Single Port, VDSL2 Differential Line Driver
ISL1550
The ISL1550 is a dual operational amplifier intended to be
used as a differential line driver. ISL1550’s high bandwidth
and low distortion performance enables the support of VDSL2
8b, 17a and 30a modem applications.
Features
• 20dBm output power capability
• Drives up to ±750mA from a +12V supply
• 18V
P-P
differential output drive into 20Ω
• -89dBc typical driver output distortion at full output at
200kHz, 12V differential
This device features a high current drive capability of ±750mA
required to drive large voltage peaks into heavy loads. In
Central Office (CO) applications, the driver achieves a typical
Missing Band Power Ratio (MBPR) of -66dBc in VDSL2 8b
upstream (US) 1 band and MBPR’s of -61dBc and -60dBc in
VDSL2 17a US1 and US2 respectively.
P-P
• -61dBc US1, -60dBc US2 avg. MBPR 17a
• Supply range: ±4.0V to ±6.6V, +8.0V to +13.2V
• Thermal shutdown
• K.20, GR-1089 Surge Robustness Validated
The ISL1550 has two bias current control pins (C0, C1) to allow
for four power settings (disable, low, medium, high). The VDSL
modem DSP configures the line driver’s power setting based
on the desired mode of operation. The line driver operates on a
nominal single +12V or a dual ±6V supplies with bias current
in active mode between 15mA to 32mA, depending on its
power setting. The ISL1550’s gain setting is configurable at
the application level by setting the Rf and Rg resistor values.
The surge current handling of ISL1550 has been enhanced to
allow ITU-T K.20 and GR1089 compliance with minimal
external surge protection circuitry.
Applications
• VDSL2 Profiles: 8MHz, 17MHz, and 30MHz
Related Literature
• AN1325 “Choosing and Using Bypass Capacitors”
TABLE 1. ALTERNATE SOLUTIONS
NOMINAL ±V
(V)
BANDWIDTH
(MHz)
CC
PART #
ISL1557
ISL1539A
APPLICATIONS
VDSL2
±6,+12
200
240
The ISL1550 is available in the thermally-enhanced, Pb-free
RoHS compliant 16 Ld QFN package and is specified for
operation over the full -40°C to +85°C temperature range.
±12,+24
VDSL2
+6V
-40
-50
SUPPLY
DECOUPLING
NOT SHOWN
100n
+
-60
500
½
-70
ISL1550
2.2
-80
-
Rf
750
1:2.5
-90
Rg
1.5k
1k
1k
AFE
-100
-110
-120
-130
-140
100
NOMINAL
LINE
2.2n
Rf
750
-
½
ISL1550
500
100n
2.2
+
8.40M 8.90M 9.40M 9.90M 10.4M 10.9M 11.4M 11.9M
FREQUENCY (Hz)
-6V
FIGURE 1. TYPICAL APPLICATION CIRCUIT
FIGURE 2. US2 MBPR 17a VDSL2 PERFORMANCE
March 16, 2012
FN6795.0
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 |Copyright Intersil Americas Inc. 2012. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
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