MAX6322HPUK26A+T [MAXIM]
Power Supply Support Circuit, Fixed, 1 Channel, +2.63VV, PDSO5, SOT-23, 5 PIN;
| 型号： | MAX6322HPUK26A+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Power Supply Support Circuit, Fixed, 1 Channel, +2.63VV, PDSO5, SOT-23, 5 PIN 光电二极管 |
| 文件： | 总14页 (文件大小：1516K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
General Description
Benefits and Features
● Integrated Configuration Enables Flexible Designs
• Available in 26 Reset-Threshold Voltages
- 2.5V to 5V, in 100mV Increments
• Four Reset Timeout Periods
- 1ms, 20ms, 140ms, or 1.12s (min)
• Four Watchdog Timeout Periods
- 6.3ms, 102ms, 1.6s, or 25.6s (typ)
• Four Reset Output Stages
The MAX6316–MAX6322 family of microprocessor (μP)
supervisory circuits monitors power supplies and micro-
processor activity in digital systems. It offers several com-
binations of push/pull, open-drain, and bidirectional (such
as Motorola 68HC11) reset outputs, along with watchdog
and manual reset features. The Selector Guide below lists
the specific functions available from each device.
These devices are available in 26 factory-trimmed reset
threshold voltages (from 2.5V to 5V, in 100mV increments),
featuring four minimum power-on reset timeout periods
(from 1ms to 1.12s), and four watchdog timeout periods
(from 6.3ms to 25.6s). Thirteen standard versions are
available with an order increment requirement of 2500
pieces (see Standard Versions table); contact the factory
for availability of other versions, which have an order
increment requirement of 10,000 pieces.
- Active-High, Push/Pull
- Active-Low, Push/Pull
- Active-Low, Open-Drain
- Active-Low, Bidirectional
● Integrated Features Increase Robustness
• Guaranteed Reset Valid to V
• Immune to Short-Negative V
● Saves Board Space
= 1V
Transients
CC
CC
• No External Components
The MAX6316–MAX6322 are offered in a miniature 5-pin
SOT23 package.
• Small 5-Pin SOT23 Package
• AECQ-100 Qualified
Ordering Information
Applications
● Portable Computers
● Computers
● Controllers
PART
TEMP RANGE PIN-PACKAGE
MAX6316LUK____-T
-40°C to +125°C 5 SOT23
MAX6316LUK____/V+T -40°C to +125°C 5 SOT23
MAX6316MUK____-T
MAX6317HUK____-T
MAX6318HUK____-T
MAX6318MHUK____-T
-40°C to +125°C 5 SOT23
-40°C to +125°C 5 SOT23
-40°C to +125°C 5 SOT23
-40°C to +125°C 5 SOT23
● Intelligent Instruments
● Portable/Battery-Powered Equipment
● Embedded Control Systems
Devices are available in both leaded and lead(Pb)-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
/V Denotes an automotive-qualified part.
Typical Operating Circuit and Pin Configurations appears at
end of data sheet.
Ordering Information appears at end of data sheet.
Selector Guide
RESET OUTPUTS*
MANUAL
RESET
INPUT
WATCHDOG
PART
ACTIVE-LOW
PUSH/PULL
ACTIVE-HIGH
PUSH/PULL
ACTIVE-LOW
BIDIRECTIONAL
ACTIVE-LOW
OPEN-DRAIN
INPUT
✔
✔
✔
✔
✔
—
—
✔
✔
✔
—
✔
✔
—
—
✔
MAX6316L
—
—
✔
✔
✔
✔
—
✔
—
—
—
—
—
—
—
✔
MAX6316M
MAX6317H
✔
✔
✔
—
—
✔
—
—
✔
MAX6318LH
MAX6318MH
MAX6319LH
MAX6319MH
MAX6320P
MAX6321HP
MAX6322HP
—
✔
—
✔
✔
—
—
—
—
—
✔
—
—
—
✔
✔
✔
✔
—
*The MAX6318/MAX6319/MAX6321/MAX6322 feature two types of reset output on each device.
19-0496; Rev 13; 5/17
MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Absolute Maximum Ratings
Voltage (with respect to GND)
Operating Temperature Range......................... -40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range............................ -65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow)
V
......................................................................-0.3V to +6V
CC
RESET (MAX6320/MAX6321/MAX6322 only)....-0.3V to +6V
All Other Pins........................................ -0.3V to (V + 0.3V)
Input/Output Current, All Pins.............................................20mA
CC
Continuous Power Dissipation (T = +70°C)
SOT23 (derate 7.1mW/°C above +70°C)....................571mW
Leaded Package..........................................................+240°C
Lead-Free Package.....................................................+260°C
A
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
(V
= 2.5V to 5.5V, T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
5.5
20
UNITS
Operating Voltage Range
V
T = -40°C to +125°C
1.0
V
CC
A
V
V
V
V
= 5.5V
= 3.6V
= 5.5V
= 3.6V
10
5
CC
CC
CC
CC
MAX6316/MAX6317/MAX
6318/MAX6320/MAX6321
12
Supply Current
I
µA
CC
3
12
MAX6319/MAX6322:
MR unconnected
3
8
Reset Threshold Temperature
Coefficient
DV /°C
40
ppm/°C
TH
T = +25°C
V
V
- 1.5%
V
V
V
V
+ 1.5%
A
TH
TH
TH
TH
Reset Threshold (Note 2)
V
V
RST
T = -40°C to +125°C
A
- 2.5%
+ 2.5%
TH
TH
3
Reset Threshold Hysteresis
mV
MAX63__A_-T
MAX63__B_-T
MAX63__C_-T
MAX63__D_-T
1
1.4
28
2
20
40
Reset Active Timeout Period
t
ms
µs
RP
140
200
1600
40
280
1120
2240
V
to RESET Delay
t
V
falling at 1mV/µs
CC
CC
RD
PUSH/PULL RESET OUTPUT (MAX6316L/MAX6317H/MAX6318_H/MAX6319_H/MAX6321HP/MAX6322HP)
V
V
V
V
V
V
≥ 1.0V, I
≥ 1.2V, I
≥ 2.7V, I
≥ 4.5V, I
≥ 2.7V, I
≥ 4.5V, I
= 50µA
0.3
0.3
0.3
0.4
CC
CC
CC
CC
CC
CC
SINK
SINK
SINK
SINK
= 100µA
= 1.2mA
= 3.2mA
V
OL
RESET Output Voltage
V
= 500µA
= 800µA
0.8 x V
CC
SOURCE
SOURCE
V
OH
V
- 1.5
CC
RESET Rise Time (MAX6316L,
Rise time is measured from 10% to 90%
of V ; C = 5pF, V = 3.3V (Note 3)
t
5
25
ns
V
R
MAX6318LH, MAX6319LH)
CC
L
CC
V
V
V
V
V
≥ 2.7V, I
≥ 4.5V, I
≥ 1.8V, I
≥ 2.7V, I
≥ 4.5V, I
= 1.2mA
= 3.2mA
0.3
0.4
CC
CC
CC
CC
CC
SINK
V
OL
SINK
RESET Output Voltage
= 150µA
= 500µA
= 800µA
0.8 x V
0.8 x V
SOURCE
SOURCE
SOURCE
CC
V
OH
CC
V
- 1.5
CC
Note 1: Overtemperature limits are guaranteed by design, not production tested.
Note 2: A factory-trimmed voltage divider programs the nominal reset threshold (V ). Factory-trimmed reset thresholds are avail-
TH
able in 100mV increments from 2.5V to 5V (see Table 1 at end of data sheet).
Note 3: Guaranteed by design.
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Electrical Characteristics (continued)
(V
= 2.5V to 5.5V, T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
BIDIRECTIONAL RESET OUTPUT (MAX6316M/MAX6318MH/MAX6319MH)
Transitional Flip-Flop Setup Time
t
(Note 4)
400
ns
S
V
V
V
V
V
V
= 3.0V, C = 120pF
333
333
666
666
CC
CC
CC
CC
CC
CC
L
= 5.0V, C = 200pF
RESET Output Rise Time
L
t
ns
R
(Note 5)
= 3.0V, C = 250pF
L
= 5.0V, C = 400pF
L
Active Pullup Enable Threshold
V
= 5.0V
= 5.0V
0.4
0.65
20
V
PTH
RESET Active Pullup Current
mA
T
T
= -40°C to +85°C
= -40°C to +125°C
4.2
3.6
4.7
4.7
5.2
5.8
A
A
RESET Pullup Resistance
kΩ
OPEN-DRAIN RESET OUTPUT (MAX6320P/MAX6321HP/MAX6322HP)
V
V
V
V
> 1.0V, I
> 1.2V, I
> 2.7V, I
> 4.5V, I
= 50µA
0.3
0.3
0.3
0.4
CC
CC
CC
CC
SINK
SINK
SINK
SINK
= 100µA
= 1.2mA
= 3.2mA
RESET Output Voltage
V
V
OL
Open-Drain Reset Output
Leakage Current
I
1.0
µA
ms
LKG
WATCHDOG INPUT (MAX6316/MAX6317H/MAX6318_H/MAX6320P/MAX6321HP)
MAX63_ _ _W-T
4.3
71
6.3
102
1.6
9.3
153
2.4
MAX63_ _ _X-T
Watchdog Timeout Period
t
WD
MAX63_ _ _Y-T
MAX63_ _ _Z-T
1.12
17.9
50
s
ns
V
25.6
38.4
WDI Pulse Width
t
V
= 0.3 x V
V
= 0.7 x V
WDI
IL
CC, IH CC
V
0.3 x V
CC
IL
WDI Input Threshold
(Note 6)
WDI = V , time average
V
0.7 x V
CC
IH
120
-15
160
WDI Input Current
(Note 7)
CC
I
µA
WDI
V
= 0V, time average
-20
0.8
WDI
MANUAL RESET INPUT (MAX6316_/MAX6317H/MAX6319_H/MAX6320P/MAX6322HP)
V
IL
V
V
> 4.0V
< 4.0V
TH
TH
V
2.0
IH
MR Input Threshold
V
V
0.3 x V
CC
IL
V
0.7 x V
IH
CC
T
T
= -40°C to +85°C
= -40°C to +125°C
1
A
A
MR Input Pulse Width
µs
1.5
MR Glitch Rejection
MR Pullup Resistance
MR to Reset Delay
100
52
ns
kΩ
ns
35
75
V
= 5V
230
CC
Note 4: This is the minimum time RESET must be held low by an external pulldown source to set the active pullup flip-flop.
Note 5: Measured from RESET V to (0.8 x V ), R = ∞.
OL
CC
LOAD
Note 6: WDI is internally serviced within the watchdog period if WDI is left unconnected.
Note 7: The WDI input current is specified as the average input current when the WDI input is driven high or low. The WDI input is
designed for a three-stated-output device with a 10μA maximum leakage current and capable of driving a maximum capaci-
tive load of 200pF. The three-state device must be able to source and sink at least 200μA when active.
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Typical Operating Characteristics
T
= +25°C, unless otherwise noted.)
A
MAX6316/MAX6317/MAX6319/MAX6320/MAX6322
MANUAL RESET TO RESET
PROPAGATION DELAY vs. TEMPERATURE
MAX6316/MAX6317/MAX6318/MAX6320/MAX6321
V
FALLING TO RESET PROPAGATION
DELAY vs. TEMPERATURE
CC
SUPPLY CURRENT vs. TEMPERATURE
10
100
90
80
70
60
50
40
30
20
10
0
320
300
280
260
240
220
200
180
160
140
V
V
FALLING AT 1mV/µs
CC
9
V
CC
= 5V
- V = 100mV
CC
RST
V
CC
= 5V
8
7
6
5
4
V
V
= 3V
= 1V
CC
3
2
CC
1
0
-40 -20
0
20
40
60
80 100
-40 -20
0
20
40
60
80 100
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
MAX6316/MAX6317/MAX6318/MAX6320/MAX6321
NORMALIZED WATCHDOG TIMEOUT
PERIOD vs. TEMPERATURE
NORMALIZED RESET TIMEOUT
PERIOD vs. TEMPERATURE
1.05
1.05
1.04
1.03
1.02
1.01
1.00
0.99
0.98
0.97
0.96
0.95
1.04
1.03
1.02
1.01
1.00
0.99
0.98
0.97
0.96
0.95
-40 -20
0
20
40
60
80 100
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
MAX6316M/6318MH/6319MH
BIDIRECTIONAL
MAXIMUM V TRANSIENT DURATION
CC
vs. RESET THRESHOLD OVERDRIVE
PULLUP CHARACTERISTICS
MAX6316toc07
80
70
60
+5V
4.7kΩ
PASSIVE
4.7kΩ
PULLUP
2V/div
RESET OCCURS ABOVE LINES
74HC05
V
RST
= 3.3V
100pF
INPUT
V
= 4.63V
RST
V
50
40
30
20
10
0
RESET, ACTIVE
PULLUP
2V/div
+5V
= 2.63V
74HC05
100pF
RST
V
CC
INPUT
RESET
RESET
INPUT
5V/div
GND
MR
200ns/div
10
100
1000
- V
RESET THRESHOLD OVERDRIVE (mV) V
RST
CC
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Pin Description
PIN
MAX6318LH
MAX6316L
MAX6316M
MAX6320P
MAX6319LH
MAX6318MH MAX6319MH
NAME
FUNCTION
MAX6317H
MAX6321HP
MAX6322HP
MAX6316L/MAX6318LH/MAX6319LH: Active-
Low, Reset Output. CMOS push/pull output
(sources and sinks current).
MAX6316M/MAX6318MH/MAX6319MH:
Bidirectional, Active-Low, Reset Output.
Intended to interface directly to microprocessors
with bidirectional resets such as the Motorola
68HC11.
1
—
1
1
RESET
MAX6320P/MAX6321HP/MAX6322HP:
Open-Drain,Active-Low, Reset Output. NMOS out-
put (sinks current only). Connect a pullup resistor
from RESET to any supply voltage up to 6V.
Active-High, Reset Output. CMOS push/pull output
(sources and sinks current). Inverse of RESET.
—
2
1
2
3
2
3
2
RESET
GND
Ground
Active-Low, Manual Reset Input. Pull low to force
a reset. Reset remains asserted for the duration
of the Reset Timeout Period after MR transitions
from low to high. Leave unconnected or connected
3
4
5
3
4
5
—
4
—
5
MR
to V
if not used.
CC
Watchdog Input. Triggers a reset if it remains either
high or low for the duration of the watchdog timeout
period. The internal watchdog timer clears
whenever a reset asserts or whenever WDI sees a
rising or falling edge. To disable the watchdog
fea- ture, leave WDI unconnected or three-state the
dri- ver connected to WDI.
4
WDI
Supply Voltage. Reset is asserted when V
drops below the ResetThreshold Voltage (V
CC
RST
).
V
5
Reset remains asserted until V
rises above
CC
CC
V
and for the duration of the ResetTimeout
RST
Period (t ) once V
rises above V
.
RP
CC
RST
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
V
CC
MAX6316–MAX6322
RESET
(ALL EXCEPT MAX6317)
RESET
GENERATOR
RESET
(ALL EXCEPT
MAX6316/MAX6320P)
V
CC
1.23V
52kΩ
MR
(ALL EXCEPT
MAX6318/MAX6321)
WATCHDOG
TRANSITION
DETECTOR
WATCHDOG
TIMER
WDI
(ALL EXCEPT
MAX6319/MAX6322)
52kΩ
GND
Figure 1. Functional Diagram
within the watchdog timeout period (t ). Reset remains
WD
Detailed Description
asserted for the specified reset active timeout period (t
)
RP
A microprocessor’s (μP) reset input starts or restarts the
μP in a known state. The reset output of the MAX6316–
MAX6322 μP supervisory circuits interfaces with the
reset input of the μP, preventing code-execution errors
during power-up, power-down, and brownout condi-
tions (see the Typical Operating Circuit). The MAX6316/
MAX6317/MAX6318/MAX6320/MAX6321 are also capa-
ble of asserting a reset should the μP become stuck in
an infinite loop.
after V
rises above the reset threshold, after MR transi-
CC
tions low to high, or after the watchdog timer asserts the
reset (MAX6316_/MAX6317H/MAX6318_H/MAX6320P/
MAX6321HP). After the reset active timeout period (t
)
RP
expires, the reset output deasserts, and the watchdog
timer restarts from zero (Figure 2).
V
CC
Reset Output
V
RST
V
RST
1V
1V
The
MAX6316L/MAX6318LH/MAX6319LH
fea-
GND
ture an active-low reset output, while the MAX6317H
MAX6318_H/MAX6319_H/MAX6321HP/MAX6322HP
feature an active-high reset output. RESET is guaranteed
to be a logic low and RESET is guaranteed to be a logic
t
RP
RP
t
RD
RESET
t
t
RESET
GND
RD
high for V
down to 1V.
CC
The MAX6316–MAX6322 assert reset when V
is
CC
below the reset threshold (V
low (MAX6316_/MAX6317H/MAX6319_H/MAX6320P/
MAX6322HP only), or if the WDI pin is not serviced
), when MR is pulled
RST
Figure 2. Reset Timing Diagram
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
is erased and processing begins from scratch. If, on the
other hand, RESET is high after a delay of two external-
clock cycles, the processor knows that it caused the reset
itself and can jump to a different vector and use stored-
state information to determine what caused the reset.
Bidirectional RESET Output
The
MAX6316M/MAX6318MH/MAX6319MH
are
designed to interface with μPs that have bidirectional
reset pins, such as the Motorola 68HC11. Like an open-
drain output, these devices allow the μP or other devices
to pull the bidirectional reset (RESET) low and assert a
reset condition. However, unlike a standard open-drain
output, it includes the commonly specified 4.7kΩ pullup
resistor with a P-channel active pullup in parallel.
A problem occurs with faster μPs; two external-clock
cycles are only 500ns at 4MHz. When there are several
devices on the reset line, and only a passive pullup resis-
tor is used, the input capacitance and stray capacitance
can prevent RESET from reaching the logic high state
This configuration allows the MAX6316M/MAX6318MH/
MAX6319MH to solve a problem associated with μPs that
have bidirectional reset pins in systems where several
devices connect to RESET (Figure 3). These μPs can
often determine if a reset was asserted by an external
device (i.e., the supervisor IC) or by the μP itself (due to
a watchdog fault, clock error, or other source), and then
jump to a vector appropriate for the source of the reset.
However, if the μP does assert reset, it does not retain the
information, but must determine the cause after the reset
has occurred.
(0.85 x V ) in the time allowed. If this happens, all resets
CC
will be interpreted as external. The μP output stage is
guaranteed to sink 1.6mA, so the rise time can not be
reduced considerably by decreasing the 4.7kΩ internal
pullup resistance. See Bidirectional Pullup Characteristics
in the Typical Operating Characteristics.
The MAX6316M/MAX6318MH/MAX6319MH overcome
this problem with an active pullup FET in parallel with the
4.7kΩ resistor (Figures 4 and 5). The pullup transistor
holds RESET high until the μP reset I/O or the supervi-
sory circuit itself forces the line low. Once RESET goes
The following procedure describes how this is done in
the Motorola 68HC11. In all cases of reset, the μP pulls
RESET low for about four external-clock cycles. It then
releases RESET, waits for two external-clock cycles, then
checks RESET’s state. If RESET is still low, the μP con-
cludes that the source of the reset was external and, when
RESET eventually reaches the high state, it jumps to the
normal reset vector. In this case, stored-state information
below V
, a comparator sets the transition edge flip-
PTH
flop, indicating that the next transition for RESET will be
low to high. When RESET is released, the 4.7kΩ resistor
pulls RESET up toward V . Once RESET rises above
CC
V
but is below (0.85 x V ), the active P-channel
PTH
CC
pullup turns on. Once RESET rises above (0.85 x V
)
CC
or the 2μs one-shot times out, the active pullup turns
off. The parallel combination of the 4.7kΩ pullup and the
V
CC
V
CC
WDI*
MR**
4.7kΩ
68HC11
RESET
CIRCUITRY
RESET
RESET
RESET
RESET
CIRCUITRY
RESET***
C
IN
C
STRAY
C
IN
MAX6316M
MAX6318MH
MAX6319MH
C
IN
OTHER DEVICES
*
**
MAX6316M/MAX6318MH
MAX6316M/MAX6319MH
***
ACTIVE-HIGH PUSH/PULL MAX6318MH/MAX6319MH
Figure 3. MAX6316M/MAX6318MH/MAX6319MH Supports Additional Devices on the Reset Bus
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
V
CC
MAX6316M
MAX6318MH
MAX6319MH
LASER-
TRIMMED
RESISTORS
V
CC
VREF
52kΩ
MR
(MAX6316M/
MAX6319MH)
RESET
GENERATOR
(MAX6316M/
MAX6318MH)
WATCHDOG ON
CIRCUITRY
WDI
V
CC
2µs ONE SHOT
TRANSITION
FLIP-FLOP
R
S
Q
4.7kΩ
FF
RESET
ACTIVE PULLUP
ENABLE COMPARATOR
0.65V
0.85V
CC
GND
Figure 4. MAX6316/MAX6318MH/MAX6319MH Bidirectional Reset Output Functional Diagram
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
P-channel transistor on-resistance quickly charges stray
capacitance on the reset line, allowing RESET to transi-
tion from low to high within the required two electronic-
clock cycles, even with several devices on the reset line.
This process occurs regardless of whether the reset was
ter a logic low (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 pullup is sufficient in most applications.
Manual-Reset Input
caused by V
dipping below the reset threshold, the
CC
The MAX6316_/MAX6317H/MAX6319_H/MAX6320P/
MAX6322HP feature a manual reset input. A logic low on
MR asserts a reset. After MR transitions low to high, reset
remains asserted for the duration of the reset timeout
watchdog timing out, MR being asserted, or the μP or
other device asserting RESET. The parts do not require
an external pullup. To minimize supply current con-
sumption, the internal 4.7kΩ pullup resistor disconnects
from the supply whenever the MAX6316M/MAX6318MH/
MAX6319MH assert reset.
period (t ). The MR input is connected to V
through
RP
CC
an internal 52kΩ pullup resistor and therefore can be left
unconnected when not in use. MR can be driven with
TTL-logic levels in 5V systems, with CMOS-logic levels in
3V systems, or with open-drain or open-collector output
devices. A normally-open momentary switch from MR to
ground can also be used; it requires no external debounc-
ing circuitry. MR is designed to reject fast, negative-going
transients (typically 100ns pulses). A 0.1μF capacitor from
MR to ground provides additional noise immunity.
Open-Drain RESET Output
The MAX6320P/MAX6321HP/MAX6322HP have an
active-low, open-drain reset output. This output structure
will sink current when RESET is asserted. Connect a pul-
lup resistor from RESET to any supply voltage up to 6V
(Figure 6). Select a resistor value large enough to regis-
The MR input pin is equipped with internal ESD-protection
circuitry that may become forward biased. Should MR
V
CC
t
0.8 x V
RP
CC
be driven by voltages higher than V , excessive cur-
RESET
CC
OR
rent would be drawn, which would damage the part. For
example, assume that MR is driven by a +5V supply other
µC RESET DELAY
0.7V
than V . If V
maximum rating is violated [-0.3V to (V
drops lower than +4.7V, MR’s absolute
CC
CC
t
R
t
S
+ 0.3V)], and
CC
undesirable current flows through the ESD structure from
MR to V . To avoid this, use the same supply for MR as
ACTIVE
PULLUP
TURNS ON
RESET PULLED LOW
BY µC OR
RESET GENERATOR
CC
the supply monitored by V . This guarantees that the
CC
voltage at MR will never exceed V
.
CC
Figure 5. Bidirectional RESET Timing Diagram
Watchdog Input
The MAX6316_/MAX6317H/MAX6318_H/MAX6320P/
MAX6321HP feature a watchdog circuit that monitors the
μP’s activity. If the μP does not toggle the watchdog input
+3.3V
+5.0V
(WDI) within the watchdog timeout period (t ), reset
WD
asserts. The internal watchdog timer is cleared by reset
or by a transition at WDI (which can detect pulses as
short as 50ns). The watchdog timer remains cleared while
reset is asserted. Once reset is released, the timer begins
counting again (Figure 7).
V
CC
MR*
10kΩ
WDI**
RESET
5V SYSTEM
RESET***
The WDI input is designed for a three-stated output
device with a 10μA maximum leakage current and the
capability of driving a maximum capacitive load of 200pF.
The three-state device must be able to source and sink at
least 200μA when active. Disable the watchdog function
by leaving WDI unconnected or by three-stating the driver
connected to WDI. When the watchdog timer is left open
circuited, the timer is cleared internally at intervals equal
to 7/8 of the watchdog period.
MAX6320
MAX6321
MAX6322
GND
* MAX6320/MAX6322
** MAX6320/MAX6321
*** MAX6321/MAX6322
Figure 6. MAX6320P/MAX6321HP/MAX6322HP Open-Drain
RESET Output Allows Use with Multiple Supplies
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
V
CC
t
RST
V
CC
MAX6316
MAX6318
MAX6319
RESET
t
RP
t
t
RP
WD
V
CC
WDI
GND
RESET
100kΩ
MAX6316/MAX6317
MAX6318/MAX6320
MAX6321
Figure 7. Watchdog Timing Relationship
Figure 8. Ensuring RESET Valid to V
Push/Pull and Bidirectional Outputs
= 0V on Active-Low
CC
Applications Information
Watchdog Input Current
MAX6317
MAX6318
MAX6319
MAX6321*
MAX6322*
The WDI input is internally driven through a buffer and
series resistor from the watchdog counter. For minimum
watchdog input current (minimum overall power con-
sumption), leave WDI low for the majority of the watchdog
timeout period. When high, WDI can draw as much as
160μA. Pulsing WDI high at a low duty cycle will reduce
the effect of the large input current. When WDI is left
unconnected, the watchdog timer is serviced within the
watchdog timeout period by a low-high-low pulse from the
counter chain.
V
CC
100kΩ
V
CC
GND
RESET
*THIS SCHEMATIC DOES NOT WORK ON THE OPEN-DRAIN
OUTPUTS OF THE MAX6321/MAX6322.
Negative-Going VCC Transients
These supervisors are immune to short-duration, negative-
Figure 9. Ensuring RESET Valid to V
Push/Pull Outputs
= 0V on Active-High
CC
going V transients (glitches), which usually do not require
CC
the entire system to shut down. Typically, 200ns large-
scheme does not work with the open-drain outputs of the
MAX6320/MAX6321/MAX6322. The resistor value used
is not critical, but it must be large enough not to load the
amplitude pulses (from ground to V ) on the supply will
CC
not cause a reset. Lower amplitude pulses result in greater
immunity. Typically, a V transient that goes 100mV under
CC
reset output when V
is above the reset threshold. For
CC
the reset threshold and lasts less than 4μs will not trigger a
reset. An optional 0.1μF bypass capacitor mounted close to
most applications, 100kΩ is adequate.
V
provides additional transient immunity.
CC
Watchdog Software Considerations
(MAX6316/MAX6317/MAX6318/
MAX6320/MAX6321)
Ensuring Valid Reset Outputs
Down to V = 0V
CC
One way to help the watchdog timer monitor software
execution more closely is to set and reset the watchdog
input at different points in the program, rather than puls-
ing the watchdog input high-low-high or low-high-low. This
technique avoids a stuck loop, in which the watchdog
timer would continue to be reset inside the loop, keeping
the watchdog from timing out.
The MAX6316_/MAX6317H/MAX6318_H/MAX6319_H/
MAX6321HP/MAX6322HP are guaranteed to operate
properly down to V
= 1V. In applications that require
CC
valid reset levels down to V
= 0V, a pulldown resistor to
CC
active-low outputs (push/pull and bidirectional only, Figure
8) and a pullup resistor to active-high outputs (push/pull
only, Figure 9) will ensure that the reset line is valid while
the reset output can no longer sink or source current. This
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Figure 10 shows an example of a flow diagram where the
I/O driving the watchdog input is set high at the beginning
of the program, set low at the end of every subroutine or
loop, then set high again when the program returns to the
beginning. If the program should hang in any subroutine,
the problem would be quickly corrected, since the I/O is
continually set low and the watchdog timer is allowed to
time out, causing a reset or interrupt to be issued. As
described in the Watchdog Input Current section, this
scheme results in higher time average WDI current than
does leaving WDI low for the majority of the timeout
period and periodically pulsing it low-high-low.
START
SET WDI
HIGH
PROGRAM
CODE
POSSIBLE
INFINITE LOOP PATH
SUBROUTINE OR
PROGRAM LOOP
SET WDI LOW
RETURN
Figure 10. Watchdog Flow Diagram
Pin Configurations
Typical Operating Circuit
TOP VIEW
V
IN
V
V
CC
RESET
GND
MR
1
2
3
5
4
V
RESET
GND
MR
1
2
3
5
4
V
CC
CC
CC
RESET
MAX6316
RESET
MAX6316
MAX6320
MAX6317
SOT23
µP
I/O
MR
WDI
MANUAL
RESET
WDI
WDI
GND
GND
SOT23
RESET
GND
1
2
3
5
4
V
RESET
GND
1
2
3
5
4
V
CC
CC
MAX6318
MAX6321
MAX6319
MAX6322
RESET
WDI
RESET
MR
SOT23
SOT23
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Table 1. Factory-Trimmed Reset Thresholds
T
=
+25°C
T
= -40°C to +125°C
A
A
PART
MIN
TYP
MAX
5.075
4.974
4.872
4.771
4.699
4.568
4.446
4.365
4.263
4.162
4.060
3.959
3.857
3.756
3.654
3.553
3.451
3.350
3.248
3.126
3.045
2.974
2.842
2.741
2.669
2.538
MIN
MAX
MAX63___50_ _-T
MAX63___49_ _-T
MAX63___48_ _-T
MAX63___47_ _-T
MAX63___46_ _-T
MAX63___45_ _-T
MAX63___44_ _-T
MAX63___43_ _-T
MAX63___42_ _-T
MAX63___41_ _-T
MAX63___40_ _-T
MAX63___39_ _-T
MAX63___38_ _-T
MAX63___37_ _-T
MAX63___36_ _-T
MAX63___35_ _-T
MAX63___34_ _-T
MAX63___33_ _-T
MAX63___32_ _-T
MAX63___31_ _-T
MAX63___30_ _-T
MAX63___29_ _-T
MAX63___28_ _-T
MAX63___27_ _-T
MAX63___26_ _-T
MAX63___25_ _-T
4.925
7.827
4.728
4.630
4.561
4.433
4.314
4.236
4.137
4.039
3.940
3.842
3.743
3.645
3.546
3.448
3.349
3.251
3.152
3.034
2.955
2.886
2.758
2.660
2.591
2.463
5.000
4.900
4.800
4.700
4.630
4.500
4.390
4.300
4.200
4.100
4.000
3.900
3.800
3.700
3.600
3.500
3.400
3.300
3.200
3.080
3.000
2.930
2.800
2.700
2.630
2.500
4.875
4.778
4.680
4.583
4.514
4.388
4.270
4.193
4.095
3.998
3.900
3.803
3.705
3.608
3.510
3.413
3.315
3.218
3.120
3.003
2.925
2.857
2.730
2.633
2.564
2.438
5.125
5.023
4.920
4.818
4.746
4.613
4.490
4.408
4.305
4.203
4.100
3.998
3.895
3.793
3.690
3.588
3.485
3.383
3.280
3.157
3.075
3.000
2.870
2.768
2.696
2.563
Table 2. Standard Versions
MINIMUM
RESET
TIMEOUT (ms)
TYPICAL
WATCHDOG
TIMEOUTS (s)
SOT
TOP
MARK
RESET
THRESHOLD (V)
PART
MAX6316LUK29CY-T
MAX6316LUK46CY-T
MAX6316MUK29CY-T
MAX6316MUK46CY-T
MAX6317HUK46CY-T
MAX6318LHUK46CY-T
MAX6318MHUK46CY-T
MAX6319LHUK46C-T
MAX6319MHUK46C-T
2.93
4.63
2.93
4.63
4.63
4.63
4.63
4.63
4.63
140
140
140
140
140
140
140
140
140
1.6
1.6
1.6
1.6
1.6
1.6
1.6
—
ACDE
ACDD
ACDG
ACDF
ACDQ
ACDH
ACDJ
ACDK
ACDM
—
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Table 2. Standard Versions (continued)
MINIMUM
RESET
TIMEOUT (ms)
TYPICAL
WATCHDOG
TIMEOUTS (s)
SOT
TOP
MARK
RESET
PART
THRESHOLD (V)
MAX6320PUK29CY-T
MAX6320PUK46CY-T
MAX6321HPUK46CY-T
MAX6322HPUK46C-T
2.93
4.63
4.63
4.63
140
140
140
140
1.6
1.6
1.6
1.6
ACDO
ACDN
ACGL
ACGN
Note: Thirteen standard versions are available, with a required order increment of 2500 pieces. Sample stock is generally held on
standard versions only. The required order increment for nonstandard versions is 10,000 pieces. Contact factory for availability.
Table 3. Reset/Watchdog Timeout Periods
Ordering Information (continued)
PART
TEMP RANGE PIN-PACKAGE
RESET TIMEOUT PERIODS
MAX6319LHUK___-T
MAX6319MHUK___-T
MAX6320PUK____-T
-40°C to +125°C 5 SOT23
-40°C to +125°C 5 SOT23
-40°C to +125°C 5 SOT23
SUFFIX
MIN
1
TYP
1.6
MAX
2
UNITS
ms
A
B
C
D
20
30
40
MAX6320PUK____/V+T -40°C to +125°C 5 SOT23
140
1.12
200
1.60
280
2.24
MAX6321HPUK___-T
MAX6322HPUK___-T
-40°C to +125°C 5 SOT23
-40°C to +125°C 5 SOT23
s
Devices are available in both leaded and lead(Pb)-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
/V Denotes an automotive-qualified part.
WATCHDOG TIMEOUT
W
X
Y
Z
4.3
6.3
102
1.6
9.3
ms
s
71
153
2.4
1.12
17.9
Note: These devices are available with factory-set V
reset
CC
25.6
38.4
thresholds from 2.5V to 5V, in 0.1V increments. Insert the
desired nominal reset threshold (25 to 50, from Table 1) into
the blanks following the letters UK. All devices offer factory-pro-
grammed reset timeout periods. Insert the letter corresponding
to the desired reset timeout period (A, B, C, or D from Table 3)
into the blank following the reset threshold suffix. Parts that offer
a watchdog feature (see Selector Guide) are factory-trimmed
to one of four watchdog timeout periods. Insert the letter corre-
sponding to the desired watchdog timeout period (W, X, Y, or Z
from Table 3) into the blank following the reset timeout suffix.
Chip Information
SUBSTRATE IS INTERNALLY CONNECTED TO V+
Package Information
For the latest package outline information and land patterns
(footprints), 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.
5 SOT23
U5+2
21-0057
90-0174
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MAX6316–MAX6322
5-Pin μP Supervisory Circuits with
Watchdog and Manual Reset
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
1
2
1/98
4/98
7/98
Initial release.
—
Update to show MAX6319 as an existing part.
Update specifications, Selector Guide, and Table 2.
1, 2, 12
1, 12, 14
Include extended temperature range in EC table globals, Table 1, Ordering
Information.
3
1/99
1, 2, 3, 12, 13, 14
4
5
6
11/99
9/02
Update available products and versions in Table 2 and Ordering Information.
Addition of RESET rise time specification to Electrical Characteristics table.
Add lead-free option to Ordering Information.
1, 12, 14
1, 2
12/05
1, 13, 14
Add automotive temperature to Ordering Information, Electrical Characteristics
table, Table 1, and updated Package Information.
7
11/07
1, 2, 3, 12, 13, 14
8
8/09
6/10
10/11
2/13
4/15
5/17
Updated Ordering Information.
13
9
Added automotive part and soldering temperatures.
Added automotive-qualified part ordering option for MAX6316 family
Changed /V-T suffix to /V+T in Ordering Information
Updated the General Description and Benefits and Features sections
Added AECQ-100 qualification
2, 13
10
11
12
13
1
1
1
1
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.
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.
2017 Maxim Integrated Products, Inc.
│ 14
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