MAX709L [MAXIM]
Power-Supply Monitor with Reset;
| 型号： | MAX709L |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Power-Supply Monitor with Reset |
| 文件： | 总8页 (文件大小：178K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-0136; Rev. 2; 12/05
Power-Supply Monitor with Reset
_______________General Description
___________________________Features
♦ +5V, +3.3V, and +3V Versions
The MAX709 provides a system reset during power-up,
power-down, and brownout conditions. When VCC falls
below the reset threshold, RESET goes low and holds
the µP in reset for 140ms min after VCC rises above the
threshold.
♦ No External Components
♦ Low Cost
♦ Precise Power-Down Reset Threshold
♦ 140ms Min Power-On Reset Delay
♦ Immune to Short Negative VCC Transients
♦ 8-Pin DIP, µMAX, and SO Packages
The RESET output is guaranteed to be in the correct
state with VCC down to 1V. The MAX709 provides
excellent circuit reliability and low cost by eliminating
external components and adjustments when used with
+5V, +3.3V, or +3V powered systems. The MAX709 is
available 8-pin DIP, µMAX, and SO packages.
♦ Low Supply Current: 35µA - MAX709R/S/T
65µA - MAX709L/M
______________Ordering Information
PART
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 µMAX
MAX709_CPA
MAX709_CUA
MAX709_CSA
MAX709_C/D
MAX709_EPA
MAX709_EUA
MAX709_ESA
8 SO
Dice
8 Plastic DIP
8 µMAX
_______________________Applications
8 SO
Minimum Component Count,
Low-Cost Processor Systems
Devices are available in both leaded and lead-free packaging.
Specify lead free by adding the + symbol at the end of the part
number when ordering.
*Dice are specified at T = +25°C, DC parameters only.
A
Note: This part offers a choice of five different reset threshold
voltages. Select the letter corresponding to the desired
nominal reset threshold voltage, and insert it into the
blank to complete the part number.
RESET THRESHOLD
SUFFIX
VOLTAGE (V)
4.65
L
M
T
__________Typical Operating Circuit
4.40
3.08
S
2.93
R
2.63
__________________Pin Configuration
V
V
CC
CC
µP
TOP VIEW
MAX709
N.C.
N.C.
RESET
N.C.
RESET
1
2
3
4
8
7
6
5
RESET
V
CC
MAX709
GND
N.C.
GND
GND
N.C.
DIP/SO/µMAX
________________________________________________________________ Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
Power-Supply Monitor with Reset
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
Operating Temperature Ranges
V
CC................................................ -0.3V to 6.0V
MAX709_C___ ...................................0°C to +70°C
MAX709_E___ . ................................-40°C to +85°C
Storage Temperature Range ..................-65°C to +160°C
Lead Temperature (soldering, 10sec)....................+300°C
RESET....................................-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)
Plastic DIP (derate 9.09mW/°C above +70°C) ........727mW
µMAX (derate 4.10mW/°C above +70°C) .............330mW
SO (derate 5.88mW/°C above +70°C).................471mW
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, TA = TMIN to TMAX, unless otherwise noted.)
PARAMETER
VCC Range
CONDITIONS
MIN
1.0
TYP
MAX
UNITS
MAX709_C
MAX709_E
5.5
V
1.2
5.5
85
MAX709_C, VCC < 3.6V
35
35
MAX709R/S/T only
All versions
MAX709_E, VCC < 3.6V
MAX709_C, VCC < 5.5V
MAX709_E, VCC < 5.5V
110
150
200
4.75
4.50
3.15
3.00
2.70
Supply Current (Note 1)
RESET Threshold, VTH
µA
65
65
MAX709L
MAX709M
MAX709T
MAX709S
MAX709R
4.50
4.25
3.00
2.85
2.55
4.65
4.40
3.08
2.93
2.63
20
V
VCC to RESET Delay
VCC = reset threshold max to reset threshold min
VCC = reset threshold max, VCC rising
µs
Reset Active Timeout Period
140
280
560
0.3
ms
ISINK = 1.2mA, VCC = reset threshold min,
MAX709R/S/T only
ISINK = 3.2mA, VCC = reset threshold min,
MAX709L/M only
0.4
ISINK = 50µA, VCC ≥ 1.0V, MAX709_C
ISINK = 100µA, VCC ≥ 1.2V, MAX709_E
0.3
0.4
RESET Output Voltage
V
ISOURCE = 500µA, VCC ≥ reset threshold max,
MAX709R/S/T only
0.8 x VCC
VCC - 1.5
ISOURCE = 800µA, VCC ≥ reset threshold max,
MAX709L/M only
Note 1: Supply current is measured with VCC = 3.6V for MAX709R/S/T, and VCC = 5.5V for all versions.
_______________________________________________________________________________________
2
Power-Supply Monitor with Reset
__________________________________________Typical Operating Characteristics
POWER-UP RESET DELAY
vs. TEMPERATURE
POWER-DOWN RESET DELAY
vs. TEMPERATURE
300
250
24
20
V
CC
V
CC
= RESET THRESHOLD MAX,
RISING
200
150
100
50
16
12
8
4
V
CC
STEPPED FROM RESET THRESHOLD
MAX TO RESET THRESHOLD MIN
0
0
-60
-20
20
60
100
-60
-20 20
60
100
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY CURRENT
vs. TEMPERATURE
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
100
80
1.005
1.003
1.001
0.999
NOTE: STEADY-STATE SUPPLY
CURRENT IS INDEPENDENT
OF RESET OUTPUT STATUS
THE RESET THRESHOLD IS SHOWN
NORMALIZED TO 1, REPRESENTING
ALL AVAILABLE MAX709 RESET
THRESHOLDS
NO LOAD
V
CC
= +5V
60
V
V
= +4V
= +3V
CC
40
CC
20
0
0.997
0.995
V
V
= +2V
= +1V
CC
CC
-60
-20
20
60
100
-60
-20
20
60
100
TEMPERATURE (°C)
TEMPERATURE (°C)
_________________________________________________________________________________________________
3
Power-Supply Monitor with Reset
____________________Pin Description
150
T
= +25°C
A
PIN
NAME
FUNCTION
No Connect. There is no internal
connection to this pin.
1, 4, 5,
6, 8
N.C.
VCC
100
50
0
2
3
+5V, +3.3V, or +3V Supply Voltage
Ground
MAX709L/M
GND
10ns
Reset Output remains low while VCC is
below the reset threshold, and for
280ms after VCC rises above the reset
threshold.
MAX709R/S/T
7
RESET
10
100
1k
10k
RESET COMPARATOR OVERDRIVE, V - V (mV)
TH
CC
Figure 1. Maximum Transient Duration without Causing a
Reset Pulse vs. Reset Comparator Overdrive
__________Applications Information
Negative-Going VCC Transients
In addition to issuing a reset to the microprocessor
(µP) during power-up, power-down, and brownout con-
ditions, the MAX709 is relatively immune to short dura-
tion negative-going VCC transients (glitches).
A 0.1µF bypass capacitor mounted as close as possible
to pin 2 (VCC) provides additional transient immunity.
Ensuring a Valid RESET Output
Down to VCC = 0V
Figure 1 shows typical transient duration vs. reset com-
parator overdrive, for which the MAX709 does not gen-
erate a reset pulse. The graph was generated using a
negative-going pulse applied to VCC, starting 1.5V
above the actual reset threshold and ending below it
by the magnitude indicated (reset comparator over-
drive). The graph indicates the typical maximum pulse
width that a negative-going VCC transient may have
without causing a reset pulse to be issued. As the
magnitude of the transient increases (goes farther
below the reset threshold), the maximum allowable
When VCC falls below 1V, the MAX709 RESET output
no longer sinks current—it becomes an open circuit.
Therefore, high-impedance CMOS logic inputs con-
nected to the RESET output can drift to undermined
voltages. This presents no problem in most applica-
tions, since most µP and other circuitry is inoperative
with VCC below 1V. However, in applications where the
RESET output must be valid down to 0V, adding a pull-
down resistor to the RESET pin will cause any stray
leakage currents to flow to ground, holding RESET low
(see Figure 2). The resistance value of R1 is not criti-
cal. It should be about 100kΩ, which is large enough
not to load RESET and small enough to pull RESET to
ground.
pulse width decreases.
Typically, for the
MAX709L/MAX709M, a VCC transient that goes 100mV
below the reset threshold and lasts 40µs or less will not
cause a reset pulse to be issued.
4
_______________________________________________________________________________________
Power-Supply Monitor with Reset
BUFFERED RESET
TO OTHER SYSTEM
COMPONENTS
BUFFER
V
CC
V
V
CC
CC
MAX709
µP
RESET
4.7k
MAX709
RESET
RESET
R1
GND
GND
GND
Figure 2. RESET Valid to VCC = Ground Circuit
Figure 3. Interfacing to µPs with Bidirectional Reset I/O
Interfacing to µPs with
Bidirectional Reset Pins
Microprocessors with bidirectional reset pins (such as
the Motorola 68HC11 series) can contend with the
MAX709 reset output. If, for example the MAX709
RESET output is asserted high and the µP wants to pull
it low, indeterminate logic levels may result. To correct
this, connect a 4.7kΩ resistor between the MAX709
RESET output and the µP reset I/O (see Figure 3).
Buffer the MAX709 RESET output to other system com-
ponents.
_______________________________________________________________________________________
5
Power-Supply Monitor with Reset
_____________________________________________________µP Supervisory Circuits
Minimum Nominal
Nominal
Reset
Threshold Width
Reset
Pulse
Watchdog
Timeout Backup- CE -
Period
(sec)
Power-
Fail
Com-
Manual- Watch- Low-
Reset dog Line
Output Output Reset
Active- Battery-
Part
Number
Battery Write
High
On
(V)
(ms)
Switch Protect parator Input
Output
MAX690A/692A 4.65/4.40
MAX691A/693A 4.65/4.40
140
1.6
✔
✔
✔
✔
✔
✔
✔
140/adj.
35/adj.
35/adj.
200
1.6/adj.
1.6/adj.
1.6/adj.
-
✔/10ns
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
MAX696
Adj.
MAX697
Adj.
✔
MAX700
4.65/adj.
4.65/4.40
4.65/4.40
2.63
✔
✔
✔
✔
✔
MAX703/704
MAX705/706
MAX706P
MAX706R/S/T
140
-
✔
✔
✔
✔
✔
140
1.6
✔
✔
✔
140
1.6
✔
2.63/2.93/
3.08
140
1.6
MAX707/708
4.65/4.40
140
140
-
-
✔
✔
✔
✔
✔
✔
MAX708R/S/T
2.63/2.93/
3.08
MAX709L/M/
R/S/T
4.65/4.40/
2.63/2.93/3.08
140
-
MAX791
4.65
140
140
1
1
✔
✔/10ns
✔/10ns
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
MAX792L/M/
R/S/T
4.65/4.40/
2.63/2.93/3.08
MAX800L/M
MAX802L/M
MAX805L
4.60/4.40
4.60/4.40
4.65
140
140
140
140
140
1.6/adj.
1.6
✔
✔
✔
✔/10ns
✔/ 2ꢀ
✔/ 2ꢀ
✔
✔
✔
✔
1.6
✔
✔
✔
MAX813L
4.65
1.6
✔
✔
✔
✔
✔
MAX820L/M/
R/S/T
4.65/4.40/
2.63/2.93/3.08
1
✔/10ns
✔/ 2ꢀ
✔
MAX1232
MAX1259
4.37/4.62
-
250
-
0.15/0.60/1.2
-
✔
✔
✔
6
_______________________________________________________________________________________
Power-Supply Monitor with Reset
___________________Chip Topography
V
CC
RESET
0.045"
(1.143mm)
GND
0.056"
(1.422mm)
TRANSISTOR COUNT: 380
SUBSTRATE CONNECTED TO V
CC
_______________________________________________________________________________________
7
Power-Supply Monitor with Reset
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
4X S
8
8
MILLIMETERS
INCHES
DIM MIN
MAX
MAX
MIN
-
-
0.043
0.006
0.037
0.014
0.007
0.120
1.10
0.15
0.95
0.36
0.18
3.05
A
0.002
0.030
0.010
0.005
0.116
0.05
0.75
0.25
0.13
2.95
A1
A2
b
E
H
Ø0.50±0.1
c
D
e
0.0256 BSC
0.65 BSC
0.6±0.1
E
H
0.116
0.188
0.016
0°
0.120
2.95
4.78
0.41
0°
3.05
5.03
0.66
6°
0.198
0.026
6°
L
1
1
α
S
0.6±0.1
0.0207 BSC
0.5250 BSC
D
BOTTOM VIEW
TOP VIEW
A1
A2
A
c
α
e
L
b
SIDE VIEW
FRONT VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, 8L uMAX/uSOP
APPROVAL
DOCUMENT CONTROL NO.
REV.
1
21-0036
J
1
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
© 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
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