OPA567 datasheet(13/27 Pages) TI2

13 / 27 page

OPA567

SBOS287A

www.ti.com

APPLICATIONS INFORMATION

BASIC CONFIGURATION

Figure 1 shows the OPA567 connected as a basic non-

inverting amplifier. However, the OPA567 can be used in

virtually any op amp configuration. A current limit setting

resistor (RSET, in Figure 1) is essential to the OPA567

operation, and cannot be omitted.

Power-supply terminals should be bypassed with low series

impedance capacitors. Using larger tantalum and smaller

ceramic type capacitors in parallel is recommended. Power-

supply wiring should have low series impedance.

POWER SUPPLIES

The OPA567 operates with excellent performance from a

single (+2.7V to +5.5V) supply or from dual supplies. Power

supply voltages do not need to be equal as long as the total

voltage remains below 5.5V. Parameters that vary signifi-

cantly with operating voltage are shown in the

Typical

Characteristics section.

ADJUSTABLE CURRENT LIMIT AND CURRENT

LIMIT FLAG PIN

The OPA567 provides over-current protection to the load

through its accurate, user-adjustable current limit (pin 6). The

current limit value, ILIMIT, can be set from 0.2A to 2.2A by

controlling the current to the ISET pin. The current limit, ILIMIT,

will be 9800 • ISET, where ISET is the current through the ISET

pin. Setting the current limit requires no special power

resistors. The output current does not flow through this pin.

Setting the current limit

As illustrated in Figure 2, the simplest method of setting the

current limit is to connect a resistor or potentiometer between

FIGURE 1. Basic Connections.

FIGURE 2. Setting the Current Limit—Resistor Method.

the ISET pin and V–, the negative supply, according to the

formula:

ILIMIT = 9800 • (1.18V/RSET)

Alternatively, the output current limit can be set by applying

a voltage source in series with a resistance using the equa-

tion:

ILIMIT = 9800 • [(1.18V – VADJUST)/RSET]

The voltage source must be referenced to V–.

µF

Enable(2)

µF

0.1

µF

SET

µF

1, 12

2, 3

4, 5

0.1

µF

SET (Ω)ILIMIT (A)

23.2k

11.5k

7.68k

5.76k

0.5

1.0

1.5

2.0

SET

(1)

V+

NOTES: (1) R

SET sets the current

limit value from 0.2A to 2.2A.

SET can be a potentiometer to

easily adjust current limit and

calibrate out errors at the current

limit node. (2) Enable—pull Low

to disable output.

V–

OPA567

SET

ADJUST

(1)

(b) Resistor/Voltage Source Method

NOTE: (1) This voltage source must be able to

sink the current from the I

SET pin, which is ILIMIT/9800.

1.18V

V–

LIMIT = 9800 (1.18V – VADJUST)

SET

2, 3

4, 5

POT

(a) Resistor or Potentiometer Method

Putting a set resistor in series with the potentiometer

will prevent potential short-circuit on pin.

1.18V

V–

LIMIT = 9800 (1.18V/RSET)

OPA567 Datasheet(PDF) 13 Page - Texas Instruments

OPA567 Datasheet(HTML) 13 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Datasheet Download

Link URL