Op-Amp Bandwidth Calculator Formula
Understand the math behind the op-amp bandwidth calculator. Each variable explained with a worked example.
Formulas Used
Closed-Loop Bandwidth
bandwidth_khz = gbw_mhz * 1000 / closed_loop_gainBandwidth (Hz)
bandwidth_hz = gbw_mhz * 1000000 / closed_loop_gainGain (dB)
gain_db = 20 * log10(closed_loop_gain)Variables
| Variable | Description | Default |
|---|---|---|
gbw_mhz | Gain-Bandwidth Product(MHz) | 1 |
closed_loop_gain | Closed-Loop Gain(V/V) | 10 |
How It Works
Op-Amp Gain-Bandwidth Product
Formula
BW = GBW / A_CL
Where GBW is the gain-bandwidth product and A_CL is the closed-loop gain. Higher gain means lower bandwidth. This is a fundamental trade-off in op-amp circuits.
Worked Example
An op-amp with GBW = 1 MHz set to a gain of 10.
gbw_mhz = 1closed_loop_gain = 10
- 01BW = 1 MHz / 10 = 100 kHz
- 02BW in Hz = 1,000,000 / 10 = 100,000 Hz
- 03Gain in dB = 20 x log10(10) = 20 dB
Frequently Asked Questions
What is gain-bandwidth product?
A constant for each op-amp: the product of open-loop gain and frequency at the -3 dB point. Typical values range from 1 MHz to over 1 GHz.
Does this apply to inverting and non-inverting?
For both, use the noise gain: (1 + Rf/R1) for non-inverting, (1 + Rf/Rin) for inverting.
How do I get more bandwidth at high gain?
Choose an op-amp with higher GBW, or cascade lower-gain stages to achieve the desired total gain.
Ready to run the numbers?
Open Op-Amp Bandwidth Calculator