MAX16056_13 Datasheet, PDF (6/17 Pages) Maxim Integrated Products – 125nA Supervisory Circuits with Capacitor- Adjustable Reset and Watchdog Timeouts

MAX16056–MAX16059
125nA Supervisory Circuits with Capacitor-
Adjustable Reset and Watchdog Timeouts
Pin Description
PIN
MAX16056/ MAX16057/
MAX16058 MAX16059
1
1
2
2
NAME
FUNCTION
RESET
Push-Pull or Open-Drain Reset Output. RESET asserts whenever V_CC drops below the
selected reset threshold voltage (V_TH) or manual reset is pulled low. RESET remains low
for the reset timeout period after all reset conditions are deasserted, and then goes high.
The watchdog timer triggers a reset pulse (t_RP) whenever a watchdog fault occurs
(MAX16056/MAX16058).
GND Ground
Watchdog Timeout Input. Connect a capacitor between SWT and GND to set the basic
watchdog timeout period (t_WD). Determine the period by the formula t_WD = Floor[C_SWT x
3
—
SWT ^{5.15 x 106/6.4ms] x 6.4ms + 3.2ms (Note 6) with tWD in seconds and CSWT in Farads, or}
use Table 2. Extend the basic watchdog timeout period by using the WDS input. Connect
SWT to ground to disable the watchdog timer function. The value of the capacitor must be
between 2275pF and 0.54µF to have a valid watchdog timeout period.
Manual-Reset Input. Drive MR low to manually reset the device. RESET remains asserted
4
3
MR for the reset timeout period after MR is released. There is no internal pullup on MR. MR
must not be left unconnected. Connect MR to V_CC if not used.
Reset Timeout Input. Connect a capacitor from SRT to GND to select the reset timeout
5
4
SRT
period. Determine the period as follows: t_RP = 5.15 x 10⁶ x C_SRT with t_RP in seconds and
C_SRT in Farads, or use Table 2. The value of the capacitor must be between 39pF and
4.7µF.
Watchdog Input. A falling transition must occur on WDI within the selected watchdog
6
—
WDI
timeout period or a reset pulse occurs. The watchdog timer clears when a falling transition
occurs on WDI or whenever RESET is asserted. Connect SWT to ground to disable the
watchdog timer function.
7
—
WDS
8
6
V_CC
—
5
N.C.
—
—
EP
Note 6: Floor: take the integral value.
Watchdog Select Input. WDS selects the watchdog timeout mode. Connect WDS to
ground to select normal mode. The watchdog timeout period is t_WD. Connect WDS to V_CC
to select extended mode, multiplying the basic timeout period (t_WD) by a factor of 128. A
change in the state of WDS clears the watchdog timer.
Supply Voltage. V_CC is the power-supply input and the input for fixed threshold V_CC
monitor. For noisy systems, bypass V_CC with a 0.1µF capacitor to GND.
No Connection. Not internally connected.
Exposed Pad. Connect EP to GND or leave unconnected.
6
Maxim Integrated