AS1923A-BSTT-K

AS1923A-BSTT-K Datasheet


AS1923

Part Datasheet
AS1923A-BSTT-K AS1923A-BSTT-K AS1923A-BSTT-K (pdf)
Related Parts Information
AS1923A-BSTT-A AS1923A-BSTT-A AS1923A-BSTT-A
AS1923A-BSTT-O AS1923A-BSTT-O AS1923A-BSTT-O
AS1923A-BSTT-C AS1923A-BSTT-C AS1923A-BSTT-C
AS1923A-BSTT-I AS1923A-BSTT-I AS1923A-BSTT-I
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Datasheet

AS1923

Quad-Voltage Microprocessor Supervisory Circuit
1 General Description
2 Key Features

The AS1923 microprocessor supervisory circuit was designed to monitor up to four system supply voltages without the need for external components, and asserts a single reset if any of the monitored supply voltages drops below its reset threshold.
lid The AS1923 features an active-low reset output that is asserted
when any of the 4 monitored voltages are below their respective reset threshold. The reset output is open-drain with a weak internal
a pullup 10uA to IN2. Reset remains low for a specified reset timeout
period 120ms min after all voltages have stabilized. The output is
v valid as long as the IN1 or IN2 input voltage remains >1V.

Minimal external component requirements, small size, and wide tem-
ill perature range -40 to +85°C greatly improves reliability compared
to individual supervisory circuits or discrete components.
t A wide range of factory-trimmed threshold voltages are available to
accommodate many different supply voltages/tolerances with mini-

G s mal external component requirements.

Factory-trimmed options are available for monitoring

A t and -5.0V supplies with -5% and/or -10% toler-
ances. The device is also available with one or two user-adjustable
s n threshold options via external resistor-divider network if non-stan-
dard voltage thresholds are required.
e The AS1923 is available in an 6-pin SOT23 package.

Quad-Voltage Monitoring Factory-Trimmed Reset Threshold Options:
and -5.0V Voltage Monitoring Threshold Options Supply Current 55uA AS1923A Current Source Pullup AS1923B Timeout Period 120ms Valid to IN1 = 1V or IN2 = 1V to Fast INx Transients Components not Required Performance Operating Temperature Range = -40
to +85ºC SOT23 Package
am o3 nApptlications Figure AS1923 - Typical Application

The device is ideal for portable and battery-powered systems, embedded controllers, intelligent instruments, automotive systems, critical CPU monitoring, and any multi-supply application.
l c Monitoring

Voltage 1 IN1
a Monitoring
ic Voltage 2

AS1923

RESETN

Monitoring

Voltage 3 IN3
Input Voltage See Ordering Information on page 14 for monitored voltages.

Ground
Reset Output. AS1923A see Ordering Information on page 14 supports an external pullup resistor AS1923B contains an internal 10uA current source pullup. RESETN goes low reset asserted when any one of the INx voltages goes below its specified threshold. After all inputs have stabilized, RESETN remains low for at least 120ms min before going high.
Input Voltage See Ordering Information on page 14 for monitored voltages.
Input Voltage See Ordering Information on page 14 for monitored voltages. Note IN2 is the power supply input for the AS1923.
Input Voltage See Ordering Information on page 14 for monitored voltages.
2 - 16

AS1923

Datasheet - Absolute Maximum Ratings
5 Absolute Maximum Ratings

Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Table Absolute Maximum Ratings

Parameter

Electrical Parameters
lid IN1, IN2 Monitored Voltage , IN3, IN4 to GND

IN4 to GND Device Variants M, N, O, and P, see Table 5 on page 14

RESETN to GND
a Latchup immunity v Continuous Power Dissipation

Continuous Power Dissipation
ill TAMB = +70ºC

Temperature Ranges and Storage Conditions
t Junction Temperature

Storage Temperature Range

AG t s Package Body Temperature s en Humidity non-condensing Technicaaml cont Moisture Sensitive Level

Min Max +7 -7 +6
+150 -55 +150
+260
5 85 1

Units

Comments

Class I Level A in accordance with EIA/JEDEC 78

Derate 8.7mW/ºC above +70ºC

The reflow peak soldering temperature body
temperature specified is in accordance with IPC/JEDEC

J-STD-020 “Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices”.

The lead finish for Pb-free leaded packages is matte tin
100% Sn .

Represents a max. floor life time of unlimited
3 - 16

AS1923

Datasheet - Electrical Characteristics
6 Electrical Characteristics

VIN2 = +1V to +5.5V, Typ values VIN2 = +3.0V to +3.3V, TAMB = +25ºC unless otherwise specified .

Table Electrical Characteristics

Parameter 1

Conditions
Preset voltage monitoring values of and -5.0V see Ordering Information on page 14 are available for a wide range
of applications such as telecommunications equipment, desktop and notebook computers, high-end printers, data storage equipment, and networking equipment applications.

The device is powered via the IN2 input to 3.3V and a reset is asserted if VIN1 or VIN2 is > 1V. For improved performance, the AS1923 was
lid also designed to ignore fast INx transients.

Figure AS1923 - Block Diagram
va 4 + IN1
ill t 5

G s IN2 s A nt 6 +
e IN3 m t
5V Pullup

Timeout 220ms
3 RESETN
a n 1 +
o IN4
al c Bandgap ic Reference

AS1923

Optional on AS1923B Only
hn The quad-voltage monitor/reset circuitry includes an accurate bandgap reference, four precision comparators, and a series of internal trimmed
resistor-divider networks to set the factory-trimmed reset threshold values.
c The resistor networks scale the specified INx reset voltages to match the internal bandgap reference/comparator voltage. User-adjustable e threshold options bypass the internal resistor networks and connect directly to one of the comparator inputs an external resistor-divider network
is required for threshold matching .

TEach of the internal comparators has a typical hysteresis of with respect to its reset threshold. This built-in hysteresis improves device
immunity to ambient noise without significantly reducing threshold accuracy when an input sits at its specified reset voltage.
Note Threshold voltage options fixed and adjustable are designated by the single-letter code in the model number see Ordering Information on page
8 - 16

AS1923

Datasheet - Application Information
9 Application Information

Reset Output

The AS1923 RESETN output is asserted low when any of the monitored INx voltages drop below its specified reset threshold above for -5V option and remains asserted for the duration of the reset timeout period 120ms minimum after all inputs have stabilized Figure

Figure RESETN Output Timing Diagram
lid INx a RESETN

VTHL
ill v The AS1923B output driver is driven by an internal 10uA current source pullup resistor. For most applications there is no need for an external
pullup resistor to interface with other logic supplies.
t Note An external pullup resistor must not be connected to the AS1923B. G s The AS1923A supports an external pullup resistor to any voltage from 0 to +5.5V if interfaced to non-standard logic supply voltages see Figure
ams Antent Figure Interfacing to Various Logic Supply Voltages
+5V 100k:
3 RESETN

VCC RESETN
co AS1923A TechnicalGND 2
9 - 16

AS1923

Datasheet - Application Information

User-Adjustable Thresholds

The AS1923 provides several voltage monitoring values as well as user-adjustable reset thresholds.

The threshold voltage at each adjustable INx input is typically 1.23V. To monitor a voltage >1.23V, connect a resistor-divider network to the circuit as shown in Figure

Figure Setting User-Adjustable Thresholds

VINTH
lid R1 va R2

VREF =
1.23V
till For the circuit shown in Figure 13, calculate R1 and R2 as:

G s VINTH
1,23V

R-----1----+----R-----2 R2
s A ent or, calculated in terms of R1:

V-----I--N---T---H-1,23V

EQ 1 EQ 2
m t Note Because the AS1923 has a guaranteed input current of ±0.1uA on its adjustable inputs, resistor values up to 100k can be used for a n R2 with <1% error.
o Unused Inputs c The IN2 input must always be used for normal operation AS1923 power-supply pin . Otherwise, in cases where one or more of the AS1923
monitoring inputs will not be used, these inputs must be tied to a supply voltage greater in magnitude than their specified threshold voltages.
l Notes a For unused IN3 or IN4 applications with positive thresholds fixed or adjustable , the inputs can be connected directly to the IN2 supply.

For unused IN4 options with negative thresholds, the input must be tied to a more negative supply.
Datasheet - Ordering Information
11 Ordering Information

The device is available as the standard products listed in Table
Table Ordering Information
Ordering Code

Marking

Descriptiom

Delivery Form

Package

AS1923A-BSTT-A AS1923A-BSTT-C
lid AS1923A-BSTT-I

AS1923A-BSTT-K
va AS1923A-BSTT-O ill AS1923A-BSTT-x*

AS1923B-BSTT-x*
t * on request

ASJD ASJF ASJP ASJR ASJV tbd

Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output

Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output

Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output

Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output

Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output

Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output

Quad-Voltage Microprocessor Supervisory Circuit with Internal 10uA Current Source Pullup Output

Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel

AG t s Note All products are RoHS compliant. Buy our products or get free samples online at ICdirect s n For further information and requests, please contact us e or find your local distributor at
6-pin SOT23 6-pin SOT23 6-pin SOT23 6-pin SOT23 6-pin SOT23 6-pin SOT23 6-pin SOT23
am nt These devices are available in factory-set input voltage thresholds. Choose the desired reset threshold suffix from Table 5 and insert it instead of o “x” in the part number.

Table Variants Suffix Guide x
c Variant x l IN1
5.0V
5.0V
5.0V
5.0V
5.0V
5.0V
5.0V

TeH1
5.0V

Thresholds
3.3V
2.5V
3.3V
2.5V 2
3.3V
1.8V
Datasheet - Ordering Information

Table Variants Suffix Guide x

Thresholds

Variant x

Tolerance
5.0V
3.3V
2.5V 2
1.8V
5.0V
3.3V
2.5V 2
1.8V 2
adjustable 3.3V
2.5V adjustable
adjustable 3.3V
2.5V 2 adjustable
lid M1
5.0V
3.0V adjustable -5.0V
5.0V
3.0V adjustable -5.0V
5.0V
3.3V adjustable -5.0V
5.0V
3.3V adjustable -5.0V
v Available upon request Technicaaml scoAnGtent still Specifiedfor10%tolerances
15 - 16

AS1923

Datasheet

Copyrights

Copyright 1997-2011, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies.

Disclaimer
lid Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale.
austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for
a current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range,
unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are
v specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100
parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location.
ill The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not
be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing,
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Datasheet ID: AS1923A-BSTT-K 519669