Technical Note

15/16

BH76806FVM, BH76809FVM, BH76812FVM, BH76816FVM

www.rohm.com

2014.08 - Rev.B

© 2009 ROHM Co., Ltd. All rights reserved.

●Cautions on use

1.

Numbers and data in entries are representative design values and are not guaranteed values of the items.

2.

Although ROHM is confident that the example application circuit reflects the best possible recommendations, be sure

to verify circuit characteristics for your particular application. Modification of constants for other externally connected

circuits may cause variations in both static and transient characteristics for external components as well as this Rohm

IC. Allow for sufficient margins when determining circuit constants.

3.

Absolute maximum ratings

Use of the IC in excess of absolute maximum ratings, such as the applied voltage or operating temperature range

(Topr), 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 using the IC at times where the absolute maximum ratings may be exceeded.

4.

Thermal design

Perform thermal design, in which there are adequate margins, by taking into account the permissible dissipation

(Pd) in actual states of use.

5.

Short circuit between terminals and erroneous mounting

Pay attention to the assembly direction of the ICs. Wrong mounting direction or shorts between terminals, GND, or other

components on the circuits, can damage the IC.

6.

Operation in strong electromagnetic field

Using the ICs in a strong electromagnetic field can cause operation malfunction.

7.

Wiring from the decoupling capacitor C2 to the IC should be kept as short as possible.

This capacitance value may have ripple effects on the IC, and may affect the S-N ratio. It is recommended to use

as large a decoupling capacitor as possible. (Recommendations: 3.3 µF, B characteristics, 6.3 V or higher)

8.

Target capacitor

It is recommended to use a ceramic capacitor with good temperature characteristics (B).

9.

The NVCC (7 pin) terminal generates a voltage that is used within the IC, so it should not be connected to a load

unless necessary. This capacitor (C7) has a large capacitance value with low negative voltage ripple.

10.

Capacitors C18 and C2 should be placed as close as possible to the IC.

If the wire length to the capacitor is too

long, it can lead to switching noise. (Recommended C18: 1.0 µF; C2: 3.3 µF, B characteristics, 6.3 V or higher

maximum voltage)

11.

The HPF consists of input coupling capacitor C3 and 150 k

Ω of the internal input.

Be sure to check for video signal sag before determining the C3 value.

The cut-off frequency fc can be calculated using the following formula.

fc = 1/(2

π× C3 × 150 kΩ) (Recommendations: 1.0 µF, B characteristics, 6.3 V or higher maximum voltage)

12.

The output resistor R5 should be placed close to the IC.

13.

Improper mounting may damage the IC.

14.

A large current transition occurs in the power supply pin when the charge pump circuit is switched.

If this affects

other ICs (via the power supply line), insert a resistor (approximately 10

Ω) in the VCC line to improve the power

supply's ripple effects. Although inserting a 10

Ω resistor lowers the voltage by about 0.2 V, this IC has a wide margin

for low-voltage operation, so dynamic range problems or other problems should not occur. (See Figures 12 to 14.)

0

5

10

15

20

0.0

0.5

1.0

1.5

2.0

Fig. 48 Circuit current vs. STBY terminal voltage

STBY TERMINAL VOLTAGE [V]

VCC=3V Ta=25℃

BH76812FVM