7
Biasing and Operation
AMMP-5024 is biased with a single positive drain supply
(Vd) a negative gate supply (Vg1) and has a positive
control gate supply (Vg2). For best overall performance
the recommended bias condition for the AMMP-5024 is
Vd =7V and Id = 200 mA. To achieve this drain current
level, Vg1 is typically between –2.5 to –3.5V. Typically, DC
current ow for Vg1 is –10 mA. Open circuit is the default
setting for Vg2 when not utilizing gain control.
Using the simplest form of assembly, the device is
capable of delivering at gain over a 2–40 GHz range.
However, this device is designed with DC coupled RF
I/O ports, and operation may be extended to lower
frequencies (<2 GHz) through the use of o-chip low-
frequency extension circuitry and proper external
biasing components. With low frequency bias extension
it may be used in a variety of time domain applications
(through 40 Gb/s).
When bypass capacitors are connected to the AUX
pads, the low frequency limit is extended down to the
corner frequency determined by the bypass capacitor
and the combination of the on-chip 50 ohm load and
small de-queing resistor. At this frequency the small
signal gain will increase in magnitude and stay at this
elevated level down to the point where the Caux bypass
Typical Scattering Parameters
Please refer to <http://www.avagotech.com> for typical scattering parameters data.
capacitor acts as an open circuit, eectively rolling o
the gain completely. The low frequency limit can be
approximated from the following equation:
1
f
Caux
=
2pCaux (Ro + R
DEQ
)
where:
Ro is the 50Ω gate or drain line termination resistor.
RDEQ is the small series dequeing resistor and 10Ω.
Caux is the capacitance of the bypass capacitor connected
to the AUX Drain and AUX Gate pad in farads.
With the external bypass capacitors connected to the
AUX gate and AUX drain pads, gain will show a slight
increase between 1.0 and 1.5 GHz. This is due to a series
combination of Caux and the on-chip resistance but
is exaggerated by the parasitic inductance (Lc) of the
bypass capacitor and the inductance of the bond wire
(Ld).
Input and output RF ports are DC coupled; therefore, DC
decoupling capacitors are required if there are DC paths.
(Do not attempt to apply bias to these pads.)
