Datenblatt-Suchmaschine für elektronische Bauteile |
|
AD825AR-16-REEL Datenblatt(PDF) 10 Page - Analog Devices |
|
AD825AR-16-REEL Datenblatt(HTML) 10 Page - Analog Devices |
10 / 12 page AD825 Rev. F | Page 10 of 12 DRIVING CAPACITIVE LOADS The internal compensation of the AD825, together with its high output current drive, permits excellent large signal performance while driving extremely high capacitive loads. TEKTRONIX P6204 FET PROBE HP PULSE GENERATOR 50 Ω RIN 1k Ω CL VOUT VIN TEKTRONIX 7A24 PREAMP AD825 7 4 3 6 2 +VS 0.01 µF 10 µF –VS 0.01 µF 10 µF 1k Ω Figure 30. Inverting Amplifier Driving a Capacitive Load INPUT OUTPUT 5V 5V 500ns Figure 31. Inverting Amplifier Pulse Response While Driving a 400 pF Capacitive Load THEORY OF OPERATION The AD825 is a low cost, wideband, high performance FET input operational amplifier. With its unique input stage design, the AD825 ensures no phase reversal, even for inputs that exceed the power supply voltages, and its output stage is designed to drive heavy capacitive or resistive loads with small changes relative to no load conditions. The AD825 (Figure 32) consists of common-drain, common- base FET input stage driving a cascoded, common-base matched NPN gain stage. The output buffer stage uses emitter followers in a Class AB amplifier that can deliver large current to the load while maintaining low levels of distortion. POS NEG VNEG VPOS VOUT CF Figure 32. Simplified Schematic The capacitor, CF, in the output stage, enables the AD825 to drive heavy capacitive loads. For light loads, the gain of the output buffer is close to unity, CF is bootstrapped, and not much happens. As the capacitive load is increased, the gain of the output buffer is decreased and the bandwidth of the amplifier is reduced through a portion of CF adding to the dominant pole. As the capacitive load is further increased, the amplifier’s bandwidth continues to drop, maintaining the stability of the AD825. INPUT CONSIDERATION The AD825 with its unique input stage ensures no phase reversal for signals as large as or even larger than the supply voltages. Also, layout considerations of the input transistors ensure functionality even with a large differential signal. The need for a low noise input stage calls for a larger FET transistor. One should consider the additional capacitance that is added to ensure stability. When filters are designed with the AD825, one needs to consider the input capacitance (5 pF to 6 pF) of the AD825 as part of the passive network. GROUNDING AND BYPASSING The AD825 is a low input bias current FET amplifier. Its high frequency response makes it useful in applications, such as photodiode interfaces, filters, and audio circuits. When designing high frequency circuits, some special precautions are in order. Circuits must be built with short interconnects, and resistances should have low inductive paths to ground. Power supply leads should be bypassed to common as close as possible to the amplifier pins. Ceramic capacitors of 0.1 µF are recommended. |
Ähnliche Teilenummer - AD825AR-16-REEL |
|
Ähnliche Beschreibung - AD825AR-16-REEL |
|
|
Link URL |
Privatsphäre und Datenschutz |
ALLDATASHEETDE.COM |
War ALLDATASHEET hilfreich? [ DONATE ] |
Über Alldatasheet | Werbung | Kontakt | Privatsphäre und Datenschutz | Linktausch | Hersteller All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |