lt5572 Linear Technology Corporation, lt5572 Datasheet - Page 12

• Manufacturer Part Number: lt5572
• Description: 1.5ghz To 2.5ghz High Linearity Direct Quadrature Modulator
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
LT5572
current could be sourced through the EN pin ESD pro-
tection 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 Exposed Pad. If this
is not done properly, the RF performance will degrade.
Additionally, the Exposed Pad provides heat sinking for
the part and minimizes the possibility of the chip over-
heating. R1 (optional) limits the EN pin current in the
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: DC945A
EN
GND
LO
GND
U
V
BBMQ GND
BBMI
CC
16
5
GND
LT5572
U
75k
15
R5
49.9Ω
6
BBPQ V
BBPI V
7
25k
14
CC
GND
GND
GND
GND
8
CC
W
RF
13
C2
100nF
J2
5572 F06
R4
49.9Ω
12
11
10
9
17
BBIP
J6
J3
5572 F07
C1
100nF
BBQP
U
RF
OUT
V
CC
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
5572f