14 of 20

RF5345

DS120215

7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical

support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.

Figure 2. WiFi Transmit Control Settings and Signal Flow Diagram

Once the test setup and DUT have been configured as indicated in figure 1 and 2, the off branches of the SP3T switch (C_RX,

and C_BT) must be set to a logic state “low” (0.2V max) or grounded. In the event that one of these branches are left floating

or in logic state “high” the performance of the PA will degrade significantly. Likewise, unused RF Ports must be terminated in

50

 to simulate actual system conditions and prevent RF signals from coupling back to the PA.

The following sequence for turning the PA “ON” is recommended:

1. Bias VCC to 3.3V (pins 6, 7, and 9) while Vreg and C_TX (pins 4 and 14) are at 0.0v and RF is “OFF.”

2. Set C_TX “high”. This properly terminates the PA berfore turning Vreg “ON.”

3. Turn Vreg (pin 4) “ON” to 2.8V. This pin controls the current drawn by the PA and it should quickly reach the quiescent cur-

rent approximately 110mA±20mA. Care must be exercised not to exceed 3.4V on this pin or the PA may be damaged.

4. Turn RF “ON.”

Note that setting LNA_Bias “low” enables the LNA bypass switch. Therefore, if LNA_Bias is set “high” during Transmit mode, TX

to RX isolation improves. This is an optional setting if additional TX to RX isolation is required for the system.

Case

Mode

C_TX

C_RX

C_Shared_RX

C_BT

LNA_Bias

1

WiFi TX

HIGH

LOW*

X

LOW*

LOW or HIGH**

*These controls must be set to a logic low or grounded. Do not leave floating.

**LNA_Bias “HIGH” disables the bypass switch and improves TX-RX isolation.

8

7

6

5

1

2

3

4

12

11

10

9

13

14

15

16

LNA_Bias

RX_OUT

TX_IN

Vreg

C_BT

ANT

GND

VCC_2