BD8132FV_09 Datasheet, PDF (19/21 Pages) Rohm – High-precision Gamma Correction ICs with built-in DAC

BD8132FV, BD8139AEFV
Technical Note
●Notes for use
1) Absolute maximum ratings
Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may
result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open mode) when such
damage is suffered. A physical safety measure such as a fuse should be implemented when use of the IC in a special
mode where the absolute maximum ratings may be exceeded is anticipated.
2) GND potential
Ensure a minimum GND pin potential in all operating conditions.
3) Setting of heat
Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
4) Pin short and mistake fitting
Use caution when orienting and positioning the IC for mounting on printed circuit boards. Improper mounting may result in
damage to the IC. Shorts between output pins or between output pins and the power supply and GND pins caused by the
presence of a foreign object may result in damage to the IC.
5) Actions in strong magnetic field
Use caution when using the IC in the presence of a strong magnetic field as doing so may cause the IC to malfunction.
6) Testing on application boards
When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress.
Always discharge capacitors after each process or step. Ground the IC during assembly steps as an antistatic measure,
and use similar caution when transporting or storing the IC. Always turn the IC's power supply off before connecting it to or
removing it from a jig or fixture during the inspection process.
7) Ground wiring patterns
When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns,
placing a single ground point at the application's reference point so that the pattern wiring resistance and voltage
variations caused by large currents do not cause variations in the small signal ground voltage. Be careful not to change the
GND wiring patterns of any external components.
8) Regarding input pin of the IC
This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated.
P/N junctions are formed at the intersection of these P layers with the N layers of other elements to create a variety of
parasitic elements.For example, when the resistors and transistors are connected to the pins as shown in Fig.39, a
parasitic diode or a transistor operates by inverting the pin voltage and GND voltage.The formation of parasitic elements
as a result of the relationships of the potentials of different pins is an inevitable result of the IC's architecture. The
operation of parasitic elements can cause interference with circuit operation as well as IC malfunction and damage. For
these reasons, it is necessary to use caution so that the IC is not used in a way that will trigger the operation of parasitic
elements, such as the application of voltages lower than the GND (P substrate) voltage to input and output pins.
(Pin A)
Resistor
(Pin B)
Transistor (NPN)
B
C
E
(Pin B)
B
C
P＋
N
P
P
N
P＋
N
P＋
N
N
P
N
GND
P＋
N
(Pin A)
Parasitic element
P substrate
GND
Parasitic elements
GND
Fig.39 Example of a Simple Monolithic IC
E
GND
Parasitic
elements
Parasitic
element
GND
9) Overcurrent protection circuits
An overcurrent protection circuit designed according to the output current is incorporated for the prevention of IC damage
that may result in the event of load shorting. This protection circuit is effective in preventing damage due to sudden and
unexpected accidents. However, the IC should not be used in applications characterized by the continuous operation or
transitioning of the protection circuits. At the time of thermal designing, keep in mind that the current capacity has negative
characteristics to temperatures.
10) TSD (Thermal shutdown) circuit
This IC incorporates a built-in TSD circuit for the protection from thermal destruction. The IC should be used within the
specified power dissipation range. However, in the event that the IC continues to be operated in excess of its power
dissipation limits, the attendant rise in the chip's junction temperature Tj will trigger the TSD circuit to turn off all output
power elements. The circuit automatically resets once the junction temperature Tj drops.
Operation of the TSD circuit presumes that the IC's absolute maximum ratings have been exceeded. Application designs
should never make use of the TSD circuit.
11) Testing on application boards
At the time of inspection of the installation boards, when the capacitor is connected to the pin with low impedance, be sure
to discharge electricity per process because it may load stresses to the IC. Always turn the IC's power supply off before
connecting it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly steps as
an antistatic measure, and use similar caution when transporting or storing the IC.
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19/20
2009.07 - Rev.B