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Электронный компонент: 600I25

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LT6600-2.5
1
660025i
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
Programmable Differential Gain via Two External
Resistors
s
Adjustable Output Common Mode Voltage
s
Operates and Specified with 3V, 5V,
5V Supplies
s
0.5dB Ripple 4th Order Lowpass Filter with 2.5MHz
Cutoff
s
86dB S/N with 3V Supply and 1V
RMS
Output
s
Low Distortion, 1V
RMS
, 800
Load
1MHz: 95dBc 2nd, 88dBc 3rd
s
Fully Differential Inputs and Outputs
s
Compatible with Popular Differential Amplifier
Pinouts
s
SO-8 Package
Very Low Noise, Differential
Amplifier and 2.5MHz Lowpass Filter
June 2003
s
High Speed ADC Antialiasing and DAC Smoothing in
Networking or Cellular Base Station Applications
s
High Speed Test and Measurement Equipment
s
Medical Imaging
s
Drop-in Replacement for Differential Amplifiers
The LT
6600-2.5 combines a fully differential amplifier
with a 4th order 2.5MHz lowpass filter approximating a
Chebyshev frequency response. Most differential amplifi-
ers require many precision external components to tailor
gain and bandwidth. In contrast, with the LT6600-2.5, two
external resistors program differential gain, and the filter's
2.5MHz cutoff frequency and passband ripple are inter-
nally set. The LT6600-2.5 also provides the necessary level
shifting to set its output common mode voltage to accom-
modate the reference voltage requirements of A/Ds.
Using a proprietary internal architecture, the LT6600-2.5
integrates an antialiasing filter and a differential amplifier/
driver without compromising distortion or low noise
performance. At unity gain the measured in band
signal-to-noise ratio is an impressive 86dB. At higher
gains the input referred noise decreases so the part can
process smaller input differential signals without signifi-
cantly degrading the output signal-to-noise ratio.
The LT6600-2.5 also features low voltage operation. The
differential design provides outstanding performance for
a 4V
P-P
signal level while the part operates with a single 3V
supply. The LT6600-2.5 is available in an SO-8 package.
For similar devices with higher cutoff frequency, refer to
the LT6600-10 and LT6600-20 data sheets.
Amplitude Response
DESCRIPTIO
U
FEATURES
APPLICATIO S
U
TYPICAL APPLICATIO
U
Final Electrical Specifications
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
1580
1580
0.01
F
0.1
F
LT6600-2.5
5V
+
V
IN
+
V
IN
V
OUT
660025 TA01a
V
OUT
+
3
4
1
7
2
8
5
6
FREQUENCY (Hz)
100k
36
GAIN (dB)
24
12
0
12
1M
10M
50M
660025 TA01b
48
60
84
96
72
V
S
=
2.5V
LT6600-2.5
2
660025i
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Filter Gain, V
S
= 3V
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
0.5
0.1
0.4
dB
R
IN
= 1580
V
IN
= 2V
P-P
, f
IN
= 700kHz (Gain Relative to 260kHz)
q
0.15
0
0.1
dB
V
IN
= 2V
P-P
, f
IN
= 1.9MHz (Gain Relative to 260kHz)
q
0.2
0.2
0.6
dB
V
IN
= 2V
P-P
, f
IN
= 2.2MHz (Gain Relative to 260kHz)
q
0.6
0.1
0.5
dB
V
IN
= 2V
P-P
, f
IN
= 2.5MHz (Gain Relative to 260kHz)
q
2.1
0.9
0
dB
V
IN
= 2V
P-P
, f
IN
= 7.5MHz (Gain Relative to 260kHz)
q
34
31
dB
V
IN
= 2V
P-P
, f
IN
= 12.5MHz (Gain Relative to 260kHz)
q
51
dB
Filter Gain, V
S
= 5V
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
0.5
0.1
0.4
dB
R
IN
= 1580
V
IN
= 2V
P-P
, f
IN
= 700kHz (Gain Relative to 260kHz)
q
0.15
0
0.1
dB
V
IN
= 2V
P-P
, f
IN
= 1.9MHz (Gain Relative to 260kHz)
q
0.2
0.2
0.6
dB
V
IN
= 2V
P-P
, f
IN
= 2.2MHz (Gain Relative to 260kHz)
q
0.6
0.1
0.5
dB
V
IN
= 2V
P-P
, f
IN
= 2.5MHz (Gain Relative to 260kHz)
q
2.1
0.9
0
dB
V
IN
= 2V
P-P
, f
IN
= 7.5MHz (Gain Relative to 260kHz)
q
34
31
dB
V
IN
= 2V
P-P
, f
IN
= 12.5MHz (Gain Relative to 260kHz)
q
51
dB
Filter Gain, V
S
=
5V
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
0.6
0.1
0.4
dB
Filter Gain, R
IN
= 402
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz, V
S
= 3V
11.3
11.8
12.3
dB
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz, V
S
= 5V
11.3
11.8
12.3
dB
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz, V
S
=
5V
11.2
11.7
12.2
dB
Filter Gain Temperature Coefficient (Note 2)
f
IN
= 260kHz, V
IN
= 2V
P-P
780
ppm/C
Noise
Noise BW = 10kHz to 2.5MHz
51
V
RMS
Distortion (Note 4)
1MHz, 1V
RMS
, R
L
= 800
2nd Harmonic
95
dBc
3rd Harmonic
88
dBc
Differential Output Swing
Measured Between Pins 4 and 5
V
S
= 5V
q
8.8
9.3
V
P-P DIFF
V
S
= 3V
q
5.1
5.5
V
P-P DIFF
Input Bias Current
Average of Pin 1 and Pin 8
q
35
15
A
Total Supply Voltage ................................................ 11V
Operating Temperature Range (Note 6) ...40
C to 85
C
Specified Temperature Range (Note 7) ....40
C to 85
C
Junction Temperature ........................................... 150
C
Storage Temperature Range ................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
ORDER PART
NUMBER
S8 PART MARKING
T
JMAX
= 150
C,
JA
= 100
C/W
660025
600I25
ABSOLUTE AXI U
RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
(Note 1)
ELECTRICAL CHARACTERISTICS
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
q
denotes specifications that apply over the full operating temperature
range, otherwise specifications are at T
A
= 25
C. Unless otherwise specified V
S
= 5V (V
+
= 5V, V
= 0V), R
IN
= 1580
, and R
LOAD
= 1k.
LT6600CS8-2.5
LT6600IS8-2.5
TOP VIEW
IN
+
V
MID
V
OUT
IN
V
OCM
V
+
OUT
+
S8 PACKAGE
8-LEAD PLASTIC SO
1
2
3
4
8
7
6
5
LT6600-2.5
3
660025i
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: This is the temperature coefficient of the internal feedback
resistors assuming a temperature independent external resistor (R
IN
).
Note 3: The input common mode voltage is the average of the voltages
applied to the external resistors (R
IN
). Specification guaranteed for
R
IN
402
.
Note 4: Distortion is measured differentially using a single-ended
stimulus. The input common mode voltage, the voltage at Pin 2, and the
voltage at Pin 7 are equal to one half of the total power supply voltage.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Referred Differential Offset
R
IN
= 1580
V
S
= 3V
q
5
25
mV
V
S
= 5V
q
5
30
mV
V
S
=
5V
q
5
35
mV
R
IN
= 402
V
S
= 3V
q
3
13
mV
V
S
= 5V
q
3
16
mV
V
S
=
5V
q
3
20
mV
Differential Offset Drift
10
V/
C
Input Common Mode Voltage (Note 3)
Differential Input = 500mV
P-P
,
V
S
= 3V
q
0.0
1.5
V
R
IN
= 402
V
S
= 5V
q
0.0
3.0
V
V
S
=
5V
q
2.5
1.0
V
Output Common Mode Voltage (Note 5)
Differential Input = 2V
P-P
,
V
S
= 3V
q
1.0
1.5
V
Pin 7 at Mid-Supply
V
S
= 5V
q
1.5
3.0
V
V
S
=
5V
q
1.0
2.0
V
Output Common Mode Offset
V
S
= 3V
q
25
10
45
mV
(with Respect to Pin 2)
V
S
= 5V
q
30
5
45
mV
V
S
=
5V
q
55
10
35
mV
Common Mode Rejection Ratio
63
dB
Voltage at V
MID
(Pin 7)
V
S
= 5V
q
2.46
2.51
2.55
V
V
S
= 3V
1.5
V
V
MID
Input Resistance
q
4.3
5.7
7.7
k
V
OCM
Bias Current
V
OCM
= V
MID
= V
S
/2
V
S
= 5V
q
15
3
A
V
S
= 3V
q
10
3
A
Power Supply Current
V
S
= 3V, V
S
= 5V
26
30
mA
V
S
= 3V, V
S
= 5V
q
33
mA
V
S
=
5V
q
28
36
mA
ELECTRICAL CHARACTERISTICS
Note 5: Output common mode voltage is the average of the voltages at
Pins 4 and 5. The output common mode voltage is equal to the voltage
applied to Pin 2.
Note 6: Both the LT6600CS8-2.5 and LT6600IS8-2.5 are guaranteed
functional over the operating temperature range of 40
C to 85
C.
Note 7: The LT6600CS8-2.5 is guaranteed to meet specified performance
from 0
C to 70
C and is designed, characterized and expected to meet
specified performance from 40
C and 85
C, but is not tested or QA
sampled at these temperatures. The LT6600IS8-2.5 is guaranteed to meet
specified performance from 40
C to 85
C.
The
q
denotes specifications that apply over the full operating temperature
range, otherwise specifications are at T
A
= 25
C. Unless otherwise specified V
S
= 5V (V
+
= 5V, V
= 0V), R
IN
= 1580
, and R
LOAD
= 1k.
LT6600-2.5
4
660025i
U
U
U
PI FU CTIO S
IN
and IN
+
(Pins 1, 8): Input Pins. Signals can be applied
to either or both input pins through identical external
resistors, R
IN
. The DC gain from differential inputs to the
differential outputs is 1580
/R
IN
.
V
OCM
(Pin 2): Is the DC Common Mode Reference Voltage
for the 2nd Filter Stage. Its value programs the common
mode voltage of the differential output of the filter. Pin 2 is
a high impedance input, which can be driven from an
external voltage reference, or Pin 2 can be tied to Pin 7 on
the PC board. Pin 2 should be bypassed with a 0.01
F
ceramic capacitor unless it is connected to a ground plane.
V
+
and V
(Pins 3, 6): Power Supply Pins. For a single
3.3V or 5V supply (Pin 6 grounded) a quality 0.1
F
ceramic bypass capacitor is required from the positive
supply pin (Pin 3) to the negative supply pin (Pin 6). The
bypass should be as close as possible to the IC. For dual
supply applications, bypass Pin 3 to ground and Pin 6 to
ground with a quality 0.1
F ceramic capacitor.
OUT
+
and OUT
(Pins 4, 5): Output Pins. Pins 4 and 5 are
the filter differential outputs. Each pin can drive a 100
and/or 50pF load to AC ground.
V
MID
(Pin 7): The V
MID
pin is internally biased at mid-
supply, see block diagram. For single supply operation,
the V
MID
pin should be bypassed with a quality 0.01
F
ceramic capacitor to Pin 6. For dual supply operation, Pin
7 can be bypassed or connected to a high quality DC
ground. A ground plane should be used. A poor ground
will increase noise and distortion. Pin 7 sets the output
common mode voltage of the 1st stage of the filter. It has
a 5.5k
impedance, and it can be overridden with an
external low impedance voltage source.
LT6600-2.5
5
660025i
BLOCK DIAGRA
W
+
+
V
OCM
+
+
V
OCM
1580
1580
800
800
800
800
1
2
3
4
V
+
V
11k
11k
8
7
6
5
OP AMP
PROPRIETARY
LOWPASS
FILTER STAGE
V
IN
V
IN
+
R
IN
R
IN
660025 BD
IN
+
V
OCM
V
+
OUT
+
OUT
V
V
MID
IN