Rainbow Electronics MAX6764 User Manual

Page 14

MAX6754–MAX6764

Low-Power, Single/Dual-Voltage Window
Detectors

______________________________________________________________________________________

Choose R2 to have a resistance of up to 500k

Ω.

Calculate R1 by:

R1 = ((V

- 0.4255V) x R2) / 0.4255V

The MAX6763/MAX6764 provide inputs to a window
detector allowing the programming of the threshold
voltage to within V

(see

Figure

6).

Choose R1, R2, and R3 such that:

(V+ / (R1 + R2 + R3))

≥ 1µA

SET

The MAX6754–MAX6762 allow the setting of the window
voltage range of the voltage detector. Connect SET to
GND to set a

±5% window. Connect SET to V

for a

±10% window. Bias SET to V

/2 for a ±15% window.

Manual Reset (

)

The MAX6754–MAX6762 include an active-low manual
reset input. Drive MR low to assert a reset output
(MAX6754/MAX6755/MAX6756) or an undervoltage
output (MAX6757/MAX6758/MAX6759). The output
remains asserted for the specified propagation delay
time (see

Figure

7) after MR goes high. MR is internally

pulled to V

with a 26k

Ω resistor.

Overvoltage Latch Control Input

(OVLATCH)

The MAX6760/MAX6761/MAX6762 provide an overvolt-
age latch control input (OVLATCH). Drive OVLATCH
high to latch the overvoltage output for any V

CC2

overvoltage condition. Drive OVLATCH low to

clear the latch after overvoltage conditions have been
removed. The latch is transparent when OVLATCH is
connected to GND. OVLATCH is a high impedance
input. Use external pullup or pulldown.

Reset, Undervoltage, and Overvoltage

Outputs (RESET,

RESET

, UV, OV)

RESET, RESET, UV, UV, and OV outputs assert when
the monitored supply is below the selected UV

threshold or above the selected OV

threshold. The

reset output deasserts after the specified timeout peri-
od when the monitored supply rises above the UV

threshold or drops below the OV

threshold. The

push-pull versions are referenced to V

The MAX6760/MAX6761/MAX6762 monitor both V

and V

CC2

. An under/overvoltage condition on either

voltage supply asserts the corresponding output.
RESET and UV are guaranteed to be in the correct
logic state when V

or V

CC2

> 1V.

INTERNAL

REFERENCE

0.5V

GND

OV MONITOR

UV MONITOR

UVIN

OVIN

MAX6763/MAX6764

V+

OVERVOLTAGE ASSERTS WHEN

UNDERVOLTAGE ASSERTS WHEN

V+ x R3

R1 + R2 + R3

> 0.5V

< 0.5V

V+ x (R2 + R3)

R1 + R2 + R3

Figure 6. Setting the Under/Overvoltage Window

RESET, UV

D-MR

MR_P

Figure 7a. Manual Reset/

Reset

Timing Diagram

D-UV

RESET, UV

(RESET IS THE COMPLEMENT OF RESET)

Figure 7b. V

/RESET,

Timing Diagram