DS1834AS ,Dual EconoReset with pushbuttonPIN DESCRIPTION5V - 5V Power Supply InputIN5V RST (*RST) - 5V Reset Output5V TOL - Selects 5V Input ..
DS1834AS+ ,Dual EconoReset with PushbuttonPIN DESCRIPTION5V - 5V Power Supply InputIN5V RST (*RST) - 5V Reset Output5V TOL - Selects 5V Input ..
DS1834AU ,Dual EconoReset with pushbuttonFEATURES PIN ASSIGNMENT 5V power-on reset3.3VIN5V 1 8IN 3.3V power-on reset25V RST 7 3.3V RST In ..
DS1834D ,Dual EconoReset with pushbuttonFEATURES PIN ASSIGNMENT 5V power-on reset3.3VIN5V 1 8IN 3.3V power-on reset25V RST 7 3.3V RST In ..
DS1836C-10+ ,3.3V/5V MicroManagerapplications V - Power Supply Input CCV - Battery Supply Input BATNC - No Connect V - P ..
DS1842 ,76V, APD, Bias Output Stage with Current MonitoringApplicationsAPD BiasingOrdering InformationGPON Optical Network Unit and Optical LineTransmission P ..
DZ23C22 ,Zener DiodesFeatures
DS1834A+-DS1834AS-DS1834AS+-DS1834AU
Dual EconoReset with Pushbutton
FEATURES5V power-on reset3.3V power-on resetInternal power is drawn from higher of eitherthe 5VIN input or the 3.3VIN inputExcellent for systems designed to operate
with dual power suppliesAsserts resets during power transientsPushbutton reset input for system overrideMaintains reset for 350 ms after VCC returns
to an in-tolerance conditionReduces need for discrete componentsPrecision temperature-compensated voltage
reference and voltage sensor8-pin DIP, 8-pin SOIC, and 8-pin μ-SOP
availableCMOS output for low current operation on
the DS1834 and DS1834DOperating temperature of -40°C to +85°C
PIN ASSIGNMENT
PIN DESCRIPTION5VIN - 5V Power Supply Input
5VRST (*RST) - 5V Reset Output
5V TOL - Selects 5V Input Tolerance
GND - Ground
PBRST - Pushbutton Reset
3.3V TOL - Selects 3.3V Input Tolerance
3.3V RST(*RST)- 3.3V Reset Output3.3VIN - 3.3V Power Supply Input
*DS1834D Active High Reset
DESCRIPTIONThe DS1834 Dual EconoResets monitors three vital system conditions: 5-volt supply, 3.3-volt supply,
and an external override. First a precision temperature reference and comparator circuit monitor the statusof the 5-volt supply and the 3.3-volt supply. When an out-of-tolerance condition is detected, an internal
power-fail signal is generated which forces the reset of the affected supply to an active state.
Lastly, the DS1834 supports an external reset via an internally debounced pushbutton input. When the
DS1834/A/D
Dual EconoReset with Pushbutton5VIN
5V RST
5V TOL
GND
3.3VIN
3.3V RST
3.3V TOL
PBRST
DS1834 8-Pin μ-SOP (118-mil)
DS1834 8-Pin DIP (300-mil)
5VIN
5V RST
5V TOL
GND
3.3VIN
3.3V RST
3.3V TOL
PBRST
DS1834/A/D
OPERATION
Power MonitorThe DS1834 provides the functions of detecting out-of-tolerance conditions on a 3.3-volt and 5-voltpower supply and warning a processor-based system of impending power failure. When an input is
detected as out of tolerance on either voltage input the RST for that supply will be forced active. When
that input returns to a valid state the RST will remain active for about 350 ms and then return to an
inactive state until the next input out-of-tolerance condition.
On power-up both resets are kept active for approximately 350 ms after the power supply inputs have
reached the selected tolerance. This allows the power supply and system power to stabilize before RST is
released.
All internal operating current for the DS1834 will be drawn from the input with the highest voltage level.The outputs will draw current only from the controlling input (5V IN or 3.3V IN).
DS1834 BLOCK DIAGRAM Figure 1
DS1834A BLOCK DIAGRAM OUTPUT Figure 2
DS1834/A/D
Tolerance SelectThe DS1834 provides two TOL inputs for individual customization of the DS1834 to specific application
requirements. If the TOL for the 5-volt supply is tied to the 5-volt input a 10% tolerance is selected for
the 5 volt supply. If the TOL for the 3.3-volt supply is tied to the 3.3-volt input, a 20% tolerance is
selected for the 3.3-volt supply. If TOL inputs are tied to ground, the 5-volt input will be set at a 5%
tolerance and the 3.3-volt input would be set to a 10% tolerance.
Pushbutton ResetThe DS1834 provides a pushbutton switch for manual reset control. When at least one of the DS1834
resets are not in a reset cycle, a pushbutton reset can be generated by pulling the PBRST pin low for at
least 2 ms. When the pushbutton is held low, both resets are forced active and will remain active for about
350 ms after the pushbutton is released. The pushbutton input is pulled high through an internal
40 kΩ=pull-up resistor and debounced via internal circuitry. See Figure 3 for an application example andFigure 4 for the timing diagram.
PUSHBUTTON RESET Figure 3
TIMING DIAGRAM: PUSHBUTTON RESET Figure 4
DS1834/A/D
OUTPUT VALID CONDITIONSAll versions of the DS1834 can maintain valid outputs as long as one input remains above 1.2 volts.
However, the RST outputs on the DS1834 use a push-pull output structure which can maintain a valid
output below 1.2 volts. To sink current below 1.2 volts a resistor can be connected from RST to GND
(see Figure 5). This arrangement will maintain a valid value on the RST outputs even if all inputs are at 0
volts. During both power-up and power-down this arrangement will draw current when RST is in the high
state. A value of about 100 kΩ=should be adequate to maintain a valid condition.
The DS1834A requires pull-up resistors on the outputs to maintain a valid output. The value of the
resistors is not critical in most cases but must be set low enough to pull the output to a high state. A
common value used is 10 kΩs (see Figure 6 and Figure 7).
APPLICATION DIAGRAM:
RST VALID TO 0 VOLTS VCC ON THE DS1834 Figure 5
APPLICATION DIAGRAM: DS1834A NMOS OUTPUTS Figure 6Note: If outputs are pulled-up to different voltages the outputs can not be connected to form a wired
"AND".
APPLICATION DIAGRAM: DS1834A WIRED "AND" OUTPUT Figure 7
DS1834/A/D
TIMING DIAGRAM: POWER-DOWN Figure 8
TIMING DIAGRAM: POWER-UP Figure 9
DS1834/A/D
ABSOLUTE MAXIMUM RATINGS*Voltage on VIN Pin Relative to Ground -0.5V to +7.0V
Voltage on RST (5V) Pin Relative to Ground -0.5V to +0.5VIN + 0.5V (DS1834 & DS1834D)
Voltage on RST (3.3V) Pin Relative to Ground -0.5V to +3.3VIN + 0.5V (DS1834 & DS1834D)
Voltage on PBRST & RST (DS1834A) Pin
Relative to Ground -0.5 to the greater of 0.5VIN + 0.5V or 3VIN + 0.5V
Operating Temperature -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 conditionsabove 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)
DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=1.2V to 5.5V)
