lt5554 Linear Technology Corporation, lt5554 Datasheet - Page 13

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

ENB = 3V, MODE = 5V, STROBE = 3V, V
PIN FUNCTIONS
GND (Pins 1, 2, 7, 8, 10, 13, 15, 16, 19, 22, 25, 26, 28,
31): Ground Pins.
DEC (Pins 3, 6): Decoupling Pin for the Internal DC Bias
Voltage for the Differential Inputs, IN
connected to the ‘virtual ground’ of the input resistive
attenuator. Capacitive de-coupling to ground is recom-
mended in order to preserve linearity performance when
IN
IN
Bias to 2V.
IN
Bias to 2V.
PG5 (Pin 9): 4dB Step Amplifi er Programmable Gain Con-
trol Input Pin. Input levels are controlled by MODE pin.
PG6 (Pin 11): 8dB Step Amplifi er Programmable Gain
Control Input Pin. Input levels are controlled by the
MODE pin.
TYPICAL PERFORMANCE CHARACTERISTICS
0.1V/DIV
1V/DIV
+
+
–
, IN
(Pin 5): Negative Signal Input Pin with Internal DC
(Pin 4): Positive Signal Input Pin with Internal DC
2dB-Step Response (PG4)
120MHz Signal
MODE = HIGH
8dB-Step (PG6) 120MHz Pulse
Signal for 8dB Overdrive
MODE = HIGH
–
inputs are driven with up to 3dB imbalance.
10ns/DIV
5ns/DIV
5554 G46
5554 G49
IH
= 2.2V, V
+
and IN
0.1V/DIV
1V/DIV
IL
= 0.6V (Test circuit shown in Figure 16), maximum gain, unless otherwise noted.
–
MODE = HIGH
8dB-Step Response (PG6)
120MHz Signal
8dB-Step (PG6) 120MHz
Sinusoidal Signal for 2dB
Overdrive
MODE = HIGH
. It is also
10ns/DIV
5ns/DIV
PG0 (Pin 12): 0.125dB Step Amplifi er Programmable
Gain Control Input Pin. Input levels are controlled by
MODE pin.
STROBE (Pin 14): Strobe Pin for the Programmable Gain
Control Inputs (PGx). With STROBE in Low-state, the
Amplifi er Gain is not changed by PGx state changes (latch
mode). With STROBE in High-state, the Amplifi er Gain is
asynchronously set by PGx inputs transitions (transpar-
ent-mode). A positive STROBE transition updates the
PGx state. Low-state and High-state depends on MODE
pin level (Table1).
V
internally connected together.
MODE (Pin 18): PGx and STROBE Functionality and Level
Control Pin. When MODE is higher than V
PGx and STROBE are DC-coupled. When the MODE pin
is lower than 0.6V, the PGx and STROBE are AC-coupled.
CC
(Pins 17, 24): Power Supply Pins. These pins are
5554 G50
5554 G47
(R
OUT
= 50Ω) T
0.2V/DIV
1V/DIV
A
MODE = HIGH
8dB-Step Response (PG6)
120MHz Pulse Signal
MODE = HIGH
8dB-Step (PG6) 120MHz
Sinusoidal Signal for 8dB
Overdrive
= 25°C. V
CC
= 5V, V
10ns/DIV
5ns/DIV
CC
LT5554
CCO
– 0.4V, the
= 5V,
13
5554 G51
5554 G48
5554f