LE87220KQC Zarlink, LE87220KQC Datasheet - Page 8

• Manufacturer Part Number: LE87220KQC
• Description: World Wide xDSL Line Driver 24-Pin QFN Tray
• Manufacturer: Zarlink

Specifications of LE87220KQC

• Package: 24QFN
• Transmission Media Type: Copper
• Power Supply Type: Analog
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3.13 V
• Maximum Operating Supply Voltage: 3.46 V

Notes:
1.
2.
3.
APPLICATION CIRCUIT
Refer to the datapath reference design.
PCB Layout
The Le87220 device contains high gain and high bandwidth amplifiers. The amplifier inputs of each line are connected to the
DDWNP/DDWNN pins, the output are connected to the AY and BY pins. To prevent coupling of the high level output signals into
the low level DDWNP/DDWNN pins, PCB tracks and components connected to AY, BY, and going to the TIP (A) and RING (B)
terminals must be well separated from tracks connected to DDWNP/DDWNN pins. The components C1, C2, R1, R10, and R11
(and the corresponding components of line 2) should be as close as practical to DDWNP/DDWNN pins. The Le87220 device
provides an analog ground pin (AGND) as a return for low level currents and a battery ground pin (BGND) as a return for high
level currents.
The differential drivers of the Le87220 device do not produce any load current into the AGND leads, but the amplifier currents are
still circulating in the VBAT and BGND pins. A bypass capacitor between VBAT and BGND is required to be close to the device.
AGND and BGND tracks should only be tied together at a single point, close to the power connector of the card.
The Le87220 device uses a thermally enhanced package equipped with an exposed pad on the bottom side. The printed circuit
board surface must have a copper pad covering the full surface of the thermal pad. The copper pad must be fitted with a minimum
of 16 thermal transfer vias on a 1 mm pitch with a via diameter of 0.3 to 0.33 mm, and be connected to a large internal copper
plane for proper heat dissipation. The AGND plane is recommended. The thermal transfer vias should be connected to the
thermal pad and to the AGND plane without thermal relieve tracks. The AGND plane should be the second layer from the top of
the PCB for the best power dissipation.
In multi-line applications, the Le87220 devices must be positioned in the layout to ensure a minimum distance of 1 inch (center
to center) between devices. Passive non-heat producing components can be placed between the Le87220 devices.
Crosstalk is measured with one line transmitting signal, the other line is enabled but V
Crosstalk:
Measured with a 2.45:1 transformer and a 100-
Table 2. Pdown = 1 (Power Down)
Vn
R
V
Crosstalk
between lines
V
Iout, max
S
HD2
HD3
MTPR
K
K
vs. frequency
Specification
AYDC
IN, DWN
R
DWN
DWN
DDWN
DWN
Xtalk dB
, V
BYDC
(
)
=
Output Differential Noise Voltage,
V
Differential Input Impedance DDWNP to DDWNN
AY, BY DC bias voltage
Xtalk
Input Amplitude, AC coupled
Iout max into 100 ohm load
Slew Rate at V
f
f
Downstream multitone power ratio ITU, G.992.1
MTPR test peak to rms ratio = 5.8
K
25 kHz to 1104 kHz
-3 dB
20
at (AY, BY)
c=1MHz, RL=100Ohms, Vout=2Vp-p
c=1MHz, RL=100Ohms, Vout=2Vp-p
TX
DWN
log
=0 V, 25 kHz to 1104 kHz



= V
V AY BY
-------------------------------- -
V AY BY
(
(
AY,BY
,
,
AY–BY
/V
fc=1104 kHz, Vout=2Vpp
fc=100 kHz, Vout=2Vpp
DWN
)1
)2
Condition



Ω
load.
Zarlink Semiconductor Inc.
Device Performance
AC Characteristics
8
V
---------------- 0.25
BAT
2
Min
28k
200
70
50
46
4
–
TX
is set to 0 V.
V
----------------
BAT
2
-67.5
-67.5
67.5
Typ
40k
250
0.6
80
60
48
+
0.75
V
----------------
BAT
2
Max
52k
1.0
1.0
80
50
+
1.75
-----------
MHz
Unit
V/µs
µV
dBc
dBc
mA
V/V
kΩ
dB
dB
Hz
V
V
Note
1.,
3.
2.