10
LT1795
1795fa
SW Package
20-Lead Plastic Small Outline (Wide .300 Inch)
(Reference LTC DWG # 05-08-1620)
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 0.01µF bypass capacitor between
the output and the COMP pins connects the compensation
APPLICATIONS INFORMATION
WUU
U
Figure 9
FREQUENCY (MHz)
1
VOLTAGE GAIN (dB)
14
12
10
8
6
4
2
0
–2
–4
–6
10 100
1795 F09
V
S
= ±15V
C
L
= 200pF
R
F
= 3.4k
NO
COMPENSATION
R
F
= 1k
COMPENSATION
R
F
= 3.4k
COMPENSATION
PACKAGE DESCRIPTIO
U
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
L
in the range of 0pF to 1000pF.
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 25Ω
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.
S20 (WIDE) 0502
NOTE 3
.496 – .512
(12.598 – 13.005)
NOTE 4
20
N
19 18
17
16
15
14 13
1
23
4
5
6
78
.394 – .419
(10.007 – 10.643)
910
N/2
1112
.037 – .045
(0.940 – 1.143)
.004 – .012
(0.102 – 0.305)
.093 – .104
(2.362 – 2.642)
.050
(1.270)
BSC
.014 – .019
(0.356 – 0.482)
TYP
0° – 8° TYP
NOTE 3
.009 – .013
(0.229 – 0.330)
.016 – .050
(0.406 – 1.270)
.291 – .299
(7.391 – 7.595)
NOTE 4
× 45°
.010 – .029
(0.254 – 0.737)
.420
MIN
.325 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
N
1 2 3 N/2
.050 BSC
.030 ±.005
TYP
.005
(0.127)
RAD MIN
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
