STM6905 STMicroelectronics, STM6905 Datasheet - Page 9

• Manufacturer Part Number: STM6905
• Description: Quintuple, ultralow voltage supervisor with push-button reset
• Manufacturer: STMicroelectronics

Specifications of STM6905

• Primary Supply (vcc) Monitor. Fixed (factory - Programmed) Reset Thresholds: 3.078 V to 2.866 V
• Second Fixed (v2in) Monitor. Fixed (factoryprogrammed) Reset Thresholds: 2.333 V to 1.050 V
• Reset Delay Time (trec) On Power-up: 210 ms (typ)
• Operating Temperature: –40°C to 85°C (industrial grade)

3
3.1
3.2
Operation
The STM6905 provides the ability to monitor critical voltages such as power-supply and
battery voltage levels, while interfacing easily to the system controllers/microprocessors.
Figure 4
(customer-selectable, factory-programmed ) and three adjustable monitor inputs. RST
output is open drain and requires a 10k ohms pull-up resistor tied to V
Setting the adjustable voltage levels for V3IN, V4IN, and V5IN
inputs
The user can customize the minimum voltage levels for the three adjustable voltage inputs
by connecting an external resistor divider network to the V3IN, V4IN and V5IN pins in order
to set the trip point at some voltage above the 600 mv (V
formula.
During normal operation, the STM6905 monitors the voltage levels at all the five pins (Vcc,
V2IN, V3IN, V4IN and V5IN).
Power on reset (t
On power up, the STM6905 activates a power on reset circuit which asserts the reset pin
(i.e. RST goes low). The RST signal remains active until V
and MR) rises above the minimum voltage level for the time period t
that the supply voltage has stabilized to sufficient operating levels.
shows typical hardware hookup for monitoring five voltages; two fixed thresholds
REC
)
VTRIP
=
0
6 .
V
×
R
1
R
+
2
R
REF
2
CC
) according to the following
(and V2IN, V3IN, V4IN, V5IN
REC
CC
thereby ensuring
.
9/19