MAX704MJA Maxim Integrated, MAX704MJA Datasheet - Page 4

• Manufacturer Part Number: MAX704MJA
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX703, MAX704r

Specifications of MAX704MJA

• Number Of Voltages Monitored: 1
• Monitored Voltage: 4.4 V
• Undervoltage Threshold: 4.25 V
• Overvoltage Threshold: 4.5 V
• Output Type: Active Low, Push-Pull
• Manual Reset: Resettable
• Watchdog: No Watchdog
• Battery Backup Switching: Backup
• Power-up Reset Delay (typ): 280 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: Through Hole
• Package / Case: CDIP-8
• Chip Enable Signals: No
• Maximum Power Dissipation: 640 mW
• Minimum Operating Temperature: - 55 C
• Power Fail Detection: Yes
• Supply Current (typ): 500 uA
• Supply Voltage - Min: 0 V

Low-Cost Microprocessor Supervisory
Circuits with Battery Backup
Figure 1. Block Diagram
4
V
BATT
V
MR
PIN
PFI
CC
1
2
3
4
5
6
7
8
_______________________________________________________________________________________
RESET
NAME
V
V
GND
V
PFO
PFI
MR
BATT
OUT
CC
BATTERY-SWITCHOVER
1.25V
CIRCUITRY
Supply Output for CMOS RAM. When V
channel MOSFET switch. When V
+5V Supply Input
Ground
Power-Fail Comparator Input. When PFI is less than 1.25V, PFO goes low; otherwise PFO remains high. Connect
PFI to GND or V
P ow er - Fai l C om p ar ator O utp ut. It g oes l ow and si nks cur r ent w hen P FI i s l ess than 1.25V ; other w i se P FO r em ai ns hi g h.
Manual Reset Input. Generates a reset pulse when pulled below 0.8V. This active-low input is TTL/CMOS
compatible and can be shorted to ground with a switch. It has an internal 250µA pullup current. Leave floating
when not used.
Reset Output. Remains low while V
It remains low for 200ms after V
Backup-Battery Input. When V
greater than V
repeated switching if V
1.25V
GND
CC
CC
. When V
when not used.
MAX703
MAX704
CC
GENERATOR
CC
falls slowly.
RESET
rises 20mV above V
CC
CC
CC
falls below the reset threshold, V
CC
rises above the reset threshold (Figure 2) or MR goes from low to high.
is below the reset threshold, the higher of V
is below the reset threshold (4.65V for the MAX703, 4.40V for the MAX704).
CC
V
RESET
PFO
OUT
is above the reset threshold, V
BATT
FUNCTION
Figure 2. Timing Diagram
RESET
*PFO DEPENDS ON PFI EXCEPT IN BATTERY-BACKUP MODE, WHERE PFO IS LOW.
, V
V
PFO*
V
+5V
+5V
+5V
+5V
OUT
0V
0V
0V
CC
0V
CC
is switched to V
V
3.0V
RST
BATT
is switched to V
OUT
OUT
connects to V
. The 40mV hysteresis prevents
CC
or V
OUT
BATT
Pin Description
CC
if V
is connected to V
through a p-
BATT
t
RST
V
is 20mV
BATT
= 3.0V
OUT
.