FEATURES
■
■
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LT1993-4
900MHz Low Distortion, Low
Noise Differential Amplifier/
ADC Driver (A
V
= 4V/V)
DESCRIPTIO
The LT
®
1993-4 is a low distortion, low noise Differential
Amplifier/ADC driver for use in applications from DC to
900MHz. The LT1993-4 has been designed for ease of
use, with minimal support circuitry required. Exception-
ally low input-referred noise and low distortion products
(with either single-ended or differential inputs) make the
LT1993-4 an excellent solution for driving high speed 12-
bit and 14-bit ADCs. In addition to the normal unfiltered
outputs (+OUT and –OUT), the LT1993-4 has a built-in
175MHz differential lowpass filter and an additional pair
of filtered outputs (+OUTFILTERED, –OUTFILTERED) to
reduce external filtering components when driving high
speed ADCs. The output common mode voltage is easily set
via the V
OCM
pin, eliminating either an output transformer
or AC-coupling capacitors in many applications.
The LT1993-4 is designed to meet the demanding require-
ments of communications transceiver applications. It can
be used as a differential ADC driver, a general-purpose
differential gain block, or in any other application requir-
ing differential drive. The LT1993-4 can be used in data
acquisition systems required to function at frequencies
down to DC.
The LT1993-4 operates on a 5V supply and consumes
100mA. It comes in a compact 16-lead 3
×
3 QFN package
and operates over a –40°C to 85°C temperature range.
4-Tone WCDMA Waveform,
LT1993-4 Driving LTC2255
14-Bit ADC at 92.16Msps
0
–10
32768 POINT FFT
TONE CENTER FREQUENCIES
AT 62.5MHz, 67.5MHz,
72.5MHz, 77.5MHz
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■
■
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■
■
■
900MHz –3dB Bandwidth
Fixed Gain of 4V/V (12dB)
Low Distortion:
40dBm OIP3, –73dBc HD3 (70MHz 2V
P-P
)
51dBm OIP3, –94dBc HD3 (10MHz 2V
P-P
)
Low Noise: 14.5dB NF, e
n
= 2.35nV/√Hz (70MHz)
Differential Inputs and Outputs
Additional Filtered Outputs
Adjustable Output Common Mode Voltage
DC- or AC-Coupled Operation
Minimal Support Circuitry Required
Small 0.75mm Tall 16-Lead 3
×
3 QFN Package
APPLICATIO S
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■
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■
Differential ADC Driver for:
Imaging
Communications
Differential Driver/Receiver
Single Ended to Differential Conversion
Differential to Single Ended Conversion
Level Shifting
IF Sampling Receivers
SAW Filter Interfacing/Buffering
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
1:1
Z-RATIO
ADC Driver with Single-Ended to Differential Conversion
0.1µF
–OUT
82nH
AMPLITUDE (dBFS)
–INB
–INA
12.2Ω
AIN–
52.3pF
LTC2255
ADC
AIN+
12.2Ω
LTC2255 125Msps
14-BIT ADC SAMPLING
AT 92.16Msps
19934 TA01
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
0
70MHz
IF IN
100Ω
MA/COM
ETC1-1-13
0.1µF
–OUTFILTERED
LT1993-4
+OUTFILTERED
+INB
+OUT
+INA
V
OCM
ENABLE
2.2V
12dB GAIN
U
U
U
•
•
5
10
15 20 25 30 35
FREQUENCY (MHz)
40
45
LT19934 TA02
19934fa
1
LT1993-4
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
+INA
+INB
–INA
–INB
16 15 14 13
V
CCC
1
V
OCM
2
V
CCA
3
V
EEA
4
5
+OUT
6
+OUTFILTERED
7
–OUTFILTERED
8
–OUT
17
12 V
EEC
11 ENABLE
10 V
CCB
9
V
EEB
Total Supply Voltage (V
CCA
/V
CCB
/V
CCC
to
V
EEA
/V
EEB
/V
EEC
) ...................................................5.5V
Input Current (+INA, –INA, +INB, –INB,
V
OCM
, ENABLE)................................................±10mA
Output Current (Continuous) (Note 6)
+OUT, –OUT (DC) ..........................................±100mA
(AC) ..........................................±100mA
+OUTFILTERED, –OUTFILTERED (DC) .............±15mA
(AC) .............±45mA
Output Short Circuit Duration (Note 2) ............ Indefinite
Operating Temperature Range (Note 3) ... –40°C to 85°C
Specified Temperature Range (Note 4) .... –40°C to 85°C
Storage Temperature Range................... –65°C to 125°C
Junction Temperature ........................................... 125°C
Lead Temperature Range (Soldering 10 sec) ........ 300°C
UD PACKAGE
16-LEAD (3mm
×
3mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 68°C/W,
θ
JC
= 4.2°C/W
EXPOSED PAD IS V
EE
(PIN 17)
MUST BE SOLDERED TO THE PCB
ORDER PART NUMBER
LT1993CUD-4
LT1993IUD-4
UD PART MARKING*
LBNS
LBNS
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
*The temperature grade is identified by a label on the shipping container.
DC ELECTRICAL CHARACTERISTICS
SYMBOL
GDIFF
V
SWINGMIN
V
SWINGMAX
V
SWINGDIFF
I
OUT
V
OS
TCV
OS
I
VRMIN
I
VRMAX
R
INDIFF
C
INDIFF
Output Voltage Swing
Output Current Drive
Input Offset Voltage
PARAMETER
Gain
CONDITIONS
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CCA
= V
CCB
= V
CCC
= 5V, V
EEA
= V
EEB
= V
EEC
= 0V, ENABLE = 0.8V, +INA
shorted to +INB (+IN), –INA shorted to –INB (–IN), V
OCM
= 2.2V, Input common mode voltage = 2.2V, no R
LOAD
unless otherwise noted.
MIN
●
●
●
●
●
●
TYP
11.9
0.25
MAX
12.4
0.35
0.5
UNITS
dB
V
V
V
V
V
P-P
V
P-P
mA
Input/Output Characteristics (+INA, +INB, –INA, –INB, +OUT, –OUT, +OUTFILTERED, –OUTFILTERED)
Differential (+OUT, –OUT), V
IN
= ±0.4V Differential
Single-Ended +OUT, –OUT, +OUTFILTERED,
–OUTFILTERED. V
IN
= ±1.2V Differential
Single-Ended +OUT, –OUT, +OUTFILTERED,
–OUTFILTERED. V
IN
= ±1.2V Differential
Differential (+OUT, –OUT), V
IN
= ±1.2V
P-P
Differential
(Note 5)
11.6
3.6
3.5
6.5
6
±40
–6.5
–10
3.75
7
±45
1
2.5
0.5
6.5
10
Input Offset Voltage Drift
Input Voltage Range, MIN
Input Voltage Range, MAX
Differential Input Resistance
Differential Input Capacitance
T
MIN
to T
MAX
Single-Ended
Single-Ended
●
●
●
●
µV/°C
V
V
Ω
pF
19934fa
4.3
77
100
1
122
2
U
mV
mV
W
U
U
W W
W
LT1993-4
DC ELECTRICAL CHARACTERISTICS
SYMBOL
CMRR
R
OUTDIFF
C
OUTDIFF
GCM
V
OCMMIN
V
OCMMAX
V
OSCM
I
BIASCM
R
INCM
C
INCM
ENABLE Pin
V
IL
V
IH
I
IL
I
IH
Power Supply
V
S
I
S
I
SDISABLED
PSRR
Operating Range
Supply Current
Supply Current (Disabled)
Power Supply Rejection Ratio
ENABLE = 0.8V
ENABLE = 2V
4V to 5.5V
●
●
●
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CCA
= V
CCB
= V
CCC
= 5V, V
EEA
= V
EEB
= V
EEC
= 0V, ENABLE = 0.8V, +INA
shorted to +INB (+IN), –INA shorted to –INB (–IN), V
OCM
= 2.2V, Input common mode voltage = 2.2V, no R
LOAD
unless otherwise noted.
PARAMETER
Common Mode Rejection Ratio
Output Resistance
Output Capacitance
Common Mode Gain
Output Common Mode Voltage
Adjustment Range, MIN
Output Common Mode Voltage
Adjustment Range, MAX
Output Common Mode Offset
Voltage
V
OCM
Input Bias Current
V
OCM
Input Resistance
V
OCM
Input Capacitance
ENABLE Input Low Voltage
ENABLE Input High Voltage
ENABLE Input Low Current
ENABLE Input High Current
ENABLE = 0.8V
ENABLE = 2V
●
●
●
●
CONDITIONS
Input Common Mode 0.5V to 4.3V
●
MIN
45
TYP
70
0.3
0.8
MAX
UNITS
dB
Ω
pF
Common Mode Voltage Control (V
OCM
Pin)
Differential (+OUT, –OUT), V
OCM
= 1.2V to 3.6V
Differential (+OUT, –OUT), V
OCM
= 1.4V to 3.4V
Measured Single-Ended at +OUT and –OUT
●
0.9
●
1
1.1
1.1
1.2
1.4
V/V
V/V
V
V
V
V
0.9
Measured Single-Ended at +OUT and –OUT
●
3.6
3.4
–30
2
5
0.8
3
1
0.8
2
0.5
1
4
88
55
5
100
250
90
3
5.5
112
500
30
15
Measured from V
OCM
to Average of +OUT and –OUT
●
●
●
mV
µA
MΩ
pF
V
V
µA
µA
V
mA
µA
dB
AC ELECTRICAL CHARACTERISTICS
SYMBOL
–3dBBW
0.1dBBW
0.5dBBW
SR
t
s1%
t
ON
t
OFF
PARAMETER
–3dB Bandwidth
Bandwidth for 0.1dB Flatness
Bandwidth for 0.5dB Flatness
Slew Rate
1% Settling Time
Turn-On Time
Turn-Off Time
Input/Output Characteristics
T
A
= 25°C, V
CCA
= V
CCB
= V
CCC
= 5V, V
EEA
= V
EEB
= V
EEC
= 0V,
ENABLE = 0.8V, +INA shorted to +INB (+IN), –INA shorted to –INB (–IN), V
OCM
= 2.2V, Input common mode voltage = 2.2V, no R
LOAD
unless otherwise noted.
CONDITIONS
200mV
P-P
Differential (+OUT, –OUT)
200mV
P-P
Differential (+OUT, –OUT)
200mV
P-P
Differential (+OUT, –OUT)
3.2V
P-P
Differential (+OUT, –OUT)
1% Settling for a 1V
P-P
Differential Step
(+OUT, –OUT)
MIN
500
TYP
900
50
100
1100
4
40
250
MAX
UNITS
MHz
MHz
MHz
V/µs
ns
ns
ns
19934fa
3
LT1993-4
AC ELECTRICAL CHARACTERISTICS
SYMBOL
–3dBBW
CM
SRCM
1kHz Signal
Second/Third Harmonic Distortion
2V
P-P
Differential (+OUTFILTERED, –OUTFILTERED)
2V
P-P
Differential (+OUT, –OUT)
2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
3.2V
P-P
Differential (+OUTFILTERED,
–OUTFILTERED)
3.2V
P-P
Differential (+OUT, –OUT)
3.2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
Third-Order IMD
2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 0.95kHz, f2 = 1.05kHz
2V
P-P
Differential Composite (+OUT, –OUT),
R
L
= 100Ω, f1 = 0.95kHz, f2 = 1.05kHz
3.2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 0.95kHz, f2 = 1.05kHz
Differential (+OUTFILTERED, –OUTFILTERED),
f1 = 0.95kHz, f2 = 1.05kHz
–100
–100
–100
–91
–91
–91
–102
–102
–93
54
2.15
22.7
2V
P-P
Differential (+OUTFILTERED, –OUTFILTERED)
2V
P-P
Differential (+OUT, –OUT)
2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
3.2V
P-P
Differential (+OUTFILTERED,
–OUTFILTERED)
3.2V
P-P
Differential (+OUT, –OUT)
3.2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
Third-Order IMD
2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 9.5MHz, f2 = 10.5MHz
2V
P-P
Differential Composite (+OUT, –OUT),
R
L
= 100Ω, f1 = 9.5MHz, f2 = 10.5MHz
3.2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 9.5MHz, f2 = 10.5MHz
Differential (+OUTFILTERED, –OUTFILTERED),
f1 = 9.5MHz, f2 = 10.5MHz
Measured Using DC800A Demo Board
–94
–94
–86
–85
–85
–77
–96
–96
–87
51
13.7
2.15
22.6
2V
P-P
Differential (+OUTFILTERED, –OUTFILTERED)
2V
P-P
Differential (+OUT, –OUT)
2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
–80
–78
–75
dBc
dBc
dBc
dBc
dBc
dBc
dBc
dBc
dBc
dBm
nV/√Hz
dBm
dBc
dBc
dBc
dBc
dBc
dBc
dBc
dBc
dBc
dBm
dB
nV/√Hz
dBm
dBc
dBc
dBc
19934fa
T
A
= 25°C, V
CCA
= V
CCB
= V
CCC
= 5V, V
EEA
= V
EEB
= V
EEC
= 0V,
ENABLE = 0.8V, +INA shorted to +INB (+IN), –INA shorted to –INB (–IN), V
OCM
= 2.2V, Input common mode voltage = 2.2V, no R
LOAD
unless otherwise noted.
PARAMETER
Common Mode Small-Signal –3dB
Bandwidth
Common Mode Slew Rate
CONDITIONS
0.1V
P-P
at V
OCM
, Measured Single-Ended at +OUT
and –OUT
1.2V to 3.6V Step at V
OCM
MIN
TYP
300
500
MAX
UNITS
MHz
V/µs
Common Mode Voltage Control (V
OCM
Pin)
Noise/Harmonic Performance Input/output Characteristics
OIP3
1k
e
n1k
10MHz Signal
Output Third-Order Intercept
Input Referred Noise Voltage Density
1dB Compression Point
Second/Third Harmonic Distortion
OIP3
10M
NF
e
n10M
50MHz Signal
Output Third-Order Intercept
Noise Figure
Input Referred Noise Voltage Density
1dB Compression Point
Second/Third Harmonic Distortion
4
LT1993-4
AC ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
T
A
= 25°C, V
CCA
= V
CCB
= V
CCC
= 5V, V
EEA
= V
EEB
= V
EEC
= 0V,
ENABLE = 0.8V, +INA shorted to +INB (+IN), –INA shorted to –INB (–IN), V
OCM
= 2.2V, Input common mode voltage = 2.2V, no R
LOAD
unless otherwise noted.
CONDITIONS
3.2V
P-P
Differential (+OUTFILTERED,
–OUTFILTERED)
3.2V
P-P
Differential (+OUT, –OUT)
3.2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
Third-Order IMD
2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 49.5MHz, f2 = 50.5MHz
2V
P-P
Differential Composite (+OUT, –OUT),
R
L
= 100Ω, f1 = 49.5MHz, f2 = 50.5MHz
3.2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 49.5MHz, f2 = 50.5MHz
Differential (+OUTFILTERED, –OUTFILTERED),
f1 = 49.5MHz, f2 = 50.5MHz
Measured Using DC800A Demo Board
MIN
TYP
–71
–69
–66
–81
–80
–72
43
14.1
2.25
19.7
2V
P-P
Differential (+OUTFILTERED, –OUTFILTERED)
2V
P-P
Differential (+OUT, –OUT)
2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
Third-Order IMD
2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 69.5MHz, f2 = 70.5MHz
2V
P-P
Differential Composite (+OUT, –OUT),
R
L
= 100Ω, f1 = 69.5MHz, f2 = 70.5MHz
Differential (+OUTFILTERED, –OUTFILTERED),
f1 = 69.5MHz, f2 = 70.5MHz
Measured Using DC800A Demo Board
–73
–71
–70
–74
–71
40
14.5
2.35
18.5
2V
P-P
Differential (+OUTFILTERED, –OUTFILTERED)
2V
P-P
Differential (+OUT, –OUT)
2V
P-P
Differential (+OUT, –OUT), R
L
= 100Ω
Third-Order IMD
2V
P-P
Differential Composite (+OUTFILTERED,
–OUTFILTERED), f1 = 99.5MHz, f2 = 100.5MHz
2V
P-P
Differential Composite (+OUT, –OUT),
R
L
= 100Ω, f1 = 99.5MHz, f2 = 100.5MHz
Differential (+OUTFILTERED, –OUTFILTERED),
f1 = 99.5MHz, f2 = 100.5MHz
Measured Using DC800A Demo Board
–61
–63
–62
–61
–63
33.5
15.1
2.55
17.8
MAX
UNITS
dBc
dBc
dBc
dBc
dBc
dBc
dBm
dB
nV/√Hz
dBm
dBc
dBc
dBc
dBc
dBc
dBm
dB
nV/√Hz
dBm
dBc
dBc
dBc
dBc
dBc
dBm
dB
nV/√Hz
dBm
OIP3
50M
NF
e
n50M
70MHz Signal
Output Third-Order Intercept
Noise Figure
Input Referred Noise Voltage Density
1dB Compression Point
Second/Third Harmonic Distortion
OIP3
70M
NF
e
n70M
100MHz Signal
Output Third-Order Intercept
Noise Figure
Input Referred Noise Voltage Density
1dB Compression Point
Second/Third Harmonic Distortion
OIP3
100M
NF
e
n100M
Output Third-Order Intercept
Noise Figure
Input Referred Noise Voltage Density
1dB Compression Point
Note 1:
Absolute Maximum Ratings are those values beyond which the life of a
device may be impaired.
Note 2:
As long as output current and junction temperature are kept below the
Absolute Maximum Ratings, no damage to the part will occur.
Note 3:
The LT1993C-4 is guaranteed functional over the operating temperature
range of –40°C to 85°C.
Note 4:
The LT1993C-4 is guaranteed to meet specified performance from 0°C to
70°C. It 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
LT1993I-4 is guaranteed to meet specified performance from –40°C to 85°C.
Note 5:
This parameter is pulse tested.
Note 6:
This parameter is guaranteed to meet specified performance through design
and characterization. It has not been tested.
19934fa
5
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