LTC5598IUF LINER [Linear Technology], LTC5598IUF Datasheet - Page 8

• Manufacturer Part Number: LTC5598IUF
• Description: 5MHz to 1600MHz High Linearity Direct Quadrature Modulator
• Manufacturer: LINER [Linear Technology]

PIN FUNCTIONS
LTC5598
EN (Pin 1): Enable Input. When the Enable Pin voltage is
higher than 2 V, the IC is turned on. When the input voltage
is less than 1 V, the IC is turned off. If not connected, the
IC is enabled.
GND (Pins 2, 5, 8, 11, 12, 19, 20, 23 and 25): Ground.
Pins 2, 5, 8, 11, 12, 19, 20, 23 and exposed pad 25 are
connected to each other internally. For best RF performance,
pins 2, 5, 8, 11, 12, 19, 20, 23 and the Exposed Pad 25
should be connected to RF ground.
LOP (Pin 3): Positive LO Input. This LO input is internally
biased at about 2.3V. An AC de-coupling capacitor should
be used at this pin to match to an external 50Ω source.
LOM (Pin 4): Negative LO Input. This input is internally biased
at about 2.3V. An AC de-coupling capacitor should be used at
this pin via a 50Ω to ground for best OIP2 performance.
CAPA, CAPB (Pins 6, 7): External capacitor pins. A cap-
acitor between the CAPA and the CAPB pin can be used in
order to improve the image rejection for frequencies below
100MHz. A capacitor value of 470nF is recommended.
These pins are internally biased at about 2.3V.
BBMQ, BBPQ (Pins 9, 10): Baseband Inputs for the
Q-channel, each high input impedance. They should be
externally biased at 0.5V common-mode level and not be
left fl oating. Applied common-mode voltage must stay
below 0.6V
BLOCK DIAGRAM
8
DC
.
BBMQ
BBPQ
BBMI
BBPI
EN
21
22
10
1
9
2
V-I
V-I
20
5
GND
GND
23
8
25
11
90
0
LOP LOM CAPA CAPB
3
V
24
CC1
4
V
CC2
18
6
NC (Pins 13, 15): No Connect. These pins are fl oating.
GNDRF (Pins 14, 17): Ground. Pins 14 and 17 are connected
to each other internally and function as the ground return for
the RF output buffer. They are connected via back-to-back
diodes to the exposed pad 25. For best LO suppression
performance those pins should be grounded separately
from the exposed paddle 25. For best RF performance,
pins 14 and 17 should be connected to RF ground.
RF (Pin 16): RF Output. The RF output is a DC-coupled
single-ended output with approximately 50Ω output
impedance at RF frequencies. An AC coupling capacitor
should be used at this pin to connect to an external
load.
V
use 1nF and 4.7μF capacitors for decoupling to ground
on each of these pins.
BBPI, BBMI (Pins 21, 22): Baseband Inputs for the Q-
channel, each high input impedance. They should be
externally biased at 0.5V common-mode level and not be
left fl oating. Applied common-mode voltage must stay
below 0.6V
Exposed Pad (Pin 25): Ground. This pin must be soldered
to the printed circuit board ground plane.
7
CC
(Pins 18, 24): Power Supply. It is recommended to
12
13
NC
DC
15
GND
.
LTC5598
19
5598 BD
16
14
17
RF
GNDRF
5598f