LTC5593IUH#TRPBF Linear Technology, LTC5593IUH#TRPBF Datasheet - Page 25

• Manufacturer Part Number: LTC5593IUH#TRPBF
• Manufacturer: Linear Technology

Specifications of LTC5593IUH#TRPBF

• Operating Supply Voltage: 3.3V
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Lead Free Status / Rohs Status: Compliant

elements R2A and C9A (in parallel with the internal RIF and
CIF), and series inductors L1A and L2A. Resistor R2A is
used to reduce the IF output resistance for greater band-
width, or it can be deleted for the highest conversion gain.
The final impedance transformation to 50Ω is realized by
transformer T1A. The measured IF output return loss for
lowpass IF matching with R2A and C9A open is plotted
in Figure 13. The LTC5593 demo board (see Figure 2) has
been laid out to accommodate this matching topology with
only minor modifications.
IF Amplifier Bias
The IF amplifier delivers excellent performance with V
= 3.3V, which allows a single supply to be used for V
V
limited by the output voltage swing. For higher P1dB, in
this case, resistor R2A (Figure 1) can be used to reduce
the output impedance and thus the voltage swing, thus
improving P1dB. The trade-off for improved P1dB will be
lower conversion gain.
With V
3dB, at the expense of higher power consumption. Mixer
P1dB performance at 2500MHz is tabulated in Table 4 for
APPLICATIONS INFORMATION
CCIF
Figure 13. IF Output Return Loss with Lowpass Matching
. At V
CCIF
CCIF
increased to 5V the P1dB increases by over
10
15
20
25
30
0
5
50
= 3.3V, the RF input P1dB of the mixer is
150nH
L1, L2
L1, L2
47nH
90
IF FREQUENCY (MHz)
130
L1, L2
82nH
170
210
5591 F13
250
CC
CCIF
and
V
gain, high-Q wire-wound chip inductors are recommended
for L1A and L2A, especially when using V
cost multilayer chip inductors may be substituted, with a
slight reduction in conversion gain.
Table 4. Performance Comparison with V
(RF = 2500MHz, Low Side LO, IF = 190MHz, ENA = ENB = High)
The IFBA pin (Pin 20) is available for reducing the DC
current consumption of the IF amplifier, at the expense of
IIP3. The nominal DC voltage at Pin 20 is 2.1V, and this pin
should be left open-circuited for optimum performance.
The internal bias circuit produces a 4mA reference for the
IF amplifier, which causes the amplifier to draw approxi-
mately 100mA. If resistor R1A is connected to Pin 20 as
shown in Figure 8, a portion of the reference current can
be shunted to ground, resulting in reduced IF amplifier
current. For example, R1A = 470Ω will shunt away 1.4mA
from Pin 20 and the IF amplifier current will be reduced
by 35% to approximately 65mA. Table 5 summarizes RF
performance versus total IF amplifier current when both
channels are enabled.
Table 5. Mixer Performance with Reduced IF Amplifier Current
RF =
R1A, R1B
CCIF
V
3.3kΩ
1.0kΩ
470Ω
(V)
3.3
Open
CCIF
5
2500MHz
values of 3.3V and 5V. For the highest conversion
Open
Open
R2A
953
953
(Ω)
, Low Side LO, IF = 190MHz, V
(mA)
I
200
176
151
130
CCIF
(mA)
I
200
200
207
207
CCIF
(dB)
8.5
8.4
8.1
8.0
G
C
(dB)
8.5
9.6
8.4
9.5
G
C
(dBm)
27.7
26.7
24.9
23.5
IIP3
(dBm)
P1dB
10.4
13.7
13.3
9.6
CCIF
CC
= V
LTC5593
= 3.3V and 5V
(dBm)
CCIF
P1dB
CCIF
10.4
10.5
10.5
10.4
(dBm)
27.7
27.2
28.5
27.4
IIP3
= 3.3V
= 3.3V. low
25
(dB)
(dB)
9.5
9.5
9.4
9.3
9.5
9.5
9.7
9.7
NF
NF
5593p