6604-5 consists of two matched, fully differential
amplifiers, each with a 4th order, 5MHz lowpass filter. The
fixed frequency lowpass filter approximates a Chebyshev
response. By integrating a filter and a differential ampli-
fier, distortion and noise are made exceptionally low. At
unity gain, the measured in-band signal-to-noise ratio is
an impressive 82dB. At higher gains, the input referred
noise decreases, allowing the part to process smaller
input differential signals without significantly degrading
the signal-to-noise ratio.
Gain and phase are well matched between the two chan-
nels. Gain for each channel is independently programmed
using two external resistors. The LT6604-5 enables level
shifting by providing an adjustable output common mode
voltage, making it ideal for directly interfacing to ADCs.
The LT6604-5 is fully specified for 3V operation. The dif-
ferential design enables outstanding performance at a
2V
P-P
signal level for a single 3V supply.
See the back page of this datasheet for a complete list of
related single and dual differential amplifiers with integrated
2.5MHz to 20MHz lowpass filters.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
n
n
n
n
n
n
Dual Differential Amplifier with 5MHz Lowpass Filters
4th Order Filters
Approximates Chebyshev Response
Guaranteed Phase and Gain Matching
Resistor-Programmable Differential Gain
>82dB Signal-to-Noise (3V Supply, 2V
P-P
Output)
Low Distortion (1MHz, 2V
P-P
Output, 800Ω Load)
HD2: 93dBc
HD3: 96dBc
Specified for Operation with 3V, 5V and ±5V Supplies
Fully Differential Inputs and Outputs
Adjustable Output Common Mode Voltage
Small 4mm
×
7mm
×
0.75mm QFN Package
APPLICATIONS
n
n
n
n
n
n
n
Dual Differential ADC Driver and Filter
Single-Ended to Differential Converter
Matched, Dual, Differential Gain or Filter Stage
Common Mode Translation of Differential Signals
High Speed ADC Antialiasing and DAC Smoothing in
Wireless Infrastructure or Networking Applications
High Speed Test and Measurement Equipment
Medical Imaging
TYPICAL APPLICATION
3V
LT6604-5
V
+
A
3V
50Ω
50Ω
18pF
LTC22xx
DUAL ADC
25
Channel to Channel Gain Matching
50 TYPICAL UNITS
T
A
= 25°C
GAIN = 1
20 f = 5MHz
IN
NUMBER OF UNITS
15
–
806Ω
+INA
V
MIDA
V
OCMA
–INA
+
–
+
–OUTA
+OUTA
V
+
B
+
AIN
DOUT
0.01μF
+
806Ω
–
+
–
–
806Ω
3V
50Ω
50Ω
18pF
+INB
V
MIDB
V
OCMB
–INB
10
–
+
V
–
–OUTB
+OUTB
+
AIN
DOUT
0.01μF
5
+
806Ω
–
–
0
66045 TA01
–0.20
–0.10
0
0.10
GAIN MATCH (dB)
0.20
66045 TA01b
66045fa
1
LT6604-5
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
34 V
MIDA
33 NC
32 V
–
31 V
–
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
Input Current
+IN, –IN, V
OCM
, V
MID
(Note 8) ........................±10mA
NC 1
+INA 2
NC 3
–INA 4
NC 5
V
OCMA
6
V
–
7
V
MIDB
8
NC 9
+INB 10
NC 11
–INB 12
NC 13
V
OCMB
14
NC 15
NC 16
V
+
B 17
35
30 NC
29 –OUTA
28 NC
27 +OUTA
26 NC
25 V
+
A
24 V
–
23 NC
22 NC
21 –OUTB
20 NC
19 +OUTB
18 NC
UFF PACKAGE
34-LEAD (4mm 7mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 43°C/W,
θ
JC
= 4°C/W
EXPOSED PAD (PIN 35) IS V
–
, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT6604CUFF-5#PBF
LT6604IUFF-5#PBF
TAPE AND REEL
LT6604CUFF-5#TRPBF
LT6604IUFF-5#TRPBF
PART MARKING*
66045
66045
PACKAGE DESCRIPTION
34-Lead (4mm
×
7mm) Plastic QFN
34-Lead (4mm
×
7mm) Plastic QFN
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
66045fa
2
LT6604-5
ELECTRICAL CHARACTERISTICS
PARAMETER
Filter Gain Either Channel, V
S
= 3V
CONDITIONS
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
V
IN
= 2V
P-P
, f
IN
= 500kHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 2.5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 4MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 15MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 25MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
V
IN
= 2V
P-P
, f
IN
= 500kHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 2.5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 4MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 15MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 25MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 2.5MHz
V
IN
= 2V
P-P
, f
IN
= 4MHz
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
V
IN
= 2V
P-P
, f
IN
= 500kHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 2.5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 4MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 15MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 25MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
V
IN
= 2V
P-P
, f
IN
= 500kHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 2.5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 4MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 5MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 15MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 25MHz (Gain Relative to 260kHz)
V
IN
= 2V
P-P
, f
IN
= 2.5MHz
V
IN
= 2V
P-P
, f
IN
= 4MHz
V
IN
= 2V
P-P
, f
IN
= DC to 260kHz
V
IN
= 0.5V
P-P
, f
IN
= DC to 260kHz
V
S
= 3V
V
S
= 5V
V
S
= ±5V
f
IN
= 260kHz, V
IN
= 2V
P-P
Noise BW = 10kHz to 5MHz, R
IN
= 806Ω
V
IN
= 2V
P-P
, f
IN
= 1MHz, R
L
= 800Ω
2nd Harmonic
3rd Harmonic
V
IN
= 2V
P-P
, f
IN
= 5MHz, R
L
= 800Ω
2nd Harmonic
3rd Harmonic
V
IN
= 2V
P-P
, f
IN
= 1MHz
Measured Between OUT+ and OUT–, V
OCM
Shorted to V
MID
V
S
= 5V
V
S
= 3V
Average of IN+ and IN–
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
The
l
denotes the specifications which 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
= 806Ω, and
R
LOAD
= 1k.
MIN
–0.5
–0.15
–0.4
–0.7
–1.1
TYP
0
0
–0.1
–0.1
–0.2
–28
–44
0.05
0.005
0.01
0.03
0.05
0.15
0.1
0.2
0.5
–0.5
–0.15
–0.4
–0.7
–1.1
0
0
–0.1
–0.1
–0.2
–28
–44
0.05
0.005
0.01
0.03
0.05
0.15
0.1
0.2
0.5
–0.6
10.4
10.3
10.1
–0.1
10.9
10.8
10.7
780
45
93
96
66
73
–117
l
l
l
MAX
0.5
0.1
0.3
0.6
0.8
–25
0.7
0.1
0.2
0.5
0.6
1.8
2.8
2
3
0.5
0.1
0.3
0.6
0.8
–25
0.7
0.1
0.2
0.5
0.6
1.8
2.8
2
3
0.4
11.5
11.4
11.3
UNITS
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
deg
deg
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
deg
deg
dB
dB
dB
dB
ppm/°C
μV
RMS
dBc
dBc
dBc
dBc
dB
V
P-P_DIFF
V
P-P_DIFF
μA
Matching of Filter Gain, V
S
= 3V
Matching of Filter Phase, V
S
= 3V
Filter Gain Either Channel, V
S
= 5V
Matching of Filter Gain, V
S
= 5V
Matching of Filter Phase, V
S
= 5V
Filter Gain Either Channel, V
S
= ±5V
Filter Gain, R
IN
= 229Ω
Filter Gain Temperature Coefficient (Note 2)
Noise
Distortion (Note 4)
Channel Separation (Note 9)
Differential Output Swing
Input Bias Current
3.85
3.85
–70
4.8
4.8
–30
66045fa
3
LT6604-5
ELECTRICAL CHARACTERISTICS
PARAMETER
Input Referred Differential Offset
CONDITIONS
R
IN
= 806Ω
V
S
= 3V
V
S
= 5V
V
S
= ±5V
R
IN
= 229Ω
V
S
= 3V
V
S
= 5V
V
S
= ±5V
Differential Input = 500mV
P-P
, R
IN
= 229Ω
V
S
= 3V
V
S
= 5V
V
S
= ±5V
Differential Output = 2V
P-P
, V
MID
= OPEN
V
S
= 3V
V
S
= 5V
V
S
= ±5V
V
S
= 3V
V
S
= 5V
V
S
= ±5V
V
S
= 5V
V
S
= 3V
V
OCM
= V
MID
= V
S
/2
V
S
= 5V
V
S
= 3V
V
S
= 3V, V
S
= 5V
V
S
= 3V, V
S
= 5V
V
S
= ±5V
l
l
l
l
l
l
The
l
denotes the specifications which 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
= 806Ω, and
R
LOAD
= 1k.
MIN
TYP
5
10
8
5
5
5
10
0
0
–2.5
1
1.5
–1
–25
–30
–55
2.45
4.3
–15
–10
MAX
25
30
35
13
16
20
UNITS
mV
mV
mV
mV
mV
mV
μV/°C
V
V
V
V
V
V
mV
mV
mV
dB
V
V
kΩ
μA
μA
mA
mA
mA
Differential Offset Drift
Input Common Mode Voltage (Note 3)
l
l
l
l
l
l
l
l
l
l
l
l
1.5
3
1
1.5
3
2
50
45
35
2.56
7.7
Output Common Mode Voltage (Note 5)
Output Common Mode Offset
(with Respect to V
OCM
)
Common Mode Rejection Ratio
Voltage at V
MID
V
MID
Input Resistance
V
OCM
Bias Current
Power Supply Current
(Per Channel)
5
5
–5
61
2.51
1.5
5.5
–3
–3
28
30
l
l
31
34
38
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
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
≥
229Ω.
Note 4:
Distortion is measured differentially using a differential stimulus.
The input common mode voltage, the voltage at V
OCM
, and the voltage at
V
MID
are equal to one half of the total power supply voltage.
Note 5:
Output common mode voltage is the average of the +OUT and
–OUT voltages. The output common mode voltage is equal to V
OCM
.
Note 6:
The LT6604C-5 is guaranteed functional over the operating
temperature range –40°C to 85°C.
Note 7:
The LT6604C-5 is guaranteed to meet 0°C to 70°C specifications
and is designed, characterized and expected to meet the extended
temperature limits, but is not tested at –40°C to 85°C. The LT6604I-5 is
guaranteed to meet specified performance from –40°C to 85°C.
Note 8:
Input pins (+IN, –IN, V
OCM
and V
MID
) are protected by steering
diodes to either supply. If the inputs should exceed either supply voltage,
the input current should be limited to less than 10mA. In addition, the
inputs +IN, –IN are protected by a pair of back-to-back diodes. If the
differential input voltage exceeds 1.4V, the input current should be limited
to less than 10mA
Note 9:
Channel separation (the inverse of crosstalk) is measured by
driving a signal into one input while terminating the other input. Channel
separation is the ratio of the resulting output signal at the driven channel
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