BD87A41FVM-TR Rohm Semiconductor, BD87A41FVM-TR Datasheet - Page 6

• Manufacturer Part Number: BD87A41FVM-TR
• Description: IC, VOLTAGE DETECTION, MSOP8
• Manufacturer: Rohm Semiconductor
• Series: -r
• Type: Watchdog Circuitr

Specifications of BD87A41FVM-TR

• Threshold Voltage: 4.1V
• No. Of Supervisors / Monitors: 1
• Supply Voltage Range: 1V To 10V
• Reset Type: Active-Low
• Supply Current: 5µA
• Digital Ic Case Style: MSOP
• No. Of Pins: 8
• Operating Temperature: RoHS Compliant
• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: Adjustable/Selectable
• Voltage - Threshold: 4.1V
• Mounting Type: Surface Mount
• Package / Case: 8-VSSOP, 8-MSOP (0.110", 2.80mm Width)
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

●Heat reduction curve
●External settings for pins and precautions
●Operation Notes
1.
2.
3.
4.
GND voltage
Thermal design
(5) The CTW pin state switches from charge to discharge when VCTW reaches VthL, and RESET switches from low to high. The watchdog
(6) The CTW pin state may not switch from charge to discharge when the CLK input pulse width TWCLK is short. Use a TWCLK input pulse
(7) When a pulse (positive edge trigger) of at least 500 ns is input to the CLK pin while the CTW pin is charging, the CTW state switches from
(8) Watchdog timer operation is forced off when the INH pin switches to low:BD37A□□FVM (Switches to high:BD87A□□FVM,BD97A41F).
(9) The watchdog timer function turns on when the INH pin switches to high. The external capacitor connected to the CTW pin begins to
(10) RESET switches from high to low when VDD falls to the RESET detection voltage (VDET) or lower.
(11) When VDD falls to 0 V, the RESET signal stays low until VDD reaches 0.8 V.
1) Connect a capacitor (0.001 µF to 1,000 µF) between the VDD and GND pins when the power line impedance is high. Use of the IC when
2) External capacitance
Absolute maximum ratings
Inter-pin shorts and mounting errors
An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down the
devices, thus making impossible to identify breaking mode, such as a short circuit or an open circuit. If any over rated values will expect to
exceed the absolute maximum ratings, consider adding circuit protection devices, such as fuses.
The potential of GND pin must be minimum potential in all operating conditions.
Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
Use caution when positioning the IC for mounting on printed circuit boards. The IC may be damaged if there is any connection error or if pins
are shorted together.
the power line impedance is high may result in oscillation.
A capacitor must be connected to the CTW pin. When using a large capacitor such as 1 µF, the INH pin must allow a CTW discharge time of
at least 2 ms. The power-on reset time is given by equation [1] on page 5. The WDT time is given by equations [2] and [3] on page 5, 6. The
setting times are proportional to the capacitance value from the equations, so the maximum and minimum setting times can be calculated
from the electrical characteristics according to the capacitance. Note however that the electrical characteristics do not include the external
capacitor's temperature characteristics.
timer reset time TWL is given by the following equation:
ICTWO denotes the CTW discharge current and is designed to be 1.50 µA (Typ.).
width of at least 500 ns.
charge to discharge. Once it discharges to VthL, it will charge again.
At that time, only the watchdog timer is turned off. Reset detection is performed normally.
charge at that time.
TWCLK ≥ 500 ns (Min.)
TWL (s) ≈ (0.5 × CTW (µF))/(ICTWO)
200
600
400
800
G
0
470mW
When mounted on a glass epoxy board
(70 mm × 70 mm × 1.6mm) θ ja = 212.8 (°C /W)
25
AMBIENT TEMPERATURE: Ta [℃]
MSOP8
50
75
100
[3]
105 ℃
125
Fig.17
6/8
200
600
400
800
0
0
550mW
When mounted on a glass epoxy board
(70 mm × 70 mm × 1.6mm) θ ja = 181.8 (°C /W)
25
AMBIENT TEMPERATURE: Ta [℃]
50
SOP8
75
100
105 ℃
125