DS1830AS ,Reset Sequence PushbuttonFEATURES 5V (DS1830) or 3.3V (DS1830A) power-onPIN ASSIGNMENTreset Excellent for systems that nee ..
DS1831AS ,Multisupply MicroMonitor™FEATURESPIN ASSIGNMENT 5V power-on resetDS1831 3.3V power-on reset Two referenced comparators wi ..
DS1831BS ,Multisupply MicroMonitor™DS1831/A/BMultisupply Micromonitor
DS1831C ,3.3V/2.5V Multisupply MicromonitorFEATURESPIN ASSIGNMENT 2.5V power-on resetDS1831C 3.3V power-on reset Two referenced comparators ..
DS1831CS , 3.3V/2.5V Multi-Supply MicroMonitor
DS1831S ,Multisupply MicroMonitor™PIN DESCRIPTIONIN 5V Power Supply Input MPBRST Master Pushbutton (DS1831)5VTD Watchdog Time Delay S ..
DZ23C10 ,Zener DiodesDZ23C2V7–DZ23C51Vishay Telefunken300 mW Dual Surface Mount Zener Diodes
DZ23C15-7-F , 300mW DUAL SURFACE MOUNT ZENER DIODE
DZ23C16-7-F , 300mW DUAL SURFACE MOUNT ZENER DIODE
DZ23C18 ,Zener DiodesAbsolute Maximum RatingsT = 25
DS1830-DS1830AS
Reset Sequence Pushbutton
FEATURES5V (DS1830) or 3.3V (DS1830A) power-on
resetExcellent for systems that need power-on
resets in a consistent sequenceAsserts resets during power transientsPushbutton reset input for system overrideSelectable reset timingReduces need for discrete componentsPrecision temperature-compensated voltagereference8-pin DIP, 8-pin SO, or space saving 8-pin
µSOPOperating temperature of -40°C to +85°COpen-drain, active-low inputs
PIN ASSIGNMENT
PIN DESCRIPTION1 PBRST- Pushbutton Reset Input
2 TD- Time Delay Select Input
3 TOL- VCC Tolerance Select Input
4 GND- Ground
8 VCC- Power Supply
7 RST1- Reset 1 Output
6 RST2- Reset 2 Output
5 RST3- Reset 3 Output
DESCRIPTIONThe DS1830 Reset Sequencer monitors the power supply for an in-tolerance condition and the pushbutton
reset input for a manual reset. First a precision temperature-compensated reference and comparator circuitmonitors the status of the power supply and when an out-of-tolerance condition is detected, an internal
power fail signal is generated that forces the reset lines to go to an active state. If the power supply
returns to an in-tolerance condition, RST1will release followed by RST2 and finally RST3. Sequencing of
resets allows for systems to power-up in an orderly manner providing superior reliability.
DS1830/A
Reset Sequence Pushbutton
D1830/A
OPERATION — POWER MONITORThe DS1830 provides the functions of detecting out-of-tolerance conditions on a power supply andwarning a processor based system of impending power failure. When VCC is detected as out-of-toleranceall reset outputs will be forced active. When VCC returns to a valid state, RST1 will remain active for
period of time based on the condition of the TD input. Reset outputs RST2 and RST3 follow RST1, each
one at the proper delays for the condition of the TD input. All resets will remain in the inactive state
(high) until the next VCC out-of-tolerance condition or pushbutton reset. On power-up all resets are kept
active for an appropriate period determined by the status of the TD input after the power supply inputs
have reached the selected tolerance. This allows the power supply and system power to stabilize before
the reset sequences are released.
BLOCK DIAGRAM Figure 1
OPERATION — TOLERANCE SELECTThe DS1830/A provides a TOL input for individual customization of the DS1830x to specific application
requirements (see Table 1). For the tolerance selection, see Table 1 below. The TOL input is only
sampled while VCC is below the lowest potential trip value and can not be changed after the VCC voltageexceeds the lowest potential trip value.
TOL — TOLERANCE SELECT Table 1
D1830/A
OPERATION — PUSHBUTTON RESETThe DS1830 provides a pushbutton switch for manual reset control. When any of the DS1830/A resets
are not active (low) a reset cycle can be initiated by a pushbutton reset. The pushbutton reset is generatedby pulling the PBRST pin low for at least 1ms. When the push- button is held low all resets are forced
active. The reset will remain active until the pushbutton input is released and then will start a sequenced
time-out based on the condition of the TD input. The Pushbutton input is pulled high through an internal
40k� pull-up resistor and debounced via internal circuitry. See Figure 2 for an application example and
Figure 3 for the timing diagram.
PUSHBUTTON RESET Figure 2
TIMING DIAGRAM — PUSHBUTTON RESET Figure 3
OPERATION — TIME DELAY SELECTThe DS1830 provides an input to select three time delay characteristics for the reset outputs. The TD
input has 3 states high (VCC), low (ground) and no connect (N.C.). Table 2 details the minimum timing
based on the state of the TD input. If the TD input is connected to ground; RST1 will have a minimum
time delay of 10 ms after VCC is in tolerance. If the TD input is floated; RST1 will have a minimum time
delay of 20 ms after VCC is in tolerance. If the TD input is connected to VCC, RST1 will have a minimum
time delay of 50 ms after VCC is in tolerance. An oscillator and clock chain generate the reset timing witheach time delay based on the same device oscillator. The time delay for RST2 will be 5 times as long as
RST1 and RST3will be 10 times the duration of RST1.
TD CONTROL MINIMUM RESET TIMING Table 2
D1830/A
APPLICATION DIAGRAM — CASCADE DELAY CONFIGURATIONS Figure 4
Note 1: The RST3 output tied to the pushbutton reset would be pulled to VCC through the 40k� resistor in
the pushbutton input. If a stronger pull-up is required an additional pull-up resistor could be added.
Note 2: When using the cascade configuration, it is important that the TOL pins of the master and theslave are configured so that the master’s VCCTP is greater than the slave’s VCCTP. This will ensure that
when the master’s higher VCCTP is crossed, the resets will ripple through to the slave.
TIMING DIAGRAM — POWER-DOWN Figure 5MASTER
SLAVE
SEE NOTE 2
SEE NOTE 2
SEE NOTE 1
D1830/A
TIMING DIAGRAM — POWER-UP Figure 6
ABSOLUTE MAXIMUM RATINGS*Voltage on any Pin Relative toGround-0.5V to +6.0V
Operating Temperature-40°C to +85°C
Storage Temperature-55°C to +125°C
Soldering TemperatureSee IPC/JEDEC J-STD-020A
* This is a stress rating only and functional operation of the device at these or any other conditions above
those indicated in the operation sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS (-40°C to +85°C)
D1830/A
DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC = 1.0V to 5.5V)
AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC = 1.0V to 5.5V)
CAPACITANCE (TA = +25°C)
