LT5554IUH#TRPBF Linear Technology, LT5554IUH#TRPBF Datasheet - Page 24

• Manufacturer Part Number: LT5554IUH#TRPBF
• Description: IC VGA DIG CONTROL 32-QFN
• Manufacturer: Linear Technology

Specifications of LT5554IUH#TRPBF

• Applications: Variable Gain (VGA)
• Number Of Circuits: 1
• -3db Bandwidth: 1GHz
• Current - Supply: 200mA
• Voltage - Supply, Single/dual (±): 4.75 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: 32-WFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LT5554
APPLICATIONS INFORMATION
The LT5554 output power P
3dB for matching-loss and the transformer loss IL(T2) in
Table 3 to the board output power at J3 connector. The
transformer insertion loss (frequency and temperature
dependent) has been included in characterization.
The output power matching is required when LT5554
drives a 50Ω transmission line as shown on the evalua-
tion board.
When LT5554 drives local (on-board) loads such that
an ADC part, output power matching is not required and
OIP3 is defi ned based on P
open collector outputs.
Figure 17 shows the evaluation board for wide-band
characterization at R
of the output balun is about –1dB at 1GHz. Several R
options are given in Table 4 as well as the output padding
insertion-loss and required V
The LT5554 output power at open collector outputs is:
24
P
OUT
= P
50
J1
WR
(J3) + IL(T2) + 3dB + IL
V
V
CC
CCO
1, 3, 5, 7
0.1μF
= 5V
ETC1-1-13
= 7V
C4
MACOM
V
•
CC
OUT
1:1
T1
•
V
DEC
= 50Ω, where the insertion loss
0.1μF
9
C8
CCO
OUT
11
OUT
ENB
for 5V on LT5554 outputs.
, total power at LT5554
was obtained by adding
13
Figure 17. Single Ended Test Board (Simplifi ed Schematic)
PG0
C5
1μF
R20
10k
15
IN
IN
PG1
+
–
PAD
PG0
R
OUT
17
PG2
R21
R
50Ω
10k
400Ω
IN
= 50Ω
PG1
R
19
O
PG3
OUT
OUT
R22
10k
21
–
+
LT5554
PG4
PG2
400Ω
R
O
OUT
23
R23
10k
PG5
PG3
R
57.1Ω
LOAD
25
PG6
R24
10k
15.4Ω
15.4Ω
Table 4. Balun Board R
R
R3, R4 (Ω)
R5, R6 (Ω)
IL
V
The differential-output board from Figure 18 was used
for R
single-ended outputs.
Both Figure 17 and Figure 18 boards V
up with the voltage drop on R5, R6 produced by 45mA
output DC current such that OUT
is still 5V. The LT5554 part should be always enabled when
V
OUT
possible LT5554 failure.
PG4
R3
R4
OUT
CCO
CCO
PAD
STROBE
27
0.1μF
R25
10k
(V)
(Ω)
–
OUT
C3
>6V. If disabled, the V
PG5
28Ω
28Ω
exceeding the absolute maximum 6V limit with
R5
R6
= 50Ω wide-band characterization of the LT5554
R26
10k
V
PG
29
PG6
0.1μF
28.7
6.29
C9
25
0
0
31
MATCHING
MODE
50Ω
OUT
0.1μF
33, 35, 37, 38
C18
6.49
28.7
1.88
6.57
Options
36
V
CCO
CCO
4.7μF
C19
ETC1-1-13
15.4
3.66
6.96
will be applied at OUT
+
50
28
J5, 40 PINS
SMT-TB
2, 4, ...40
•
, OUT
1:1
T2
•
5554 F17
–
CCO
DC bias voltage
30.1
5.76
7.61
71
28
was shifted
J3
50
53.6
8.08
8.66
100
28
5554f
+
,