MAX6705ATKA+T Maxim Integrated Products, MAX6705ATKA+T Datasheet - Page 9

• Manufacturer Part Number: MAX6705ATKA+T
• Description: IC SUPERVISOR MPU LV SOT23-8
• Manufacturer: Maxim Integrated Products
• Type: Multi-Voltage Supervisorr

Specifications of MAX6705ATKA+T

• Number Of Voltages Monitored: 2
• Output: Push-Pull, Totem Pole
• Reset: Active Low
• Reset Timeout: 140 ms Minimum
• Voltage - Threshold: 3.08V, Adj
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-8
• Monitored Voltage: 2.5 V, 3 V, 3.3 V, 5 V
• Undervoltage Threshold: 3 V
• Overvoltage Threshold: 3.15 V
• Output Type: Active Low, Push-Pull
• Manual Reset: Resettable
• Watchdog: Watchdog
• Battery Backup Switching: No Backup
• Power-up Reset Delay (typ): 300 ms
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 1.2 V
• Supply Current (typ): 12 uA
• Maximum Power Dissipation: 714 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX6701(A)/MAX6702(A)/MAX6703(A) include two
adjustable reset inputs for monitoring up to a total of
three system voltages (including V
for the monitored RST_IN supplies are externally set
with resistor-divider networks (Figure 8). The reset out-
put is asserted if any of the monitored supplies (V
RST_IN1, or RST_IN2) go below its specified threshold
and remains asserted for the reset timeout period after
all supplies are above their thresholds.
When V
RESET output no longer sinks current—it becomes an
open circuit. High-impedance CMOS logic inputs can
drift to undetermined voltages if left undriven. If a pull-
down resistor is added to the RESET pin as shown in
Figure 9, any stray charge or leakage currents are
drained to ground, holding RESET low. A resistor value
(R1) is not critical; 100kΩ is large enough not to load
RESET and small enough to pull RESET to ground. This
application works for push-pull output only (not for
open-drain resets).
Figure 7. MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX6705(A)/
MAX6706(A)/MAX6707(A) Watchdog Timing
Low-Voltage, SOT23 µP Supervisors with Power-
(RESET)
( ) ARE FOR MAX6702(A)/MAX6706(A) ONLY.
Fail In/Out, Manual Reset, and Watchdog Timer
RESET
WDO
WDI
MR
+5V
t
+5V
+5V
+5V
+5V
CC
WDI
0V
0V
0V
0V
0V
falls below 1V, the MAX6701–MAX6708
Applications Information
_______________________________________________________________________________________
t
WD
Output Down to V
Ensuring a Valid
t
WD
CC
). The thresholds
Reset Input
t
RP
t
WD
RESET
CC
= 0
CC
,
Other systems can be monitored by connecting a volt-
age-divider to PFI and adjusting the ratio appropriately.
In noisy systems, a capacitor between PFI and GND
reduces the power-fail circuit’s sensitivity to high-fre-
quency noise on the line being monitored. Reset can
be asserted on other voltages in addition to the V
supply line. Connect PFO to MR to initiate a reset out-
put pulse when PFI drops below 0.62V. Figure 10
shows the MAX6704–MAX6708 configured to assert a
reset output when the secondary supply falls below the
reset threshold.
Connect WDO to MR to force a watchdog timeout to gen-
erate a reset pulse for only the reset timeout period on the
MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX6705(A)/
MAX6706(A)/MAX6707(A). When the MAX6704 watch-
dog times out, reset outputs are automatically asserted
(no external connections required). For the MAX6701/
MAX6702/MAX6703/MAX6705/MAX6706/MAX6707 non-A
versions, do not connect WDO to MR; this creates a
locked condition.
Figure 8. Calculating Adjustable Voltage Thresholds
V
EXTERNAL
V
WHERE V
EXT-TH
Monitoring Other System Voltages
=
R1
R2
(
EXT-TH
1 + R1
R2
IS THE EXTERNAL VOLTAGE TRIP LEVEL.
)
x 0.62V
from Watchdog Overflow
PFI, RST_IN1, OR RST_IN2
0.62V
MAX6701(A)–
MAX6708
Generating a Reset
R1 = R2 x
(
V
0.62
EXT-TH
- 1
)
CC
9