
M
Upstream CATV Amplifier
_______________________________________________________________________________________
7
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, V
CC
= 3.3V, V
IN
= 34dBmV, TXEN =
SHDN
= high, f
IN
= 20MHz, Z
LOAD
= 75
, T
A
= +25
°
C, unless oth-
erwise noted.)
Pin Description
PIN
NAME
DESCRIPTION
1
V
CC
Programmable-Gain Amplifier (PGA) 3.3V Supply. Bypass to GND with a 0.1μF decoupling
capacitor as close to the part as possible.
2
IN+
Positive PGA Input. Along with IN-, this port forms a high-impedance differential input to the PGA.
Driving this port differentially increases the rejection of second-order distortion at low output levels.
3
GND
PGA RF Ground. As with all ground connections, maintain the shortest possible (low-inductance)
length to the ground plane.
4
5
6
7
8
9
10
IN-
GND
SDA
SCLK
CS
TXEN
SHDN
N.C.
Negative PGA Input. When not used, this port must be AC-coupled to ground. See IN+.
Ground
Serial-Interface Data. TTL-compatible input. See
Serial Interface
section.
Serial-Interface Clock. TTL-compatible input. See
Serial Interface
section.
Serial-Interface Enable. TTL-compatible input. See
Serial Interface
section.
Transmit Enable. Drive TXEN high to place the device in transmit-enable mode.
Shutdown. When
SHDN
is set low, all functions (including the serial interface) are disabled.
No Connection
11,13,17
–
20
12
OUT-
Negative Output. Along with OUT+, this port forms a 75
impedance output. This port is matched
to a 75
load using a 1:1 transformer.
Positive Output. See OUT-.
14
OUT+
15
V
CC
Output Amplifier Bias, 3.3V Supply. Bypass to GND with a 0.1μF decoupling capacitor as close to
the part as possible.
16
CEXT
RF Output Bypass. Bypass to GND with a 0.1μF capacitor.
Exposed
Paddle
GND
Ground
-70
-80
-50
-60
-30
-40
-20
0
-10
10
100kHz/div
OUTPUT SPECTRUM
M
(
V
OUT
= 61dBmV
α
= 0.25
160ksps
-70
-80
-50
-60
-30
-40
-20
0
-10
10
6MHz/div
OUTPUT SPECTRUM
M
(
V
OUT
= 61dBmV
α
= 0.25
1280ksps