,

ringing, etc., the following circuit at the input of each control pin is recommended. This applies to control pins

16, 17, 18, and 19 as shown below.

16

17

18

19

20

1

4

3

2

5

11

6

7

8

9

10

15

12

13

14

50

Ω

50

Ω

50

Ω

Control

Circuit

CTL2

5Kohm

2pf

5Kohm

2pf

CTL1

5Kohm

2pf

LogicCTL

5Kohm

2pf

ModeCTL

Pin Compatibility

The F2912 switch is compatible with other supplier parts which only support two wire control and 3 volt logic.

Other suppliers’ parts with limited functionality have pins 18 and 19 grounded. Grounding pins 18 and 19 on

the F2912 will make it fully compatible with the other products.

Per Table 3 when pin 19 is grounded, the F2912 is set for 2-wire control.

Per Table 4 when pin 18 is grounded, the F2912 is set for 3.3 volt control logic. JEDEC 3.3 volt logic

(JESD8C.01) allows logic high to be as low as 2.7 volts which the F2912 supports.

Contact your IDT representative for more information about compatibility with other suppliers’ products.