lt5571 Linear Technology Corporation, lt5571 Datasheet - Page 12

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

APPLICATIONS INFORMATION
LT5571
full chip supply current could be sourced through the EN
pin ESD protection diodes, which are not designed for this
purpose. Damage to the chip may result.
Evaluation Board
Figure 7 shows the evaluation board schematic. A good
ground connection is required for the LT5571’s Exposed
Pad. If this is not done properly, the RF performance will
degrade. Additionally, the Exposed Pad provides heat sink-
ing for the part and minimizes the possibility of the chip
12
BBQM
V
CC
LO IN
BBIM
EN
J5
J1
J4
100Ω
Figure 7. Evaluation Circuit Schematic
R1
49.9Ω
R3
49.9Ω
EN
1
2
3
4
R2
Figure 6. EN Pin Interface
BOARD NUMBER: DC944A
EN
GND
LO
GND
V
BBMQ GND
BBMI
CC
16
5
GND
LT5571
75k
15
R5
49.9Ω
6
BBPQ V
BBPI V
7
25k
14
CC
GND
GND
GND
GND
8
CC
RF
13
C2
100nF
J2
5571 F06
R4
49.9Ω
12
11
10
9
17
BBIP
J6
J3
5571 F07
C1
100nF
BBQP
RF
OUT
V
CC
overheating. R1 (optional) limits the EN pin current in the
event that the EN pin is pulled high while the V
are low. The application board PCB layouts are shown in
Figures 8 and 9.
Figure 8. Component Side of Evaluation Board
Figure 9. Bottom Side of Evaluation Board
CC
inputs
5571f