MAX16059ATT21+T Maxim Integrated Products, MAX16059ATT21+T Datasheet - Page 7

• Manufacturer Part Number: MAX16059ATT21+T
• Description: IC SUPERVISOR OD 2.1V 6-TDFN
• Manufacturer: Maxim Integrated Products
• Type: Simple Reset/Power-On Resetr

Specifications of MAX16059ATT21+T

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: Adjustable/Selectable
• Voltage - Threshold: 2.1V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 6-TDFN Exposed Pad
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX16056–MAX16059 are ultra-low-current 125nA
(typ) µP supervisory circuits that monitor a single sys-
tem supply voltage. These devices assert an active-low
reset signal whenever the V
below the factory-trimmed reset threshold, manual
reset is pulled low, or the watchdog timer runs out
(MAX16056/MAX16058). The reset output remains
asserted for an adjustable reset timeout period after
V
watchdog delay periods are adjustable using external
capacitors.
The MAX16056–MAX16059 µP supervisory circuits assert
a reset to prevent code-execution errors during power-
up, power-down, and brownout conditions. The reset
output is guaranteed to be valid for V
When V
output asserts low. Once V
old plus the hysteresis, an internal timer keeps the reset
output asserted for the capacitor-adjusted reset timeout
period (t
deasserts (see Figure 1). The reset function features
immunity to power-supply voltage transients.
Many µP-based products require manual-reset capabil-
ity, allowing the operator, a test technician, or external
logic circuitry to initiate a reset. The MAX16056–
MAX16059 feature an MR input. A logic-low on MR
asserts a reset. RESET remains asserted while MR is
low and for the timeout period, t
high. Connect MR to V
with CMOS logic levels or with open-drain/collector out-
puts (with a pullup resistor). Connect a normally open
momentary switch from MR to GND and a resistor from
MR to V
nal debounce circuitry is not required. If MR is driven
by long cables or the device is used in a noisy environ-
ment, connect a 0.1µF capacitor from MR to GND to
provide additional noise immunity.
CC
rises above the reset threshold. The reset and
CC
CC
RP
125nA Supervisory Circuits with Capacitor-
to implement a manual-reset function; exter-
falls below the reset threshold, the RESET
), then after this interval the reset output
Adjustable Reset and Watchdog Timeouts
_______________________________________________________________________________________
Detailed Description
CC
Manual-Reset Input ( MR )
if unused. MR can be driven
CC
CC
exceeds the reset thresh-
supply voltage drops
RP
CC
, after MR returns
RESET Output
down to 1.1V.
The MAX16056/MAX16058’s watchdog timer circuitry
monitors the µP’s activity. If the µP does not toggle
(high-to-low) the watchdog input (WDI) within the
capacitor-adjustable watchdog timeout period (t
RESET asserts for the reset timeout period (t
internal watchdog timer is cleared by: 1) any event that
asserts RESET, by 2) a falling transition at WDI (that
can detect pulses as short as 150ns) or by 3) a transi-
tion (high-to-low or low-to-high) at WDS. While reset is
asserted, the watchdog timer remains cleared and
does not count. As soon as reset deasserts, the watch-
dog timer resumes counting.
There are two modes of watchdog operation, normal
mode and extended mode. In normal mode (Figure 2),
the watchdog timeout period is determined by the
value of the capacitor connected between SWT and
ground. In extended mode (Figure 3), the watchdog
timeout period is multiplied by 128. For example, in
extended mode, a 0.33µF capacitor gives a watchdog
timeout period of 217s (see Table 2). To disable the
watchdog timer function, connect SWT to ground.
When V
external SWT capacitor is sampled after RESET goes
high. When sampling is finished, the capacitor value is
stored in the device and is used to set watchdog time-
out. If RESET goes low before sampling is finished, the
device interrupts sampling, and sampling is restarted
when RESET goes high again.
If the external SWT capacitor is less than 470pF, the
sampling result sets the watchdog timeout to zero. This
causes the watchdog to assert RESET continuously
after sampling is finished. If a PCB manufacturing
defect caused the connection to C
the capacitance is very low and RESET is continuously
asserted. If the external SWT capacitor is greater than
0.47µF, the sampling result sets the watchdog timeout
to be infinite, disabling the watchdog function.
CC
ramps above V
TH
+ V
HYST
Watchdog Timer
SWT
, the value of the
to be broken,
RP
). The
WD
),
7