LTC55933
2
APPLICATIONS NOTE
For detailed applications information, please refer
to the LTC5593 datasheet.
ABSOLUTE MAXIMUM RATINGS
NOTE. Stresses beyond Absolute Maximum Ratings may cause
permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Supply Voltage (VCC) ............................................. 4.0V
IF Supply Voltage (VCCIF) ...................................... 5.5V
Enable Voltage (ENA, ENB) ............. -0.3V to V
CC
+ 0.3V
Bias Adjust Voltage (IFBA, IFBB) ...... -0.3V to V
CC
+ 0.3V
Power Select Voltage (ISEL)............. -0.3V to V
CC
+ 0.3V
LO Input Power (1GHz to 3GHz) ........................... 9dBm
RFA, RFB Input Power (1GHz to 3GHz)................15dBm
Operating Temperature Range .................-40°C to 105°C
SUPPLY VOLTAGE RAMPING
Fast ramping of the supply voltage can cause a
current glitch in the internal ESD protection circuits.
Depending on the supply inductance, this could
result in a supply voltage transient that exceeds the
maximum rating. A supply voltage ramp time of
greater than 1ms is recommended.
Do not clip powered test leads directly onto the
demonstration circuit’s VCC and VCCIF turrets.
Instead, make all necessary connections with
power supplies turned off, then increase to operat-
ing voltage.
ENABLE FUNCTION
The LTC5593’s two mixer channels can be inde-
pendently enabled or disabled. When the Enable
voltage (ENA or ENB) is logic high (>2.5V), the cor-
responding mixer channel is enabled. When the
Enable voltage is logic low (<0.3V), the mixer
channel is disabled. The voltages at the enable
pins should never fall below -0.3V or exceed the
power supply voltage by more than 0.3V. The En-
able pins must be pulled high or low. If left floating,
the on/off state of the IC will be indeterminate. A
logic table for the Enable control (ENA, ENB) is
shown in Table 1.
TABLE 1. ENABLE CONTROL LOGIC TABLE
ENA, ENB
MIXER CHANNEL STATE
Low
Disabled
High
Enabled
LOW CURRENT MODE
The LTC5593 features a low current mode, which
allows the flexibility to choose a 37% total power
saving when lower RF performance is acceptable.
When the ISEL voltage is logic low (<0.3V), both
mixer channels operate at nominal DC current and
best performance. When the ISEL voltage is logic
high (>2.5V), both mixer channels are in low cur-
rent mode and operate with reduced performance.
The ISEL voltage should never fall below -0.3V or
exceed the power supply voltage by more than
0.3V. The ISEL pin must be pulled low or high. If
left floating, the operating current state of the IC will
be indeterminate. A logic table for ISEL is shown in
Table 2.
TABLE 2. ISEL LOGIC TABLE
ISEL
OPERATING MODE
Low
Normal current, best performance
High
Low current, reduced performance
RF INPUTS
Demonstration Circuit 1710A-D’s RF inputs of
channel A and channel B are identical. For the RF
inputs to be matched, the appropriate LO sig-
nal must be applied. The RF inputs’ impedance is
dependent on LO frequency, but the Demonstra-
tion Circuit 1710A-D’s RF inputs are well matched
to 50
Ω
from 2.3GHz to 4.5GHz, with better than
12dB return loss, when a 2.1GHz to 4.2GHz LO
signal is applied.
LO INPUTS
Demonstration Circuit 1710A-D’s LO input is well
matched to 50
Ω
from 2.1GHz to 3.4GHz, with bet-
