MAXIM MAX6315US26D2-T

19-2000; Rev 2; 1/00
Open-Drain SOT µP Reset Circuit
____________________________Features
♦ Small SOT143 Package
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 threshold 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
♦ Open-Drain RESET Output Can Exceed VCC
♦ Precision, Factory-Set VCC Reset Thresholds:
100mV Increments from 2.5V to 5V
♦ Four Reset Timeout Periods Available:
1ms, 20ms, 140ms, or 1120ms (minimum)
♦ Immune to Short VCC Transients
♦ 5µA Supply Current
♦ Pin-Compatible with MAX811
♦ Guaranteed Over Temperature
Ordering and Marking Information appear at end of
data sheet.
Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
__________Typical Operating Circuit
Portable/Battery-Powered Equipment
VCC
__________________Pin Configuration
VCC
LASERTRIMMED
RESISTORS
TOP VIEW
GND
1
4
VCC
µP
MAX6315
MR
RESET
2
3
MR
RESET
CIRCUITRY
RESET
RESET
MAX6315
GND
SOT143
________________________________________________________________ Maxim Integrated Products
1
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MAX6315
________________General Description
The MAX6315 low-power CMOS microprocessor (µP)
supervisory circuit is designed to monitor power supplies in µP and digital systems. It provides excellent circuit reliability and low cost by eliminating external
components and adjustments. The MAX6315 also provides a debounced manual reset input.
MAX6315
Open-Drain SOT µP Reset Circuit
ABSOLUTE MAXIMUM RATINGS
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
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 = +2.5V to +5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Operating Voltage Range
SYMBOL
VCC
VCC Supply Current
ICC
Reset Threshold (Note 1)
VTH
Reset Threshold Tempco
VCC to Reset Delay
∆VTH/°C
Reset Timeout Period
tRP
CONDITIONS
MIN
TA = -40°C to +85°C
1.0
VCC = 5.5V, no load (-40°C to +85°C)
VCC = 5.5V, no load (-40°C to +125°C)
VCC = 3.6V, no load (-40°C to +85°C)
VCC = 3.6V, no load (-40°C to +125°C)
TA = +25°C
VTH - 1.8%
TA = -40°C to +85°C
VTH - 2.5%
TA = -40°C to +125°C
VTH - 3.5%
VCC = falling at 1mV/µs
MAX6315US_ _D1-T (-40°C to +85°C)
MAX6315US_ _D1-T (-40°C to +125°C)
MAX6315US_ _D2-T (-40°C to +85°C)
MAX6315US_ _D2-T (-40°C to +125°C)
MAX6315US_ _D3-T (-40°C to +85°C)
MAX6315US_ _D3-T (-40°C to +125°C)
MAX6315US_ _D4-T (-40°C to +85°C)
MAX6315US_ _D4-T (-40°C to +125°C)
1
0.8
20
16
140
112
1120
896
TYP
5
4
VTH
MAX
UNITS
5.5
12
15
10
12
VTH + 1.8%
VTH + 2.5%
VTH + 3.5%
V
60
35
1.4
µA
V
ppm/°C
µs
2
2.4
40
48
280
336
2240
2688
28
200
1570
ms
MANUAL RESET INPUT
MR Input Threshold
VIL
VIH
VIL
VIH
VTH > 4.0V
VTH < 4.0V
MR Minimum Input Pulse
0.8
2.4
0.3 x VCC
0.7 x VCC
1
MR Glitch Rejection
MR to Reset Delay
RESET Output Voltage
µs
100
32
VOL
63
ns
100
VCC > 4.25V, ISINK = 3.2mA
0.4
VCC > 2.5V, ISINK = 1.2mA
0.3
VCC > 1.2V, ISINK = 0.5mA
VCC > 1.0V, ISINK = 80µA
RESET Output Leakage Current
ns
500
MR Pull-Up Resistance
V
VCC > VTH, RESET deasserted
kΩ
V
0.3
1
µA
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 Ordering Information).
2
_______________________________________________________________________________________
Open-Drain SOT µP Reset Circuit
VCC = 5V
4
3
VCC = 3V
2
VCC = 1V
4
TA = +85°C
3
TA = +25°C
2
TA = -40°C
1
0
VCC FALLING AT 1mV/µs
-30
-10
10
30
50
70
90
40
30
VTH = 4.63V
20
VTH = 3.00V
10
0
0
-50
MAX6315-03
50
POWER-DOWN RESET DELAY (µs)
SUPPLY CURRENT (µA)
5
1
0
1
2
3
-50
5
4
-30
-10
10
30
50
90
70
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE (VCC RISING)
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE (VCC FALLING)
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
1.00
0.99
0.98
0.97
0.96
1.004
1.002
1.000
0.998
0.996
0.994
-50
-30
-10
10
30
50
TEMPERATURE (°C)
70
90
100
MAXIMUM TRANSIENT DURATION (µs)
1.01
MAX6315-05
MAX6315-04
1.02
1.006
NORMALIZED RESET THRESHOLD
1.03
TA = +25°C
RESET OCCURS
ABOVE CURVE
80
MAX6315-06
TEMPERATURE (°C)
1.04
NORMALIZED RESET TIMEOUT PERIOD
MAX6315-02
5
SUPPLY CURRENT (µA)
6
MAX6315-01
6
POWER-DOWN RESET DELAY
vs. TEMPERATURE
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
VTH = 4.63V
60
40
20
VT = 3.00V
0
-50
-30
-10
10
30
50
70
TEMPERATURE (°C)
90
10
100
1000
RESET COMP. OVERDRIVE, VTH - VCC (mV)
______________________________________________________________Pin Description
PIN
NAME
1
GND
FUNCTION
2
RESET
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 the reset conditions are terminated. Connect to VCC if not used.
4
VCC
Supply Voltage and Reset Threshold Monitor Input
Ground
Active-Low Open-Drain Output. Connect to an external pull-up resistor. Can be pulled up to a voltage
higher than VCC, but less than 6V.
_______________________________________________________________________________________
3
MAX6315
__________________________________________Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
MAX6315
Open-Drain SOT µP Reset Circuit
_______________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 Electrical Characteristics).
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 pullup 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 Electrical Characteristics),
and small enough to register a logic high while supplying all input current and leakage paths connected to the
RESET line. A 10kΩ pull-up is sufficient in most applications.
Often, the pull-up 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 V CC
decreases below 1V, so does the IC’s ability to sink
current at RESET. Finally, with any pull-up, RESET will
be pulled high as VCC decays toward 0V. The voltage
where this occurs depends on the pull-up resistor value
and the voltage to which it connects (see Electrical
Characteristics).
Manual-Reset Input
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 63kΩ pull-up resistor, so it can be
left open 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.
4
+3.3V
+5.0V
VCC
10k
MR
RESET
5V SYSTEM
MAX6315
GND
Figure 1. MAX6315 Open-Drain RESET Output Allows Use
with Multiple Supplies
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 Characteristics show the Maximum Transient Duration vs. Reset
Threshold Overdrive, for which reset pulses are not
generated. The graph was produced using negativegoing pulses, starting at VRST max and ending below
the programmed reset threshold by the magnitude indicated (reset threshold overdrive). The graph shows the
maximum pulse width that a negative-going VCC transient 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.
_______________________________________________________________________________________
Open-Drain SOT µP Reset Circuit
NOMINAL
VTH (V)
PART†
MAX6315US50D1-T
MAX6315US49D1-T
MAX6315US48D1-T
MAX6315US47D1-T
MAX6315US46D1-T
MAX6315US45D1-T
MAX6315US44D1-T†††
MAX6315US43D1-T
MAX6315US42D1-T
MAX6315US41D1-T
MAX6315US40D1-T
MAX6315US39D1-T
MAX6315US38D1-T
MAX6315US37D1-T
MAX6315US36D1-T
MAX6315US35D1-T
MAX6315US34D1-T
MAX6315US33D1-T
MAX6315US32D1-T
MAX6315US31D1-T
MAX6315US30D1-T
MAX6315US29D1-T
MAX6315US28D1-T
MAX6315US27D1-T
MAX6315US26D1-T†††
MAX6315US25D1-T
5.00
4.90
4.80
4.70
4.63
4.50
4.39
4.30
4.20
4.10
4.00
3.90
3.80
3.70
3.60
3.50
3.40
3.30
3.20
3.08
3.00
2.93
2.80
2.70
2.63
2.50
MIN tRP
(ms)
SOT TOP
MARK††
PART†
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
FX_ _
FY_ _
FZ_ _
GA_ _
GB_ _
GC_ _
GD_ _
GE_ _
GF_ _
GG_ _
GH_ _
GI_ _
GJ_ _
GK_ _
GL_ _
GM_ _
GN_ _
GO_ _
GP_ _
GQ_ _
GR_ _
GS_ _
GT_ _
GU_ _
GV_ _
GW_ _
MAX6315US50D2-T
MAX6315US49D2-T
MAX6315US48D2-T
MAX6315US47D2-T
MAX6315US46D2-T
MAX6315US45D2-T
MAX6315US44D2-T†††
MAX6315US43D2-T
MAX6315US42D2-T
MAX6315US41D2-T
MAX6315US40D2-T
MAX6315US39D2-T
MAX6315US38D2-T
MAX6315US37D2-T
MAX6315US36D2-T
MAX6315US35D2-T
MAX6315US34D2-T
MAX6315US33D2-T
MAX6315US32D2-T
MAX6315US31D2-T
MAX6315US30D2-T
MAX6315US29D2-T
MAX6315US28D2-T
MAX6315US27D2-T
MAX6315US26D2-T†††
MAX6315US25D2-T
NOMINAL
VTH (V)
5.00
4.90
4.80
4.70
4.63
4.50
4.39
4.30
4.20
4.10
4.00
3.90
3.80
3.70
3.60
3.50
3.40
3.30
4.20
3.08
3.00
2.93
2.80
2.70
2.63
2.50
MIN tRP
(ms)
SOT TOP
MARK††
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
GX_ _
GY_ _
GZ_ _
HA_ _
HB_ _
HC_ _
HD_ _
HE_ _
HF_ _
HG_ _
HH_ _
HI_ _
HJ_ _
HK_ _
HL_ _
HM_ _
HN_ _
HO_ _
HP_ _
HQ_ _
HR_ _
HS_ _
HT_ _
HU_ _
HV_ _
HW_ _
†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.
Note: All devices available in tape-and-reel only. Contact factory for availability.
_______________________________________________________________________________________
5
MAX6315
________________________________________________________Ordering Information
MAX6315
Open-Drain SOT µP Reset Circuit
___________________________________________Ordering Information (continued)
PART†
MAX6315US50D3-T
MAX6315US49D3-T
MAX6315US48D3-T
MAX6315US47D3-T
MAX6315US46D3-T†††
MAX6315US45D3-T
MAX6315US44D3-T†††
MAX6315US43D3-T
MAX6315US42D3-T
MAX6315US41D3-T
MAX6315US40D3-T
MAX6315US39D3-T
MAX6315US38D3-T
MAX6315US37D3-T
MAX6315US36D3-T
MAX6315US35D3-T
MAX6315US34D3-T
MAX6315US33D3-T
MAX6315US32D3-T
MAX6315US31D3-T†††
MAX6315US30D3-T
MAX6315US29D3-T†††
MAX6315US28D3-T
MAX6315US27D3-T
MAX6315US26D3-T†††
MAX6315US25D3-T
NOMINAL
VTH (V)
5.00
4.90
4.80
4.70
4.63
4.50
4.39
4.30
4.20
4.10
4.00
3.90
3.80
3.70
3.60
3.50
3.40
3.30
3.20
3.08
3.00
2.93
2.80
2.70
2.63
2.50
MIN tRP
(ms)
SOT TOP
MARK††
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
140
HX_ _
HY_ _
HZ_ _
IA_ _
IB_ _
IC_ _
ID_ _
IE_ _
IF_ _
IG_ _
IH_ _
II_ _
IJ_ _
IK_ _
IL_ _
IM_ _
IN_ _
IO_ _
IP_ _
IQ_ _
IR_ _
IS_ _
IT_ _
IU_ _
IV_ _
IW_ _
PART†
NOMINAL
VTH (V)
MIN tRP
(ms)
SOT TOP
MARK††
MAX6315US50D4-T
5.00
1120
IX_ _
MAX6315US49D4-T
MAX6315US48D4-T
MAX6315US47D4-T
MAX6315US46D4-T
MAX6315US45D4-T
MAX6315US44D4-T†††
MAX6315US43D4-T
MAX6315US42D4-T
MAX6315US41D4-T
MAX6315US40D4-T
MAX6315US39D4-T
MAX6315US38D4-T
MAX6315US37D4-T
MAX6315US36D4-T
MAX6315US35D4-T
MAX6315US34D4-T
MAX6315US33D4-T
MAX6315US32D4-T
MAX6315US31D4-T
MAX6315US30D4-T
MAX6315US29D4-T
MAX6315US28D4-T
MAX6315US27D4-T
MAX6315US26D4-T†††
MAX6315US25D4-T
4.90
4.80
4.70
4.63
4.50
4.39
4.30
4.20
4.10
4.00
3.90
3.80
3.70
3.60
3.50
3.40
3.30
3.20
3.08
3.00
2.93
2.80
2.70
2.63
2.50
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
1120
IY_ _
IZ_ _
JA_ _
JB_ _
JC_ _
JD_ _
JE_ _
JF_ _
JG_ _
JH_ _
JI_ _
JJ_ _
JK_ _
JL_ _
JM_ _
JN_ _
JO_ _
JP_ _
JQ_ _
JR_ _
JS_ _
JT_ _
JU_ _
JV_ _
JW_ _
†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.
Note: All devices available in tape-and-reel only. Contact factory for availability.
6
_______________________________________________________________________________________
Open-Drain SOT µP Reset Circuit
TRANSISTOR COUNT: 519
SOT1434.EPS
________________________________________________________Package Information
_______________________________________________________________________________________
7
MAX6315
___________________Chip Information
MAX6315
Open-Drain SOT µP Reset Circuit
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
© 2000 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.