DS1846E-010+ Maxim Integrated Products, DS1846E-010+ Datasheet - Page 10

• Manufacturer Part Number: DS1846E-010+
• Description: IC NV TRI-POT MEM MON 20TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS1846E-010+

• Taps: 100, 256
• Resistance (ohms): 10K, 100K
• Number Of Circuits: 3
• Temperature Coefficient: 750 ppm/°C Typical
• Memory Type: Non-Volatile
• Interface: 2-Wire Serial
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Resistance In Ohms: 10K, 100K
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DEVICE OPERATION
Power Monitor
The DS1846 detects out-of-tolerance power-supply conditions and warns a processor-based system of an
impending power failure. When V
RST and
power supply and processor to stabilize.
Pushbutton Reset
The DS1846 provides an input pin for direct connection to a pushbutton reset (see Figure 4). The
pushbutton reset input requires an active-low signal. Internally, this input is debounced and timed such
that RST and
pushbutton reset input is released from the low level. The pushbutton can be initiated by connecting the
Nonmaskable Interrupt
The DS1846 generates a nonmaskable interrupt (
comparator monitors the voltage level at the IN pin relative to an on-chip reference generated by an
internal bandgap. The IN pin is a high-impedance input allowing for a user-defined sense point. An
external resistor voltage-divider network (Figure 4) is used to set a trip point. This sense point may be
derived from a regulated supply or from a higher DC voltage level closer to the main system power input.
With the IN trip point, V
in Figure 4. Proper operation of the DS1846 requires that the voltage at the IN pin be limited to V
Therefore, the maximum allowable voltage at the supply being monitored (V
shown in Figure 4. A simple approach to solving the equation is to select a value for R2 high enough to
keep power consumption low, and solve for R1. The flexibility of the IN input pin allows for detection of
power loss at the earliest point in a power-supply system, maximizing the amount of time for system
shut-down between
When the supply being monitored decays to the voltage sense point, the DS1846 pulses the
to the active state for a minimum t
comparator are disabled from generating an interrupt until V
Connecting
of-tolerance condition occurred in a monitored supply. An example is shown in Figure 4.
NMI
NMI
output to the
pulse is not initiated until V
RST
NMI
RST
signals. On power-up, RST and
to
PBRST
NMI
signals of at least t
PBRST
TP
and RST/
input as shown in Figure 4.
, the proper values for R1 and R2 can be determined by the equation as shown
allows the nonmaskable interrupt to generate an automatic reset when an out-
CC
NMI
CC
RST
reaches V
. During a power-up, any detected IN pin levels below V
falls below the minimum V
.
RST
minimum are generated. The t
CCTP
RST
NMI
.
10 of 18
are kept active for a minimum of t
) for early warning of a power failure. A precision
CC
rises to V
CC
tolerance, a comparator asserts the
CCTP
RST
MAX
. As a result, any potential
delay commences as the
) can also be derived as
RST
to allow the
NMI
TP
output
by the
CC
.