Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Dual voltage detector PDIP 16

1 of 14 060303

FEATURES

§ 5V power-on reset

§ 3.3V power-on reset

§ Two referenced comparators with separate

outputs for monitoring additional supplies

§ Internal power is drawn from higher of either

the IN

input or the IN

3.3V

input

§ Excellent for systems designed to operate

with multiple power supplies

§ Asserts resets during power transients

§ Pushbutton reset input for system override

§ Maintains reset for user configurable times

of 10ms, 100ms, or 1s

§ Watchdog timer for software monitoring

(DS1831A)

§ Precision temperature-compensated voltage

reference and voltage sensor

§ 16 pin DIP and 16 pin 150mil SO available

§ Operating Temperature of -40°C to +85°C

PIN ASSIGNMENT

DESCRIPTION

The DS1831 multisupply monitor and reset monitors up to four system voltages: 5V supply, 3.3V (or 3V)

supply, and two additional user configurable voltage monitors. DS1831 power for internal operation

comes from the higher voltage level of the 3.3V input or the 5V input. One of these inputs must be greater

than 1V for device operation. Pushbutton (manual reset) functionality is provided for the 5V reset, the

DS1831/A/B

Multisupply Micromonito

www.maxim-ic.com

3.3V

RST

3.3V

TOL

3.3V

PBRST

3.3V

MI1

MI2

MPBRST

RST

TOL

PBRST

IN1

IN2

GND

DS1831

16-Pin (300mil) DIP

16-Pin

(

150mil

)

3.3V

RST

3.3V

TOL

3.3V

PBRST

3.3V

MI1

WDS

RST

TOL

PBRST

IN1

GND

DS1831

16-Pin (300mil) DIP

16-Pin

(

150mil

)

3.3V

RST

3.3V

TOL

3.3V

PBST

MI1

MI2

MPBRST

RST

TOL

PBRST

IN1

IN2

GND

DS1831B

16-Pin (300mil) DIP

16-Pin

(

150mil

)

Summary of content (14 pages)

PAGE 1
DS1831/A/B Multisupply Micromonitor www.maxim-ic.com FEATURES § § § § § § § § § § § § 5V power-on reset 3.3V power-on reset Two referenced comparators with separate outputs for monitoring additional supplies Internal power is drawn from higher of either the IN5V input or the IN3.
PAGE 2
DS1831/A/B 3.3V reset or for all reset outputs by the master pushbutton. The DS1831A replaces one reference comparator and the master pushbutton with watchdog and the DS1831B replaces the 3.3V PBRST with a last reset status output. TOL and TD inputs allow user configuration of the DS1831 for multiple applications. The TOL inputs configure the tolerance for the specified output and the TD inputs configure the reset time delays.
PAGE 3
DS1831/A/B OPERATION—POWER MONITOR The DS1831 provides the functions of detecting out-of-tolerance conditions on a 3.3V (or 3V) and 5V 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 low.
PAGE 4
DS1831/A/B PUSHBUTTON RESET SEQUENCING Figure 2 3.3V Supply 5V Supply IN5V RST5V 1 16 2 DS1831 15 3 14 4 13 5 12 TOL5V TD5V PBRST5V IN3.3V RST3.3V TOL3.3V TD3.3V PBRST3.3V GND NOTE: The RST 5V output is connected to the IN3.3V via a 100 kW resistor in the push-button input and therefore does not require a pull-up resistor (an addition pull up can be used to accelerate responses). If an external pull up is used in this example it must be connected to the 3.3V power supply.
PAGE 5
DS1831/A/B PUSHBUTTON RESET Figure 3 5V Supply IN5V 10 kW RST5V 1 16 2 DS1831 15 3 14 4 13 5 12 TOL5V TD5V PBRST5V GND TIMING DIAGRAM—MASTER PUSHBUTTON RESET Figure 4 tPB MPBRST tPDLY VIH VIL tRST RST5V and RST3.
PAGE 6
DS1831/A/B TIMING DIAGRAM—5V OR 3.3V PUSHBUTTON RESET Figure 5 tPB PBRST5V (or PBRST3.3V) tPDLY VIH VIL tRST RST5V (or RST3.3V) VOH VIL OPERATION—PUSHBUTTON STATUS The DS1831B provides a master pushbutton status open drain output. The PBST output indicates the status of the most recent reset condition. If the last reset was generated by the master pushbutton input it would maintain a low condition until cleared by another event (except the master pushbutton) generating a reset.
PAGE 7
DS1831/A/B OUTPUT VALID CONDITIONS The DS1831 can maintain valid outputs as long as one input remains above 1.0V. Accurate voltage monitoring additionally requires that either the 3.3V IN or 5V IN input be above 1.5V. If this condition is not met and at least one of the supply inputs are at or above 1.0V all outputs are maintained in the active condition. The DS1831 requires pull-up resistors on the outputs to maintain a valid output.
PAGE 8
DS1831/A/B The output associated with the specific input will be held low if the voltage on the input pin is less than 1.25V. If the voltage is above 1.25V the output will not sink current and will be pulled up by the required pull up resistor. 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 10kW.
PAGE 9
DS1831/A/B NON-MASKABLE INTERRUPT CIRCUIT EXAMPLE Figure 9 VSENSE1 VSENSE2 VCC R1 PBRST3.3V PBRST5V R3 R2 IN1 DS1831 IN2 R4 NMI1 10 KW NMI2 GND MPBRST Example: VSENSE1 = 11.50V trip point VSENSE1 = Therefore: 11.50V = R1 + 100 k W 100 kW R1 + R2 R2 X 1.25V X 1.25V Resulting In: R1 = 820kW Repeat the same steps to solve for R3 and R4 with VSENSE2.
PAGE 10
DS1831/A/B The ST input can be derived from many microprocessor outputs. The most typical signals used are the microprocessor address signals, data signals, or control signals. When the microprocessor functions normally, these signals would, as a matter of routine, cause the watchdog to be reset prior to time-out. To guarantee that the watchdog timer does not time-out, a transition must occur at or less than the minimum times shown in Table 1. A typical circuit example is shown in Figure 10.
PAGE 11
DS1831/A/B RESET TIMING DIAGRAM—POWER UP Figure 12 tR VINTP (MAX) VINTP (MIN) VINTP IN5V (or IN3.3V) tRPU VOH RST5V (or RST3.3V) RESET TIMING DIAGRAM — POWER DOWN Figure 13 IN5V (or IN3.3V) VINTP (MAX) RST5V (or RST3.
PAGE 12
DS1831/A/B ABSOLUTE MAXIMUM RATINGS* Voltage on IN5V or IN3.3V Pins Relative to Ground Voltage on either RST Relative to Ground Voltage on PBRST 3.3V Relative to Ground Voltage on PBRST 5V Relative to Ground Voltage on MPBRST, IN1, IN2 Relative to Ground Operating Temperature Range Storage Temperature Range Soldering Temperature * -0.5V to +6.0V -0.5V to the greater of IN5V + 0.5V or IN3.3V + 0.5V -0.5V to IN3.3V + 0.5V -0.5V to IN5V + 0.5V -0.5V to the greater of IN5V + 0.5V or IN3.3V + 0.
PAGE 13
DS1831/A/B CAPACITANCE PARAMETER Input Capacitance Input Capacitance (tA = +25°C) SYMBOL CIN COUT MAX 5 7 UNITS pF pF NOTES AC ELECTRICAL CHARACTERISTICS (-40°C to 85°C; IN3.3V, IN5V = 1.0V to 5.
PAGE 14
DS1831/A/B ORDERING INFORMATION Ordering Part Package Type Description Number DS1831 16-Pin DIP 300mil 5V/3.3V Multisupply Monitor DS1831S 16-Pin SO 150mil 5V/3.3V Multisupply Monitor DS1831A 16-Pin DIP 300mil 5V/3.3V Multisupply Monitor w/Watchdog DS1831AS 16-Pin SO 150mil 5V/3.3V Multisupply Monitor w/Watchdog DS1831B 16-Pin DIP 300mil 5V/3.3V Multisupply Monitor w/Pushbutton Status DS1831BS 16-Pin SO 150mil 5V/3.