Maxim MAX633US21D 4-pin, ultra-low-voltage, low-power î¼p reset circuits with manual reset Datasheet

19-1412; Rev 0; 12/98
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
The MAX6335/MAX6336/MAX6337 microprocessor (µP)
supervisory circuits monitor the power supplies in 1.8V
to 3.3V µP and digital systems. They increase circuit reliability and reduce cost by eliminating external components and adjustments. They also feature a debounced
manual-reset input.
These devices perform a single function: they assert a
reset signal whenever the VCC supply voltage declines
below a preset threshold or whenever manual reset is
asserted. Reset remains asserted for a preset timeout
period after VCC has risen above the reset threshold or
after manual reset is deasserted. The only difference
among the three devices is their output. The MAX6336
(push/pull) and MAX6337 (open-drain) have an activelow RESET output, while the MAX6335 (push/pull) has
an active-high RESET output. The MAX6335/MAX6336
are guaranteed to be in the correct state for VCC down
to 0.7V. The MAX6337 is guaranteed to be in the correct state for VCC down to 1.0V.
The reset comparator in these ICs is designed to ignore
fast transients on VCC. Reset thresholds are factorytrimmable between 1.6V and 2.5V, in approximately
100mV increments. There are 15 standard versions
available (2500 piece minimum-order quantity); contact
the factory for availability of nonstandard versions
(10,000 piece minimum-order quantity). For space-critical applications, the MAX6335/MAX6336/MAX6337
come packaged in a 4-pin SOT143.
Features
♦ Ultra-Low 0.7V Operating Supply Voltage
♦ Low 3.3µA Supply Current
♦ Precision Monitoring of 1.8V and 2.5V PowerSupply Voltages
♦ Reset Thresholds Available from 1.6V to 2.5V,
in Approximately 100mV Increments
♦ Debounced Manual Reset
♦ Fully Specified over Temperature
♦ Three Power-On Reset Pulse Widths Available
(1ms min, 20ms min, 100ms min)
♦ Low Cost
♦ Three Available Output Structures: Push/Pull
RESET, Push/Pull RESET, Open-Drain RESET
♦ Guaranteed RESET/RESET Valid to VCC = 0.7V
(MAX6335/MAX6336)
♦ Power-Supply Transient Immunity
♦ No External Components
♦ 4-Pin SOT143 Package
♦ Pin-Compatible with MAX811/MAX812 and
MAX6314/MAX6315
Applications
Ordering Information
Pentium II™ Computers
Computers
PART*
TEMP. RANGE
PIN-PACKAGE
Controllers
MAX6335US__D_-T
-40°C to +85°C
4 SOT143
Intelligent Instruments
MAX6336US__D_-T
Critical µP/µC Power Monitoring
MAX6337US__D_-T
-40°C to +85°C
-40°C to +85°C
4 SOT143
4 SOT143
Portable/Battery-Powered Equipment
Automotive
Typical Operating Circuit and Pin Configuration appear
at end of data sheet.
Selector Guide appears at end of data sheet.
* These devices are available in factory-set VCC reset thresholds from 1.6V to 2.5V, in approximately 0.1V increments.
Choose the desired reset threshold suffix from Table 1 and
insert it in the blanks following “US” in the part number.
Factory-programmed reset timeout periods are also available.
Insert the number corresponding to the desired nominal reset
timeout period (1 = 1ms min, 2 = 20ms min, 3 = 100ms min) in
the blank following “D” in the part number. There are 15 standard versions with a required order increment of 2500 pieces.
Sample stock is generally held on the standard versions only
(see Selector Guide). Contact the factory for availability of nonstandard versions (required order increment is 10,000 pieces).
All devices available in tape-and-reel only.
Pentium II is a trademark of Intel Corp.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX6335/MAX6336/MAX6337
General Description
MAX6335/MAX6336/MAX6337
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
VCC ......................................................................-0.3V to +6V
Push/Pull RESET or RESET, MR ............-0.3V to (VCC + 0.3V)
Open-Drain RESET ..............................................-0.3V to +6V
Input Current (VCC) .............................................................20mA
Output Current (RESET, RESET).........................................20mA
Rate of Rise, VCC ............................................................100V/µs
Continuous Power Dissipation (TA = +70°C)
SOT143 (derate 4mW/°C above +70°C) .....................320mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°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 = full range, MR = VCC or unconnected, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C and
VCC = 3V, reset not asserted.)
PARAMETER
SYMBOL
CONDITIONS
TA = 0°C to +85°C
Supply Voltage Range
VCC
TA = -40°C to +85°C
Supply Current
Reset Threshold
No load
VTH
MAX633_US_ _D_-T,
Table 1
MAX
1.0
5.5
0.78
5.5
MAX6337
1.2
6.0
3.3
7.0
TA = +25°C
VTH 1.8%
VTH
VTH +
1.8%
TA = -40°C to +85°C
VTH 3%
VTH
VTH +
3%
1
1.5
20
30
40
100
150
200
VOL
Reset
asserted
ISINK = 50µA, VCC ≥ 1.0V
0.4
ISINK = 500µA, VCC ≥ 1.8V
0.3
RESET Output High Voltage
(MAX6336)
VOH
Reset not
asserted
ISOURCE = 200µA, VCC ≥ 1.8V
0.8VCC
ISOURCE = 500µA, VCC ≥ 2.7V
0.8VCC
VOH
Reset
asserted
ISOURCE = 1µA, VCC ≥ 1.0V
0.8VCC
ISOURCE = 200µA, VCC ≥ 1.8V
0.8VCC
VOL
Reset not
asserted
ISINK = 500µA, VCC ≥ 1.8V
0.3
ISINK = 1.2mA, VCC ≥ 2.7V
0.3
1
MR Reset Delay
VCC = 2.6V
0.42
RESET Output Leakage
Current (MAX6337)
2
V
µs
160
0.3VCC
12
V
V
VCC = 2.6V
MR Pull-Up Resistance
ms
V
MR Glitch Immunity
MR Threshold
V
2
MAX633_US_ _D3-T
V MR
µA
µs
24
MAX633_US_ _D2-T
MR Minimum Pulse Width
V
5.5
3.0
RESET Output Low Voltage
(MAX6336/MAX6337)
RESET Output Voltage
(MAX6335)
UNITS
5.5
MAX6335/MAX6336
VCC falling at 10V/ms
tRP
TYP
0.7
MAX6337
MAX633_US_ _D1-T
Reset Active Timeout Period
MIN
VCC = 1.8V
VCC = 2.5V
ICC
VCC Falling Reset Delay
MAX6335/MAX6336
20
VCC > VTH, RESET deasserted
_______________________________________________________________________________________
ns
µs
0.7VCC
V
30
kΩ
0.5
µA
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
VCC = 2.5V
3.0
2.8
VCC = 1.8V
2.6
2.4
2.2
1.010
1.000
0.990
0.980
0.970
-20
0
20
40
60
80
100
50
40
TA = +25°C
TA = +85°C
30
20
TA = -40°C
0
-60
-40
-20
0
20
40
60
80
100
0.50
1.00
1.50
2.00
2.50
TEMPERATURE (°C)
TEMPERATURE (°C)
VCC (V)
OUTPUT VOLTAGE HIGH
vs. SUPPLY VOLTAGE
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
140
120
100
80
60
TA = +25°C
TA = -40°C
40
20
600
500
400
RESET OCCURS
300
200
RESET DOES
NOT OCCUR
100
80
70
PROPAGATION DELAY (µs)
VTH = 2.2V
ISOURCE = 100µA
RESET ASSERTED
MAX6335/36/37 toc-5
160
MAX6335/36/37 toc-4
-40
60
10
0.950
-60
VTH = 2.5V
ISINK = 500µA
RESET ASSERTED
70
0.960
RESET NOT ASSERTED
2.0
OUTPUT VOLTAGE HIGH (VCC - VOH) (mV)
1.020
80
3.00
MAX6332/33/34 toc-6
3.2
1.030
MAXIMUM TRANSIENT DURATION (µs)
ICC (µA)
3.4
VTH = 2.2V
1.040
MAX6335/36/37 toc-3
3.6
1.050
MAX6335/36/37-2
3.8
NORMALIZED RESET TIMEOUT PERIOD
MAX6335/36/37 toc-1
4.0
OUTPUT VOLTAGE LOW
vs. SUPPLY VOLTAGE
OUTPUT VOLTAGE LOW (mV)
SUPPLY CURRENT vs. TEMPERATURE
60
VCC FALLING AT 1V/ms
50
40
30
VCC FALLING AT 10V/ms
20
TA = +85°C
10
0
0
0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5
VCC (V)
0.1
1
10
100
1000
RESET COMPARATOR OVERDRIVE (mV)
-60
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
_______________________________________________________________________________________
3
MAX6335/MAX6336/MAX6337
__________________________________________Typical Operating Characteristics
(Reset not asserted, TA = +25°C, unless otherwise noted.)
MAX6335/MAX6336/MAX6337
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
Pin Description
PIN
MAX6335
1
—
MAX6336
MAX6337
1
2
NAME
GND
FUNCTION
Ground
RESET
Active-Low Reset Output. RESET remains low while VCC is below the reset
threshold, or MR is asserted and for a reset timeout period (tRP) after VCC
rises above the reset threshold, or MR is deasserted. RESET on the
MAX6337 is open-drain.
Active-High Reset Output. RESET remains high while VCC is below the
reset threshold, or MR is asserted and for a reset timeout period (tRP) after
VCC rises above the reset threshold, or MR is deasserted. RESET also
asserts when MR is low.
2
—
RESET
3
3
MR
Manual-Reset Input. A logic low on MR asserts reset. Reset remains
asserted as long as MR is low, and for the reset timeout period (tRP) after
MR goes high. Leave unconnected or connect to VCC if not used.
4
4
VCC
Supply Voltage (0.7V to 5.5V)
Applications Information
Manual-Reset Inputs
Many µP-based products require manual-reset capability, allowing the operator, a test technician, or external
logic circuitry to initiate a reset. A logic low on MR
asserts reset. Reset remains asserted while MR is low,
and for the reset active timeout period after MR returns
high. MR has an internal 20kΩ pull-up resistor, so it can
be left unconnected if not used. Connect a normally
open momentary switch from MR to GND to create a
manual-reset function; external debounce circuitry is
not required.
Interfacing to µPs with
Bidirectional Reset Pins
Since the RESET output on the MAX6337 is open-drain,
this device interfaces easily with µPs that have bidirectional reset pins, such as the Motorola 68HC11.
Connecting the µP supervisor’s RESET output directly
to the microcontroller’s (µC’s) RESET pin with a single
pull-up resistor allows either device to assert reset
(Figure 1).
signal. As the amplitude of the transient increases, the
maximum allowable pulse width decreases.
Ensuring a Valid Reset Output
down to VCC = 0
When VCC falls below 1V and approaches the minimum
operating voltage of 0.7V, push/pull-structured reset
sinking (or sourcing) capabilities decrease drastically.
High-impedance CMOS-logic inputs connected to the
RESET pin can drift to indeterminate voltages. This
does not present a problem in most cases, since most
µPs and circuitry do not operate at VCC below 1V. For
the MAX6336, where RESET must be valid down to 0,
adding a pull-down resistor between RESET and GND
removes stray leakage currents, holding RESET low
VCC
VCC
VCC
MAX6337
Negative-Going VCC Transients
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, these devices
are relatively immune to short-duration, negative-going
V CC transients (glitches). The Typical Operating
Characteristics show the Maximum Transient Duration
vs. Reset Comparator Overdrive graph. The graph
shows the maximum pulse width that a negative-going
VCC transient may typically have without issuing a reset
4
MR
RESET
µP
MOTOROLA
68HCXX
RESET
INPUT
GND
GND
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
_______________________________________________________________________________________
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
MAX6336
MR
RESET
100k
GND
(a)
VCC
100k*
MAX6335
RESET
MR
(b)
GND
RESET
THRESHOLD
SUFFIX
MAX633_US25D_
MIN TYP MAX
MIN
MAX
2.46 2.50
2.55
2.43
2.58
MAX633_US24D_
2.36 2.40
2.44
2.33
2.47
MAX633_US23D_
2.26 2.30
2.34
2.23
2.37
MAX633_US22D_
2.16 2.20
2.24
2.13
2.27
MAX633_US21D_
2.06 2.10
2.14
2.04
2.16
MAX633_US20D_
1.96 2.00
2.04
1.94
2.06
MAX633_US19D_
1.87 1.90
1.93
1.84
1.96
MAX633_US18D_
1.77 1.80 1.83
1.75
1.85
MAX633_US17D_
1.67 1.70 1.73
1.65
1.75
MAX633_US16D_
1.57 1.60
1.55
1.65
TA = +25°C
1.63
TA = -40°C to +85°C
* Factory-trimmed reset thresholds are available in approximately
100mV increments, with a ±1.8% room-temperature variance.
*ASSUMES HIGH-Z RESET INPUT TO THE µP
Figure 2. Ensuring Reset Valid down to VCC = 0
(Figure 2a). The pull-down resistor value is not critical;
100kΩ is large enough not to load RESET, and small
enough to pull it low. For the MAX6335, where RESET
must be valid to VCC = 0, a 100kΩ pull-up resistor
between RESET and VCC will hold RESET high when
VCC falls below 0.7V (Figure 2b).
Since the MAX6337 has an open-drain, active-low output, it typically uses a pull-up resistor. With this device,
RESET will most likely not maintain an active condition,
but will drift to a non-active level due to the pull-up
resistor and the reduced sinking capability of the opendrain device. Therefore, this device is not recommended for applications where the RESET pin is required to
be valid down to VCC = 0.
_______________________________________________________________________________________
5
MAX6335/MAX6336/MAX6337
Table 1. Factory-Trimmed Reset
Thresholds*
VCC
MAX6335/MAX6336/MAX6337
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
Selector Guide (standard versions*)
PART
OUTPUT STAGE
NOMINAL VTH (V)
MINIMUM RESET
TIMEOUT (ms)
SOT TOP MARK
MAX6335US23D3-T
Push/Pull RESET
2.30
100
KABQ
MAX6335US22D3-T
Push/Pull RESET
2.20
100
KAAR
MAX6335US20D3-T
Push/Pull RESET
2.00
100
KABP
MAX6335US18D3-T
Push/Pull RESET
1.80
100
KAAQ
MAX6335US16D3-T
Push/Pull RESET
1.60
100
KAAP
MAX6336US23D3-T
Push/Pull RESET
2.30
100
KAAW
MAX6336US22D3-T
Push/Pull RESET
2.20
100
KAAV
MAX6336US20D3-T
Push/Pull RESET
2.00
100
KAAU
MAX6336US18D3-T
Push/Pull RESET
1.80
100
KAAT
MAX6336US16D3-T
Push/Pull RESET
1.60
100
KAAS
MAX6337US23D3-T
Open-Drain RESET
2.30
100
KABS
MAX6337US22D3-T
Open-Drain RESET
2.20
100
KAAZ
MAX6337US20D3-T
Open-Drain RESET
2.00
100
KABR
MAX6337US18D3-T
Open-Drain RESET
1.80
100
KAAY
MAX6337US16D3-T
Open-Drain RESET
1.60
100
KAAX
* Sample stock is generally held on all standard versions.
Pin Configuration
TOP VIEW
Typical Operating Circuit
VCC
GND
1
4
VCC
MAX6335
MAX6336
MAX6337
RESET (RESET)
2
VCC
MAX6335
MAX6336
µP
MR
3
SOT143
VCC
MR
RESET
(RESET)
RESET
GND
PUSHBUTTON
SWITCH
( ) ARE FOR MAX6335
6
GND
_______________________________________________________________________________________
( ) ARE FOR MAX6335
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
TRANSISTOR COUNT: 505
SOT1434.EPS
Package Information
_______________________________________________________________________________________
7
MAX6335/MAX6336/MAX6337
Chip Information
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
MAX6335/MAX6336/MAX6337
NOTES
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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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