REF193GRU View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

REF193GRU

0.3-18V; precision micropower, low dropout, voltage reference. For portable instrumentation, A-to-D and D-to-A converters, smart sensors

Analog Devices 

5V

100

90

10

0%

200mV

200␮s

Figure 12. Line Transient Response

REF19x Series

35

30

25

20

15

10

5

0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

REF195 DROPOUT VOLTAGE – V

Figure 13. Dropout Voltage vs. Load Current

+V

VOUT

SHUTDOWN

GND

Figure 14. Simplified Schematic

APPLICATIONS SECTION

Output Short Circuit Behavior

The REF19x family of devices is totally protected from damage

due to accidental output shorts to GND or to V+. In the event

of an accidental short circuit condition, the reference device will

shutdown and limit its supply current to 100 µA.

Device Power Dissipation Considerations

The REF19x family of references is capable of delivering load

currents to 30 mA with an input voltage that ranges from 3.3 V

to 15 V. When these devices are used in applications with large

input voltages, care should be exercised to avoid exceeding these

devices’ maximum internal power dissipation. Exceeding the

published specifications for maximum power dissipation or

junction temperature could result in premature device failure.

The following formula should be used to calculate a device’s

maximum junction temperature or dissipation:

PD

=

TJ – TA

θ JA

In this equation, TJ and TA are the junction and ambient tem-

peratures, respectively, PD is the device power dissipation and

θJA is the device package thermal resistance.

Output Voltage Bypassing

For stable operation, low dropout voltage regulators and refer-

ences, in general, require a bypass capacitor connected from

their VOUT pins to their GND pins. Although the REF19x

family of references is capable of stable operation with capacitive

loads exceeding 100 µF, a 1 µF capacitor is sufficient to guaran-

tee rated performance. The addition of a 0.1 µF ceramic ca-

pacitor in parallel with the bypass capacitor will improve load

current transient performance. For best line voltage transient

performance, it is recommended that the voltage inputs of these

devices be bypassed with a 10 µF electrolytic capacitor in paral-

lel with a 0.1 µF ceramic capacitor.

Sleep Mode Operation

All REF19x devices include a sleep capability that is TTL/CMOS

level compatible. Internal to the REF19x at the SLEEP pin, a

pull-up current source to VIN is connected. This permits the

SLEEP pin to be driven from an open collector/drain driver.

A logic LOW or a zero volt condition on the SLEEP pin is re-

quired to turn the output stage OFF. During sleep, the output

of the references becomes a high impedance state where its

potential would then be determined by external circuitry. If the

sleep feature is not used, it is recommended that the SLEEP pin

be connected to VIN (Pin 2).

Basic Voltage Reference Connections

The circuit in Figure 15 illustrates the basic configuration for

the REF19x family of references. Note the 10 µF/0.1 µF bypass

network on the input and the 1 µF/0.1 µF bypass network on the

output. It is recommended that no connections be made to

Pins 1, 5, 7 and 8. If the sleep feature is not required, Pin 3

should be connected to VIN.

10␮F

NC 1

VIN

2

0.1␮F

SLEEP 3

REF19x

8 NC

7 NC

6

4

5 NC

OUTPUT

1␮F

TANT

0.1␮F

Figure 15. Basic Voltage Reference Configuration

REV. D

–17–

Share Link: