View LT1225_159696.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

LT1225 Very High Speed Operational Amplifier
FEATURES
s s s s s s s s s s
DESCRIPTIO
Gain of 5 Stable 150MHz Gain Bandwidth 400V/s Slew Rate 20V/mV DC Gain, RL = 500 1mV Maximum Input Offset Voltage 12V Minimum Output Swing into 500 Wide Supply Range: 2.5V to 15V 7mA Supply Current 90ns Settling Time to 0.1%, 10V Step Drives All Capacitive Loads
The LT1225 is a very high speed operational amplifier with excellent DC performance. The LT1225 features reduced input offset voltage and higher DC gain than devices with comparable bandwidth and slew rate. The circuit is a single gain stage with outstanding settling characteristics. The fast settling time makes the circuit an ideal choice for data acquisition systems. The output is capable of driving a 500 load to 12V with 15V supplies and a 150 load to 3V on 5V supplies. The circuit is also capable of driving large capacitive loads which makes it useful in buffer or cable driver applications. The LT1225 is a member of a family of fast, high performance amplifiers that employ Linear Technology Corporation's advanced bipolar complementary processing.
APPLICATI
s s s s s s
S
Wideband Amplifiers Buffers Active Filters Video and RF Amplification Cable Drivers Data Acquisition Systems
TYPICAL APPLICATI
20MHz,AV = 50 Instrumentation Amplifier +
LT1225
Gain of 5 Pulse Response
-
1k 10k 1k
+
VIN
250
200pF
+
LT1225 VOUT
1k 250 1k
-
-
10k
-
LT1225
+
LT1225 TA01
U
LT1225 TA02
UO
UO
1
LT1225 ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW NULL -IN +IN V- 1 2 3 4 8 7 6 5 NULL V+ OUT NC
Total Supply Voltage (V + to V -) .............................. 36V Differential Input Voltage ......................................... 6V Input Voltage ............................................................VS Output Short Circuit Duration (Note 1) ............ Indefinite Operating Temperature Range LT1225C ................................................ 0C to 70C Maximum Junction Temperature Plastic Package .............................................. 150C Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec.)................. 300C
ORDER PART NUMBER LT1225CN8 LT1225CS8 S8 PART MARKING 1225
N8 PACKAGE S8 PACKAGE 8-LEAD PLASTIC DIP 8-LEAD PLASTIC SOIC
LT1225 PO01
TJ MAX = 15OC, JA = 130C/ W (N8) TJ MAX = 15OC, JA = 220C/ W (S8)
ELECTRICAL CHARACTERISTICS
SYMBOL VOS IOS IB en in RIN CIN PARAMETER Input Offset Voltage Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Resistance Input Capacitance Input Voltage Range + Input Voltage Range - CMRR PSRR AVOL VOUT IOUT SR GBW tr, tf Common-Mode Rejection Ratio Power Supply Rejection Ratio Large Signal Voltage Gain Output Swing Output Current Slew Rate Full Power Bandwidth Gain Bandwidth Rise Time, Fall Time Overshoot Propagation Delay ts Settling Time Differential Gain Differential Phase RO IS Output Resistance Supply Current
VS = 15V, TA = 25C, VCM = 0V unless otherwise noted.
MIN TYP 0.5 100 4 MAX 1.0 400 8 UNITS mV nA A nV/Hz pA/Hz M k pF V -12 V dB dB V/mV V mA V/s MHz MHz ns % ns ns % Deg 9 mA
CONDITIONS (Note 2)
f = 10kHz f = 10kHz VCM = 12V Differential 24
7.5 1.5 40 70 2 12 14 -13 115 95 20 13.3 40 400 6.4 150 7 20 7 90 1.0 1.7 4.5 7
VCM = 12V VS = 5V to 15V VOUT = 10V, RL = 500 RL = 500 VOUT = 12V (Note 3) 10V Peak, (Note 4) f = 1MHz AVCL = 5, 10% to 90%, 0.1V AVCL = 5, 0.1V 50% VIN to 50% VOUT 10V Step, 0.1%, AV = - 5 f = 3.58MHz, AV = 5, RL = 150 f = 3.58MHz, AV = 5, RL = 150 AVCL = 5, f = 1MHz
94 86 12.5 12.0 24 250
2
U
W
U
U
WW
W
LT1225
ELECTRICAL CHARACTERISTICS VS = 5V, TA = 25C, VCM = 0V unless otherwise noted.
SYMBOL VOS IOS IB PARAMETER Input Offset Voltage Input Offset Current Input Bias Current Input Voltage Range + Input Voltage Range - CMRR AVOL VOUT IOUT SR GBW tr, tf Common-Mode Rejection Ratio Large-Signal Voltage Gain Output Voltage Output Current Slew Rate Full Power Bandwidth Gain Bandwidth Rise Time, Fall Time Overshoot Propagation Delay ts IS Settling Time Supply Current VCM = 2.5V VOUT = 2.5V, RL = 500 VOUT = 2.5V, RL = 150 RL = 500 RL = 150 VOUT = 3V (Note 3) 3V Peak, (Note 4) f = 1MHz AVCL = 5, 10% to 90%, 0.1V AVCL = 5, 0.1V 50% VIN to 50% VOUT - 2.5V to 2.5V, 0.1%, AV = - 4 94 10 3.0 3.0 20 2.5 CONDITIONS (Note 2) MIN TYP 1.0 100 4 4 -3 115 15 13 3.7 3.3 40 250 13.3 100 9 10 9 70 7 9 - 2.5 MAX 2.0 400 8 UNITS mV nA A V V dB V/mV V/mV V V mA V/s MHz MHz ns % ns ns mA
ELECTRICAL CHARACTERISTICS
SYMBOL VOS PARAMETER Input Offset Voltage Input VOS Drift IOS IB CMRR PSRR AVOL VOUT IOUT SR IS Input Offset Current Input Bias Current Common-Mode Rejection Ratio Power Supply Rejection Ratio Large Signal Voltage Gain Output Swing Output Current Slew Rate Supply Current CONDITIONS
0C TA 70C, VCM = 0V unless otherwise noted.
MIN TYP 0.5 1.0 10 100 4 93 85 10 8 12.0 3.0 24 20 250 115 95 12.5 10 13.3 3.3 40 40 400 7 10.5 MAX 1.5 2.5 600 9 UNITS mV mV V/C nA A dB dB V/mV V/mV V V mA mA V/s mA
VS = 15V, (Note 2) VS = 5V, (Note 2) VS = 15V and VS = 5V VS = 15V and VS = 5V VS = 15V, VCM = 12V and VS = 5V, VCM = 2.5V VS = 5V to 15V VS = 15V, VOUT = 10V, RL = 500 VS = 5V, VOUT = 2.5V, RL = 500 VS = 15V, RL = 500 VS = 5V, RL = 500 or 150 VS = 15V, VOUT = 12V VS = 5V, VOUT = 3V VS = 15V, (Note 3) VS = 15V and VS = 5V
Note 1: A heat sink may be required to keep the junction temperature below absolute maximum when the output is shorted indefinitely. Note 2: Input offset voltage is tested with automated test equipment in <1 second.
Note 3: Slew rate is measured between 10V on an output swing of 12V on 15V supplies, and 2V on an output swing of 3.5V on 5V supplies. Note 4: Full power bandwidth is calculated from the slew rate measurement: FPBW = SR/2Vp.
3
LT1225
TYPICAL PERFOR A CE CHARACTERISTICS
Input Common-Mode Range vs Supply Voltage
20
MAGNITUDE OF INPUT VOLTAGE (V)
SUPPLY CURRENT (mA)
15
7.5
OUTPUT VOLTAGE SWING (V)
TA = 25C VOS < 1mV
10 +VCM 5 -VCM
0 0 5 10 15 20
LT1225 TPC01
SUPPLY VOLTAGE (V)
Output Voltage Swing vs Resistive Load
30
OUTPUT VOLTAGE SWING (Vp-p)
25 20 15 10 5 0 10
TA = 25C VOS = 30mV INPUT BIAS CURRENT (A)
VS = 15V
OPEN-LOOP GAIN (dB)
VS = 5V
100
1k
LOAD RESISTANCE ()
LT1225 TPC04
Supply Current vs Temperature
10 VS = 15V 9 4.75 5.0
INPUT BIAS CURRENT (A)
VS = 15V I +I IB = B+ B-
2
OUTPUT SHORT-CIRCUIT CURRENT (mA)
SUPPLY CURRENT (mA)
8 7 6 5 4 -50
-25
0
25
50
75
TEMPERATURE (C)
LT1225 TPC07
4
UW
100
Supply Current vs Supply Voltage
8.0 TA = 25C 15 20
Output Voltage Swing vs Supply Voltage
TA = 25C RL = 500 VOS = 30mV
+VSW 10 -VSW 5
7.0
6.5
6.0 0 5 10 15 20
LT1225 TPC02
0 0 5 10 15 20
LT1225 TPC03
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Input Bias Current vs Input Common-Mode Voltage
5.0 VS = 15V TA = 25C IB+ + IB- IB = 2 100
Open-Loop Gain vs Resistive Load
TA = 25C 90 VS = 15V VS = 5V
4.5
80
4.0
70
3.5
60
10k
3.0 -15
50 -10 -5 0 5 10 15 10 100 1k 10k
LT1225 TPC06
INPUT COMMON-MODE VOLTAGE (V)
LT1225 TPC05
LOAD RESISTANCE ()
Input Bias Current vs Temperature
55 50 45 40
Output Short-Circuit Current vs Temperature
VS = 5V
4.5 4.25 4.0 3.75 3.5 -50
SOURCE 35 30 25 -50
SINK
125
-25
0
25
50
75
100
125
-25
0
25
50
75
100
125
TEMPERATURE (C)
LT1225 TPC08
TEMPERATURE (C)
LT1225 TPC09
LT1225
TYPICAL PERFOR A CE CHARACTERISTICS
Input Noise Spectral Density
1000
INPUT VOLTAGE NOISE (nV/Hz)
POWER SUPPLY REJECTION RATIO (dB)
COMMON MODE REJECTION RATIO (dB)
in 100 1.0
10 VS = 15V TA = 25C AV = 101 RS = 100k 10 100
en
1
1k FREQUENCY (Hz)
10k
Voltage Gain and Phase vs Frequency
100 VS = 15V 80 80 VS = 5V 60 VS = 5V VS = 15V 60 100
VOLTAGE MAGNITUDE (dB)
VOLTAGE GAIN (dB)
OUTPUT SWING (V)
40
20 TA = 25C 0 100 10k 100k 1M 1k FREQUENCY (Hz)
Closed-Loop Output Impedance vs Frequency
100 VS = 15V TA = 25C AV = 5
153
OUTPUT IMPEDANCE ()
GAIN BANDWIDTH (MHz)
10
SLEW RATE (V/s)
1
0.1
0.01 10k
100k
1M FREQUENCY (Hz)
10M
UW
LT1225 TPC10
Power Supply Rejection Ratio vs Frequency
10
INPUT CURRENT NOISE (pA/Hz)
Common-Mode Rejection Ratio vs Frequency
120 100 80 60 40 20 0 VS = 15V TA = 25C
100 VS = 15V TA = 25C 80 +PSRR 60 -PSRR 40
0.1
20
0.01 100k
0 100
1k
10k 100k 1M FREQUENCY (Hz)
10M
100M
1k
10k
100k 1M FREQUENCY (Hz)
10M
100M
LT1225 TPC11
LTXXXX * TPCXX
Output Swing vs Settling Time
10 8 6
PHASE MARGIN (DEG)
Frequency Response vs Capacitive Load
24 22 20 18 16 14 12 10 8 6 4 C = 1000pF C = 500pF VS = 15V TA = 25C AV = -5 C = 100pF C = 50pF C = 0pF
VS = 15 TA = 25C 10mV SETTLING AV = -5 AV = 5
4 2 0 -2 -4 -6 -8
40
20
AV = -5 AV = 5
10M
0 100M
-10
0
20
60 80 40 SETTLING TIME (ns)
100
120
1M
10M FREQUENCY (HZ)
100M
LT1225 TPC15
LT1225 TPC13
LTC1225 TPC14
Gain Bandwidth vs Temperature
500
VS = 15V 152 151 150 149 148 147 -50 -25
Slew Rate vs Temperature
VS = 15V AV = -5 -SR 400 +SR 350 300 250 200 -50 -25
450
100M
LT1225 TPC16
50 25 75 0 TEMPERATURE (C)
100
125
50 25 75 0 TEMPERATURE (C)
100
125
LT1225 TPC17
LT1225 TPC18
5
LT1225
APPLICATI S I FOR ATIO U
Small Signal, AV = 5 Small Signal, AV = - 5
LT1225 AI02
The LT1225 may be inserted directly into HA2541, HA2544, AD847, EL2020 and LM6361 applications, provided that the amplifier configuration is a noise gain of 5 or greater, and the nulling circuitry is removed. The suggested nulling circuit for the LT1225 is shown below.
Offset Nulling
V+ 5k 1 3
+ -
8 7 LT1225 4 0.1F V-
LT1225 AI01
6
2
Layout and Passive Components As with any high speed operational amplifier, care must be taken in board layout in order to obtain maximum performance. Key layout issues include: use of a ground plane, minimization of stray capacitance at the input pins, short lead lengths, RF-quality bypass capacitors located close to the device (typically 0.01F to 0.1F), and use of low ESR bypass capacitors for high drive current applications (typically 1F to 10F tantalum). Sockets should be avoided when maximum frequency performance is required, although low profile sockets can provide reasonable performance up to 50MHz. For more details see Design Note 50. Feedback resistor values greater than 5k are not recommended because a pole is formed with the input capacitance which can cause peaking. If feedback resistors greater than 5k are used, a parallel capacitor of 5pF to 10pF should be used to cancel the input pole and optimize dynamic performance. Transient Response The LT1225 gain-bandwidth is 150MHz when measured at 1MHz. The actual frequency response in gain of 5 is considerably higher than 30MHz due to peaking caused by a second pole beyond the gain of 5 crossover point. This is reflected in the small-signal transient response. Higher noise gain configurations exhibit less overshoot as seen in the inverting gain of 5 response.
6
W
U
UO
0.1F
The large-signal response in both inverting and noninverting gain shows symmetrical slewing characteristics. Normally the noninverting response has a much faster rising edge than falling edge due to the rapid change in input common-mode voltage which affects the tail current of the input differential pair. Slew enhancement circuitry has been added to the LT1225 so that the noninverting slew rate response is balanced.
Large Signal, AV = 5 Large Signal, AV = - 5
LT1225 AI03
Input Considerations Resistors in series with the inputs are recommended for the LT1225 in applications where the differential input voltage exceeds 6V continuously or on a transient basis. An example would be in noninverting configurations with high input slew rates or when driving heavy capacitive loads. The use of balanced source resistance at each input is recommended for applications where DC accuracy must be maximized. Capacitive Loading The LT1225 is stable with all capacitive loads. This is accomplished by sensing the load induced output pole and adding compensation at the amplifier gain node. As the capacitive load increases, both the bandwidth and phase margin decrease so there will be peaking in the frequency
LT1225
APPLICATI
S I FOR ATIO
domain and in the transient response. The photo of the small-signal response with 1000pF load shows 50% peaking. The large-signal response with a 10,000pF load shows the output slew rate being limited by the short-circuit current.
AV = - 5, CL = 1000pF AV = 5, CL = 10,000pF
The LT1225 can drive coaxial cable directly, but for best pulse fidelity the cable should be doubly terminated with a resistor in series with the output.
TYPICAL APPLICATI
VIN 500 100pF
S
VIN
Lag Compensation
+
LT1225
LT1225 VOUT
+ -
2k AV = 1, f < 3MHz
LT1225 TA03
Wein Bridge Oscillator
#327 LAMP 430
-
1.5k LT1225
+
100pF 1.5k
VOUT >10VP-P 1MHz
100pF
LT1225 TA05
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 representation that the interconnection of circuits as described herein will not infringe on existing patent rights.
U
Compensation The LT1225 has a typical gain-bandwidth product of 150MHz which allows it to have wide bandwidth in high gain configurations (i.e., in a gain of 10 it will have a bandwidth of about 15MHz). The amplifier is stable in a noise gain of 5 so the ratio of the output signal to the inverting input must be 1/5 or less. Straightforward gain configurations of 5 or -4 are stable, but there are a few configurations that allow the amplifier to be stable for lower signal gains (the noise gain, however, remains 5 or more). One example is the summing amplifier shown in the typical applications section below. Each input signal has a gain of -RF/RIN to the output, but it is easily seen that this configuration is equivalent to a gain of -4 as far as the amplifier is concerned. Lag compensation can also be used to give a low frequency gain less than 5 with a high frequency gain of 5 or greater. The example below has a DC gain of one, but an AC gain of 5. The break frequency of the RC combination across the amplifier inputs should be approximately a factor of 10 less than the gain bandwidth of the amplifier divided by the high frequency gain (in this case 1/10 of 150MHz/5 or 3MHz).
Cable Driving
R3 75 75 CABLE VOUT R4 75
LT1225 AI04
W
UO
U
UO
-
R1 1k R2 250
LT1225 TA04
Summing Amplifier
RF RIN VIN1 RIN VIN2 RIN VINn RIN = nRF 4
LT1225 TA06
-
LT1225 VOUT
+
7
LT1225
SI PLIFIED SCHE ATIC
V+ 7 NULL 1 8
+IN
3
V-
4
LT1224 * TA10
PACKAGE DESCRIPTIO
0.300 - 0.320 (7.620 - 8.128)
0.009 - 0.015 (0.229 - 0.381)
0.065 (1.651) TYP 0.125 (3.175) MIN 0.020 (0.508) MIN
(
+0.025 0.325 -0.015 +0.635 8.255 -0.381
)
0.045 0.015 (1.143 0.381) 0.100 0.010 (2.540 0.254)
0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0.016 - 0.050 0.406 - 1.270
0.053 - 0.069 (1.346 - 1.752) 0.004 - 0.010 (0.101 - 0.254) 0.228 - 0.244 (5.791 - 6.197)
0- 8 TYP
8
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977
U
W
W
BIAS 1
2 -IN
BIAS 2 6 OUT
Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead Plastic DIP
0.045 - 0.065 (1.143 - 1.651) 0.130 0.005 (3.302 0.127)
0.400 (10.160) MAX 8 7 6 5
0.250 0.010 (6.350 0.254)
1
2
3
4
N8 0392
0.018 0.003 (0.457 0.076)
S8 Package 8-Lead Plastic SOIC
8
0.189 - 0.197 (4.801 - 5.004) 7 6 5
0.014 - 0.019 (0.355 - 0.483)
0.050 (1.270) BSC
0.150 - 0.157 (3.810 - 3.988)
1
2
3
4
SO8 0392
LT/GP 1092 5K REV A
(c) LINEAR TECHNOLOGY CORPORATION 1992

▲Up To Search▲

Price & Availability of LT1225

	To Download LT1225 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .