lt5554 Linear Technology Corporation, lt5554 Datasheet - Page 7

• Manufacturer Part Number: lt5554
• Description: Broadband Ultra Low Distortion 7-bit Digitally Controlled Vga
• Manufacturer: Linear Technology Corporation

ELECTRICAL CHARACTERISTICS
Note 5: RTI (Referred-To-Input) stands for the total input-referred noise
voltage source. RTI is close to output noise voltage divided by voltage gain
(the exact equation is given in Defi nition of Specifi cation section). The
equivalent noise source e
Note 6: The external loading at LT5554 OUT
R
Note 7: The IN
of input coupling capacitor sets the low frequency corner (LF) at input.
The output coupling capacitors or the transformer sets the low frequency
corner (LF) at the output. The LT5554 operates internally down to DC.
TYPICAL PERFORMANCE CHARACTERISTICS
ENB = 3V, MODE = 5V, STROBE = 3V, V
OUT
–0.1
–0.2
0.3
0.2
0.1
= R
20
18
16
14
12
10
8
6
4
2
0
0
0
0
Gain vs Frequency for
0.5dB Steps, Figure 17
Differential Gain Error vs
Attenuation at 50MHz
LOAD
100
|| R
+
200
–40°C
25°C
85°C
, IN
O
–4
–
300
= 50Ω.
, DEC pins are internally biased. The time-constant
FREQUENCY (MHz)
ATTENUATION (dB)
400
N
500
is twice the RTI value.
–8
600
700
–12
800
900
+
IH
5554 G01
5554 G04
/OUT
1000
= 2.2V, V
–16
–
pins is R
IL
–0.1
–0.2
–0.1
–0.2
0.3
0.2
0.1
0.3
0.2
0.1
= 0.6V (Test circuit shown in Figure 16), unless otherwise noted.
0
0
LOAD
50
0
Differential Gain Error vs
Frequency at –40°C
Differential Gain Error vs
Attenuation at 100MHz
= 57Ω.
75
–40°C
25°C
85°C
–4
100
FREQUENCY (MHz)
ATTENUATION (dB)
125
–8
Note 8: The external loading at OUT
R
Note 9: Depending on the actual input matching conditions and frequency
of operation, the LT5554 steps involving the input attenuator tap change
may show less than 0.125dB change. These steps are G
–8dB, G
The LT5554 monotonic operation for 0.125dB step resolution can still be
obtained by skipping any such code with a gain error excedding 0.125dB.
OUT
12dB
= R
150
MAX
4dB
–12
LOAD
175
–12dB, and the code is given in the Programmable Gain Table.
8dB
|| R
(R
5554 G02
5554 G05
O
OUT
200
–16
= 100Ω.
= 50Ω) T
–0.1
–0.2
–0.1
–0.2
0.3
0.2
0.1
0.3
0.2
0.1
0
0
A
50
0
Differential Gain Error vs
Frequency at 85°C
Differential Gain Error vs
Attenuation at 200MHz
= 25°C. V
+
/OUT
75
–40°C
25°C
85°C
–
–4
pins is R
100
FREQUENCY (MHz)
ATTENUATION (dB)
CC
4dB
= 5V, V
12dB
125
LOAD
–8
8dB
MAX
LT5554
CCO
= 133Ω.
150
–4dB, G
= 5V,
–12
175
MAX
5554 G03
5554 G06
7
5554f
200
–16