1
LT1221
150MHz, 250V/
s, A
V
4
Operational Amplifier
S
FEATURE
D
U
ESCRIPTIO
s
Gain-Bandwidth: 150MHz
s
Gain of 4 Stable
s
Slew Rate: 250V/
s
s
Input Noise Voltage: 6nV/
Hz
s
C-Load
TM
Op Amp Drives Capacitive Loads
s
Maximum Input Offset Voltage: 600
V
s
Maximum Input Bias Current: 300nA
s
Maximum Input Offset Current: 300nA
s
Minimum Output Swing Into 500
:
12V
s
Minimum DC Gain: 50V/mV, R
L
= 500
s
Settling Time to 0.1%: 65ns, 10V Step
s
Settling Time to 0.01%: 85ns, 10V Step
s
Differential Gain: 0.08%, A
V
= 4, R
L
= 150
s
Differential Phase: 0.2
, A
V
= 4, R
L
= 150
The LT1221 is a very high speed operational amplifier with
superior DC performance. The LT1221 is stable in a noise
gain of 4 or greater. It features reduced input offset
voltage, lower input bias currents and higher DC gain than
devices with comparable bandwidth and slew rate. The
circuit is a single gain stage that includes proprietary DC
gain enhancement circuitry to obtain precision with high
speed. The high gain and fast settling time make the circuit
an ideal choice for data acquisition systems. The circuit is
also capable of driving capacitive loads which makes it
useful in buffer or cable driver applications.
The LT1221 is a member of a family of fast, high perfor-
mance amplifiers that employ Linear Technology
Corporation's advanced complementary bipolar process-
ing. For unity-gain stable applications the LT1220 can be
used, and for gains of 10 or greater the LT1222 can be used.
TYPICAL APPLICATIO
N
U
Summing Amplifier
Summing Amplifier Large-Signal Response
LT1221 TA02
V
S
=
15V
V
IN
= 10V
P-P
f = 2MHz
U
S
A
O
PPLICATI
s
Wideband Amplifiers
s
Buffers
s
Active Filters
s
Video and RF Amplification
s
Cable Drivers
s
8-, 10-, 12-Bit Data Acquisition Systems
LT1221 TA01
+
1k
1k
1k
1k
LT1221
V
A
V
B
V
C
V
OUT
and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.
C-Load is a trademark of Linear Technology Cortporation.
2
LT1221
A
U
G
W
A
W
U
W
A
R
BSOLUTE
XI
TI
S
Total Supply Voltage (V
+
to V
) ............................. 36V
Differential Input Voltage ........................................
6V
Input Voltage ..........................................................
V
S
Output Short-Circuit Duration (Note 1) ........... Indefinite
Specified Temperature Range
LT1221C (Note 2) ................................... 0
C to 70
C
LT1221M ......................................... 55
C to 125
C
Operating Temperature Range
LT1221C ........................................... 40
C TO 85
C
LT1221M ......................................... 55
C to 125
C
Maximum Junction Temperature (See Below)
Plastic Package ............................................... 150
C
Ceramic Package ............................................. 175
C
Storage Temperature Range ................ 65
C to 150
C
Lead Temperature (Soldering, 10 sec) ................. 300
C
W
U
U
PACKAGE/ORDER I FOR ATIO
Consult factory for Industrial grade parts.
LT1221CN8
LT1221MJ8
LT1221CS8
ORDER PART
NUMBER
1
2
3
4
8
7
6
5
TOP VIEW
NULL
IN
+IN
V
NULL
V
+
V
OUT
NC
N8 PACKAGE
8-LEAD PLASTIC DIP
S8 PACKAGE
8-LEAD PLASTIC SOIC
J8 PACKAGE
8-LEAD CERAMIC DIP
T
JMAX
= 175
C,
JA
= 100
C/W (J)
T
JMAX
= 150
C,
JA
= 130
C/W (N)
T
JMAX
= 150
C,
JA
= 190
C/W (S)
S8 PART MARKING
1221
ORDER PART
NUMBER
SPECIAL
ORDER
CONSULT
FACTORY
T
JMAX
= 175
C,
JA
= 150
C/W
TOP VIEW
V
+
NULL
NULL
IN
V
OUT
NC
+IN
V
8
7
6
5
3
2
1
4
H PACKAGE
8-LEAD TO-5 METAL CAN
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
(Note 3)
200
600
V
I
OS
Input Offset Current
100
300
nA
I
B
Input Bias Current
100
300
nA
e
n
Input Noise Voltage
f = 10kHz
6
nV/
Hz
i
n
Input Noise Current
f = 10kHz
2
pA/
Hz
R
IN
Input Resistance
V
CM
=
12V
20
45
M
Differential
80
k
C
IN
Inut Capacitance
2
pF
Input Voltage Range (Positive)
12
14
V
Input Voltage Range (Negative)
13
12
V
CMRR
Common-Mode Rejection Ratio
V
CM
=
12V
92
114
dB
PSRR
Power Supply Rejection Ratio
V
S
=
5V to
15V
90
110
dB
A
VOL
Large-Signal Voltage Gain
V
OUT
=
10V, R
L
= 500
50
100
V/mV
V
OUT
Output Swing
R
L
= 500
12
13
V
I
OUT
Output Current
V
OUT
=
12V
24
26
mA
SR
Slew Rate
(Note 4)
200
250
V/
s
Full Power Bandwidth
10V Peak (Note 5)
4
MHz
GBW
Gain-Bandwidth
f = 1MHz
150
MHz
V
S
=
15V, T
A
= 25
C, V
CM
= 0V, unless otherwise specified.
ELECTRICAL CHARACTERISTICS
3
LT1221
ELECTRICAL CHARACTERISTICS
V
S
=
15V, T
A
= 25
C, V
CM
= 0V, unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t
r
, t
f
Rise Time, Fall Time
A
V
= 4, 10% to 90%, 0.1V
3.2
ns
Overshoot
A
V
= 4, 0.1V
10
%
Propagation Delay
A
V
= 4, 50% V
IN
to 50% V
OUT
, 0.1V
5.4
ns
t
s
Settling Time
10V Step, 0.1%
65
ns
10V Step, 0.01%
85
ns
Differential Gain
f = 3.58MHz, R
L
= 150
(Note 6)
0.08
%
f = 3.58MHz, R
L
= 1k (Note 6)
0.02
%
Differential Phase
f = 3.58MHz, R
L
= 150
(Note 6)
0.20
DEG
f = 3.58MHz, R
L
= 1k (Note 6)
0.05
DEG
R
O
Output Resistance
A
V
= 4, f = 1MHz
0.3
I
S
Supply Current
8
10.5
mA
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
(Note 3)
q
0.2
1.5
mV
Input V
OS
Drift
15
V/
C
I
OS
Input Offset Current
q
100
400
nA
I
B
Input Bias Current
q
100
400
nA
CMRR
Common-Mode Rejection Ratio
V
CM
=
12V
q
92
114
dB
PSRR
Power Supply Rejection Ratio
V
S
=
5V to
15V
q
90
110
dB
A
VOL
Large-Signal Voltage Gain
V
OUT
=
10V, R
L
= 500
q
40
100
V/mV
V
OUT
Output Swing
R
L
= 500
q
12
13
V
I
OUT
Output Current
V
OUT
=
12V
q
24
26
mA
SR
Slew Rate
(Note 4)
q
180
250
V/
s
I
S
Supply Current
q
8
11
mA
V
S
=
15V, 0
C
T
A
70
C, V
CM
= 0V, unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
(Note 3)
q
0.2
2
mV
Input V
OS
Drift
15
V/
C
I
OS
Input Offset Current
q
100
800
nA
I
B
Input Bias Current
q
100
1000
nA
CMRR
Common-Mode Rejection Ratio
V
CM
=
12V
q
92
114
dB
PSRR
Power Supply Rejection Ratio
V
S
=
5V to
15V
q
90
110
dB
A
VOL
Large-Signal Voltage Gain
V
OUT
=
10V, R
L
= 500
q
12.5
100
V/mV
V
OUT
Output Swing
R
L
= 500
q
10
13
V
R
L
= 1k
q
12
13
V
I
OUT
Output Current
V
OUT
=
10V
q
20
26
mA
V
OUT
=
12V
q
12
13
mA
SR
Slew Rate
(Note 4)
q
130
250
V/
s
I
S
Supply Current
q
8
11
mA
V
S
=
15V, 55
C
T
A
125
C, V
CM
= 0V, unless otherwise specified.
The
q
denotes specifications which apply over the full temperature range.
Note 1: A heat sink may be required when the output is shorted indefinitely.
Note 2: Commercial parts are designed to operate over 40
C to 85
C, but
are not tested nor guaranteed beyond 0
C to 70
C. Industrial grade parts
specified and tested over 40
C to 85
C are available on special request.
Consult factory.
Note 3: Input offset voltage is pulse tested and is exclusive of warm-up drift.
Note 4: Slew rate is measured between
10V on an output swing of
12V.
Note 5: FPBW = SR/2
V
P
.
Note 6: Differential Gain and Phase are tested in A
V
= 4 with five amps in
series. Attenuators of 1/4 are used as loads (36.5
, 110
and
249
, 750
).
4
LT1221
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
Input Common-Mode Range
vs Supply Voltage
Output Voltage Swing
vs Resistive Load
Output Short-Circuit Current
vs Temperature
Power Supply Rejection Ratio
vs Frequency
Open-Loop Gain
vs Resistive Load
Output Voltage Swing
vs Supply Voltage
Supply Current vs Supply Voltage
and Temperature
Input Bias Current
vs Input Common-Mode Voltage
SUPPLY VOLTAGE (V)
0
0
MAGNITUDE OF INPUT VOLTAGE (V)
5
10
15
20
5
10
15
20
LT1221 TPC01
T
A
= 25C
V
OS
= 0.5mV
+V
CM
V
CM
SUPPLY VOLTAGE (V)
0
5
SUPPLY CURRENT (mA)
6
7
8
9
10
11
5
10
15
20
LT1221 TPC02
T = 125C
T = 25C
T = 55C
0
0
MAGNITUDE OF OUTPUT VOLATGE (V)
5
10
15
20
5
10
15
20
LT1221 TPC03
+V
SW
V
SW
SUPPLY VOLTAGE (V)
T
A
= 25C
R
L
= 500
V
OS
= 30mV
LOAD RESISTANCE (
)
10
0
OUTPUT VOLTAGE SWING (V
P-P
)
10
20
25
30
100
1k
10k
LT1221 TPC04
5
15
5V SUPPLIES
15V SUPPLIES
T
A
= 25C
V
OS
= 30mV
INPUT COMMON-MODE VOLTAGE (V)
15
500
INPUT BIAS CURRENT (nA)
0
500
0
5
15
LT1221 TPC05
10
5
10
400
300
200
100
100
200
300
400
I
B
+
I
B
T
A
= 25C
V
S
= 15V
LOAD RESISTANCE (
)
10
60
OPEN-LOOP GAIN (dB)
80
100
110
100
1k
10k
LT1221 TPC06
70
90
T
A
= 25C
V
S
= 15V
V
S
= 5V
TEMPERATURE (C)
50
20
OUTPUT SHORT-CIRCUIT CURRENT (mA)
30
35
45
50
25
50
100
125
LT1221 TPC07
25
40
0
25
75
V
S
= 5V
FREQUENCY (Hz)
100
0
POWER SUPPLY REJECTION RATIO (dB)
10
20
40
60
80
100
1k
100k
10M
100M
LT1221 TPC09
10k
1M
V
S
= 15V
T
A
= 25C
PSRR
+PSRR
Input Noise Spectral Density
FREQUENCY (Hz)
INPUT NOISE VOLTAGE (nV/
Hz)
100
10
1000
10
1k
10k
100k
LT1221 TPC08
1
100
INPUT NOISE CURRENT (pA/
Hz)
10
1
100
0.1
V
S
= 15V
T
A
= 25C
A
V
= 101
R
S
= 100k
e
n
i
n
5
LT1221
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
Common-Mode Rejection Ratio
vs Frequency
Voltage Gain and Phase
vs Frequency
Total Harmonic Distortion
vs Frequency
Slew Rate vs Temperature
Closed-Loop Output Impedance
vs Frequency
Output Swing and Error
vs Settling Time (Inverting)
Output Swing and Error
vs Settling Time (Noninverting)
Gain-Bandwidth vs Temperature
FREQUENCY (Hz)
1k
0
COMMON-MODE REJECTION RATIO (dB)
20
40
60
80
100
120
100k
10M
100M
LT1221 TPC10
10k
1M
V
S
= 15V
T
A
= 25C
SETTLING TIME (ns)
0
OUTPUT SWING (V)
2
6
10
100
LT1220 TPC11
2
6
0
4
8
4
8
10
25
50
75
125
10mV
10mV
1mV
1mV
V
S
= 15V
T
A
= 25C
SETTLING TIME (ns)
0
OUTPUT SWING (V)
2
6
10
100
LT1221 TPC12
2
6
0
4
8
4
8
10
25
50
75
125
10mV
10mV
1mV
1mV
V
S
= 15V
T
A
= 25C
20
60
100
80
FREQUENCY (Hz)
100
20
VOLTAGE GAIN (dB)
40
10k
1M
100M
LT1221 TPC13
1k
100k
V
S
= 15V
0
10M
20
60
100
80
20
PHASE MARGIN (DEG)
40
0
V
S
= 5V
V
S
= 15V
V
S
= 5V
T
A
= 25C
FREQUENCY (Hz)
0.01
OUTPUT IMPEDANCE (
)
0.1
1
10
10k
1M
10M
100M
LT1221 TPC15
0.001
100k
V
S
= 15V
T
A
= 25C
A
V
= 4
Frequency Response
vs Capacitive Load
180
TEMPERATURE (C)
50
120
GAIN-BANDWIDTH (MHz)
125
LT1221 TPC16
0
130
150
170
25
75
V
S
= 15V
160
140
25
50
100
325
TEMPERATURE (C)
50
175
SLEW RATE (V/
s)
125
LT1221 TPC19
0
200
250
300
25
75
275
225
25
50
100
V
S
= 15V
A
V
= 5
SR =
(SR
+
) + (SR
)
2
FREQUENCY (Hz)
10
100
0.0001
TOTAL HARMONIC DISTORTION AND NOISE (%)
0.001
0.01
1k
10k
100k
LT1220 TPC18
A
V
= 4
V
S
= 15V
V
O
= 3V
RMS
R
L
= 500
A
V
= 4
10
18
24
22
FREQUENCY (MHz)
1
4
VOLTAGE MAGNITUDE (dB)
14
100
LT1221 TPC14
10
8
6
12
16
20
C = 1000pF
C = 50pF
C = 0
V
S
= 15V
T
A
= 25C
A
V
= 5
C = 500pF
C = 100pF
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