The SC25 is an updated, "slightly improved" version of the API 2520 discrete op-amp. This all-discrete 13 transistor design retains the original's basic topology but uses a different compensation scheme, adds improved current sources, and employs more modern transistors throughout. The SC25 is best used in circuits with medium to high source impedance and with mic input transformers with 1:8 or higher turns ratios.
Specifications and Measurements| Absolute Maximum Ratings | Power Supply Voltage | (VS = V+ - V-) 48V | ||
| Input Voltage | (V-) - 0.7V to (V+) + 0.7V | |||
| Output Short Circuit | Continuous | |||
| Power Dissipation | Internally Limited | |||
| Supply Voltage Range | ±12V < VS < ± 24V | |||
| The following specifications apply for VS = ±24V, RL = 600 Ohm, fIN = 1kHz, and TA = 25°C, unless otherwise specified. | ||||
| Symbol | Parameter | Conditions | Specification (Typical) | Units |
| THD+N | Total Harmonic Distortion + Noise | fIN = 20kHz, VOUT = +24dBu, RL = 75 Ohms, gain = 20dB | 0.00 | % |
| fIN = 20kHz, VOUT = +24dBu, RL = 75 Ohms, gain = 40dB | 0.00 | % | ||
| fIN = 20kHz, VOUT = +24dBu, RL = 600 Ohms, gain = 40dB | 0.00 | % | ||
| IMD | Intermodulation Distortion | AV = 1, VOUT = 3VRMS Two-tone, 60Hz & 7kHz 4:1 | 0.0 | % |
| GBWP | Gain Bandwidth Product | 0 | MHz | |
| SR | Slew Rate | RL = 150 Ohms | ±0 | V/µs |
| RL = 75 Ohms | ±0 | V/µs | ||
| FPBW | Full Power Bandwidth | VOUT = 1V P-P, –3dB referenced to output magnitude at f = 1kHz | 0 | MHz |
| Large-signal bandwidth | RL = 150 Ohm | 0 | kHz | |
| Ft | Small-signal bandwidth | RL = 150 Ohm | 0 | MHz |
| Phase margin | Calculated, Av=1, Fin = Ft | 0 | deg | |
| Cmax | Maximum Stable Capacitive Load | Av=1 | 0 | pF |
| CLOAD | Capacitive Load Drive Overshoot | 100pF | 0 | % |
| Ts | Settling time | AV = 1, 10V step, CL = 100pF 0.1% error range | 0.0 | µs |
| En | Equivalent Input Noise Voltage | fBW = 20Hz to 20kHz | 0.0 | µVRMS |
| ±0.0 | dBu | |||
| En | Equivalent Input Noise Density | f = 1kHz | 0.0 | nV/vHz |
| f = 10Hz | 0.0 | nV/vHz | ||
| In | Current Noise Density | f = 1kHz | 0.0 | pA/vHz |
| f = 10Hz | 0.0 | pA/vHz | ||
| Noise index, 1k Ohm source resistance | 0.0 | dB | ||
| VOS | Offset Voltage | ±0.0 | mV | |
| PSRR | Average Input Offset Voltage Shift vs Power Supply Voltage | Delta VS = 20V | 0 | dB |
| IB | Input Bias Current | Vcm = 0V | 0 | nA |
| IOS | Input Offset Current | Vcm = 0V | 0 | nA |
| VINMAX | Maximum input voltage at unity gain | 0.0 | V | |
| ±0.0 | dBu | |||
| VIN-CM | Common-Mode Input Voltage Range | +0.0 | V | |
| -0.0 | V | |||
| CMRR | Common-Mode Rejection Ratio | –10V < Vcm < 10V | 0 | dB |
| ZIN | Differential Input Impedance | 0 | Ohms | |
| Input impedance, non-inverting input | 0 | Ohms | ||
| ZIN | Common Mode Input Impedance | –10V < Vcm < 10V | 0 | Ohms |
| AVOL | Open Loop Voltage Gain | –10V < VOUT < 10V, RL = 600 Ohms, 20Hz | 0 | dB |
| VOUTMAX | Maximum Output Voltage Swing | RL = 75 Ohms | ±0.0 | V |
| ±0.0 | dBu | |||
| RL = 600 Ohms | ±0.0 | V | ||
| ±0.0 | dBu | |||
| RL = 10K Ohms | ±0.0 | V | ||
| ±0.0 | dBu | |||
| IOUT | Output Current | RL = 600 Ohms, VS = ±24V | ±0 | mA |
| IOUT-CC | Short Circuit Current | +0 | mA | |
| -0 | mA | |||
| ROUT | Output Impedance | fIN = 10kHz Closed-Loop | 0.0 | Ohms |
| fIN = 10kHz Open-Loop | 0.0 | Ohms | ||
| IS | Quiescent Current | IOUT = 0mA | 0.0 | mA |