Data Sheet
FEATURES
Ultralow Power, 3-Lead, SOT-23
Microprocessor Reset Circuits
ADM6326/ADM6328/ADM6346/ADM6348
FUNCTIONAL BLOCK DIAGRAMS
ADM6326/ADM6346
V
CC
V
REF
RESET
GENERATOR
(100ms)
Ultralow supply current of 1 µA maximum (ADM6326/ADM6328)
Accurate monitoring of 2.5 V, 3 V, 3.3 V, and 5 V rails
Reset thresholds available in increments from 2.2 V to 4.63 V
Glitch immunity from negative-going V
CC
transients
2 reset output options
Push-pull RESET (ADM6326/ADM6346)
Open-drain RESET (ADM6328/ADM6348)
Minimum reset timeout of 100 ms
Operating temperature range of −40°C to +85°C
3-lead SOT-23 package
RESET
GND
Figure 1.
ADM6328/ADM6348
V
CC
V
REF
RESET
GENERATOR
(100ms)
RESET
APPLICATIONS
Telecommunications
Microprocessor systems
Desktop and notebook computers
Portable equipment
GND
Figure 2.
GENERAL DESCRIPTION
The
ADM6326/ADM6328/ADM6346/ADM6348
devices provide
low cost solutions for protecting sensitive circuitry, such as micro-
processor and telecommunications circuitry.
With built-in glitch immunity, ultralow supply currents, and
24 reset threshold voltage options, the
ADM6326/ADM6328/
ADM6346/ADM6348
not only ensure that systems are immune
to fast transients on V
CC
, but also that the devices are suitable
for monitoring a variety of supply voltages in low power,
portable equipment.
These devices provide a reset output during power-up, power-
down, and brownout conditions. On power-up, an internal
timer holds RESET asserted for at least 100 ms. This holds the
microprocessor in a reset state until conditions have stabilized.
The reset output remains operational with V
CC
as low as 1 V.
The
ADM6326
and
ADM6346
have an active low push-pull reset
output. The
ADM6328
and
ADM6348
have an active low open-
drain reset output, which requires an external pull-up resistor.
The
ADM6326
and
ADM6328
offer a choice of ten reset thresholds
in increments between 2.2 V and 3.08 V, whereas the
ADM6346
and
ADM6348
offer a choice of 14 reset thresholds between 3.3 V
and 4.63 V.
These devices are available in a 3-lead SOT-23 package and
operate over the extended temperature range of −40°C to +85°C.
Rev. A
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
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08052-002
08052-001
ADM6326/ADM6328/ADM6346/ADM6348
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagrams ............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
Thermal Resistance ...................................................................... 4
ESD Caution .................................................................................. 4
Data Sheet
Pin Configuration and Function Descriptions..............................5
Typical Performance Characteristics ..............................................6
Theory of Operation .........................................................................7
Reset Output ..................................................................................7
Interfacing to Other Devices .......................................................7
Transient Immunity ......................................................................7
Outline Dimensions ..........................................................................8
Ordering Guide .............................................................................9
REVISION HISTORY
6/14—Rev. 0 to Rev. A
Changes to Figure 1 and Figure 2 ................................................... 1
9/09—Revision 0: Initial Version
Rev. A | Page 2 of 12
Data Sheet
SPECIFICATIONS
ADM6326/ADM6328/ADM6346/ADM6348
T
A
= −40°C to +85°C, unless otherwise noted. Typical values are at T
A
= 25°C and V
CC
= 3 V. Overtemperature limits are guaranteed by design.
Table 1.
Parameter
OPERATING VOLTAGE RANGE, V
CC
INPUT CURRENT, I
CC
Min
1.0
Typ
0.5
1.0
RESET THRESHOLD
Threshold Voltage, V
TH
(See Table 2)
Temperature Coefficient
Hysteresis
ADM6326/ADM6328
ADM6346/ADM6348
TIMING CHARACTERISTICS
V
CC
to Reset Delay (t
RD
)
Reset Active Timeout Period (t
RP
)
RESET OUTPUT VOLTAGE LOW, V
OL
RESET OUTPUT VOLTAGE HIGH, V
OH
V
TH
− 2.5%
V
TH
− 1.5%
V
TH
V
TH
40
6.3
9.5
20
185
Max
5.5
1.0
1.75
V
TH
+ 2.5%
V
TH
+ 1.5%
Unit
V
µA
µA
V
V
ppm/°C
mV
mV
µs
ms
V
V
V
V
V
0.1
µA
V
CC
= V
TH
to (V
TH
− 100 mV)
V
CC
> 2.1 V, I
SINK
= 1.6 mA, reset asserted
V
CC
≥ 1.2 V, I
SINK
= 100 μA, reset asserted
ADM6326
only, V
CC
= 3.2 V, I
SOURCE
= 500 µA
ADM6326/ADM6346
only, V
CC
= 4.5 V,
I
SOURCE
= 800 µA, V
TH
≤ 4.38 V
ADM6326/ADM6346
only, V
CC
= V
TH(MAX)
,
I
SOURCE
= 800 µA, V
TH
≥ 4.5 V
Test Conditions/Comments
ADM6326/ADM6328
only, V
CC
= 3.0 V for V
TH
≤
2.93 V, V
CC
= 3.2 V for V
TH
> 2.93 V, no load
V
CC
= 5.5 V, no load
T
A
= 25°C
100
280
0.3
0.4
0.8 × V
CC
0.8 × V
CC
0.8 × V
CC
OPEN-DRAIN RESET OUTPUT LEAKAGE CURRENT
Table 2. Reset Threshold Voltage
T
A
= 25°C
Parameter
RESET THRESHOLD VOLTAGE (V
TH
)
ADM632x-22
ADM632x-23
ADM632x-24
ADM632x-25
ADM632x-26
ADM632x-27
ADM632x-28
ADM632x-29
ADM632x-30
ADM632x-31
ADM634x-33
ADM634x-34
ADM634x-35
ADM634x-36
ADM634x-37
ADM634x-38
ADM634x-39
ADM634x-40
ADM634x-41
ADM634x-42
ADM634x-43
ADM634x-44
ADM634x-45
ADM634x-46
Min
2.167
2.285
2.364
2.462
2.591
2.66
2.758
2.886
2.955
3.034
3.25
3.349
3.447
3.546
3.644
3.743
3.841
3.94
4.038
4.137
4.235
4.314
4.432
4.56
Typ
2.2
2.32
2.4
2.5
2.63
2.7
2.8
2.93
3.00
3.08
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
4.1
4.2
4.3
4.38
4.5
4.63
Max
2.233
2.355
2.436
2.537
2.669
2.741
2.842
2.974
3.045
3.126
3.35
3.451
3.552
3.654
3.755
3.857
3.958
4.06
4.161
4.263
4.364
4.446
4.567
4.699
T
A
= −40°C to +85°C
Min
2.145
2.262
2.34
2.437
2.564
2.633
2.73
2.857
2.925
3.003
3.217
3.315
3.412
3.51
3.607
3.705
3.802
3.9
3.997
4.095
4.192
4.27
4.387
4.514
Max
2.25
2.375
2.46
2.562
2.696
2.768
2.87
3.0
3.075
3.15
3.383
3.485
3.587
3.69
3.792
3.895
3.997
4.1
4.202
4.305
4.407
4.489
4.612
4.746
Unit
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
Rev. A | Page 3 of 12
ADM6326/ADM6328/ADM6346/ADM6348
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter
Supply Voltage, V
CC
Input Current, I
CC
Output Voltage
Push-Pull RESET
Open-Drain RESET
Output Current (RESET)
Rate of Rise of V
CC
Temperature
Storage
Operating
Soldering (10 sec)
Rating
−0.3 V to +6 V
20 mA
−0.3 V to (V
CC
+ 0.3 V)
−0.3 V to +6 V
20 mA
100 V/µs
−65°C to +155°C
−40°C to +85°C
300°C
Data Sheet
THERMAL RESISTANCE
θ
JA
is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Table 4. Thermal Resistance
Package Type
3-Lead SOT-23
θ
JA
270
Unit
°C/W
ESD CAUTION
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Rev. A | Page 4 of 12
Data Sheet
ADM6326/ADM6328/ADM6346/ADM6348
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
GND
1
ADM6326/
ADM6328/
ADM6346/
ADM6348
TOP VIEW
(Not to Scale)
3
V
CC
08052-003
RESET
2
Figure 3.
ADM6326/ADM6328/ADM6346/ADM6348
Pin Configuration
Table 5. Pin Function Descriptions
Pin No.
1
2
3
Mnemonic
GND
RESET
V
CC
Description
Ground Reference for All Signals; 0 V.
Active Low Logic Output. This pin is low when V
CC
is less than the reset threshold; it remains low for 185 ms
(typical) after V
CC
becomes greater than the reset threshold.
Supply Voltage Being Monitored.
Rev. A | Page 5 of 12
