DS1232LP+ ,Low-Power MicroMonitor ChipPIN DESCRIPTIONPBRST - Pushbutton Reset InputTD - Time Delay SetTOL - Selects 5% or 10% V DetectCCG ..
DS1232LPN ,Low-Power MicroMonitor ChipPIN DESCRIPTIONPBRST - Pushbutton Reset InputTD - Time Delay SetTOL - Selects 5% or 10% V DetectCCG ..
DS1232LPS ,Low power micromonitor chipPIN DESCRIPTIONPBRST – Pushbutton Reset InputTD – Time Delay SetTOL – Selects 5% or 10% V DetectCCG ..
DS1232LPS-2 ,Low power micromonitor chipPIN DESCRIPTIONPBRST - Pushbutton Reset InputTD - Time Delay SetTOL - Selects 5% or 10% V DetectCCG ..
DS1232LPS-2+ ,Low-Power MicroMonitor ChipPIN DESCRIPTIONPBRST - Pushbutton Reset InputTD - Time Delay SetTOL - Selects 5% or 10% V DetectCCG ..
DS1232LPS-2+T&R ,Low-Power MicroMonitor ChipFEATURES PIN ASSIGNMENT Super-low power version of DS1232VPBRST 1 8 CC NC 1 16 NC 50 μA quiescent ..
DTA143EM , PNP -100mA -50V Digital Transistors (Bias Resistor Built-in Transistors)
DTA143ESA , Digital transistors (built-in resistors)
DTA143TCA ,Conductor Holdings Limited - Digital Transistor
DTA143TE ,Bias Resistor TransistorMaximum ratings applied to the device are individual stress limit values (notnormal operating condi ..
DTA143TET1 ,Bias Resistor TransistorDTA114EET1 SeriesPreferred DevicesBias Resistor TransistorsPNP Silicon Surface Mount Transistorswit ..
DTA143TM , PNP -100mA -50V Digital Transistors (Bias Resistor Built-in Transistors)
DS1232LP+-DS1232LPN-DS1232LPS-2-DS1232LPS-2+-DS1232LPS-2+T&R-DS1232LPSN-2+
Low-Power MicroMonitor Chip
FEATURESSuper-low power version of DS123250 μA quiescent currentHalts and restarts an out-of-control
microprocessorAutomatically restarts microprocessor after
power failureMonitors pushbutton for external overrideAccurate 5% or 10% microprocessor power
supply monitoring8-pin DIP, 8-pin SOIC or space saving μ-SOP
package availableOptional 16-pin SOIC package availableIndustrial temperature -40°C to +85°C
available, designated N
PIN ASSIGNMENT
PIN DESCRIPTIONPBRST- Pushbutton Reset Input
TD - Time Delay Set
TOL - Selects 5% or 10% VCC Detect
GND - Ground
RST - Reset Output (Active High)
RST - Reset Output (Active Low, open
drain)- Strobe Input
VCC - +5 Volt Power
DESCRIPTIONThe DS1232LP/LPS Low Power MicroMonitor Chip monitors three vital conditions for a
microprocessor: power supply, software execution, and external over-ride. First, a precision temperature-
compensated reference and comparator circuit monitors the status of VCC. When an out-of-tolerance
condition occurs, an internal power-fail signal is generated which forces reset to the active state. When
VCC returns to an in-tolerance condition, the reset signals are kept in the active state for a minimum of
250 ms to allow the power supply and processor to stabilize.
DS1232LP/LPS
Low Power MicroMonitor Chip
www.dalsemi.comDS1232LP 8-Pin DIP (300-mil)
See Mech. Drawings Section
PBRST
TOL
GND
VCC
RSTRST
DS1232LPS 16-Pin SOIC (300-mil)
See Mech. Drawings Section
PBRST
TOL
GND
VCC
RST
RST
DS1232LPμ (118-mil μ-SOP)
See Mech. Drawings Section
PBRST
TOL
GND
VCC
RST
RST
DS1232LPS-2 8-Pin SOIC (150-mil)
See Mech. Drawings Section
PBRST
TOL
GND
VCC
RSTRST
DS1232LP/LPS
The second function the DS1232LP/LPS performs is pushbutton reset control. The DS1232LP/LPS
debounces the pushbutton input and guarantees an active reset pulse width of 250 ms minimum. The third
function is a watchdog timer. The DS1232LP/LPS has an internal timer that forces the reset signals to the
active state if the strobe input is not driven low prior to timeout. The watchdog timer function can be set
to operate on timeout settings of approximately 150 ms, 600 ms, and 1.2 seconds.
OPERATION - POWER MONITORThe DS1232LP/LPS detects out-of-tolerance power supply conditions and warns a processor-based
system of impending power failure. When VCC falls below a preset level as defined by TOL, the VCC
comparator outputs the signals RST and RST. When TOL is connected to ground, the RST and RST
signals become active as VCC falls below 4.75 volts. When TOL is connected to VCC, the RST and RST
signals become active as VCC falls below 4.5 volts. The RST and RST are excellent control signals for a
microprocessor, as processing is stopped at the last possible moments of valid VCC. On power-up, RST
and RST are kept active for a minimum of 250 ms to allow the power supply and processor to stabilize.
OPERATION - PUSHBUTTON RESETThe DS1232LP/LPS provides an input pin for direct connection to a pushbutton (Figure 1). The
pushbutton reset input requires an active low signal. Internally, this input is debounced and timed such
that RST and RST signals of at least 250 ms minimum are generated. The 250 ms delay starts as the
pushbutton reset input is released from low level.
OPERATION - WATCHDOG TIMERThe watchdog timer function forces RST and RST signals to the active state when the ST input is not
stimulated for a predetermined time period. The time period is set by the TD input to be typically 150 ms
with TD connected to ground, 600 ms with TD left unconnected, and 1.2 seconds with TD connected to
VCC. The watchdog timer starts timing out from the set time period as soon as RST and RST are inactive.
If a high-to-low transition occurs on the ST input pin prior to timeout, the watchdog timer is reset and
begins to timeout again. If the watchdog timer is allowed to timeout, then the RST and RST signals are
driven to the active state for 250 ms minimum. The ST input can be derived from microprocessor address
signals, data signals, and/or control signals. When the microprocessor is functioning normally, these
signals would, as a matter of routine, cause the watchdog to be reset prior to timeout. To guarantee that
the watchdog timer does not timeout, a high-to-low transition must occur at or less than the minimum
shown in Table 1. A typical circuit example is shown in Figure 2.
DS1232LP/LPS
MICROMONITOR BLOCK DIAGRAM
PUSHBUTTON RESET Figure 1
WATCHDOG TIMER Figure 2
DS1232LP/LPS
TIMING DIAGRAM: PUSHBUTTON RESET Figure 3
TIMING DIAGRAM: STROBE INPUT Figure 4
WATCHDOG TIME-OUTS Table 1
TIME-OUTMINTYPMAXGND62.5 ms150 ms250 ms
Float250 ms600 ms1000 ms
VCC500 ms1200 ms2000 ms
DS1232LP/LPS
TIMING DIAGRAM: POWER-DOWN Figure 5
TIMING DIAGRAM: POWER-UP Figure 6
DS1232LP/LPS
ABSOLUTE MAXIMUM RATINGS*Voltage on VCC Pin Relative to Ground -0.5V to +7.0V
Voltage on I/O Relative to Ground -0.5V to VCC + 0.5V
Operating Temperature 0°C to 70°C
Operating Temperature (Industrial Version) -40°C to +85°C
Storage Temperature -55°C to +125°C
Soldering Temperature 260°C for 10 secondsThis 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 (0°C to 70°C)
PARAMETERSYMBOLMINTYPMAXUNITSNOTESSupply VoltageVCC4.55.05.5V1 and PBRST Input High LevelVIH2.0VCC+0.3V1 and PBRST Input Low LevelVIL-0.3+0.8V1
DC ELECTRICAL CHARACTERISTICS (0°C to 70°C; VCC=4.5 to 5.5V)
PARAMETERSYMBOLMINTYPMAXUNITSNOTESInput LeakageIIL-1.0+1.0μA3
Output Current @ 2.4VIOH-8-10mA5
Output Current @ 0.4VIOL10mA
Low Level @ RSTVOL0.4V1
Output Voltage @ -500 uAVOHVCC
-0.5V
VCC
-0.1V1, 7
Output Current (CMOS)ICC150μA2
Operating Current (TTL)ICC2200500μA8
VCC Trip Point (TOL=GND)VCCTP4.504.624.74V1
VCC Trip Point (TOL=VCC)VCCTP4.254.374.49V1
CAPACITANCE (tA=25°C)
PARAMETERSYMBOLMINTYPMAXUNITSNOTESInput CapacitanceCIN5pF
Output CapacitanceCOUT7pF
