Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Dual voltage detector PDIP 8

1 of 7 071700

FEATURES

 5V power-on reset

 3.3V power-on reset

 Internal power is drawn from higher of either

the 5V

input or the 3.3V

input

 Excellent for systems designed to operate

with dual power supplies

 Asserts resets during power transients

 Pushbutton reset input for system override

 Maintains reset for 350 ms after V

returns

to an in-tolerance condition

 Reduces need for discrete components

 Precision temperature-compensated voltage

reference and voltage sensor

 8-pin DIP, 8-pin SOIC, and 8-pin µ-SOP

available

 CMOS output for low current operation on

the DS1834 and DS1834D

 Operating temperature of -40°C to +85°C

PIN ASSIGNMENT

PIN DESCRIPTION

- 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 Output

3.3V

- 3.3V Power Supply Input

*DS1834D Active High Reset

DESCRIPTION

The 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 status

of 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

pushbutton is pulled low both resets will be asserted for approximately 350 ms after the pushbutton is

released.

DS1834/A/D

Dual EconoReset with Pushbutton

www.dalsemi.com

DS1834 8-Pin SOIC (150-mil)

5V RST

5V TOL

GND

3.3V

3.3V RST

3.3V TOL

PBRST

DS1834 8-Pin

-SOP (118-mil)

5V RST

(

*RST

)

5V TOL

GND

3.3V

3.3V RST (*RST)

3.3V TOL

PBRST

DS1834 8-Pin DIP (300-mil)

5V RST

5V TOL

GND

3.3V

3.3V RST

3.3V TOL

PBRST

Summary of content (7 pages)

PAGE 1
DS1834/A/D Dual EconoReset with Pushbutton www.dalsemi.com FEATURES PIN ASSIGNMENT 5V power-on reset 3.3V power-on reset Internal power is drawn from higher of either the 5VIN input or the 3.
PAGE 2
DS1834/A/D OPERATION Power Monitor The DS1834 provides the functions of detecting out-of-tolerance conditions on a 3.3-volt and 5-volt power 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.
PAGE 3
DS1834/A/D Tolerance Select The 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.
PAGE 4
DS1834/A/D OUTPUT VALID CONDITIONS All 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.
PAGE 5
DS1834/A/D TIMING DIAGRAM: POWER-DOWN Figure 8 TIMING DIAGRAM: POWER-UP Figure 9 5 of 7
PAGE 6
DS1834/A/D ABSOLUTE MAXIMUM RATINGS* Voltage on VIN Pin Relative to Ground Voltage on RST (5V) Pin Relative to Ground Voltage on RST (3.3V) Pin Relative to Ground Voltage on PBRST & RST (DS1834A) Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * -0.5V to +7.0V -0.5V to +0.5VIN + 0.5V (DS1834 & DS1834D) -0.5V to +3.3VIN + 0.5V (DS1834 & DS1834D) -0.5 to the greater of 0.5VIN + 0.5V or 3VIN + 0.
PAGE 7
DS1834/A/D AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL tPB PBRST = VIL PBRST Stable Low to Reset (-40°C to +85°C; VCC=1.2V to 5.5V) MIN 2 TYP tPDLY MAX UNITS ms 2 ms 500 ms 2 µs NOTES Active Reset Active Time tRST 200 350 VCC Detect to RST (or RST) tRPD VCC Slew Rate (VINTP(MAX) to VINTP(MIN)) tF 300 µs VCC Slew Rate (VINTP(MIN) to VINTP(MAX)) tR 0 ns VCC Detect to RST (or RST) tRPU 200 350 500 ms 8 9 NOTES: 1. All voltages are referenced to ground. 2.