Datasheet LT1360 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | 50MHz, 800V/µs Op Amp |
| Pages / Page | 16 / 10 — APPLICATIONS INFORMATION. Capacitive Loading. Offset Nulling. Layout and … |
| File Format / Size | PDF / 229 Kb |
| Document Language | English |
APPLICATIONS INFORMATION. Capacitive Loading. Offset Nulling. Layout and Passive Components. Cable Driver Frequency Response
Model Line for this Datasheet
Text Version of Document
LT1360
U U W U APPLICATIONS INFORMATION
The LT1360 may be inserted directly into AD817, AD847,
Capacitive Loading
EL2020, EL2044, and LM6361 applications improving The LT1360 is stable with any capacitive load. This is both DC and AC performance, provided that the nulling accomplished by sensing the load induced output pole circuitry is removed. The suggested nulling circuit for the and adding compensation at the amplifier gain node. As LT1360 is shown below. the capacitive load increases, both the bandwidth and
Offset Nulling
phase margin decrease so there will be peaking in the frequency domain and in the transient response as shown V+ in the typical performance curves.The photo of the small- signal response with 500pF load shows 60% peaking. The 3 7 + large-signal response with a 10,000pF load shows the 6 LT1360 4 2 output slew rate being limited to 5V/µs by the short-circuit – 8 current. Coaxial cable can be driven directly, but for best 1 10k pulse fidelity a resistor of value equal to the characteristic impedance of the cable (i.e., 75 V– Ω) should be placed in series with the output. The other end of the cable should 1360 AI01 be terminated with the same value resistor to ground.
Layout and Passive Components Cable Driver Frequency Response
The LT1360 amplifier is easy to apply and tolerant of less 2 AV = 2 than ideal layouts. For maximum performance (for ex- RF = RG = 500Ω ample fast settling time) use a ground plane, short lead 0 RL = 150Ω VS = ±15V lengths, and RF-quality bypass capacitors (0.01µF to VS = ±10V 0.1µF). For high drive current applications use low ESR –2 VS = ±2.5V VS = ±5V bypass capacitors (1µF to 10µF tantalum). Sockets IN GAIN (dB) should be avoided when maximum frequency perfor- –4 + 75Ω OUT LT1360 mance is required, although low profile sockets can – 75Ω 510Ω –6 provide reasonable performance up to 50MHz. For 510Ω more details see Design Note 50. –8 1 10 100 The parallel combination of the feedback resistor and gain FREQUENCY (MHz) setting resistor on the inverting input can combine with 1360 AI02 the input capacitance to form a pole which can cause peaking or oscillations. For feedback resistors greater than 5kW, a parallel capacitor of value CF > RG x CIN/RF should be used to cancel the input pole and optimize dynamic performance. For unity-gain applications where a large feedback resistor is used, CF should be greater than or equal to CIN. 10
U U W U APPLICATIONS INFORMATION
The LT1360 may be inserted directly into AD817, AD847,
Capacitive Loading
EL2020, EL2044, and LM6361 applications improving The LT1360 is stable with any capacitive load. This is both DC and AC performance, provided that the nulling accomplished by sensing the load induced output pole circuitry is removed. The suggested nulling circuit for the and adding compensation at the amplifier gain node. As LT1360 is shown below. the capacitive load increases, both the bandwidth and
Offset Nulling
phase margin decrease so there will be peaking in the frequency domain and in the transient response as shown V+ in the typical performance curves.The photo of the small- signal response with 500pF load shows 60% peaking. The 3 7 + large-signal response with a 10,000pF load shows the 6 LT1360 4 2 output slew rate being limited to 5V/µs by the short-circuit – 8 current. Coaxial cable can be driven directly, but for best 1 10k pulse fidelity a resistor of value equal to the characteristic impedance of the cable (i.e., 75 V– Ω) should be placed in series with the output. The other end of the cable should 1360 AI01 be terminated with the same value resistor to ground.
Layout and Passive Components Cable Driver Frequency Response
The LT1360 amplifier is easy to apply and tolerant of less 2 AV = 2 than ideal layouts. For maximum performance (for ex- RF = RG = 500Ω ample fast settling time) use a ground plane, short lead 0 RL = 150Ω VS = ±15V lengths, and RF-quality bypass capacitors (0.01µF to VS = ±10V 0.1µF). For high drive current applications use low ESR –2 VS = ±2.5V VS = ±5V bypass capacitors (1µF to 10µF tantalum). Sockets IN GAIN (dB) should be avoided when maximum frequency perfor- –4 + 75Ω OUT LT1360 mance is required, although low profile sockets can – 75Ω 510Ω –6 provide reasonable performance up to 50MHz. For 510Ω more details see Design Note 50. –8 1 10 100 The parallel combination of the feedback resistor and gain FREQUENCY (MHz) setting resistor on the inverting input can combine with 1360 AI02 the input capacitance to form a pole which can cause peaking or oscillations. For feedback resistors greater than 5kW, a parallel capacitor of value CF > RG x CIN/RF should be used to cancel the input pole and optimize dynamic performance. For unity-gain applications where a large feedback resistor is used, CF should be greater than or equal to CIN. 10
