TLC27L2ACPSLE datasheet(28/49 Pages) TI1

28 / 49 page

TLC27L2, TLC27L2A, TLC27L2B, TLC27L7

LinCMOS PRECISION DUAL OPERATIONAL AMPLIFIERS

SLOS052D − OCTOBER 1987 − REVISED OCTOBER 2005

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

output characteristics (continued)

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

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

− 2.5 V

2.5 V

TA = 25°C

f = 1 kHz

VI(PP) = 1 V

(d) TEST CIRCUIT

Figure 41. Effect of Capacitive Loads and Test Circuit

Although the TLC27L2 and TLC27L7 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

resistor (RP) connected from the output to the positive supply rail (see Figure 42). There are two disadvantages

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 operational amplifier input is driven. With

very low values of RP, a voltage offset from 0 V at the output occurs. Second, pullup resistor RP acts as a

drain load to N4 and the gain of the operational amplifier is reduced at output voltage levels where N5 is not

supplying the output current.

TLC27L2ACPSLE 数据表(PDF) 28 Page - Texas Instruments