Datasheet LT1115 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | Ultra-Low Noise, Low Distortion, Audio Op Amp |
| Pages / Page | 16 / 7 — TYPICAL PERFOR A CE CHARACTERISTICS. Maximum Output vs Frequency. … |
| File Format / Size | PDF / 252 Kb |
| Document Language | English |
TYPICAL PERFOR A CE CHARACTERISTICS. Maximum Output vs Frequency. Small-Signal Transient Response. (Power Bandwidth*)
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Text Version of Document
LT1115
W U TYPICAL PERFOR A CE CHARACTERISTICS Maximum Output vs Frequency Small-Signal Transient Response (Power Bandwidth*) Closed-Loop Output Impedance
30 100 V I S = ± 18V O = 1mA T V A = 25°C S = ±18V 25 R T L = 2kΩ A = 25°C ) 10 Ω 20 1
FPO
AV 15 = 1000 20mV/DIVISION 0.1 *POWER BANDWIDTH 10 SLEW RATE AV = 5 f OUTPUT IMPEDANCE ( P = πEOP 0.01 PEAK-TO-PEAK OUTPUT VOLTAGE (V) 5 fP = POWER BANDWIDTH 0.2µs/DIVISION EP-P = PEAK-TO-PEAK AMPLIFIER OUTPUT VOLTAGE AV = –1, 0 0.001 RS = Rf = 2kΩ 10k 100k 1M 10M 10 100 1k 10k 100k 1M Cf = 30pF FREQUENCY (Hz) FREQUENCY (Hz) LT1115 • TPC29 CL = 80pF LT1115 • TPC30
CCIF Testing Note:
The CCIF twin-tone intermodulation test inputs two closely spaced equal amplitude tones to the device under test (DUT). The
FPO
analyzer then measures the intermodulation distortion (IMD) produced in the DUT by measuring the difference tone equal to the spacing between the tones. The amplitude of the lMD test input is in sinewave peak equivalent terms. As an example, selecting an amplitude of 1.000V will result in the complex IMD signal having the same 2.828V peak-to-peak amplitude that a 1.000V sinewave has. Clipping in a DUT will thus occur at the same input amplitude for THD + N and IMD modes.
U U W U APPLICATIO S I FOR ATIO
The LT1115 is a very high performance op amp, but
Voltage Noise vs Current Noise
not necessarily one which is optimized for universal The LT1115’s less than 1nV/√Hz voltage noise matches application. Because of very low voltage noise and the that of the LT1028 and is three times better than the lowest resulting high gain-bandwidth product, the device is most voltage noise heretofore available (on the LT1007/1037). applicable to relatively high gain applications. Thus, while A necessary condition for such low voltage noise is the LT1115 will provide notably superior performance to operating the input transistors at nearly 1mA of the 5534 in most applications, the device may require collector currents, because voltage noise is inversely circuit modifications to be used at very low noise gains. proportional to the square root of the collector current. The part is not generally applicable for unity gain followers Current noise, however, is directly proportional to the or inverters. In general, it should always be used with good square root of the collector current. Consequently, the low impedance bypass capacitors on the supplies, low LT1115’s current noise is significantly higher than on impedance feedback values, and minimal capacitive load- most monolithic op amps. ing. Ground plane construction is recommended, as is a compact layout. 1115fa 7
W U TYPICAL PERFOR A CE CHARACTERISTICS Maximum Output vs Frequency Small-Signal Transient Response (Power Bandwidth*) Closed-Loop Output Impedance
30 100 V I S = ± 18V O = 1mA T V A = 25°C S = ±18V 25 R T L = 2kΩ A = 25°C ) 10 Ω 20 1
FPO
AV 15 = 1000 20mV/DIVISION 0.1 *POWER BANDWIDTH 10 SLEW RATE AV = 5 f OUTPUT IMPEDANCE ( P = πEOP 0.01 PEAK-TO-PEAK OUTPUT VOLTAGE (V) 5 fP = POWER BANDWIDTH 0.2µs/DIVISION EP-P = PEAK-TO-PEAK AMPLIFIER OUTPUT VOLTAGE AV = –1, 0 0.001 RS = Rf = 2kΩ 10k 100k 1M 10M 10 100 1k 10k 100k 1M Cf = 30pF FREQUENCY (Hz) FREQUENCY (Hz) LT1115 • TPC29 CL = 80pF LT1115 • TPC30
CCIF Testing Note:
The CCIF twin-tone intermodulation test inputs two closely spaced equal amplitude tones to the device under test (DUT). The
FPO
analyzer then measures the intermodulation distortion (IMD) produced in the DUT by measuring the difference tone equal to the spacing between the tones. The amplitude of the lMD test input is in sinewave peak equivalent terms. As an example, selecting an amplitude of 1.000V will result in the complex IMD signal having the same 2.828V peak-to-peak amplitude that a 1.000V sinewave has. Clipping in a DUT will thus occur at the same input amplitude for THD + N and IMD modes.
U U W U APPLICATIO S I FOR ATIO
The LT1115 is a very high performance op amp, but
Voltage Noise vs Current Noise
not necessarily one which is optimized for universal The LT1115’s less than 1nV/√Hz voltage noise matches application. Because of very low voltage noise and the that of the LT1028 and is three times better than the lowest resulting high gain-bandwidth product, the device is most voltage noise heretofore available (on the LT1007/1037). applicable to relatively high gain applications. Thus, while A necessary condition for such low voltage noise is the LT1115 will provide notably superior performance to operating the input transistors at nearly 1mA of the 5534 in most applications, the device may require collector currents, because voltage noise is inversely circuit modifications to be used at very low noise gains. proportional to the square root of the collector current. The part is not generally applicable for unity gain followers Current noise, however, is directly proportional to the or inverters. In general, it should always be used with good square root of the collector current. Consequently, the low impedance bypass capacitors on the supplies, low LT1115’s current noise is significantly higher than on impedance feedback values, and minimal capacitive load- most monolithic op amps. ing. Ground plane construction is recommended, as is a compact layout. 1115fa 7
