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PDF MAX691A Data sheet ( Hoja de datos )
| Número de pieza | MAX691A | |
| Descripción | Microprocessor Supervisory Circuits | |
| Fabricantes | Maxim Integrated | |
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19-0094; Rev 7a; 12/96
Microprocessor Supervisory Circuits
_______________General Description
The MAX691A/MAX693A/MAX800L/MAX800M micro-
processor (µP) supervisory circuits are pin-compatible
upgrades to the MAX691, MAX693, and MAX695. They
improve performance with 30µA supply current, 200ms
typ reset active delay on power-up, and 6ns chip-
enable propagation delay. Features include write pro-
tection of CMOS RAM or EEPROM, separate watchdog
outputs, backup-battery switchover, and a RESET out-
put that is valid with VCC down to 1V. The MAX691A/
MAX800L have a 4.65V typical reset-threshold voltage,
and the MAX693A/MAX800M’s reset threshold is 4.4V
typical. The MAX800L/MAX800M guarantee power-fail
accuracies to ±2%.
________________________Applications
Computers
Controllers
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring
__________Typical Operating Circuit
5V
REGULATOR
+8V
0.1µF
1N4148
0.47F*
NO
CONNECTION
3
VCC
1 VBATT
5
BATT ON VOUT 2
CE OUT 12
MAX691A
CMOS RAM
9
PFI
MAX693A
MAX800L
CE IN 13
ADDRESS
DECODE
MAX800M
4 GND
11
WDI
7 OSC IN
PFO 10
8 OSC SEL
RESET 15
LOW LINE WDO
A0-A15
I/O
µP
NMI
RESET
6 14
AUDIBLE
ALARM
*MaxCap
SYSTEM STATUS INDICATORS
____________________________Features
o 200ms Power-OK/Reset Timeout Period
o 1µA Standby Current, 30µA Operating Current
o On-Board Gating of Chip-Enable Signals,
10ns Max Delay
o MaxCap™ or SuperCap™ Compatible
o Guaranteed RESET Assertion to VCC = +1V
o Voltage Monitor for Power-Fail or Low-Battery
Warning
o Power-Fail Accuracy Guaranteed to ±2%
(MAX800L/M)
o Available in 16-Pin Narrow SO and Plastic
DIP Packages
______________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX691ACPE
0°C to +70°C
16 Plastic DIP
MAX691ACSE
0°C to +70°C
16 Narrow SO
MAX691ACWE
0°C to +70°C
16 Wide SO
MAX691AC/D
0°C to +70°C
Dice*
MAX691AEPE
-40°C to +85°C
16 Plastic DIP
MAX691AESE
-40°C to +85°C
16 Narrow SO
MAX691AEWE -40°C to +85°C
16 Wide SO
MAX691AEJE
-40°C to +85°C
16 CERDIP
MAX691AMJE -55°C to +125°C 16 CERDIP
Ordering Information continued on last page.
* Dice are specified at TA = +25 °C, DC parameters only.
__________________Pin Configuration
TOP VIEW
VBATT 1
VOUT 2
VCC 3
GND 4
BATT ON 5
LOW LINE 6
OSC IN 7
OSC SEL 8
MAX691A
MAX693A
MAX800L
MAX800M
16 RESET
15 RESET
14 WDO
13 CE IN
12 CE OUT
11 WDI
10 PFO
9 PFI
DIP/SO
SuperCap is a registered trademark of Baknor Industries. MaxCap is a registered trademark of The Carborundum Corp.
________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
1 page  
Microprocessor Supervisory Circuits
__________________________________________Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
VCC SUPPLY CURRENT
vs. TEMPERATURE
(NORMAL OPERATING MODE)
36
VCC = 5V
VBATT = 2.8V
34 PFI, CE IN = 0V
32
30
28
BATTERY SUPPLY CURRENT
vs. TEMPERATURE
(BATTERY-BACKUP MODE)
2
VCC = 5V
VBATT = 2.8V
NO LOAD
1.5
1
0.5
CHIP-ENABLE ON-RESISTANCE
vs. TEMPERATURE
120
VCC = 4.75V
VBATT = 2.8V
VCE IN = VCC/2
100
80
60
26
-60 -30
0 30 60 90 120 150
TEMPERATURE (°C)
VBATT to VOUT ON-RESISTANCE
vs. TEMPERATURE
20
VBATT = 2.0V
15
VBATT = 2.8V
10
VBATT = 4.5V
5
-60 -30
VCC = 0V
0 30 60 90 120 150
TEMPERATURE (°C)
RESET THRESHOLD
vs. TEMPERATURE
4.75
VBATT = 2.8V
4.70
4.65
MAX691A
4.60 MAX800L
4.55
4.50
4.45
4.40
MAX693A
4.35 MAX800M
4.30
-60 -30
0 30 60 90 120 150
TEMPERATURE (°C)
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
VCC to VOUT ON-RESISTANCE
vs. TEMPERATURE
1.2
VCC = 5V,
VBATT = 0V
1.1
1.0
0.9
0.8
0.7
0.6
-60 -30
0 30 60 90 120 150
TEMPERATURE (°C)
RESET OUTPUT RESISTANCE
vs. TEMPERATURE
600
500
VCC = 5V, VBATT = 2.8V
SOURCING CURRENT
400
300
200
100 VCC = 0V, VBATT = 2.8V
SINKING CURRENT
0
-60 -30
0 30 60 90
TEMPERATURE (°C)
120 150
40
-60 -30
1.50
0 30 60 90 120 150 180
TEMPERATURE (°C)
PFI THRESHOLD
vs. TEMPERATURE
1.25
1.00
0.75
0.50
0.25
0
-60 -30
VCC = +5V,
VBATT = 0V
NO LOAD ON PFO
0 30 60 90 120 150
TEMPERATURE (°C)
RESET DELAY
vs. TEMPERATURE
230
VCC = 0V TO 5V STEP
VBATT = 2.8V
220
210
200
190
180
170
-60 -30
0 30 60 90 120 150
TEMPERATURE (°C)
_______________________________________________________________________________________ 5
5 Page 
Microprocessor Supervisory Circuits
2.8V
50Ω
OUTPUT
IMPEDANCE
+5V
VBATT VCC
MAX691A
MAX693A
MAX800L
MAX800M
CE IN
CE OUT
GND
CLOAD
2.0V to 5.5V
+5V
VCC
VBATT
MAX691A
MAX693A
PFI
MAX800L
MAX800M
PFO
GND
LOW BATT
Figure 6. CE Propagation Delay Test Circuit
Figure 7. Low-Battery Indicator
Table 2. Input and Output Status in Battery-Backup
Mode
PIN NAME
STATUS
1 VBATT Supply current is 1µA max.
2
VOUT
VOUT is connected to VBATT through an
internal PMOS switch.
3
VCC
Battery switchover comparator monitors
VCC for active switchover.
4 GND GND 0V, 0V reference for all signals.
5
BATT ON
Logic high. The open-circuit output is
equal to VOUT.
6 LOWLINE Logic low*
7 OSC IN OSC IN is ignored.
8 OSC SEL OSC SEL is ignored.
The power-fail comparator remains
9 PFI active in the battery-backup mode for
VCC ≥ VBATT - 1.2V typ.
The power-fail comparator remains
10
PFO
active in the battery-backup mode for
VCC ≥ VBATT - 1.2V typ. Below this volt-
age, PFO is forced low.
11 WDI Watchdog is ignored.
12
CE OUT
Logic high. The open-circuit voltage is
equal to VOUT.
13 CE IN High impedance
14
WDO
Logic high. The open-circuit voltage is
equal to VOUT.
15 RESET Logic low*
16 RESET High impedance*
* VCC must be below the reset threshold to enter battery-backup
mode.
Power-Fail Output
The Power-Fail Output (PFO) goes low when PFI goes
below 1.25V. It typically sinks 3.2mA with a saturation
voltage of 0.1V. With PFI above 1.25V, PFO is actively
pulled to VOUT.
Battery-Backup Mode
Two conditions are required to switch to battery-back-
up mode: 1) VCC must be below the reset threshold,
and 2) VCC must be below VBATT. Table 2 lists the sta-
tus of the inputs and outputs in battery-backup mode.
Battery On Output
The Battery On (BATT ON) output indicates the status
of the internal VCC/battery-switchover comparator,
which controls the internal VCC and VBATT switches.
For VCC greater than VBATT (ignoring the small hys-
teresis effect), BATT ON typically sinks 3.2mA at 0.1V
saturation voltage. In battery-backup mode, this termi-
nal sources approximately 10µA from VOUT. Use BATT
ON to indicate battery-switchover status or to supply
base drive to an external pass transistor for higher-cur-
rent applications (see Typical Operating Circuit).
Input Supply Voltage
The Input Supply Voltage (VCC) should be a regulated
5V. VCC connects to VOUT via a parallel diode and a
large PMOS switch. The switch carries the entire cur-
rent load for currents less than 250mA. The parallel
diode carries any current in excess of 250mA. Both the
switch and the diode have impedances less than 1Ω
each. The maximum continuous current is 250mA, but
power-on transients may reach a maximum of 1A.
______________________________________________________________________________________ 11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet MAX691A.PDF ] | |
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