MAX6737XKSHD3+ [MAXIM]
Power Supply Support Circuit, Fixed, 2 Channel, BICMOS, PDSO5, SC-70, 5 PIN;
| 型号： | MAX6737XKSHD3+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Power Supply Support Circuit, Fixed, 2 Channel, BICMOS, PDSO5, SC-70, 5 PIN 信息通信管理 光电二极管 电源管理电路 电源电路 |
| 文件： | 总16页 (文件大小：657K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2531; Rev 2; 12/05
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
General Description
Features
The MAX6736–MAX6745 are low-power dual-/triple-
voltage microprocessor (µP) supervisors. These
devices assert a reset if any monitored supply falls
below its factory-trimmed or adjustable threshold and
maintain reset for a minimum timeout period after all
supplies rise above their thresholds. The integrated
dual/triple supervisory circuits significantly reduce size
and power compared to separate ICs or discrete com-
ponents. The low supply current of 6µA makes these
devices ideal for portable equipment.
♦ Dual-/Triple-Supply Reset Voltage Monitors
♦ Precision Factory-Set Reset Thresholds for
Monitoring from 0.9V to 5.0V
♦ Adjustable Reset Input Down to 0.488V
♦ 150ms and 1200ms (min) Reset Timeout Period
Options
♦ V 1 Power-OK Output for Power-Supply
CC
Sequencing Applications (MAX6741/MAX6744)
♦ Power-Fail Input/Power-Fail Output
The MAX6736/MAX6737 are dual fixed-voltage µP
supervisors with a manual reset input. The MAX6738/
MAX6739 have one fixed and one adjustable reset
threshold and a manual reset input. The MAX6740/
MAX6743 are triple-voltage µP supervisors with two
fixed and one user-adjustable reset threshold inputs.
The MAX6741/MAX6744 are dual-voltage µP supervi-
sors with a power-OK (POK) output ideal for power-
supply sequencing. The MAX6742/MAX6745 monitor
(MAX6742/MAX6745)
♦ 6µA Supply Current
♦ Tiny SC70 Package
Ordering Information
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
5 SC70-5
MAX6736XK_ _D_-T
MAX6737XK_ _D_-T
the primary V
supply and have an independent
CC
5 SC70-5
power-fail comparator.
Note: The first “_ _” or “_” are placeholders for the threshold
voltage levels of the devices. Desired threshold levels are set
by the part number suffix found in Tables 1 and 2. The “_” after
the D is a placeholder for the reset timeout period suffix found
in Table 3. For example, the MAX6736XKLTD3-T is a dual-volt-
The MAX6736–MAX6745 monitor I/O supply voltages
(V 1) from 1.8V to 5.0V and core supply voltages
CC
(V 2) from 0.9V to 3.3V with factory-trimmed reset
CC
threshold voltage options (Table 1). An external
adjustable RSTIN input option allows monitoring volt-
ages down to 0.5V.
age supervisor V 1 = 4.625V, V 2 = 3.075V, and a 150ms
TH
TH
minimum reset timeout period. All devices are available in
tape-and-reel only. There is a 2500-piece minimum order
increment for standard versions (see Table 1). Sample stock is
typically held on standard versions only. Nonstandard versions
require a minimum order increment of 10,000 pieces. Contact
factory for availability.
A variety of push-pull or open-drain reset outputs along
with manual reset input and power-fail input/output fea-
tures are available (see the Selector Guide). The
MAX6736–MAX6745 are offered in a space-saving 5-pin
SC70 package and operate over the -40°C to +85°C
temperature range.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Ordering Information and Selector Guide continued at end
of data sheet.
Applications
Portable/Battery-
Powered Equipment
Controllers
Pin Configurations, Typical Application Circuits, and
Functional Diagram appear at end of data sheet.
PDAs
Multivoltage Systems
Notebook Computers
GPS Equipment
POS Equipment
Selector Guide
POWER-FAIL
INPUT/
OUTPUT
VOLTAGE
MONITORS
OPEN-DRAIN
PUSH-PULL
MANUAL
RESET
POK
OUTPUT
RSTIN
INPUT
PART
RESET
RESET
MAX6736
MAX6737
MAX6738
2 fixed
2 fixed
X
—
X
—
X
X
X
X
—
—
—
—
—
—
—
—
X
1 fixed, 1 adj
—
*Manual reset detect on RESET output.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
ABSOLUTE MAXIMUM RATINGS
CC , CC
V
1 V 2, POK1 to GND ......................................-0.3V to +6V
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Open-Drain RESET, PFO to GND.............................-0.3V to +6V
Push-Pull RESET to GND..........................-0.3V to (V 1 + 0.3V)
CC
CC
MR, RSTIN, PFI to GND............................-0.3V to (V 1 + 0.3V)
Input/Output Current, All Pins .............................................20mA
Continuous Power Dissipation (T = +70°C)
A
5-Pin SC70 (derate 3.1mW/°C above +70°C)..............247mW
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
= 1.2V to 5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
= -40°C to 0°C
MIN
1.2
TYP
MAX
5.5
UNITS
T
T
A
V
1,
CC
Operating Voltage Range
V
V
2
CC
= 0°C to +85°C
1.0
5.5
A
V
1 = 3.3V, V 1 > V 2, no load, reset
CC
CC
CC
5
5
1
10
10
2
not asserted
V
V
1 Supply Current
I
I
1
µA
µA
CC
CC
CC
V
1 = 1.8V, V 1 < V 2, no load, reset
CC
CC
CC
not asserted
V
2 = 1.8V, V 2 < V 1, no load, reset
CC
CC
CC
not asserted
2 Supply Current
2
CC
V
2 = 3.3V, V 2 > V 1, no load, reset
CC CC
CC
10
20
not asserted
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
4.500
4.425
4.250
4.175
3.000
2.950
2.850
2.800
2.550
2.505
2.250
2.213
2.125
2.088
1.620
1.593
1.530
1.503
4.625
4.750
4.825
4.500
4.575
3.150
3.200
3.000
3.050
2.700
2.745
2.375
2.413
2.250
2.288
1.710
1.737
1.620
1.647
MAX67_ _L
4.375
3.075
2.925
2.625
2.313
2.188
1.665
1.575
MAX67_ _M
MAX67_ _T
MAX67_ _S
MAX67_ _R
MAX67_ _Z
MAX67_ _Y
MAX67_ _W
MAX67_ _V
Reset Threshold for V
1
CC
V
1
TH
V
2
_______________________________________________________________________________________
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)
(V
= 1.2V to 5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
3.150
3.050
3.000
3.050
2.700
2.745
2.375
2.413
2.250
2.288
1.710
1.737
1.620
1.647
1.425
1.448
1.350
1.373
1.140
1.158
1.080
1.098
0.855
0.869
0.810
0.824
0.500
0.507
+10
UNITS
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to + 85°C
= -40°C to +85°C
3.000
2.905
2.850
2.800
2.550
2.505
2.250
2.213
2.125
2.088
1.620
1.593
1.530
1.503
1.350
1.328
1.275
1.253
1.080
1.062
1.020
1.002
0.810
0.797
0.765
0.752
0.476
0.468
-10
3.075
MAX67_ _T
MAX67_ _S
MAX67_ _R
MAX67_ _Z
MAX67_ _Y
MAX67_ _W
MAX67_ _V
MAX67_ _I
MAX67_ _H
MAX67_ _G
MAX67_ _F
MAX67_ _E
MAX67_ _D
2.925
2.625
2.313
2.188
1.665
1.575
1.388
1.313
1.110
1.050
0.833
0.788
0.488
Reset Threshold for V
2
V
2
TH
V
CC
T
T
= 0°C to +85°C
A
RSTIN Threshold (MAX6738/
MAX6739/MAX6740/MAX6743)
V
V
TH-RSTIN
= -40°C to +85°C
A
RSTIN Input Current
V
V
V
≥ 0.1V (Note 2)
nA
%
RSTIN
Reset Threshold Hysteresis
1, V 2, RSTIN, PFI
0.5
TH
TH
1 ≥ 1.0V, I
CC
= 50µA, T = 0°C to
A
SINK
0.3
+85°C
RESET, POK1 Output Low
V
V
V
V
1 ≥ 1.2V, I
= 100µA
0.3
0.3
0.4
V
V
OL
CC
CC
CC
SINK
1 ≥ 2.13V, I
1 ≥ 4.25V, I
= 1.2mA
= 3.2mA,
SINK
SINK
V
1 ≥ 2.38V, I
CC
= 500µA, output
0.8 ×
SOURCE
deasserted
V
CC
RESET Output High (Push-Pull)
V
OH
V
1 ≥ 4.75V, I
CC
= 800µA, output
0.8 ×
SOURCE
deasserted
V
CC
_______________________________________________________________________________________
3
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)
(V
= 1.2V to 5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RESET Output Open-Drain
Leakage Current
I
Output not asserted low (Note 2)
500
nA
LKG
(MAX6736/MAX6738)
POK1 Output Open-Drain
Leakage
Output not asserted low (Note 2)
500
nA
µs
V
1, V 2, or RSTIN falling at 10mV/µs
CC CC
V
Reset Delay
t
35
CC
RD
from V + 100mV to V
TH
- 100mV
TH
MAX67_ _ _ _ XK_ _D3
150
225
300
V
Reset Timeout Period
CC
t
RP
ms
(Note 3)
MAX67_ _ _ _ XK_ _ D7
1200
1800
2400
MANUAL RESET (MAX6736–MAX6739 only)
MR to V 1 Internal Pullup
Impedance
CC
0.75
1.5
3.00
300
kΩ
MR Timeout Period
t
Both D3 and D7 timing options
150
1
225
ms
µs
ns
MRP
MR Minimum Input Pulse Width
MR Glitch Rejection
t
MPW
100
0.3 ×
V
IL
V
1
CC
MR Input Voltage
V
0.8 ×
V
IH
V
1
CC
MR to RESET Delay
300
ns
V 1 POWER-OK OUTPUT (MAX6741/MAX6744 only)
CC
POK1 Timeout Period
t
37.5
56.25
75.0
ms
POKP
PUSHBUTTON RESET (MAX6740/MAX6741/MAX6742 only)
RESET to V 1 Internal Pullup
Impedance
CC
25
50
100
kΩ
ms
ms
µs
V
Manual Reset Detect Debounce
Period
t
(Note 4)
37.5
56.25
75.0
DEB
MAX67_ _ _ _ XK_ _D3
MAX67_ _ _ _ XK_ _ D7
150
225
300
Manual Reset Timeout
Period (Note 3)
t
MRP
1200
1800
2400
Manual Reset Minimum Input
Pulse Width
t
(Note 4)
1
MPW
Manual Reset Release Detect
Threshold
0.5 ×
CC
(Note 4)
(Note 4)
V
1
Manual Reset Glitch Rejection
100
300
ns
ns
Manual Reset to RESET Delay
4
_______________________________________________________________________________________
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)
(V
= 1.2V to 5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
POWER-FAIL COMPARATOR (MAX6742/MAX6745 only)
T
T
= 0°C to +85°C
0.476
0.468
-10
0.488
0.500
0.507
+10
0.3
A
A
Power Fail In Threshold (Note 5)
Power Fail In Current
V
V
TH-PFI
= -40°C to +85°C
I
V
V
V
V
≥ 0.1V (Note 2)
nA
PFI
PFI
CC
CC
CC
1 ≥ 1.53V, I
1 ≥ 2.03V, I
1 ≥ 4.25V, I
= 500µA
= 1.2mA
= 3.2mA
SINK
SINK
SINK
PFO Output Low
V
0.3
V
OL
0.4
PFI falling at 10mV/µs from V
+
TH-PFI
100mV to V
10mV/µs from V
100mV (Note 5)
- 100mV or rising at
TH-PFI
PFI to PFO Propagation Delay
PFO Startup Delay
t
35
5
µs
P
- 100mV to V
+
TH-PFI
TH-PFI
To output valid (Note 5)
ms
Note 1: All devices are 100% tested at T = +25°C. All temperature limits are guaranteed by design.
A
Note 2: Guaranteed by design.
Note 3: t timeout period begins after POK1 timeout period (t
Note 4: Refers to the manual reset function obtained by forcing the RESET output low.
) and V 2 ≥ V 2 (max) (MAX6741/MAX6744).
CC TH
RD
POKP
Note 5: V 1 ≥ 1.6V.
CC
Typical Operating Characteristics
(T = +25°C, unless otherwise noted.)
A
SUPPLY CURRENT vs. TEMPERATURE
SUPPLY CURRENT vs. TEMPERATURE
SUPPLY CURRENT vs. TEMPERATURE
10
10
9
8
7
6
5
4
3
2
1
0
10
9
8
7
6
5
4
3
2
1
0
V
1 = 3.3V, V 2 = 2.5V
CC
V
1 = 2.5V, V 2 = 1.8V
CC
V
1 = 1.8V, V 2 = 1.2V
CC CC
CC
CC
9
8
7
6
5
4
3
2
1
0
TOTAL
TOTAL
I
1
CC
TOTAL
I
1
CC
I
I
1
2
CC
CC
I
2
CC
I
2
CC
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
Typical Operating Characteristics (continued)
(T = +25°C, unless otherwise noted.)
A
MAXIMUM V 1/V 2 TRANSIENT DURATION
CC
CC
NORMALIZED V /POK1/MR
TIMEOUT PERIOD vs. TEMPERATURE
CC
vs. RESET THRESHOLD OVERDRIVE
10,000
1000
100
10
1.019
1.014
1.009
1.004
0.999
0.994
0.989
0.984
V
1
CC
RESET OCCURS ABOVE
THESE LINES
V
2
CC
0
10
100
1000
-40
-20
0
20
40
60
80
RESET THRESHOLD OVERDRIVE (mV)
TEMPERATURE (°C)
NORMALIZED V RESET THRESHOLD
CC
V
CC
TO RESET OUTPUT DELAY
vs. TEMPERATURE
vs. TEMPERATURE
1.008
1.003
0.998
0.993
0.988
100mV OVERDRIVE
48.5
43.5
38.5
33.5
28.5
NORMALIZED TO +25°C
-40
-20
20
40
60
80
-40
-20
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
POWER-FAIL INPUT TO POWER-FAIL
OUTPUT DELAY vs. TEMPERATURE
RESET INPUT TO RESET OUTPUT DELAY
vs. TEMPERATURE
35
30
25
20
49
44
39
34
29
24
100mV OVERDRIVE
100mV OVERDRIVE
RISING EDGE
FALLING EDGE
-40
-20
20
40
60
80
-40
-20
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
6
_______________________________________________________________________________________
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
Typical Operating Characteristics (continued)
(T = +25°C, unless otherwise noted.)
A
POWER-FAIL INPUT TO
POWER-FAIL OUTPUT DELAY
MR TO RESET OUTPUT DELAY
MAX6736-45 toc11
MAX6736-45 toc10
PFI
200mV/div
V
MR
2V/div
PFO
2V/div
V
RESET
2V/div
10µs/div
100ns/div
OUTPUT LOW VOLTAGE
vs. SINK CURRENT
V
CC
TO RESET OUTPUT DELAY
MAX6736-45 toc12
500
400
300
200
100
0
V
= 3.3V
CC
V
CC
200mV/div
AC-COUPLED
V
RESET
2V/div
4µs/div
0
1
2
3
4
5
6
7
8
9
10
SINK CURRENT (mA)
OUTPUT HIGH VOLTAGE
vs. SOURCE CURRENT
4
V
= 3.3V
CC
3
2
1
0
0
0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00
SOURCING CURRENT (mA)
_______________________________________________________________________________________
7
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
Pin Description
PIN
NAME
FUNCTION
MAX6736 MAX6738 MAX6740 MAX6741 MAX6742
MAX6737 MAX6739 MAX6743 MAX6744 MAX6745
Reset Output, Push-Pull or Open Drain Active Low. RESET
changes from high to low when any monitored power-supply
input (V 1, V 2, RSTIN) drops below its selected reset
CC
CC
threshold. It remains low until all monitored power-supply
inputs exceed their selected reset thresholds for the V
CC
reset timeout period. RESET is forced low if MR is low for at
least the MR minimum input pulse width. It remains low for
the MR reset timeout period after MR goes high. The push-
1
1
1
1
1
RESET
pull output is referenced to V 1. The MAX6736/MAX6738
CC
open-drain outputs require an external pullup resistor. The
MAX6740/MAX6741/MAX6742 open-drain outputs have an
internal 50kΩ pullup resistor to V 1 and provide a manual
CC
reset function.
2
3
2
3
2
2
2
GND
Ground
Manual Reset, Active Low. Pull low for at least MR minimum
input pulse width to force RESET low. Reset remains active
as long as MR is low and for the MR reset timeout period
after MR goes high. There is an internal 1.5kΩ pullup resistor
—
—
—
MR
to V 1.
CC
Voltage Input 1. Power supply and input for the secondary
µP voltage reset monitor.
4
—
5
—
4
4
3
5
4
—
5
—
—
5
V
2
CC
Adjustable Reset Threshold Input. RESET is asserted when
RSTIN is below the internal 0.488V reference level. Set the
adjustable reset threshold with an external resistor-divider
RSTIN
network. Connect RSTIN to V 1 if unused.
CC
Voltage Input 2. Power supply and input for the primary µP
voltage reset monitor.
5
V
1
CC
Power-Fail Comparator Input. PFO is asserted when PFI is
below 0.488V. PFO is deasserted without any reset timeout
period when PFI goes above 0.488V. Connect PFI to an
external resistor network to set the desired monitor
threshold.
—
—
—
—
—
—
—
—
4
3
PFI
Power-Fail Comparator Output, Open Drain Active Low. PFO
is asserted when PFI is below 0.488V.
PFO
V
1 Power-OK Output, Open Drain Active High. POK1
CC
remains low as long as V 1 is below V 1. POK1 output
CC
TH
goes high after V 1 exceeds V 1 for the POK1 timeout
CC
TH
—
—
—
3
—
POK1
period. POK1 logic is independent of the MR or V 2 inputs.
CC
The output can be used to control V 1-to-V 2 supply
CC
CC
sequencing.
8
_______________________________________________________________________________________
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
Table 1. Reset Voltage Threshold Suffix Guide for MAX6736/MAX6737/MAX6740/
MAX6741/MAX6743/MAX6744
PART NO.
SUFFIX
( _ _ )
V
1 NOMINAL
VOLTAGE
V
2 NOMINAL
CC
VOLTAGE
PART NO.
SUFFIX
( _ _ )
V
1 NOMINAL
VOLTAGE
V
2 NOMINAL
CC
VOLTAGE
CC
CC
THRESHOLD (V)
THRESHOLD (V)
THRESHOLD (V)
THRESHOLD (V)
RD
ZW
ZI
2.625
0.788
LT
MS
MR
TZ
4.625
4.375
4.375
3.075
3.075
3.075
3.075
3.075
2.925
2.925
2.925
2.925
2.925
2.625
2.625
2.625
2.625
3.075
2.925
2.625
2.313
1.665
1.388
1.110
0.833
2.188
1.575
1.313
1.050
0.788
2.188
1.575
1.313
1.050
2.313
1.665
2.313
1.388
ZG
ZE
2.313
1.110
2.313
0.833
TW
TI
YV
2.188
1.575
TG
TE
YH
YF
2.188
1.313
2.188
1.050
YD
WT
WI
2.188
0.788
SY
SV
SH
SF
1.665
3.075
1.665
1.388
WG
WE
VR
VH
VF
1.665
1.110
1.665
0.833
SD
RY
RV
RH
RF
1.575
2.625
1.575
1.313
1.575
1.050
VD
1.575
0.788
Note: Standard versions, shown in bold, are available in the D3 timeout option only. Samples are typically held on standard versions
only. There is a 10,000-piece order increment on nonstandard versions. Other threshold voltage combinations may be available;
contact factory for availability.
Table 2. Reset Voltage Threshold Suffix
Guide for MAX6738/MAX6739/MAX6742/
MAX6745
Table 3. V
Guide
Timeout Period Suffix
CC
TIMEOUT
PERIOD
SUFFIX
ACTIVE TIMEOUT PERIOD
PART NO.
SUFFIX
( _ )
V
1 NOMINAL
VOLTAGE
CC
MIN (ms)
MAX (ms)
THRESHOLD (V)
D3
D7
150
300
L
M
T
4.625
4.375
3.075
2.925
2.625
2.313
2.188
1.665
1.575
1200
2400
S
R
Z
Y
W
V
Note: Standard versions, shown in bold, are available in the
D3 timeout option only. Samples are typically held on standard
versions only. There is a 10,000-piece order increment on non-
standard versions. Other threshold voltages may be avail-
able; contact factory for availability.
_______________________________________________________________________________________
9
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
V
1
CC
V
1
TH
GND
POK1
GND
t
POKP
V
2
CC
V
2
TH
GND
MR
SWITCH
BOUNCE
SWITCH
BOUNCE
GND
RESET
GND
t
RP
t
MRP
Figure 1. Timing Diagram
Reset Output
Detailed Description
The MAX6736–MAX6745 provide an active-low reset out-
Supply Voltages
put (RESET). RESET is asserted when the voltage at
The MAX6736–MAX6745 µP supervisory circuits main-
tain system integrity by alerting the µP to fault condi-
tions. These devices are optimized for systems that
monitor two or three supply voltages. The reset output
either V 1 or V 2 falls below the voltage threshold
CC
CC
level, RSTIN drops below the threshold, or MR is pulled
low. Once reset is asserted, it stays low for the reset time-
out period. If V 1, V 2, or RSTIN goes below the reset
CC
CC
state is guaranteed to remain valid while either V 1 or
CC
threshold before the reset timeout period is completed,
the internal timer restarts. The MAX6736/MAX6738/
MAX6740/MAX6741/MAX6742 have open-drain reset out-
puts, while the MAX6737/MAX6739/MAX6743/MAX6744/
MAX6745 have push-pull reset outputs (Figure 1).
V
2 is above 1.2V.
CC
Threshold Levels
The MAX6736/MAX6737/MAX6740/MAX6741/MAX6743/
MAX6744 input voltage threshold combinations are indi-
cated by a two-letter code in Table 1. The MAX6738/
MAX6739/MAX6742/MAX6745 input voltage thresholds
are indicated by a one-letter code in Table 2. Contact the
factory for the availability of other voltage thresholds.
The MAX6740/MAX6741/MAX6742 include a RESET
output with a manual reset detect function. The open-
drain RESET output has an internal 50kΩ pullup to
V
1. The RESET output is low while the output is
CC
pulled to GND and remains low for at least the manual
reset timeout period after the external GND pulldown is
10 ______________________________________________________________________________________
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
SWITCH
BOUNCE
SWITCH
BOUNCE
SWITCH
BOUNCE
SWITCH
BOUNCE
OPEN
PUSHBUTTON
SWITCH
CLOSED
V
CC
1
t
t
t
t
MRP
DEB
DEB
MRP
RESET
GND
Figure 2. MAX6740/MAX6741/MAX6742 Manual Reset Timing Diagram
released. The manual reset detect function is internally
cally 488mV. Connect a resistor-divider network to the
circuit as shown in Figure 3 to establish an externally
debounced for the t
timeout period, so the output
DEB
can be connected directly to a momentary pushbutton
switch, if desired (Figure 2).
controlled threshold voltage, V
.
EXT_TH
V
= 0.488V((R1 + R2) / R2)
EXT_TH
Manual Reset Input
Many microprocessor-based products require manual
reset capability, allowing the operator, a test techni-
cian, or external logic circuitry to initiate a reset while
the monitored supplies remain above their reset thresh-
olds. The MAX6736–MAX6739 have a dedicated
active-low MR input. The RESET is asserted low while
MR is held low and remains asserted for the manual
reset timeout period after MR returns high. The MR
Low leakage current at RSTIN allows the use of large-
valued resistors, resulting in reduced power consump-
tion of the system.
Power-Fail Comparator
PFI is the noninverting input to an auxiliary comparator. A
488mV internal reference (V
-
) is connected to the
TH PFI
inverting input of the comparator. If PFI is less than
488mV, PFO is asserted low. PFO deasserts without a
timeout period when PFI rises above the externally set
threshold. Common uses for the power-fail comparator
include monitoring for low battery conditions or a failing
DC-DC converter input voltage (see the Typical
Application Circuits). The asserted PFO output can place
a system in a low-power suspend mode or support an
input has an internal 1.5kΩ pullup resistor to V 1 and
CC
can be left unconnected if not used. MR can be driven
with CMOS logic levels, open-drain/open-collector out-
puts, or a momentary pushbutton switch to GND to cre-
ate a manual reset function.
Adjustable Input Voltage
The MAX6738/MAX6739 and MAX6740/MAX6743 pro-
vide an additional input to monitor a second or third
system voltage. The threshold voltage at RSTIN is typi-
orderly system shutdown before monitored V
voltages
CC
drop below the reset thresholds. Connect PFI to an exter-
nal resistor-divider network as shown in Figure 4 to set
the desired trip threshold. Connect PFI to V 1 if unused.
CC
Applications Information
Interfacing to the µP with
Bidirectional Reset Pins
V
EXT_TH
MAX6738
MAX6739
MAX6740
MAX6743
Most microprocessors with bidirectional reset pins can
interface directly to open-drain RESET output options.
Systems simultaneously requiring a push-pull RESET
output and a bidirectional reset interface can be in
logic contention. To prevent contention, connect a
4.7kΩ resistor between RESET and the µP’s reset I/O
port as shown in Figure 5.
R1
R2
RSTIN
GND
Figure 3. Monitoring an Additional Voltage
______________________________________________________________________________________ 11
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
shown in Figure 6. Select the values of R1, R2, and R3
A) V IS POSITIVE
such that PFI sees V
(488mV) when V falls to
EXT
IN
TH-PFI
its power-fail trip point (V
) and when V
rises to
EXT
FAIL
its power-good trip point (V
). The hysteresis win-
GOOD
V
EXT_TH
MAX6742
MAX6745
dow extends between the specified V
and V
GOOD
FAIL
R1 + R2
R2
V
= V
TH-PFI
EXT_TH
( )
thresholds. R3 adds the additional hysteresis by sink-
ing current from the R1/R2 divider network when the
PFO output is logic low and sourcing current into the
network when PFO is logic high. R3 is typically an order
of magnitude greater than R1 or R2.
R1
R2
PFI
PFO
GND
The current through R2 should be at least 1µA to ensure
that the 10nA (max) PFI input current does not significant-
ly shift the trip points. Therefore, for most applications:
R2 < V
/ 1mA < 0.488V / 1mA < 488kΩ
TH-PFI
B) V IS NEGATIVE
IN
PFO is an open-drain output requiring an external
pullup resistor, R4. Select R4 to be less than 1% of R3.
V
R
1
1
1
CC
1
(V
)
+
TH-PFI
-
V
= R
2
V
CC
EXT_TH
( )(R )
V
V
V
= DESIRED V
GOOD VOLTAGE THRESHOLD
R
2
GOOD
EXT
MAX6742
MAX6745
V
PFI
= 488mV
= DESIRED V
FAIL VOLTAGE THRESHOLD
FAIL
EXT
R1
R2
= V
(FOR OPEN-DRAIN PFO)
PU
PULLUP
PFI
PFO
R2 = 488kΩ (FOR >1µA R2 CURRENT)
GND
V
EXT_TH
V
(V
- V
(
TH-PFI GOOD FAIL
)
V
- V
−
(
GOOD
TH−PFI
)
V
PU
R1 = R2
Figure 4. Using Power-Fail Input to Monitor an Additional
Power Supply
V
TH - PFI
R3 = (R1 x V ) / (V
PU
- V
)
FAIL
Adding Hysteresis to the
Power-Fail Comparator
The power-fail comparator has a typical input hystere-
sis of 2.5mV. This is sufficient for most applications in
which a power-supply line is being monitored through
an external voltage-divider. If additional noise margin is
desired, connect a resistor between PFO and PFI, as
GOOD
R4 ≤ 0.01 x R3
Power Sequencing Applications
Many dual-voltage processors/ASICs require specific
power-up/power-down sequences for the I/O and core
supplies.
V
PULLUP
R3
RESET TO OTHER SYSTEM COMPONENTS
V
1 V 2
CC CC
V
GOOD
V
FAIL
V
IN
PFO
MAX6737
MAX6739
MAX6743
MAX6744
MAX6745
V
MAX6742
MAX6745
EXT
µP
R1
R2
R4
4.7kΩ
V
V
2
1
RESET
RESET
CC
PFI
PFO
CC
V
V
V
= DESIRED V GOOD VOLTAGE THRESHOLD
EXT
GOOD
FAIL
OH
= DESIRED V FAIL VOLTAGE THRESHOLD
EXT
= V 1 (FOR PUSH-PULL PFO)
CC
R2 = 200kΩ (FOR > 2.5µA R2 CURRENT)
R1 = R2 ((V - V ) - (V )(V
- V ) / V ) / V
FAIL PU TH-PFI
GOOD
R3 = (R1 x V ) / (V
TH-PFI
- V )
FAIL
TH-PFI GOOD
GND
GND
GND
OH
GOOD
Figure 6. Adding Hysteresis to Power Fail for Push-Pull PFO
12 ______________________________________________________________________________________
Figure 5. Interfacing to µPs with Bidirectional Reset I/O
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
The MAX6741/MAX6744 offer a V 1 POK (POK1) ideal
Transient Immunity
CC
for V 1-to-V 2 sequencing. POK1 remains low as
The MAX6736–MAX6745 supervisors are relatively
CC
CC
long as V 1 is below its V 1 threshold. When V 1
immune to short-duration falling V
transients (glitch-
CC
TH
CC
), the
CC
exceeds V 1 for the POK1 timeout period (t
es). It is usually undesirable to reset the µP when V
TH
POKP
CC
open-drain POK1 output is deasserted. The POK1 output
experiences only small glitches. The Typical Operating
Characteristics show Maximum V 1/V 2 Transient
can then enable the V 2 power supply (use an external
CC
CC
CC
POK1 pullup resistor). RESET is deasserted when both
Duration vs. Reset Threshold Overdrive, for which reset
pulses are not generated. The graph shows the maxi-
V
CC
1 and V 2 remain above their selected thresholds
CC
for the reset timeout period (t ). The POK1 output can
mum pulse width that a falling V
transient might typi-
RP
CC
be used for I/O before core or core before I/O sequenc-
ing, depending on the selected V 1/V 2 thresholds.
cally have without causing a reset pulse to be issued.
As the amplitude of the transient increases, the maxi-
mum allowable pulse width decreases. A 0.1µF bypass
CC
CC
See the Typical Application Circuit and Figure 1.
capacitor mounted close to the V
tional transient immunity.
pin provides addi-
CC
Monitoring a Negative Voltage
The power-fail comparator can be used to monitor a
negative supply voltage using the circuit shown in
Figure 4. When the negative supply is valid, PFO is low.
When the negative supply voltage drops, PFO goes
high. The circuit’s accuracy is affected by the PFI
Chip Information
TRANSISTOR COUNT: 249
PROCESS: BiCMOS
threshold tolerance, V , R1, and R2.
CC
Functional Diagram
V
CC
1
MAX6736–
MAX6745
PFO
POK1
DELAY
V 1
CC
V 2
CC
RSTIN/PFI
RESET
TIMEOUT
PERIOD
RESET
OUTPUT
RESET
V 2
CC
V
CC
1
MR
PULLUP
V 1
CC
0.488V
1.23V
MR
______________________________________________________________________________________ 13
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
Selector Guide (continued)
POWER-FAIL
INPUT/
OUTPUT
VOLTAGE
MONITORS
OPEN-DRAIN
PUSH-PULL
MANUAL
RESET
POK
OUTPUT
RSTIN
INPUT
PART
RESET
RESET
MAX6739
MAX6740
MAX6741
MAX6742
MAX6743
MAX6744
MAX6745
1 fixed, 1 adj
2 fixed, 1 adj
2 fixed
—
X*
X*
X*
—
—
—
X
—
—
—
X
X
—
—
—
X
—
—
X
X
X
X*
X*
X*
—
—
—
—
—
X
1 fixed
—
—
X
2 fixed, 1adj
2 fixed
—
—
X
X
—
—
1 fixed
X
—
*Manual reset detect on RESET output.
Typical Application Circuits
DC/DC
CONVERTER
UNREGULATED
DC
IN
OUT
V
BATT
IN
OUT
DC/DC
CONVERTER
IN
OUT
DC/DC
CONVERTER
SHDN
V
CC
V 1
CC
PFO
V 2
CC
V 1
CC
CORE
SUPPLY SUPPLY
I/O
MAX6742
µP
RESET
PFI
RESET
GND
µP
MAX6741
GND
POK1
RESET
RESET
GND
PUSHBUTTON
SWITCH
GND
PUSHBUTTON
SWITCH
14 ______________________________________________________________________________________
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
Pin Configurations
TOP VIEW
RESET
GND
RESET
GND
MR
1
2
3
5
4
V
1
RESET
GND
1
2
3
5
4
V
1
2
CC
CC
CC
1
2
3
5
4
V
1
2
CC
CC
MAX6738
MAX6739
MAX6740
MAX6743
MAX6736
MAX6737
RSTIN
RSTIN
V
MR
V
SC70
SC70
SC70
RESET
GND
1
5
4
V
1
2
RESET
GND
PFO
1
2
3
5
V 1
CC
CC
MAX6741
MAX6744
MAX6742
MAX6745
2
3
POK1
V
CC
4
PFI
SC70
SC70
Ordering Information (continued)
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
5 SC70-5
5 SC70-5
5 SC70-5
5 SC70-5
5 SC70-5
5 SC70-5
5 SC70-5
5 SC70-5
MAX6738XK_D_-T
MAX6739XK_D_-T
MAX6740XK_ _D_-T
MAX6741XK_ _D_-T
MAX6742XK_D_-T
MAX6743XK_ _D_-T
MAX6744XK_ _D_-T
MAX6745XK_D_-T
Note: The first “_ _” or “_” are placeholders for the threshold
voltage levels of the devices. Desired threshold levels are set
by the part number suffix found in Tables 1 and 2. The “_” after
the D is a placeholder for the reset timeout period suffix found
in Table 3. For example, the MAX6736XKLTD3-T is a dual-volt-
age supervisor V 1 = 4.625V, V 2 = 3.075V, and a 150ms
TH
TH
minimum reset timeout period. All devices are available in
tape-and-reel only. There is a 2500-piece minimum order
increment for standard versions (see Table 1). Sample stock is
typically held on standard versions only. Nonstandard versions
require a minimum order increment of 10,000 pieces. Contact
factory for availability.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
______________________________________________________________________________________ 15
Low-Power Dual-/Triple-Voltage SC70 µP
Supervisory Circuits
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.)
PACKAGE OUTLINE, 5L SC70
1
21-0076
C
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.
16 ____________________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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