Op-Amp Bandwidth (GBW) Calculator
Calculate op-amp −3dB bandwidth from gain-bandwidth product.
Component Values
Results
Gain vs frequency — GBW = Gain × Bandwidth
Common Op-Amp GBW Reference
| Op-Amp | GBW (MHz) | Slew Rate (V/µs) | Application |
|---|---|---|---|
| LM741 | 1 | 0.5 | General purpose, vintage |
| LM358 | 1 | 0.6 | Dual, low-power |
| TL071 | 3 | 13 | Low noise JFET |
| NE5532 | 10 | 9 | Audio, low noise |
| OPA2134 | 8 | 20 | Hi-fi audio |
| MCP6002 | 1 | 0.6 | Rail-to-rail, 1.8V |
| AD8067 | 300 | 250 | High speed, video |
Gain-Bandwidth Product Explained
The Gain-Bandwidth Product (GBW or GBP) is a constant parameter of an op-amp. It equals the product of the closed-loop gain and the −3dB bandwidth: GBW = Gain × BW. If you increase the gain, the bandwidth decreases proportionally. A 10 MHz GBW op-amp at gain=10 has BW = 1 MHz; at gain=100, BW = 100 kHz.
This means you cannot simultaneously have high gain and high bandwidth with a single op-amp stage. The workaround is cascading stages with lower gain each. Two stages of gain=10 (20 dB each) for a total of 100 (40 dB) give 10× the bandwidth compared to a single stage at gain=100.
Slew rate (V/µs) is a separate limit. Even if GBW is sufficient, the output cannot swing faster than the slew rate allows. For a 10V output at 100 kHz, you need SR > 2π × 100kHz × 10V ≈ 6.3 V/µs. Both GBW and slew rate must be satisfied.
Gain-Bandwidth Product
GBW = Gain × BandwidthBW = GBW / GainGain_max = GBW / fKey Points
- GBW = Gain × Bandwidth — constant for a given op-amp
- BW = GBW / Gain — more gain means less bandwidth
- Always check GBW and slew rate from the datasheet
- Use 3–5× GBW margin for stability
- Cascading stages gives more bandwidth for the same total gain
- Unity-gain bandwidth = GBW (gain = 1)
Applications
- Audio amplifier frequency response verification
- Active filter design (Sallen-Key, MFB)
- Instrumentation amplifier gain-bandwidth tradeoffs
- Video amplifier op-amp selection
- Sensor signal conditioning circuits
FAQ
What is gain bandwidth product?
GBW is a constant for a given op-amp: GBW = Gain × BW. An op-amp with 1 MHz GBW at gain=10 has BW = 100 kHz. At gain=100, BW = 10 kHz.
How do I calculate op-amp bandwidth?
BW = GBW / Gain. Find GBW in the op-amp datasheet (also listed as ft or unity-gain bandwidth). Divide by your closed-loop gain.
Why does gain decrease with frequency?
Internal compensation capacitors create a dominant pole that causes gain to roll off at −20 dB/decade. This limits the GBW to a constant value.
What op-amp do I need for 100kHz?
Depends on gain. At gain=1: any op-amp with GBW > 100 kHz. At gain=10: GBW > 1 MHz. At gain=100: GBW > 10 MHz. Add 3–5× margin.
What is slew rate vs bandwidth?
GBW limits small-signal bandwidth. Slew rate (V/µs) limits large-signal output swing rate. Both must be satisfied: SR > 2π × f × Vpeak.
How to select an op-amp for my circuit?
Key specs: GBW ≥ 3× gain × fmax, SR ≥ 2π × fmax × Vpeak, supply voltage, input offset, noise, and supply current.
Common Op-Amp GBW Reference
| Op-Amp | GBW | Slew Rate | Supply | Notes |
|---|---|---|---|---|
| LM741 | 1 MHz | 0.5 V/µs | ±15V | Classic general-purpose |
| LM358 | 1 MHz | 0.6 V/µs | 3–32V | Dual, low-power, single-supply |
| TL071 | 3 MHz | 13 V/µs | ±18V | JFET input, low noise |
| LF356 | 5 MHz | 12 V/µs | ±18V | JFET, high impedance |
| NE5532 | 10 MHz | 9 V/µs | ±15V | Audio, low noise |
| OPA2134 | 8 MHz | 20 V/µs | ±18V | Hi-Fi audio, ultra-low THD |
| MCP6001 | 1 MHz | 0.6 V/µs | 1.8–6V | Low-power, microcontroller |
| AD8040 | 150 MHz | 200 V/µs | ±5V | High-speed, video |
Gain-Bandwidth Product (GBP / GBW)
GBW = Av × f₋₃dBf₋₃dB = GBW / Av (closed-loop bandwidth)Av = GBW / f (max gain at frequency f)Example: OPA2134 (GBW = 8 MHz) at Av = 40 (32 dB):
f₋₃dB = 8,000,000 / 40 = 200 kHz
Worked Examples
Required GBW ≥ 100 × 20,000 = 2 MHz
NE5532 (10 MHz) gives 5× margin ✓
Required GBW ≥ 500 × 1,000 = 0.5 MHz
LM358 (1 MHz) just barely works; TL071 recommended for margin
Did you know? The gain-bandwidth product (GBP) is constant for a voltage-feedback op-amp. A TL071 with GBP = 3 MHz will deliver a maximum gain of 30 at 100 kHz, or gain of 3 at 1 MHz. Exceeding the GBP causes phase shift and can turn your amplifier into an oscillator.