Silicon Valley Computer SHUGART 706 User Manual download pdf (Page 86)

STATE

OF

SOLID STATE

Micropower

op-amp

PRECISION

MONOLITHICS,

INC. CLAIMS

that their new OP-90

micropower

op -amp

sets new performance

standards for similar

devices. Al-

though the OP-90's

performance

is

comparable to that

of

the OP-07, it

draws

less

than 20 RA -which is

1/200,000 the

current

needed

for

the

OP

-07.

The

OP

-90's gain

ex-

ceeds

700,000

(700V

/mV),

and

common mode rejection is

better

than 100

dB.

In

addition to its unusually low

current drain, the

op -amp can op-

erate

from

a single -ended

(single)

power supply

of

+1.6

to

+

36

volts,

or

from

a bipolar (dual) supply

of

±0.8 to ±18 volts.

As a single

-

source

device, both input

and out-

put are referenced to

ground and

"zero

-in /zero

-out" (no static DC

output) operation is possible.

In-

put offset is less than 150

µV, so

external nulling is not required in

most

applications.

The

OP

-90's low

offset

voltage

and high gain

enables it to

provide

precision

performance in

low -fre-

quency micropower

applications.

Its

exceptionally

low voltage

and

current requirements make

the

device

ideal for

battery and solar -

power operation in such

applica-

tions

as portable instruments, re-

mote

sensors, and satellites.

The OP-90 has the

same pinout

as

the 741, has nulling

to

V ,

and

can

be used to upgrade low -fre-

quency equipment that presently

uses the OP-20, ICL8021,

HA5141,

LF441, or the

OPA21.

It is

available

as the OP-90GP in

an

8 -pin plastic

DIP with

a commercial tem-

perature range.

(At

TA =

25 °C,

maximum

offset voltage is 450 RV.)

It is

also available as the

OP

-90AZ

ROBERT F.

SCOTT,

SEMICONDUCTOR

EDITOR

CONTROL

+5V

R1

200K

MO OtP6-90E Z

R2

200K

R4

200K

R8

200K

R3

O

10 K

2

3

5

6

NW

!-

IC3

004066

CI

.075

I

TRIANGLE

OUT

+5V

14

+5v

13

+5V

R5

200K

2

+5V

OP-80EZ

R6

R7

200K

200K

12

11

10

9+

+5V

8

SQUARE

OUT

and OP

90EZ;

those are

hermetic

8 -pin DIP'S with the

former

operat-

ing in

the

military

temperature

range

and the

latter in

the

indus-

trial range. Both have

VOS(max)

of

150

RV at

25

°C available.

Another

version, the OP 90FZ, also in a her-

metic DIP; that device operates in

the industrial temperature range

and has 250 -µV maximum voltage

offset.

Figure 1

shows

how

two OP-90's

and a CD4066 CMOS

quad

bilat-

eral

switch

can be used

to make an

inexpensive

precision

voltage

-

controlled oscillator. The oscillator

provides

squarewave

and tri-

anglular -wave outputs up to a

few

hundred hertz, and draws only 50

µA from a 5 -volt power supply.

FIG.

1

Op -amp IC1 is

connected as

an

integrator.

Op -amp IC2 is

used as a

Schmitt

trigger, with resistors R5,

R6, R7

and the

associated

internal

CMOS switches

setting the hys-

teresis to precisely 1.67 volts.

The

Schmitt -trigger

action shapes IC1's

output

into

a trianglular waveform

of 3.33 volts peak (5.00V

1.67V).

IC2's

output is

a squarewave

whose

amplitude swing is essen-

tially

zero

to

+5

volts.

The output frequency

for the os-

cillator shown in Fig.

1 is:

tout

= Ven(volts)

X

10Hz/V

however,

frequency can be var-

ied- within limits

-by changing

the

value

of

integrating

capacitor

Cl.

R -E

1 2 ... 81 82 83 84 85 86 87 88 89 90 91 ... 107 108

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