ba00dd0w ROHM Co. Ltd., ba00dd0w Datasheet - Page 7

• Manufacturer Part Number: ba00dd0w
• Description: Standard Variable Output Ldo Regulator
• Manufacturer: ROHM Co. Ltd.

●Other
Thermal Shutdown Circuit (Thermal Protection)
Reverse Current
2) This IC is bipolar IC that has a P-board (substrate) and P+ isolation layer
IC
Fig.33:Output equivalent circuit
vary with the board’s wiring impedance, input impedance, and/or load impedance. Therefore, be certain to ascertain the final
status of these items for actual use.
connected as close to the input pin-GND as location possible. However, in situations such as rapid fluctuation of the input
voltage or the load, please check the operation in real application to determine proper capacitance.
are load shorts. This protection circuit is a “7”-shaped current control circuit that is designed such that the current is restricted
and does not latch even when a large current momentarily flows through the system with a high-capacitance capacitor.
However, while this protection circuit is effective for the prevention of destruction due to unexpected accidents, it is not
suitable for continuous operation or transient use. Please be aware when creating thermal designs that the overcurrent
protection circuit has negative current capacity characteristics with regard to temperature (Refer to Figs.4 and 16).
This system has a built-in temperature protection circuit for the purpose of protecting the IC from thermal damage. As shown
above, this must be used within the range of acceptable loss, but if the acceptable loss happens to be continuously
exceeded, the chip temperature Tj increases, causing the temperature protection circuit to operate.
When the thermal shutdown circuit operates, the operation of the circuit is suspended. The circuit resumes operation
immediately after the chip temperature Tj decreases, so the output repeats the ON and OFF states (Please refer to Figs.12
and 24 for the temperatures at which the temperature protection circuit operates).
There are cases in which the IC is destroyed due to thermal runaway when it is left in the overloaded state. Be sure to avoid
leaving the IC in the overloaded state.
placed between the Vcc and Vo and a pathway be created so that the current can escape (Refer to Fig.36).
between each devise, as shown in Fig.37. A P-N junction is formed between
this P-layer and the N-layer of each device, and the P-N junction operates
as a parasitic diode when the electric potential relationship is GND>
Terminal A, GND> Terminal B, while it operates as a parasitic transistor
when the electric potential relationship is Terminal B GND> Terminal A.
Parasitic devices are intrinsic to the IC. The operation of parasitic devices
induces mutual interference between circuits, causing malfunctions and
eventually the destruction of the IC itself. It is necessary to be careful not to
use the IC in ways that would cause parasitic elements to operate. For
example, applying a voltage that is lower than the GND (P-board) to the
input terminal.
Note, however, that the stable range suggested in the figure depends on the IC and the resistance load involved, and can
Keep capacitor capacitance within a range of 22μF～1000μF. It is also recommended that a 0.33μF bypass capacitor be
A built-in overcurrent protection circuit corresponding to the current capacity prevents the destruction of the IC when there
In order to prevent the destruction of the IC when a reverse current flows through the IC, it is recommended that a diode be
Overcurrent Protection Circuit
1) Protection Circuits
N
(Pin B)
Parasitic element
or transistor
P+
O
Transistor (NPN)
B
OUT
E
N
N
P
GND
C(ADJ)
P
22 μ F
P+
Fig. 37: Example of the basic structure of a bipolar IC
N
100
GND
10
0.1
1
0
Fig.34:Io vs. ESR characteristics
(Pin A)
P
N
200
OUTPUT CURRENT：lo(mA)
P+
(BA□□CC0,22μF)
Stable operating region
Unstable operating region
400
Unstable operating region
Resistor
N
600
P
GND
Parasitic element
7/8
800
P+
1000
N
10
0.1
100
1
1
Fig.35: Io vs. ESR characteristics
(Pin B)
10
(Pin A)
Unstable operating region
OUTPUT CURRENT：lo(mA)
(BA□□DD0,22μF)
Stable operating region
B
Fig. 36:Bypass diode
C
E
CTL
GND
GND
Vcc
100
Parasitic element
Parasitic element
or transistor
Reverse current
Unstable operating region
GND
OUT
1000