LT6600IS8-20#TR Linear Technology, LT6600IS8-20#TR Datasheet - Page 10

• Manufacturer Part Number: LT6600IS8-20#TR
• Description: IC AMP DIFF LP FLTR 20MHZ 8-SOIC
• Manufacturer: Linear Technology

Specifications of LT6600IS8-20#TR

• Amplifier Type: Differential
• Number Of Circuits: 1
• Output Type: Differential
• Current - Input Bias: 50µA
• Voltage - Input Offset: 10000µV
• Current - Supply: 46mA
• Voltage - Supply, Single/dual (±): 3 V ~ 11 V, ±1.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Output / Channel: -
• -3db Bandwidth: -
• Slew Rate: -
• Gain Bandwidth Product: -

APPLICATIONS INFORMATION
LT6600-20
Noise
The noise performance of the LT6600-20 can be evaluated
with the circuit of Figure 7.
Given the low noise output of the LT6600-20 and the
6dB attenuation of the transformer coupling network, it
is necessary to measure the noise fl oor of the spectrum
analyzer and subtract the instrument noise from the fi lter
noise measurement.
Example: With the IC removed and the 25Ω resistors
grounded, Figure 7, measure the total integrated noise (e
of the spectrum analyzer from 10kHz to 20MHz. With the
IC inserted, the signal source (V
input resistors grounded, measure the total integrated noise
out of the fi lter (e
set the frequency to 1MHz and adjust the amplitude until
V
V
compute the input referred integratednoise (e
Table 1 lists the typical input referred integrated noise for-
various values of R
density as a function of frequency for an LT6600-20 with
R
noise has been subtracted from the results).
Table 1. Noise Performance
The noise at each output is comprised of a differential
component and a common mode component. Using a
transformer or combiner to convert the differential outputs
to single-ended signal rejects the common mode noise and
gives a true measure of the S/N achievable in the system.
Conversely, if each output is measured individually and the
noise power added together, the resulting calculated noise
level will be higher than the true differential noise.
10
PASSBAND
GAIN (V/V)
IN
OUT
IN
e
measures 100mV
= 402Ω using the fi xture of Figure 7 (the instrument
IN
, and compute the passband gain A = V
4
2
1
=
(e
O
100Ω
200Ω
402Ω
R
)
2
IN
A
– (e
O
IN
). With the signal source connected,
S
. Figure 8 is plot of the noise spectral
INTEGRATED NOISE
P-P
)
INPUT REFERRED
10kHz TO 20MHz
2
. Measure the output amplitude,
118μV
42μV
67μV
RMS
RMS
RMS
IN
) disconnected, and the
INPUT REFERRED
NOISE dBm/Hz
OUT
IN
–148
–143
–139
/V
) as:
IN
. Now
S
)
Power Dissipation
The LT6600-20 amplifi ers combine high speed with large-
signal currents in a small package. There is a need to
ensure that the die junction temperature does not exceed
150°C. The LT6600-20 package has Pin 6 fused to the lead
frame to enhance thermal conduction when connecting to a
ground plane or a large metal trace. Metal trace and plated
through-holes can be used to spread the heat generated by
the device to the backside of the PC board. For example,
on a 3/32" FR-4 board with 2oz copper, a total of 660
square millimeters connected to Pin 6 of the LT6600-20
(330 square millimeters on each side of the PC board)
will result in a thermal resistance, θ
Without the extra metal trace connected to the V
provide a heat sink, the thermal resistance will be around
105°C/W. Table 2 can be used as a guide when considering
thermal resistance.
V
IN
50
40
30
20
10
Figure 8. Input Referred Noise, Gain = 1
0
0.1
V
R
R
S
IN
IN
= 5V
1
7
2
8
SPECTRAL DENSITY
LT6600-20
–
+
–2.5V
FREQUENCY (MHz)
2.5V
6
3
1
+
–
Figure 7
0.1μF
0.1μF
4
5
10
25Ω
INTEGRATED
25Ω
JA
COILCRAFT
TTWB-1010
, of about 85°C/W.
66002 F08
1:1
100
250
200
150
100
50
0
SPECTRUM
ANALYZER
INPUT
–
66002 F07
50Ω
pin to
66002fb