Maxim MAX6447UK26L Up reset circuits with long manual reset setup period Datasheet

19-2656; Rev 3; 6/10
µP Reset Circuits with Long Manual Reset
Setup Period
Features
The MAX6443–MAX6452 low-current microprocessor
reset circuits feature single or dual manual reset inputs
with an extended setup period. Because of the extended setup period, short switch closures (nuisance resets)
are ignored.
On all devices, the reset output asserts when any of the
monitored supply voltages drops below its specified
threshold. The reset output remains asserted for the
reset timeout period (210ms typ) after all monitored
supplies exceed their reset thresholds. The reset output
is one-shot pulse asserted for the reset timeout period
(140ms min) when selected manual reset input(s) are
held low for an extended setup timeout period. These
devices ignore manual reset transitions of less than the
extended setup timeout period.
o Single- or Dual-Supply Voltage Monitors
The MAX6443–MAX6448 are single fixed-voltage µP
supervisors. The MAX6443/MAX6444 have a single
extended manual reset input. The MAX6445/MAX6446
have two extended manual reset inputs. The MAX6447/
MAX6448 have one extended and one immediate manual
reset input.
o Active-Low RESET (Push-Pull or Open-Drain)
Outputs
The MAX6449–MAX6452 have one fixed-threshold µP
supervisor and one adjustable-threshold µP supervisor.
The MAX6449/MAX6450 have two delayed manual
reset inputs. The MAX6451/MAX6452 have one delayed
and one immediate manual reset input.
The MAX6443–MAX6452 have an active-low RESET
with push-pull or open-drain output logic options. These
devices, offered in small SOT packages, are fully guaranteed over the extended temperature range (-40°C to
+85°C).
Applications
Set-Top Boxes
Consumer Electronics
DVD Players
o Precision Factory-Set Reset Thresholds from
1.6V to 4.6V
o Adjustable Threshold to Monitor Voltages Down
to 0.63V (MAX6449–MAX6452)
o Single or Dual Manual Reset Inputs with Extended
Setup Period
o Optional Short Setup Time Manual Reset Input
(MAX6447/MAX6448 and MAX6451/MAX6452)
o Immune to Short Voltage Transients
o Low 6µA Supply Current
o Guaranteed Valid Reset Down to VCC = 1.0V
o 140ms (min) Reset Timeout Period
o Small SOT143 and SOT23 Packages
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX6443US_ _ _-T
-40°C to +85°C
4 SOT143
MAX6444US_ _ _-T
-40°C to +85°C
4 SOT143
Note: The first “_ _ ” is a placeholder for the threshold voltage
level of the devices. A desired threshold level is set by the twonumber suffix found in Table 1. The third "_" is a placeholder
for the manual reset setup period of the devices. A desired
setup period is set by the letter suffix found in Table 2. All
devices are available in tape-and-reel only. There is a 2500piece minimum order increment for standard versions (Table
2). Sample stock is typically held on standard versions only.
Nonstandard versions require a minimum order increment of
10,000 pieces. Contact factory for availability.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Pin Configurations
Cable/DSL Modems
MP3 Players
Industrial Equipment
Automotive
TOP VIEW
4 VCC
GND 1
Medical Devices
MAX6443
MAX6444
3 MR1
RESET 2
SOT143
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX6443–MAX6452
General Description
MAX6443–MAX6452
µP Reset Circuits with Long Manual Reset
Setup Period
ABSOLUTE MAXIMUM RATINGS
All Voltages Referenced to GND
VCC ..........................................................................-0.3V to +6V
Open-Drain RESET ..................................................-0.3V to +6V
Push-Pull RESET ........................................-0.3V to (VCC + 0.3V)
MR1, MR2, MR2, RSTIN ..........................................-0.3V to +6V
Input Current, All Pins.......................................................±20mA
Continuous Power Dissipation (TA = +70°C)
4-Pin SOT143 (derate 4.0mW/°C above +70°C)...........320mW
5-Pin SOT23 (derate 7.1mW/°C above +70°C).............571mW
6-Pin SOT23 (derate 8.7mW/°C above +70°C).............696mW
Operating Temperature Range .......................... -40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow)
Lead(Pb)-free……………………………………………..+260°C
Containing lead………………………………………… +240°C
Stresses beyond those listed under “Absolute Maximum Ratings” 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 the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = 1.0V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
VCC Supply Current
VCC Reset Threshold
SYMBOL
CONDITIONS
VCC
ICC
VTH
MIN
1.0
5.5
V
20
VCC = 3.6V, no load
6
16
46
4.50
4.63
4.75
44
4.25
4.38
4.50
31
3.00
3.08
3.15
29
2.85
2.93
3.00
26
2.55
2.63
2.70
23
2.25
2.32
2.38
22
2.12
2.19
2.25
17
1.62
1.67
1.71
16
1.52
1.58
1.62
60
MAX6449–MAX6452
RSTIN Threshold Hysteresis
VHYST
MAX6449–MAX6452
RSTIN Input Current
IRSTIN
MAX6449–MAX6452
TA = 0°C to +85°C
0.615
TA = -40°C to +85°C
0.610
Reset Timeout Period
tRP
VCC to RESET Output Delay
tRD
2.5
tMR
140
210
V
mV
+25
15
VCC falling at 1mV/µs
V
mV
0.645
0.650
-25
MAX6449–MAX6452, VRSTIN falling at
1mV/µs
RSTIN to Reset Output Delay
0.630
µA
ppm/°C
2 × VTH
VTH-RSTIN
2
UNITS
7
Reset Threshold Hysteresis
Manual Reset Minimum Setup
Period Pulse Width
MAX
VCC = 5.5V, no load
Reset Threshold Tempco
RSTIN Threshold
TYP
nA
µs
280
20
ms
µs
K
6.72
10.08
13.44
L
4.48
6.72
8.96
S
2.24
3.36
4.48
T
1.12
1.68
2.24
s
_______________________________________________________________________________________
µP Reset Circuits with Long Manual Reset
Setup Period
(VCC = 1.0V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MR2 Minimum Setup Period
Pulse Width
MAX6447/MAX6448/MAX6451/MAX6452
MR2 Glitch Rejection
MAX6447/MAX6448/MAX6451/MAX6452
100
ns
MR2 to RESET Delay
MAX6447/MAX6448/MAX6451/MAX6452
200
ns
Manual Reset Timeout Period
tMRP
140
MR1 to VCC Pullup Impedance
MR2 to VCC Pullup Impedance
RESET Output Low
(Open Drain or Push-Pull)
RESET Output High
(Push-Pull)
MAX6445/MAX6446/MAX6449/MAX6450
VOL
VOH
RESET Open-Drain Leakage
Current
ILKG
MR1, MR2, MR2
Input Low Voltage
VIL
MR1, MR2, MR2
Input High Voltage
VIH
1
µs
210
280
ms
25
50
75
kΩ
25
50
75
kΩ
VCC ≥ 1.00V, ISINK = 50µA, RESET asserted
0.3
VCC ≥ 1.20V, ISINK = 100µA, RESET
asserted
0.3
VCC ≥ 2.55V, ISINK = 1.2mA, RESET
asserted
0.3
VCC ≥ 4.25V, ISINK = 3.2mA, RESET
asserted
0.4
V
VCC ≥ 1.80V, ISOURCE = 200µA, RESET
deasserted
0.8 × VCC
VCC ≥ 3.15V, ISOURCE = 500µA, RESET
deasserted
0.8 × VCC
VCC ≥ 4.75V, ISOURCE = 800µA, RESET
deasserted
0.8 × VCC
RESET deasserted
V
1
0.3 × VCC
0.7 × VCC
µA
V
V
Note 1: Devices production tested at TA = +25°C. Overtemperature limits are guaranteed by design.
_______________________________________________________________________________________
3
MAX6443–MAX6452
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VCC = 3.3V, TA = +25°C, unless otherwise noted.)
6
5
4
TA = -40°C
3
2
1
1.03
1.02
1.01
1.00
0.99
0.98
250
0.97
MAX6443/52 toc03
1.04
TRANSIENT DURATION (µs)
TA = +25°C
7
1.05
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6443/52 toc02
TA = +85°C
NORMALIZED TIMEOUT PERIOD
200
150
RESET OCCURS
ABOVE THE CURVE
100
50
VTH = 4.4V
0.96
0
0.95
0
-40
-15
SUPPLY VOLTAGE (V)
NORMALIZED VCC RESET THRESHOLD
vs. TEMPERATURE
1.02
1.01
1.00
0.99
0.98
0.97
35
60
-15
10
35
60
400
600
22.8
22.4
22.0
21.6
21.2
24.0
RSTIN FALLING AT 1mV/µs
23.6
23.2
22.4
22.0
21.6
21.2
20.8
20.4
20.4
20.0
-40
-15
TEMPERATURE (°C)
10
35
60
85
-40
-15
10
35
TEMPERATURE (°C)
TEMPERATURE (°C)
MANUAL RESET TO RESET DELAY
(MAX6445L/MAX6446L/MAX6449L/MAX6450L)
VCC TO RESET DELAY
MAX6443/52 toc08
MAX6443/52 toc07
VCC = 5V
MR1
(5V/div)
VCC = 4.5V
VTH = 4.392V
VCC (100mV/div)
VCC = 4.3V
MR2
(5V/div)
RESET
(2V/div)
RESET
(5V/div)
4
1000
22.8
20.8
TIME (1s/div)
800
RSTIN TO RESET DELAY
vs. TEMPERATURE (RSTIN FALLING)
23.2
85
200
VCC TO RESET DELAY
vs. TEMPERATURE
20.0
-40
0
RESET THRESHOLD OVERDRIVE (mV)
VCC = FALLING AT 1mV/µs
23.6
85
TEMPERATURE (°C)
24.0
VCC TO RESET DELAY (µs)
MAX6443/52 toc04
1.03
10
RSTIN TO RESET DELAY (µs)
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
MAX6443/52 toc05
SUPPLY CURRENT (µA)
8
MAX6443/52 toc01
9
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6443/52 toc06
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
NORMALIZED VCC RESET THRESHOLD
MAX6443–MAX6452
µP Reset Circuits with Long Manual Reset
Setup Period
TIME (100µs/div)
_______________________________________________________________________________________
60
85
µP Reset Circuits with Long Manual Reset
Setup Period
PIN
MAX6443
MAX6444
MAX6445
MAX6446
MAX6447
MAX6448
MAX6449
MAX6450
MAX6451
MAX6452
NAME
1
2
2
2
2
GND
2
1
1
1
1
3
—
3
—
3
RESET
FUNCTION
Ground
Active-Low Push-Pull or Open-Drain Output. RESET
changes from high to low when VCC or RSTIN drops below
its selected reset threshold and remains low for the 210ms
reset timeout period after all monitored power-supply inputs
exceed their selected reset thresholds. RESET is one-shot
pulsed low for the reset timeout period (140ms min) after
selected manual reset inputs are asserted longer than the
specified setup period. For the open-drain output, use a
minimum 20kΩ pullup resistor to VCC .
Manual Reset Input, Active Low. Internal 50kΩ pullup to
VCC. Pull MR1 low for the typical input pulse width (tMR)
to one-shot pulse RESET for the reset timeout period.
MR1
—
3
—
3
—
4
4
4
4
4
Manual Reset Input, Active Low. Pull both MR1 and
MR2 low for the typical input pulse width (tMR) to oneshot pulse RESET for the reset timeout period.
VCC
VCC Voltage Input. Power supply and input for the
primary microprocessor voltage reset monitor.
—
5
—
6
—
MR2
Manual Reset Input, Active Low. Internal 50kΩ pullup to
VCC. Pull both MR1 and MR2 low for the typical input
pulse width (tMR) to one-shot pulse RESET for the reset
timeout period.
—
—
5
—
6
MR2
Manual Reset Input. Pull the MR2 high to immediately
one-shot pulse RESET for the reset timeout period.
—
—
—
5
5
Detailed Description
Reset Output
The reset output is typically connected to the reset
input of a microprocessor (µP). A µP’s reset input starts
or restarts the µP in a known state. The MAX6443–
MAX6452 µP supervisory circuits provide the reset
logic to prevent code-execution errors during powerup, power-down and brownout conditions (see the
Typical Operating Circuit).
RESET changes from high to low whenever the monitored voltages (RSTIN or VCC) drop below the reset
RSTIN
Reset Input. High-impedance input to the adjustable
reset comparator. Connect RSTIN to the center point of
an external resistor-divider to set the threshold of the
externally monitored voltage.
threshold voltages. Once VRSTIN and VCC exceed their
respective reset threshold voltages, RESET remains low
for the reset timeout period and then goes high. RESET
is one-shot pulsed whenever selected manual reset
inputs are asserted. RESET stays asserted for the normal reset timeout period (140ms min).
RESET is guaranteed to be in the proper output logic
state for VCC inputs ≥ 1V. For applications requiring valid
reset logic when VCC is less than 1V, see the Ensuring a
Valid RESET Output Down to VCC = 0V section.
_______________________________________________________________________________________
5
MAX6443–MAX6452
Pin Description
MAX6443–MAX6452
µP Reset Circuits with Long Manual Reset
Setup Period
Manual Reset Input Options
Unlike typical manual reset functions associated with
supervisors, each device in the MAX6443–MAX6452
family includes at least one manual reset input, which
must be held logic-low for an extended setup period
(t MR ) before the RESET output asserts. When valid
manual reset input conditions/setup periods are met,
the RESET output is one-shot pulse asserted low for a
fixed reset timeout period (140ms min). Existing frontpanel pushbutton switches (i.e., power on/off, channel
up/down, or mode select) can be used to drive the
manual reset inputs. The extended manual reset setup
period prevents nuisance system resets during normal
front-panel usage or resulting from inadvertent shortterm pushbutton closure.
The MAX6443/MAX6444, MAX6447/MAX6448, and
MAX6451/MAX6452 include a single manual reset input
with extended setup period (MR1). The MAX6445/
MAX6446 and MAX6449/MAX6450 include two manual
reset inputs (MR1 and MR2) with extended setup periods. For dual MR1, MR2 devices, both inputs must be
held low simultaneously for the extended setup period
(tMR) before the reset output is pulse asserted. The
dual extended setup provides greater protection from
nuisance resets. (For example, the user or service technician is informed to simultaneously push both the
on/off button and the channel-select button for 6.72s
(L suffix) to reset the system.)
The MAX6443–MAX6452 RESET output is pulse asserted
once for the reset timeout period after each valid manual
reset input condition. At least one manual reset input
must be released (go high) and then be driven low for the
extended setup period before RESET asserts again.
Internal timing circuitry debounces low-to-high manual
reset logic transitions, so no external circuitry is required.
Figure 1 illustrates the single manual reset function of the
MAX6443/MAX6444 single-voltage monitors, and Figure
2 represents the dual manual reset function of the
MAX6445/MAX6446 and MAX6449/MAX6450.
The MAX6447/MAX6448 and MAX6451/MAX6452
include both an extended setup period and immediate
setup period manual reset inputs. A low-to-high MR2
rising edge transition immediately pulse asserts the
RESET output for the reset timeout period (140ms min).
If the MAX6447/MAX6448 and MAX6451/MAX6452
MR2 input senses another rising edge before the end
of the 140ms timeout period (Figure 3), the internal
timer clears and begins counting again. If no rising
edges are detected within the 210ms timeout period,
RESET deasserts. The high-to-low transition on MR2
input is internally debounced for 210ms to ensure that
6
RESET TIMEOUT PERIOD
210ms
MR1 SETUP PERIOD
tMR
MR1
RESET
Figure 1. MAX6443/MAX6444 Manual Reset Timing Diagram
210ms
MR1
tMR
MR2
RESET
Figure 2. MAX6445/MAX6446/MAX6449/MAX6450 Manual
Reset Timing Diagram
there are no false RESET assertions when MR2 is driven from high to low (Figure 4). The MR2 input can be
used for system test purposes or smart-card-detect
applications (see the Applications Information section).
Adjustable Input Voltage (RSTIN)
The MAX6449–MAX6452 monitor the voltage on RSTIN
using an adjustable reset threshold set with an external
resistor voltage-divider (Figure 5). Use the following formula to calculate the externally monitored voltage
(VMON-TH):
VMON-TH = VTH-RSTIN (R1+ R2)/R2
where VMON-TH is the desired reset threshold voltage
and V TH-RSTIN is the reset input threshold (0.63V).
Resistors R1 and R2 can have very high values to minimize current consumption because of low leakage currents. Set R2 to some conveniently high value (250kΩ,
for example), and calculate R1 based on the desired
reset threshold voltage, using the following formula:
R1 = R2 (VMON-TH/VTH-RSTIN - 1) Ω
_______________________________________________________________________________________
µP Reset Circuits with Long Manual Reset
Setup Period
MAX6443–MAX6452
t < 210ms
COUNTER RESET
210ms
DEBOUNCING PERIOD
t = 210ms
POSITIVE EDGE
MR2
210ms
TIMEOUT PERIOD
MR2
NO RESET
OUTPUT
ASSERTED
RESET
RESET
Figure 3. MAX6447/MAX6448/MAX6451/MAX6452 MR2
Assertion DebouncingTiming Diagram
VCC
VMON_TH
MAX6449
MAX6451
R1
RSTIN
Figure 4. MAX6447/MAX6448/MAX6451/MAX6452 MR2
Deassertion Debouncing Timing Diagram
+3.3V
VCC
VCC
RESET
RESET
VCC
µP
MAX6443L
R2
LED
GND
RESET
GND
MR1
NMI
VMON_TH = 0.63 x (R1 + R2) / R2
Figure 5. Calculating the Monitored Threshold Voltages
Applications Information
PUSHBUTTON SWITCH:
CLOSE FOR < 4.48s
FOR SYSTEM INTERRUPT;
CLOSE FOR > 6.72s FOR
SYSTEM RESET
Interrupt Before Reset
To minimize data loss and speed system recovery,
many applications interrupt the processor or reset only
portions of the system before a processor hard reset is
asserted. The extended setup time of the MAX6443–
MAX6452 manual reset inputs allows the same pushbutton (connected to both the processor interrupt and
the extended MR1 input, as shown in Figure 6) to control both the interrupt and hard reset functions. If the
pushbutton is closed for less than tMR, the processor is
only interrupted. If the system still does not respond
properly, the pushbutton (or two buttons for the dual
manual reset) can be closed for the full extended setup
period to hard reset the processor. If desired, connect
an LED to the RESET output to blink off (or on) for the
reset timeout period to signify when the pushbutton is
Figure 6. Interrupt Before Reset Application Circuit
closed long enough for a hard reset (the same LED
might be used as the front-panel power-on display).
Smart Card Insertion/Removal
The MAX6447/MAX6448/MAX6451/MAX6452 dual manual resets are useful in applications in which both an
extended and immediate setup periods are needed.
Figure 7 illustrates the insertion and removal of a smart
card. MR1 monitors a front-panel pushbutton. When
closed for tMR, RESET one-shot pulses low for 140ms
min. Because MR1 is internally pulled to VCC through a
50kΩ resistor, the front-panel switch can be connected to
_______________________________________________________________________________________
7
MAX6443–MAX6452
µP Reset Circuits with Long Manual Reset
Setup Period
+3.3V
3.3V
5V
+1.5V
CORE SUPPLY I/O SUPPLY
VCC
RESET
µP
MAX6451
RSTIN
VCC
RESET
MR1
DIGITAL INPUT
MAX6444
MAX6446
MAX6448
MAX6450
MAX6452
100kΩ
RESET
MR2
GND
µP
RESET
N
SMART CARD DETECT:
IMMEDIATE ONE-SHOT
WHEN MANUAL
RESET CLOSES
GND
FRONT-PANEL SWITCH
STANDARD µP INPUT
AND tMR MANUAL
RESET DELAY
Figure 7. MAX6451/MAX6452 Application Circuit
a microprocessor for general-purpose I/O control. MR2
monitors a switch to detect when a smart card is inserted.
When the switch is closed high (card inserted), RESET
one-shot pulses low for 140ms. MR2 is internally
debounced for 210ms to prevent false resets when the
smart card is removed.
Interfacing to Other Voltages
for Logic Compatibility
The open-drain RESET output can be used to interface
to a µP with other logic levels. As shown in Figure 8, the
open-drain output can be connected to voltages from 0
to 6V.
Generally, the pullup resistor connected to the RESET
connects to the supply voltage that is being monitored
at the IC’s VCC pin. However, some systems may use
the open-drain output to level-shift from the monitored
supply to reset circuitry powered by some other supply
(Figure 8). Keep in mind that as the supervisor’s VCC
decreases toward 1V, so does the IC’s ability to sink
current at RESET. RESET is pulled high as VCC decays
toward 0. The voltage where this occurs depends on
the pullup resistor value and the voltage to which it is
connected.
8
Figure 8. Interfacing to Other Voltage Levels
Ensuring a Valid RESET Down to
VCC = 0V (Push-Pull RESET)
When VCC falls below 1V, RESET current-sinking capabilities decline drastically. The high-impedance CMOSlogic inputs connected to RESET can drift to
undetermined voltages. This presents no problems in
most applications, because most µPs and other circuitry
do not operate with VCC below 1V.
In applications in which RESET must be valid down to
0V, add a pulldown resistor between RESET and GND
for the push-pull outputs. The resistor sinks any stray
leakage currents, holding RESET low (Figure 9). The
value of the pulldown resistor is not critical; 100kΩ is
large enough not to load RESET and small enough to
pull RESET to ground. The external pulldown cannot be
used with the open-drain reset outputs.
Transient Immunity
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, these supervisors are relatively immune to short-duration falling transients (glitches). The graph Maximum Transient Duration
vs. Reset Threshold Overdrive in the Typical Operating
Characteristics section shows this relationship.
_______________________________________________________________________________________
µP Reset Circuits with Long Manual Reset
Setup Period
MAX6443
MAX6445
MAX6447
MAX6449
MAX6451
VCC
RESET
100kΩ
GND
Figure 9. Ensuring RESET Valid to VCC = 0V
Table 1. Reset Voltage Threshold
Table 3. Standard Versions Table
PART NO. SUFFIX
(__)
VCC NOMINAL
VOLTAGE
THRESHOLD (V)
PART
TOP
MARK
PART
TOP
MARK
MAX6443US16L
KAFW
MAX6448UK16L
AEER
46
4.625
MAX6443US23L
KAFX
MAX6448UK23L
AEES
44
4.375
MAX6443US26L
KAFY
MAX6448UK26L
AEET
31
3.075
MAX6443US29L
KAFK
MAX6448UK29L
AEEU
29
2.925
MAX6443US46L
KAFZ
MAX6448UK46L
AEEV
26
2.625
MAX6444US16L
KAGA
MAX6449UT16L
ABEL
23
2.313
MAX6444US23L
KAGB
MAX6449UT23L
ABNP
22
2.188
MAX6444US26L
KAGC
MAX6449UT26L
ABNQ
17
1.665
MAX6444US29L
KAGD
MAX6449UT29L
ABNR
16
1.575
MAX6444US46L
KAFL
MAX6449UT46L
ABNS
MAX6445UK16L
AEEF
MAX6450UT16L
ABEM
MAX6445UK23L
AEEG
MAX6450UT23L
ABNX
MAX6445UK26L
AEEH
MAX6450UT26L
ABNY
MAX6445UK29L
AEEI
MAX6450UT29L
ABNZ
MAX6445UK46L
AEAO
MAX6450UT46L
ABOA
ABNT
Table 2. Manual Reset Setup Period (tMR)
PART NO. SUFFIX
(_)
MANUAL RESET SETUP
PERIOD (s)
K
10.08
MAX6446UK16L
AEEN
MAX6451UT16L
L
6.72
MAX6446UK23L
AEEO
MAX6451UT23L
ABEN
S
3.36
MAX6446UK26L
AEEP
MAX6451UT26L
ABNU
T
1.68
MAX6446UK29L
AEAP
MAX6451UT29L
ABNV
MAX6446UK46L
AEEQ
MAX6451UT46L
ABNW
MAX6447UK16L
AEEJ
MAX6452UT16L
ABOB
MAX6447UK23L
AEEK
MAX6452UT23L
ABOC
MAX6447UK26L
AEAQ
MAX6452UT26L
ABOD
MAX6447UK29L
AEEL
MAX6452UT29L
ABOE
MAX6447UK46L
AEEM
MAX6452UT46L
ABOF
_______________________________________________________________________________________
9
MAX6443–MAX6452
The area below the curves of the graph is the region in
which these devices typically do not generate a reset
pulse. This graph was generated using a falling pulse
applied to VCC, starting above the actual reset threshold (VTH) and ending below it by the magnitude indicated (reset threshold overdrive). As the magnitude of the
transient increases (VCC goes further below the reset
threshold), the maximum allowable pulse width
decreases. Typically, a VCC transient that goes 100mV
below the reset threshold and lasts 20µs or less does
not cause a reset pulse to be asserted.
VCC
µP Reset Circuits with Long Manual Reset
Setup Period
MAX6443–MAX6452
Pin Configurations (continued)
TOP VIEW
RESET
1
GND 2
5
MR2
MAX6445
MAX6446
MR1 3
RESET
1
GND 2
4
VCC
RESET 1
GND 2
MAX6449
MAX6450
MR1 3
4
VCC
6
MR2
5
RSTIN
4
VCC
SOT23-5
RESET 1
6
MR2
5
RSTIN
GND 2
4
VCC
MR1 3
MAX6451
MAX6452
SOT23-6
SOT23-6
Typical Operating Circuit
Ordering Information (continued)
PART
TEMP RANGE
PIN-PACKAGE
MAX6445UK_ _ _-T
-40°C to +85°C
5 SOT23
MAX6446UK_ _ _-T
-40°C to +85°C
5 SOT23
MAX6447UK_ _ _-T
-40°C to +85°C
5 SOT23
MAX6448UK_ _ _-T
-40°C to +85°C
5 SOT23
MAX6449UT_ _ _-T
-40°C to +85°C
6 SOT23
MAX6450UT_ _ _-T
-40°C to +85°C
6 SOT23
MAX6451UT_ _ _-T
-40°C to +85°C
6 SOT23
MAX6452UT_ _ _-T
-40°C to +85°C
6 SOT23
Note: The first “_ _ ” is a placeholder for the threshold voltage
level of the devices. A desired threshold level is set by the twonumber suffix found in Table 1. The third "_" is a placeholder
for the manual reset setup period of the devices. A desired
setup period is set by the letter suffix found in Table 2. All
devices are available in tape-and-reel only. There is a 2500piece minimum order increment for standard versions (Table
2). Sample stock is typically held on standard versions only.
Nonstandard versions require a minimum order increment of
10,000 pieces. Contact factory for availability.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
10
MR2
MAX6447
MAX6448
MR1 3
SOT23-5
5
+3.3V
VCC
VCC
µP
MAX6444
MR1
RESET
RESET
GND
GND
RESET TIMEOUT PERIOD
210ms
MR1 SETUP PERIOD
tMR
MR1
RESET
______________________________________________________________________________________
µP Reset Circuits with Long Manual Reset
Setup Period
PART
MR1 EXT.
SETUP
MR2
(NO SETUP)
MR2 EXT.
SETUP
RSTIN
MAX6443
✔
—
—
MAX6444
✔
—
—
MAX6445
✔
—
✔
MAX6446
✔
—
✔
MAX6447
✔
✔
MAX6448
✔
MAX6449
✔
MAX6450
✔
—
MAX6451
✔
✔
MAX6452
✔
✔
—
PUSH-PULL RESET
OPEN-DRAIN RESET
—
✔
—
—
—
✔
—
✔
—
—
—
✔
—
—
✔
—
✔
—
—
—
✔
—
✔
✔
✔
—
✔
✔
—
✔
—
✔
✔
—
✔
—
✔
Functional Diagram
VCC
MAX6443–
MAX6452
RESET
TIMEOUT PERIOD
(210ms typ)
MAX6449– RSTIN
MAX6452
VCC
MANUAL RESET
SETUP PERIOD
tMR
0.63V
MR2 ONE-SHOT
DEBOUNCE
CIRCUIT
1.23V
VCC
GND
RESET
MR2
MAX6447
MAX6448
MAX6451
MAX6452
VCC
MR1
MR2
MAX6445
MAX6446
MAX6449
MAX6450
______________________________________________________________________________________
11
MAX6443–MAX6452
Selector Guide
MAX6443–MAX6452
µP Reset Circuits with Long Manual Reset
Setup Period
Package Information
Chip Information
PROCESS: BiCMOS
12
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE NO.
LAND
PATTERN NO.
4 SOT143
U4-1
21-0052
90-0183
5 SOT23
U5-1
21-0057
90-0174
6 SOT23
U6-1
21-0058
90-0175
______________________________________________________________________________________
µP Reset Circuits with Long Manual Reset
Setup Period
REVISION
NUMBER
REVISION
DATE
0
10/02
Initial release
6/10
Revised the General Description, Features, Applications, Ordering Information,
Absolute Maximum Ratings, Electrical Characteristics, Typical Operating
Characteristics, Pin Description, the Manual Reset Input Options, Interrupt Before
Reset, and Smart Card Insertion/Removal sections, Functional Diagram, Typical
Operating Circuit, Selector Guide, Figures 1, 6, and 7, as well as Tables 2 and 3
to add extended setup timeout specifications.
3
DESCRIPTION
PAGES
CHANGED
—
1, 2, 4, 5–12
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13
© 2010 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX6443–MAX6452
Revision History