CAT803 , CAT809 and CAT810 are supervisory circuits that monitor power supplies in digital systems. The CAT803, CAT809 and CAT810 are drop-in replacements for the MAX803 , MAX809 and MAX803 and the MAX810 is suitable for applications in the industrial temperature range. These devices generate a reset signal that is asserted when asserted when the supply voltage falls below a preset threshold level at least 140 ms after the supply level rises above that level. The underlying floating gate technology, using the analog EEPROM ON Semiconductor can provide any custom reset threshold. Seven industry standard threshold levels are available to support +5.0 V, +3.3 V, +3.0 V and +2.5 V systems. The CAT803 has an open-drain RESET output (active low). The CAT803 requires a pull-up resistor on the reset output. The CAT809 has a push-pull RESET output (active low) and the CAT810 has a push-pull RESET output (active high). Fast transients on the power supply are ignored and the output is guaranteed to be in the correct state at VCC levels as low as 1.0 V.

CAT803, CAT809 and CAT810 are available in compact 3-pin SOT-23 and SC-70 packages.

feature

8226 ; Accurate monitoring

+5.0 V (-5%, -10%, -20%),

+3.3 V (-5%, -10%),

+3.0 V (-10%) and

+2.5 V (-5%) power supply

• Three output configurations are available:

- CAT803: Open drain active low reset

- CAT809: push-pull active low reset

- CAT810: push-pull active high reset

• Drop-in replacements for the MAX803, MAX809 and MAX810 for applications operating in the industrial temperature range

• Reset valid to VCC = 1.0 V.

• 6 A supply current

• Power transient immunity

• Industrial temperature range: -40°C to +85°C

• Available in SOT-23 and SC-70 packages

• These devices are lead-free and RoHS compliant

application

• Computers, servers, laptops, cable modems

•Wireless communication

• Embedded control system

• White goods, power meters

• Smart Instruments

• PDAs and handheld devices

CAT803, CAT809, CAT810 block diagram

Detail reset time

The reset signal of CAT803/CAT809 is low level, when the supply voltage is lower than CAT810, it is high level and high level

The threshold trip voltage remains active for at least 140 ms after the supply voltage rises above the threshold

Reset Timing Diagram

VCC transient response

CAT803/CAT809/CAT810 protection Ps fail to power down. A short duration of 4 seconds or less and an amplitude of 100 mV usually do not result in a false RESET. The graph below shows the negative maximum pulse duration - going to VCC transients will not cause a reset condition. As the magnitude of the transient goes further below the threshold (increasing VTH - VCC), the maximum pulse duration decreases. In this test, VCC starts at 0.5 V above the threshold and below the threshold overdrive voltage (VTH - VCC) ).

RESE active when VCC is below 1.0 V To ensure that when VCC is below 1.0 V, the CAT809 RESET pin is in a known state, with a >10 k pull-down resistor between RESET pin and GND is recommended. For the CAT810, a pull-up resistor from the RESET pin to VCC is required.

Reset is active when VCC is below 1.0 V

RESET is suitable for VCC bidirectional reset pin interface below 1.1 V The CAT809/810 can be connected with the P/C bidirectional reset pin by connecting a 4.7 k resistor in series with the CAT809/810 reset output and the P/C bidirectional reset pin.

Bidirectional reset pin interface

CAT803 Open-Drain Reset The CAT803 has an open-drain RESET output and therefore requires a pull-up resistor on the output for proper operation, as shown below. The open-drain output includes the ability to "wire and sum" several outputs together to form an inexpensive logic circuit. You can also connect pull-up resistors for different power supplies that may be higher than the CAT803 VCC pin. The value of the pull-up resistor does not matter in most applications, the typical value is between 5 k and 10 k.