TLC27L4, TLC27L4A, TLC27L4B, TLC27L4Y, TLC27L9

LinCMOS

™ PRECISION QUAD OPERATIONAL AMPLIFIERS

SLOS053C – OCTOBER 1987 – REVISED AUGUST 1994

32

POST OFFICE BOX 655303

APPLICATION INFORMATION

noise performance (continued)

VI

(a) NONINVERTING AMPLIFIER

(c) UNITY-GAIN AMPLIFIER

(b) INVERTING AMPLIFIER

VI

VI

VO

VO

VO

Figure 40. Guard-Ring Schemes

output characteristics

The output stage of the TLC27L4 and TLC27L9 is designed to sink and source relatively high amounts of current

(see typical characteristics). If the output is subjected to a short-circuit condition, this high current capability can

cause device damage under certain conditions. Output current capability increases with supply voltage.

All operating characteristics of the TLC27L4 and TLC27L9 were measured using a 20-pF load. The devices

drive higher capacitive loads; however, as output load capacitance increases, the resulting response pole

occurs at lower frequencies, thereby causing ringing, peaking, or even oscillation (see Figure 41). In many

cases, adding a small amount of resistance in series with the load capacitance alleviates the problem.

2.5 V

VO

CL

– 2.5 V

VI

(a) CL = 20 pF, RL = NO LOAD

(b) CL = 260 pF, RL = NO LOAD

(c) CL = 310 pF, RL = NO LOAD

(d) TEST CIRCUIT

TA = 25°C

f = 1 kHz

VIPP = 1 V

Figure 41. Effect of Capacitive Loads and Test Circuit