lt5571 Linear Technology Corporation, lt5571 Datasheet - Page 7

• Manufacturer Part Number: lt5571
• Description: 620mhz - 1100mhz High Linearity Direct Quadrature Modulator
• Manufacturer: Linear Technology Corporation

PIN FUNCTIONS
TYPICAL PERFORMANCE CHARACTERISTICS
f
shifted, without image or LO feedthrough nulling. f
tone measurements), unless otherwise noted. (Note 3)
EN (Pin 1): Enable Input. When the Enable pin voltage is
higher than 1V, the IC is turned on. When the Enable volt-
age is less than 0.5V or if the pin is disconnected, the IC
is turned off. The voltage on the Enable pin should never
exceed V
damage to the chip.
GND (Pins 2, 4, 6, 9, 10, 12, 15, 17): Ground. Pins 6, 9,
15 and the Exposed Pad 17 are connected to each other
internally. Pins 2 and 4 are connected to each other inter-
nally and function as the ground return for the LO signal.
Pins 10 and 12 are connected to each other internally and
function as the ground return for the on-chip RF balun. For
best RF performance, Pins 2, 4, 6, 9, 10, 12, 15 and the
Exposed Pad, Pin 17, should be connected to the printed
circuit board ground plane.
LO (Pin 3): LO Input. The LO input is an AC-coupled single-
ended input with approximately 50Ω input impedance at
RF frequencies. Externally applied DC voltage should be
within the range –0.5V to (V
turning on ESD protection diodes.
RF
= 902MHz, P
CC
by more than 0.5V, in order to avoid possible
LO
= 0dBm. BBPI, BBMI, BBPQ, BBMQ CM input voltage = 0.5V
25
20
15
10
5
0
<–60
Image Rejection Distribution
V
BB
= 400mV
–56
CC
IMAGE REJECTION (dBc)
P-P
–52
+ 0.5V) in order to avoid
–48
–44
RF
–40
= f
–40°C
25°C
85°C
5571 G28
BB
–36
+ f
LO
(upper sideband selection). P
BBPQ, BBMQ (Pins 7, 5): Baseband inputs for the Q-chan-
nel with about 90kΩ differential input impedance. These
pins should be externally biased at about 0.5V. Applied
common mode voltage must stay below 0.6V.
V
to each other internally. 0.1µF capacitors are recommended
for decoupling to ground on each of these pins.
RF (Pin 11): RF Output. The RF output is an AC-coupled
single-ended output with approximately 50Ω output im-
pedance at RF frequencies. Externally applied DC voltage
should be within the range –0.5V to (V
to avoid turning on ESD protection diodes.
BBPI, BBMI (Pins 14, 16): Baseband inputs for the I-chan-
nel with about 90kΩ differential input impedance. These
pins should be externally biased at about 0.5V. Applied
common mode voltage must stay below 0.6V.
Exposed Pad (Pin 17): Ground. The Exposed Pad must
be soldered to the PCB.
CC
(Pins 8, 13): Power Supply. Pins 8 and 13 are connected
–40
–50
–60
–70
–80
–90
DC
–40
LO Feedthrough and Image
Rejection vs Temperature After
Calibration at 25°C
, Baseband Input Frequency f
IMAGE REJECTION
V
CC
–20
= 5V, EN = High, T
CALIBRATED WITH P
f
f
BBI
BBQ
= 2MHz, 0°
TEMPERATURE (°C)
= 2MHz, 90° + ϕ
0
LO FEEDTHROUGH
RF(OUT)
20
= –10dBm (–10dBm/tone for 2-
40
RF
CAL
A
= 0dBm
= 25°C, f
60
BB
5571 G29
= 2MHz, I & Q 90°
80
CC
LO
+ 0.5V) in order
= 900MHz,
LT5571
7
5571f