LT5575
9
5575f
BLOCK DIAGRAM
PIN FUNCTIONS
GND (Pins 1, 3, 4, 9, 11): Ground pin.
RF
(Pin 2): RF Input Pin. This is a single-ended 50Ω ter-
minated input. No external matching network is required
for the high frequency band. An external series capacitor
(and/or shunt capacitor) may be required for impedance
transformation to 50Ω in the low frequency band from
800MHz to 1.5GHz (see Figure 4). If the RF source is not
DC blocked, a series blocking capacitor should be used.
Otherwise, damage to the IC may result.
V
CC
(Pins 6, 7, 8, 12): Power Supply Pins. These pins
should be decoupled using 1000pF and 0.1µF capacitors.
EN (Pin 5): Enable Pin. When the input voltage is higher
than 2.0V, the circuit is completely turned on. When the
enable pin voltage is less than 1.0V, the circuit is turned
off. Under no conditions should the voltage at the EN
pin exceed V
CC
+ 0.3V. Otherwise, damage to the IC may
result. If the Enable function is not needed, then the EN
pin should be tied to V
CC
.
LO
(Pin 10): Local Oscillator Input Pin. This is a single-
ended 50Ω terminated input. No external matching net-
work is required in the high frequency band. An external
shunt capacitor (and/or series capacitor) may be required
for impedance transformation to 50Ω for the low frequency
band from 800MHz to 1.5GHz (see Figure 6). If the LO
source is not DC blocked, a series blocking capacitor must
be used. Otherwise, damage to the IC may result.
Q
OUT
–
, Q
OUT
+
(Pins 13, 14): Differential Baseband
Output Pins of the Q Channel. The internal DC bias voltage
is V
CC
– 1.1V for each pin.
I
OUT
–
, I
OUT
+
(Pins 15, 16): Differential Baseband
Output Pins of the I Channel. The internal DC bias voltage
is V
CC
– 1.1V for each pin.
Exposed Pad (Pin 17): Ground Return for the Entire IC.
This pin must be soldered to the printed circuit board
ground plane.
RF
I
OUT
+
LO
GND
0°/90°
16
I
OUT
–
15
Q
OUT
+
14
Q
OUT
–
13
LO BUFFERS
LPF
I-MIXER
LPF
Q-MIXER
EXPOSED
PAD
6
V
CC
BIAS
5
EN
1
GND
7
V
CC
8
4
V
CC
12
V
CC
GND
5575 BD
9 17
RF AMP
RF AMP
2
3
11
10
