LT1795 Linear Technology, LT1795 Datasheet - Page 10

• Manufacturer Part Number: LT1795
• Description: Dual 500mA/50MHz Current Feedback Line Driver Amplifier
• Manufacturer: Linear Technology

APPLICATIONS
LT1795
PACKAGE DESCRIPTIO
10
Figure 9 shows the effect of the network on a 200pF load.
Without the optional compensation, there is a 6dB peak at
85MHz caused by the effect of the capacitance on the
output stage. Adding a 0.01 F bypass capacitor between
the output and the COMP pins connects the compensation
14
12
10
–2
–4
–6
8
6
4
2
0
1
V
C
S
L
= 15V
= 200pF
R
COMPENSATION
F
(0.229 – 0.330)
U
0.009 – 0.013
NOTE:
1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
**
= 1k
*
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
FREQUENCY (MHz)
Figure 9.
INFORMATION
U
10
(0.254 – 0.737)
0.010 – 0.029
NOTE 1
(7.391 – 7.595)
0.291 – 0.299**
COMPENSATION
R
COMPENSATION
F
(0.406 – 1.270)
0.016 – 0.050
= 3.4k
W
R
F
= 3.4k
NO
U
45
20-Lead Plastic Small Outline (Wide 0.300)
1795 F09
Dimensions in inches (millimeters) unless otherwise noted.
100
U
0 – 8 TYP
(LTC DWG # 05-08-1620)
NOTE 1
(2.362 – 2.642)
SW Package
0.093 – 0.104
(1.270)
0.050
TYP
20
1
(0.356 – 0.482)
0.014 – 0.019
and greatly reduces the peaking. A lower value feedback
resistor can now be used, resulting in a response which is
flat to 1dB to 45MHz. The network has the greatest effect
for C
Although the optional compensation works well with
capacitive loads, it simply reduces the bandwidth when it
is connected with resistive loads. For instance, with a 25
load, the bandwidth drops from 48MHz to 32MHz when
the compensation is connected. Hence, the compensation
was made optional. To disconnect the optional compensa-
tion, leave the COMP pin open.
DEMO BOARD
A demo board (DC261A) is available for evaluating the
performence of the LT1795. The board is configured as a
differential line driver/receiver suitable for xDSL applica-
tions. For details, consult your local sales representative.
19
2
TYP
18
3
L
in the range of 0pF to 1000pF.
17
(12.598 – 13.005)
4
0.496 – 0.512*
16
5
15
6
14
7
13
8
12
9
11
10
(0.940 – 1.143)
0.037 – 0.045
(0.102 – 0.305)
0.004 – 0.012
(10.007 – 10.643)
0.394 – 0.419
S20 (WIDE) 0396