ada4320-1 Analog Devices, Inc., ada4320-1 Datasheet - Page 13

• Manufacturer Part Number: ada4320-1
• Description: High Power, Low Distortion Upstream Catv Line Driver Ada4320-1
• Manufacturer: Analog Devices, Inc.

RAMP PIN FEATURE
The RAMP pin (Pin 6) can be optionally used to control the
length of the burst on and off transients. By default, leaving the
RAMP pin unconnected results in a transient that is fully compliant
with DOCSIS 3.0. Adding capacitance to the RAMP pin slows
the dissipation even more.
MODULATOR
QPSK/QAM
BURST
DAC
(SPI-COMPATIBLE)
ENABLE/DISABLE
POWER-DOWN
LPF
TRANSMIT
CONTROL
CONTROL
CONTROL
3-WIRE
0.1µF
8
13
GND
GND
VIN–
VIN+
GND
10µF
Figure 24. Typical Application
+
ADA4320-1
Rev. 0 | Page 13 of 16
5V
OUTPUT TRANSFORMER
Matching the 300 Ω differential output impedance to unbalanced
75 Ω requires a 4:1 impedance (2:1 turns) ratio transformer.
The transformer should have minimal insertion loss over the
5 MHz to 85 MHz band and have a maximum dc current rating
of at least 200 mA.
Characterization of the ADA4320-1 was performed using a
Coilcraft PWB-4-BL surface-mount wide-band RF transformer.
Alternate choices for the output transformer are the Toko
458PT-1565 and the Tyco Electronics (M/A-COM) ABACT0018.
100pF
VOUT+
VOUT–
VOUT+
VOUT–
COMP
1
20
0.1µF
0.1µF
100nH
0.1µF
2:1*
*COILCRAFT PWB-4-BL
ALTERNATES: TOKO 458PT-1565
UPSTREAM
OR SPLITTER
TO TUNER
DIPLEXER
TYCO MABACT0018
DOWNSTREAM
ADA4320-1
F-CONNECTOR