MAX2601-MAX2602 MAXIM [Maxim Integrated Products], MAX2601-MAX2602 Datasheet - Page 5

• Manufacturer Part Number: MAX2601-MAX2602
• Description: 3.6V, 1W RF Power Transistors for 900MHz Applications
• Manufacturer: MAXIM [Maxim Integrated Products]

The source and load impedances presented to the
MAX2601/MAX2602 have a direct impact upon its gain,
output power, and linearity. Proper source- and load-
terminating impedances (Z
power transistor base and collector will ensure optimum
performance.
For a power transistor, simply applying the conjugate of
the transistor’s input and output impedances calculated
from small-signal S-parameters will yield less than opti-
mum device performance.
For maximum efficiency at V
3.6V, the optimum power-transistor source and load
impedances (as defined in Figure 3) are:
Z
sented to the transistor’s base and collector. The pack-
age parasitics are dominated by inductance (as shown
in Figure 3), and need to be accounted for when calcu-
lating Z
The internal bond and package inductances shown
in Figure 3 should be included as part of the end-
application matching network, depending upon exact
layout topology.
__________Applications Information
S
At 836MHz:
At 433MHz:
and Z
S
and Z
L
reflect the impedances that should be pre-
L
.
Z
Z
Z
Z
S
L
S
L
_______________________________________________________________________________________
= 5.5 + j2.0
= 6.5 + j1.5
= 9.5 - j2.5
= 8.5 - j1.5
Optimum Port Impedance
S
and Z
BB
= 0.75V and V
L
) presented to the
3.6V, 1W RF Power Transistors
CC
=
for 900MHz Applications
The most important connection to make to the
MAX2601/MAX2602 is the back side. It should connect
directly to the PC board ground plane if it is on the top
side, or through numerous plated through-holes if the
ground plane is buried. For maximum gain, this con-
nection should have very little self-inductance. Since it
is also the thermal path for heat dissipation, it must
have low thermal impedance, and the ground plane
should be large.
Figure 3. Optimum Port Impedance
2.8nH
2.8nH
4
5
Z
S
3
6
MAX2601
MAX2602
Slug Layout Techniques
2
7
Z
L
1
8
2.8nH
2.8nH
5