Datasheet OP275 (Analog Devices) - 7

OP275 OP275 APPLICATIONS 0.010 Circuit Protection VS =

18V
OP275 has been designed with inherent short-circuit protection
% RL = 600
 to ground. An internal 30  resistor, in series with the output, limits the output current at room temperature to ISC+ = 40 mA
0.001
and ISC– = –90 mA, typically, with ±15 V supplies.
THD + NOISE –
However, shorts to either supply may destroy the device when excessive voltages or currents are applied. If it is possible for a user to short an output to a supply for safe operation, the output
0.00010.5 1 10 OUTPUT SWING – V rms
current of the OP275 should be design-limited to ±30 mA, as shown in Figure 1. Figure 4. Headroom, THD + Noise vs. Output
Total Harmonic Distortion
Amplitude (V rms); RLOAD = 600  , VSUP = ±18 V Total Harmonic Distortion + Noise (THD + N) of the OP275 is The output of the OP275 is designed to maintain low harmonic well below 0.001% with any load down to 600 . However, this is distortion while driving 600 dependent upon the peak output swing. In Figure 2, the THD +  loads. However, driving 600  loads with very high output swings results in higher distortion if Noise with 3 V rms output is below 0.001%. In Figure 3, THD + clipping occurs. A common example of this is in attempting to Noise is below 0.001% for the 10 k and 2 k loads but increases drive 10 V rms into any load with ±15 V supplies. Clipping will to above 0.1% for the 600  load condition. This is a result of the occur and distortion will be very high. To attain low harmonic output swing capability of the OP275. Notice the results in Figure 4, distortion with large output swings, supply voltages may be showing THD versus VIN (V rms). This figure shows that the THD increased. Figure 5 shows the performance of the OP275 driving + Noise remains very low until the output reaches 9.5 V rms. This 600 performance is similar to competitive products.  loads with supply voltages varying from ±18 V to ±20 V. Notice that with ±18 V supplies the distortion is fairly high, while
RFB
with ±20 V supplies it is a very low 0.0007%.
0.0001 FEEDBACK RX – 332

A1 VOUT + 0.001 A1 = 1/2 OP275 RL = 600

% V
Figure 1. Recommended Output Short-Circuit Protection
OUT = 10V rms @ 1kHz 0.01 THD – 0.010 RL = 600

, 2k

, 10k

% 0.1 VS =

15V VIN = 3V rms AV = +1 0

17

18

19

20

21

22 THD + NOISE – SUPPLY VOLTAGE – V 0.001
Figure 5. THD + Noise vs. Supply Voltage
0.000520 100 1k 10k 20k FREQUENCY – Hz Noise
The voltage noise density of the OP275 is below 7 nV/Hz from Figure 2. THD + Noise vs. Frequency vs. RLOAD 30 Hz. This enables low noise designs to have good performance throughout the full audio range. Figure 6 shows a typical OP275
1
with a 1/f corner at 2.24 Hz.
% 600

0.1 A CH A: 80.0

V FS 10.0

V/DIV V = +1 V MKR: 45.6

V/ Hz S =

18V VIN = 10V rms 0.010 80kHz FILTER THD + NOISE – 2k

0.001 10k

0.000120 100 1k 10k 20k FREQUENCY – Hz
Figure 3. THD + Noise vs. RLOAD; VIN =10 V rms
0Hz 10Hz MKR: 2.24Hz BW: 0.145Hz
Figure 6. 1/f Noise Corner, VS = ±15 V, AV = 1000 –6– REV. C REV. C –7– Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION PIN CONNECTIONS SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ORDERING GUIDE Typical Performance Characteristics APPLICATIONS Circuit Protection Total Harmonic Distortion Noise Noise Testing Input Overcurrent Protection Output Voltage Phase Reversal Overload or Overdrive Recovery Measuring Settling Time Driving Capacitive Loads High Speed, Low Noise Differential Line Driver A 3-Pole, 40 kHz Low-Pass Filter OP275 SPICE Model OUTLINE DIMENSIONS Revision History