MAX6334UR18D2+T Maxim Integrated Products, MAX6334UR18D2+T Datasheet - Page 4

• Manufacturer Part Number: MAX6334UR18D2+T
• Description: IC MPU/RESET CIRC 1.80V SOT23-3
• Manufacturer: Maxim Integrated Products
• Type: Simple Reset/Power-On Resetr

Specifications of MAX6334UR18D2+T

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: 20 ms Minimum
• Voltage - Threshold: 1.8V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-3, TO-236-3, Micro3™, SSD3, SST3
• Monitored Voltage: 1.8 V, 2.5 V
• Undervoltage Threshold: 1.77 V
• Overvoltage Threshold: 1.83 V
• Output Type: Active Low, Open Drain
• Manual Reset: Not Resettable
• Watchdog: No Watchdog
• Battery Backup Switching: No Backup
• Power-up Reset Delay (typ): 40 ms
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 1 V
• Supply Current (typ): 3.3 uA
• Maximum Power Dissipation: 320 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
______________Applications Information
Since the RESET output on the MAX6334 is open-drain,
this device interfaces easily with µPs that have bidirec-
tional reset pins, such as the Motorola 68HC11.
Connecting the µP supervisor’s RESET output directly
to the microcontroller’s (µC’s) RESET pin with a single
pull-up resistor allows either device to assert reset
(Figure 1).
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, these devices are
relatively immune to short-duration, negative-going V
transients (glitches). The Typical Operating Characteristics
show the Maximum Transient Duration vs. Reset
Comparator Overdrive graph. The graph shows the maxi-
mum pulse width that a negative-going V
typically have without issuing a reset signal. As the ampli-
tude of the transient increases, the maximum allowable
pulse width decreases.
When V
operating voltage of 0.7V, push/pull-structured reset
sinking (or sourcing) capabilities decrease drastically.
High-impedance CMOS-logic inputs connected to the
RESET pin can drift to indeterminate voltages. This
does not present a problem in most cases, since most
µPs and circuitry do not operate at V
the MAX6333, where RESET must be valid down to 0,
adding a pull-down resistor between RESET and GND
removes stray leakage currents, holding RESET low
(Figure 2a). The pull-down resistor value is not critical;
100kΩ is large enough not to load RESET and small
enough to pull it low. For the MAX6332, where RESET
must be valid to V
between RESET and V
V
Since the MAX6334 has an open-drain, active-low out-
put, it typically uses a pull-up resistor. With this device,
RESET will most likely not maintain an active condition,
but will drift to a non-active level due to the pull-up
resistor and the reduced sinking capability of the open-
drain device. Therefore, this device is not recommend-
ed for applications where the RESET pin is required to
be valid down to V
4
CC
_______________________________________________________________________________________
falls below 0.7V (Figure 2b).
CC
Interfacing to µPs with Bidirectional
falls below 1V and approaches the minimum
Negative-Going V
Ensuring a Valid Reset Output
CC
CC
= 0.
CC
= 0, a 100kΩ pull-up resistor
will hold RESET high when
Down to V
CC
CC
CC
below 1V. For
Reset Pins
Transients
transient may
CC
= 0
CC
Table 1. Factory-Trimmed Reset
Thresholds*
* Factory-trimmed reset thresholds are available in approximately
100mV increments, with a ±1.8% room-temperature variance.
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
Figure 2. Ensuring Reset Valid Down to V
MAX633_UR25D_
MAX633_UR24D_
MAX633_UR23D_
MAX633_UR22D_
MAX633_UR21D_
MAX633_UR20D_
MAX633_UR19D_
MAX633_UR18D_
MAX633_UR17D_
MAX633_UR16D_
(a)
THRESHOLD
RESET-
SUFFIX
MAX6333
V
CC
GND
V
CC
MAX6334
RESET
GND
V
*ASSUMES HIGH-Z RESET INPUT TO THE µP
CC
RESET
MIN TYP MAX
2.46 2.50
2.36 2.40
2.26 2.30
2.16 2.20
2.06 2.10
1.96 2.00 2.04
1.87 1.90
1.77 1.80 1.83
1.67 1.70 1.73
1.57 1.60 1.63
100k
T
A
= +25°C
2.55
2.44
2.34
2.24
2.14
1.93
(b)
RESET
INPUT
MAX6332
T
CC
GND
MOTOROLA
MIN
2.43
2.33
2.23
2.13
2.04
1.94
1.84
1.75
1.65
1.55
A
V
68HCXX
CC
= -40°C to +125°C
GND
= 0
V
µP
RESET
CC
100k*
MAX
2.58
2.47
2.37
2.27
2.16
2.06
1.96
1.85
1.75
1.65