Ordering information
A3M39SL039 Airfast Power Amplifier Module with Autobias Control, Rev. 0, March 2022
Data Sheet: Technical Data
13
/
33
5.5 VGS_DAC
The VGS_DAC voltage is determined via the Sense_DAC setting, creating the top end or ceiling of the VGS_DAC voltage
range and a fixed offset voltage creating the bottom end or floor of the VGS_DAC voltage range. With a decimal VGS_DAC
setting of 0, the gate voltage developed on the reference FET is buffered with minimum offset to the gates of the RF
transistors in the carrier amplifier. As the VGS_DAC value increases, the voltage applied to the gates of the RF transistors
decreases, which also reduces I
DQ
. This allows the operating point of the four RF devices to be set to any desired value, from
Class AB to Class C.
The reference FETs and RF FETs exhibit approximately the same current density (that is, I
DQ
/mm gate width). It is important to
note that, because the reference device and RF transistors are manufactured on the same die in close proximity, they exhibit
similar process and temperature dependencies. Both the peaking amplifier and the carrier amplifier operate in the same way
with regard to the reference device and the RF transistors.
5.6 Engineering Mode (EM)
Flexibility exists to overwrite the OTP memory values, if needed. A special Engineering Mode (EM) is available to allow the
user to overwrite data that has been placed into the OTP memory space. To enter EM, issue the write address d’17 command
with the predefined EM passcode (see
). After entering EM, all DAC OTP registers (address 1–6) can be overwritten
with the normal I
2
C/SPI write instruction. This interface programmed value will be valid so long the V
CC
supply power is
maintained. The V
CC
power cycle will load OTP programmed DAC settings again. If the user writes the address d’17 register
with any value other than the passcode, EM will automatically exit.
6 Ordering information
Table 13. Ordering information
Device
Tape and Reel Information
Digital
Interface
Package
A3M39SL039IAAT2
T2 Suffix = 2,000 Units, 24 mm Tape Width, 13-inch Reel
I
2
C
10 mm × 8 mm Module
