MAX6315 Open-Drain SOT µP Reset Circuit
General Description
The MAX6315 low-power CMOS microprocessor (µP)
supervisory circuit is designed to monitor power sup-
plies in µP and digital systems. It provides excellent cir-
cuit reliability and low cost by eliminating external
components and adjustments. The MAX6315 also pro-
vides a debounced manual reset input.
This device performs a single function: it asserts a reset
signal whenever the VCC supply voltage falls below a
preset threshold or whenever manual reset is asserted.
Reset remains asserted for an internally programmed
interval (reset timeout period) after VCC has risen above
the reset threshold or manual reset is deasserted. The
MAX6315’s open-drain RESET output can be pulled up
to a voltage higher than VCC.
The MAX6315 comes with factory-trimmed reset thresh-
old voltages in 100mV increments from 2.5V to 5V.
Preset timeout periods of 1ms, 20ms, 140ms, and
1120ms (min) are also available. The device comes in a
SOT143 package.
For microcontrollers (µCs) and µPs with bidirectional
reset pins, see the MAX6314 data sheet.
Applications
Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery-Powered Equipment
Benefits and Features
•Supervisory Circuit Ensures Reliable System
Operation with Minimal Power Consumption
•Precision, Factory-Set VCC Reset Thresholds:
100mV Increments from 2.5V to 5V
•Four Reset Timeout Periods Available:
1ms, 20ms, 140ms, or 1120ms (min)
•Immune to Short VCC Transients
•Open-Drain RESET Output Can Exceed VCC
•Guaranteed Over Temperature
•5µA Supply Current
•Pin Compatible with MAX811
•Saves Space
•4-Pin SOT143 Package
1
2
4
3
VCC
MRRESET
GND
MAX6315
SOT143
TOP VIEW
Pin Configuration
MAX6315
VCC
VCC
GND
RESET
μP
RESET
MR
LASER-
TRIMMED
RESISTORS
RESET
CIRCUITRY
Typical Operating Circuit
Ordering Information continued at end of data sheet.
PART†NOMINAL
VTH (V)
MIN tRP
(ms)
TOP
MARK††
MAX6315US50D1-T 5.00 1FX_ _
Ordering Information
†
The MAX6315 is available in a SOT143 package, -40°C to
+125°C temperature range.
††
The first two letters in the package top mark identify the part,
while the remaining two letters are the lot tracking code.
Devices are available in both leaded and lead-free packaging.
Specify lead(Pb)-free by replacing “-T” with “+T” when ordering.
Note: All devices available in tape-and-reel only. Contact
factory for availability.
19-2000; Rev 4; 4/15
MAX6315 Open-Drain SOT µP Reset Circuit
Maxim Integrated | 2www.maximintegrated.com
Absolute Maximum Ratings
Electrical Characteristics
(VCC = +2.5V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at TA= +25°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.
Note 1: The MAX6315 monitors VCC through an internal factory-trimmed voltage-divider that programs the nominal reset threshold.
Factory-trimmed reset thresholds are available in 100mV increments from 2.5V to 5V (see the
Ordering Information
).
VCC ........................................................................-0.3V to +6.0V
RESET....................................................................-0.3V to +6.0V
All Other Pins..............................................-0.3V to (VCC + 0.3V)
Input Current (VCC).............................................................20mA
Output Current (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 +125°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
MAX6315US_ _D2-T (-40°C to +85°C)
MAX6315US_ _D1-T (-40°C to +125°C)
MAX6315US_ _D2-T (-40°C to +125°C)
TA= +25°C
VCC > 1.2V, ISINK = 0.5mA
VCC = 3.6V, no load (-40°C to +85°C)
VCC = 5.5V, no load (-40°C to +85°C)
15
TA= -40°C to +85°C
VTH - 2.5% VTH + 2.5%
16 48
20 28 40
0.8 2.4
VCC > VTH, RESET deasserted
VTH > 4.0V
VCC = falling at 1mV/µs
MAX6315US_ _D1-T (-40°C to +85°C)
VCC > 4.25V, ISINK = 3.2mA
CONDITIONS
VCC > 2.5V, ISINK = 1.2mA
VCC > 1.0V, ISINK = 80µA
0.3 x VCC
2.4
0.7 x VCC
0.3
0.3
0.3
V
12
TA= -40°C to +125°C
410
MAX6315US_ _D4-T (-40°C to +85°C)
MAX6315US_ _D3-T (-40°C to +125°C)
VCC = 3.6V, no load (-40°C to +125°C)
VTH - 3.5% VTH + 3.5%
MAX6315US_ _D4-T (-40°C to +125°C) 896 2688
1120 1570 2240
112 336
MAX6315US_ _D3-T (-40°C to +85°C) 140 200 280
µA1
RESET Output Leakage Current
V
0.4
VOL
RESET Output Voltage
kΩ32 63 100
MR Pullup Resistance
VTH - 1.8% VTH VTH + 1.8%
VTH
Reset Threshold (Note 1)
µA
512
ICC
V1.0 5.5VCC
Operating Voltage Range
VCC Supply Current
ns500
MR to Reset Delay
ns100
MR Glitch Rejection
µs1
MR Minimum Input Pulse
V
0.8
VIL
MR Input Threshold
ppm/°C60ΔVTH/°CReset Threshold Tempco
µs35VCC to Reset Delay
ms
1 1.4 2
tRP
Reset Timeout Period
UNITSMIN TYP MAXSYMBOLPARAMETER
VIL
VIH
VIH
VCC = 5.5V, no load (-40°C to +125°C)
TA= -40°C to +85°C
VTH < 4.0V
MANUAL RESET INPUT
6
0
-50 -30 30 90
2
1
5
MAX6315-01
TEMPERATURE (°C)
SUPPLY CURRENT (μA)
-10 10 50
3
4
70
VCC = 5V
VCC = 3V
VCC = 1V
SUPPLY CURRENT vs. TEMPERATURE
6
0
0135
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
2
1
5
MAX6315-02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (μA)
2
3
4
4
TA = -40°C
TA = +25°C
TA = +85°C
50
0
-50 -30 10 90
POWER-DOWN RESET DELAY
vs. TEMPERATURE
10
40
MAX6315-03
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (μs)
-10
20
30
30 50 70
VCC FALLING AT 1mV/μs
VTH = 4.63V
VTH = 3.00V
1.04
0.96
-50 -30 10 90
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE (VCC RISING)
0.97
0.98
1.02
1.00
1.03
MAX6315-04
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
-10
0.99
1.01
30 50 70
1.006
0.994
-50 -30 10 90
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE (VCC FALLING)
0.996
0.998
1.004
1.000
MAX6315-05
TEMPERATURE (°C)
NORMALIZED RESET THRESHOLD
-10
1.002
30 50 70
100
0
10 100 1000
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
20
MAX6315-06
RESET COMP. OVERDRIVE, VTH - VCC (mV)
MAXIMUM TRANSIENT DURATION (μs)
40
60
80
TA = +25°C
RESET OCCURS
ABOVE CURVE
VTH = 4.63V
VT = 3.00V
MAX6315 Open-Drain SOT µP Reset Circuit
Maxim Integrated | 3www.maximintegrated.com
Pin Description
NAME FUNCTION
1GND Ground
2RESET Active-Low Open-Drain Output. Connect to an external pullup resistor. Can be pulled up to a voltage
higher than VCC, but less than 6V.
PIN
3MR 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 the reset conditions are terminated. Connect to VCC if not used.
4 VCC Supply Voltage and Reset Threshold Monitor Input
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
MAX6315 Open-Drain SOT µP Reset Circuit
Maxim Integrated | 4www.maximintegrated.com
Detailed Description
Reset Output
A microprocessor’s (µP’s) reset input starts the µP in a
known state. The MAX6315 asserts reset to prevent
code-execution errors during power-up, power-
down, or brownout conditions. RESET is guaranteed to
be a logic-low for VCC > 1V (see the
Electrical
Characteristics
table). Once VCC exceeds the reset
threshold, the internal timer keeps RESET asserted for
the reset timeout period (tRP); after this interval RESET
goes high. If a brownout condition occurs (monitored
voltage dips below its programmed reset threshold),
RESET goes low. Any time VCC dips below the reset
threshold, the internal timer resets to zero and RESET
goes low. The internal timer starts when VCC returns
above the reset threshold, and RESET remains low for
the reset timeout period.
The MAX6315’s RESET output structure is a simple
open-drain n-channel MOSFET switch. Connect a pull-
up resistor to any supply in the 0V to +6V range. Select
a resistor value large enough to register a logic low
when RESET is asserted (see the
Electrical
Characteristics
table), and small enough to register a
logic high while supplying all input current and leakage
paths connected to the RESET line. A 10kΩpullup is
sufficient in most applications.
Often, the pullup connected to the MAX6315’s RESET
output will connect to the supply voltage 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 1). This is one useful feature of an open-drain
output. Keep in mind that as the MAX6315’s VCC
decreases below 1V, so does the IC’s ability to sink
current at RESET. Finally, with any pullup, RESET will
be pulled high as VCC decays toward 0V. The voltage
where this occurs depends on the pullup resistor value
and the voltage to which it connects (see the
Electrical
Characteristics
table).
Manual-Reset Input
Many µP-based products require manual-reset capa-
bility, allowing the operator, a test technician, or exter-
nal 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 63kΩpullup resistor, so it can be
left open if not used. Connect a normally open momen-
tary switch from MR to GND to create a manual-reset
function; external debounce circuitry is not required.
If MR is driven from long cables or if the device is used
in a noisy environment, connecting a 0.1µF capacitor
from MR to ground provides additional noise immunity.
Applications Information
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
transients (glitches). The
Typical Operating Character-
istics
show the Maximum Transient Duration vs. Reset
Comparator Overdrive, for which reset pulses are not
generated. The graph was produced using negative-
going pulses, starting at VRST max and ending below
the programmed reset threshold by the magnitude indi-
cated (reset threshold overdrive). The graph shows the
maximum pulse width that a negative-going VCC tran-
sient may typically have without causing a reset pulse
to be issued. As the transient amplitude increases (i.e.,
goes farther below the reset threshold), the maximum
allowable pulse width decreases. A 0.1µF bypass
capacitor mounted close to VCC provides additional
transient immunity.
Figure 1. MAX6315 Open-Drain RESET Output Allows Use
with Multiple Supplies
MAX6315
VCC
GND
RESETMR
5V SYSTEM
+5.0V+3.3V
10kΩ
MAX6315 Open-Drain SOT µP Reset Circuit
Maxim Integrated | 5www.maximintegrated.com
Ordering Information (continued)
PART†NOMINAL
VTH (V)
MIN tRP
(ms)
TOP
MARK††
MAX6315US45D1-T 4.50 1GC_ _
MAX6315US44D1-T††† 4.39 1GD_ _
MAX6315US43D1-T 4.30 1GE_ _
MAX6315US42D1-T 4.20 1GF_ _
MAX6315US41D1-T 4.10 1GG_ _
MAX6315US40D1-T 4.00 1GH_ _
MAX6315US39D1-T 3.90 1GI_ _
MAX6315US38D1-T 3.80 1GJ_ _
MAX6315US37D1-T 3.70 1GK_ _
MAX6315US36D1-T 3.60 1GL_ _
MAX6315US35D1-T 3.50 1GM_ _
MAX6315US34D1-T 3.40 1GN_ _
MAX6315US33D1-T 3.30 1GO_ _
MAX6315US32D1-T 3.20 1GP_ _
MAX6315US31D1-T 3.08 1GQ_ _
MAX6315US30D1-T 3.00 1GR_ _
MAX6315US29D1-T 2.93 1GS_ _
PART†
MAX6315US37D2-T 3.70 20 HK_ _
MAX6315US36D2-T 3.60
NOMINAL
VTH (V)
MIN tRP
(ms)
20 HL_ _
TOP
MARK††
MAX6315US50D2-T 5.00 20 GX_ _
MAX6315US49D2-T 4.90 20 GY_ _
MAX6315US48D2-T 4.80 20 GZ_ _
MAX6315US47D2-T 4.70 20 HA_ _
MAX6315US46D2-T 4.63 20 HB_ _
MAX6315US45D2-T 4.50 20 HC_ _
MAX6315US44D2-T††† 4.39 20 HD_ _
MAX6315US43D2-T 4.30 20 HE_ _
MAX6315US42D2-T 4.20 20 HF_ _
MAX6315US41D2-T 4.10 20 HG_ _
MAX6315US40D2-T 4.00 20 HH_ _
MAX6315US39D2-T 3.90 20 HI_ _
MAX6315US38D2-T 3.80 20 HJ_ _
MAX6315US34D2-T 3.40 20 HN_ _
MAX6315US33D2-T 3.30 20 HO_ _
MAX6315US35D2-T 3.50 20 HM_ _
MAX6315US47D1-T 4.70 1GA_ _
MAX6315US48D1-T 4.80 1FZ_ _
MAX6315US46D1-T 4.63 1GB_ _
MAX6315US49D1-T 4.90 1FY_ _
MAX6315US26D1-T††† 2.63 1GV_ _
MAX6315US27D1-T 2.70 1GU_ _
MAX6315US28D1-T 2.80 1GT_ _
MAX6315US25D1-T 2.50 1GW_ _
MAX6315US29D2-T 2.93 20 HS_ _
MAX6315US28D2-T 2.80 20 HT_ _
MAX6315US26D2-T††† 2.63 20 HV_ _
MAX6315US25D2-T 2.50 20 HW_ _
MAX6315US27D2-T 2.70 20 HU_ _
MAX6315US32D2-T 4.20 20 HP_ _
MAX6315US31D2-T 3.08 20 HQ_ _
MAX6315US30D2-T 3.00 20 HR_ _
†
The MAX6315 is available in a SOT143 package, -40°C to +125°C temperature range.
††
The first two letters in the package top mark identify the part, while the remaining two letters are the lot tracking code.
†††
Sample stocks generally held on the bolded products; also, the bolded products have 2,500 piece minimum-order quantities.
Non-bolded products have 10,000 piece minimum-order quantities. Contact factory for details.
Devices are available in both leaded and lead(Pb)-free packaging. Specify lead-free by replacing “-T” with “+T” when ordering.
Note: All devices available in tape-and-reel only. Contact factory for availability.
MAX6315 Open-Drain SOT µP Reset Circuit
Maxim Integrated | 6www.maximintegrated.com
Ordering Information (continued)
PART†NOMINAL
VTH (V)
MIN tRP
(ms)
TOP
MARK††
MAX6315US50D3-T 5.00 140 HX_ _
MAX6315US49D3-T 4.90 140 HY_ _
MAX6315US48D3-T 4.80 140 HZ_ _
MAX6315US47D3-T 4.70 140 IA_ _
MAX6315US46D3-T††† 4.63 140 IB_ _
MAX6315US45D3-T 4.50 140 IC_ _
MAX6315US44D3-T††† 4.39 140 ID_ _
MAX6315US43D3-T 4.30 140 IE_ _
MAX6315US42D3-T 4.20 140 IF_ _
MAX6315US41D3-T 4.10 140 IG_ _
MAX6315US40D3-T 4.00 140 IH_ _
MAX6315US39D3-T 3.90 140 II_ _
MAX6315US38D3-T 3.80 140 IJ_ _
MAX6315US37D3-T 3.70 140 IK_ _
MAX6315US36D3-T 3.60 140 IL_ _
MAX6315US35D3-T 3.50 140 IM_ _
MAX6315US34D3-T 3.40 140 IN_ _
MAX6315US33D3-T 3.30 140 IO_ _
MAX6315US32D3-T 3.20 140 IP_ _
MAX6315US31D3-T††† 3.08 140 IQ_ _
MAX6315US30D3-T 3.00 140 IR_ _
MAX6315US29D3-T††† 2.93 140 IS_ _
JW_ _11202.50MAX6315US25D4-T
JV_ _11202.63
MAX6315US26D4-T†††
JU_ _11202.70MAX6315US27D4-T
JT_ _11202.80MAX6315US28D4-T
JS_ _11202.93MAX6315US29D4-T
JR_ _11203.00MAX6315US30D4-T
JQ_ _11203.08MAX6315US31D4-T
JP_ _11203.20MAX6315US32D4-T
JO_ _11203.30MAX6315US33D4-T
JN_ _11203.40MAX6315US34D4-T
JM_ _11203.50MAX6315US35D4-T
JL_ _11203.60MAX6315US36D4-T
JK_ _11203.70MAX6315US37D4-T
JJ_ _11203.80MAX6315US38D4-T
JI_ _11203.90MAX6315US39D4-T
JH_ _11204.00MAX6315US40D4-T
JG_ _11204.10MAX6315US41D4-T
JF_ _11204.20MAX6315US42D4-T
JE_ _11204.30MAX6315US43D4-T
JD_ _11204.39
MAX6315US44D4-T†††
JC_ _11204.50MAX6315US45D4-T
JB_ _11204.63MAX6315US46D4-T
TOP
MARK††
MIN tRP
(ms)
NOMINAL
VTH (V)
PART†
†
The MAX6315 is available in a SOT143 package, -40°C to +125°C temperature range.
††
The first two letters in the package top mark identify the part, while the remaining two letters are the lot tracking code.
†††
Sample stocks generally held on the bolded products; also, the bolded products have 2,500 piece minimum-order quantities.
Non-bolded products have 10,000 piece minimum-order quantities. Contact factory for details.
Devices are available in both leaded and lead(Pb)-free packaging. Specify lead-free by replacing “-T” with “+T” when ordering.
Note: All devices available in tape-and-reel only. Contact factory for availability.
JA_ _11204.70MAX6315US47D4-T
IX_ _
IY_ _
IZ_ _1120
1120
11205.00
4.90
4.80MAX6315US48D4-T
MAX6315US49D4-T
MAX6315US50D4-T
MAX6315US28D3-T 2.80 140 IT_ _
MAX6315US27D3-T 2.70 140 IU_ _
MAX6315US26D3-T††† 2.63 140 IV_ _
MAX6315US25D3-T 2.50 140 IW_ _
Chip Information
TRANSISTOR COUNT: 519
Package Information
For the latest package outline information and land patterns (foot-
prints), go to www.maximintegrated.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 SOT35 U4+1 21-0052 90-0183
MAX6315 Open-Drain SOT µP Reset Circuit
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2015 Maxim Integrated Products, Inc. | 7
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Revision History
REVISION
NUMBER
REVISION
DATE
DESCRIPTION
PAGES
CHANGED
4 4/15
Updated Benefits and Features and Package Information, added Revision
History 1, 7
