TLC27M2, TLC27M2A, TLC27M2B, TLC27M7

LinCMOS

™ PRECISION DUAL OPERATIONAL AMPLIFIERS

SLOS051C – OCTOBER 1987 – REVISED MAY 1999

29

POST OFFICE BOX 655303

APPLICATION INFORMATION

2.5 V

VO

CL

– 2.5 V

VI

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

(b) CL = 170 pF, RL = NO LOAD

(c) CL = 190 pF, RL = NO LOAD

(d) TEST CIRCUIT

TA = 25°C

f = 1 kHz

VI(PP) = 1 V

Figure 41. Effect of Capacitive Loads and Test Circuit

output characteristics (continued)

Although the TLC27M2 and TLC27M7 possess excellent high-level output voltage and current capability,

methods for boosting this capability are available, if needed. The simplest method involves the use of a pullup

to the use of this circuit. First, the NMOS pulldown transistor N4 (see equivalent schematic) must sink a

comparatively large amount of current. In this circuit, N4 behaves like a linear resistor with an on-resistance

between approximately 60

Ω and 180 Ω, depending on how hard the op amp input is driven. With very low values

the gain of the operational amplifier is reduced at output voltage levels where N5 is not supplying the output

current.