The BH768xx series video drivers are the optimum solution for high density integration systems such as, digital still
cameras, mobile phones, and portable video devices. A built-in charge pump circuit eliminates the need for a large output
coupling capacitor. Features include: a built-in LPF, low-voltage (2.5 V) operation, and 0 µA current consumption during
standby mode.
●Features
1) Select from four video driver amp gain settings: 6 dB, 9 dB, 12 dB, and 16 dB
2) Large-output video driver with maximum output voltage of 5.2 Vpp.
Supports wide and low-voltage operation range.
3) No output coupling capacitor is needed, which makes for a more compact design
4) Built-in standby function sets circuit current to 0 µA (typ.) during standby mode
5) Clear image reproduction by on-chip 8-order 4.5-MH
6) Bias input method is used to support chroma, video, and RGB signals.
7) MSOP8 compact package
●Applications
Mobile telephones, DSCs (digital still cameras), DVCs (digital video cameras), portable game systems,
portable media players, etc.
●Line up matrix
Part No. Video driver amp gain Recommended input level
z LPF (Low Pass Filter)
BH76806FVM 6dB 1Vpp
BH76809FVM 9dB 0.7Vpp
BH76812FVM 12dB 0.5Vpp
BH76816FVM 16.5dB 0.3Vpp
Absolute maximum ratings (T
Parameter Symbol Ratings Unit
Supply voltage Vcc 3.55 V
Power dissipation Pd 470 mW
Operating temperature range Topr
Storage temperature range Tstg -55~+125 ℃
* Reduce by 4.7 mW/C over 25C, when mounted on a 70mm×70mm×1.6mm PCB board.
*1 The DC voltage in the figure is VCC = 3.0 V. These values are for reference only and are not guaranteed.
*2 These values are for reference only and are not guaranteed.
*1 The DC voltage in the figure is VCC = 3.0 V. These values are for reference only and are not guaranteed.
*2 These values are for reference only and are not guaranteed.
Description of operations
1) Principles of video driver with no output coupling capacitor
Amp (Single power supply)
Amp (Dual power supply)
VCC
1/2VCC Bias
Fig.3 Fig.4
When the amplifier operates using single voltage power supply, the operating potential point is approximately 1/2 Vcc.
Therefore, a coupling capacitor is required to prevent DC output. For the video driver, the load resistance is 150 (75
+ 75 ). Therefore, the coupling capacitor should be about 1000 µF when a low bandwidth for transmission is considered.
(See Figure 3.)
When the amplifier operates using a dual (±) power supply, the operating point can be set at GND level, and therefore,
there is no need for a coupling capacitor to prevent DC output.
Since a coupling capacitor is not needed, there is no sagging of low-frequency characteristics in output stage. (See Figure
4.)
2) Generation of negative voltage by charge pump circuit
As is shown in Figure 5, the charge pump consists of a pair of switches (SW1 and SW2) and a pair of capacitors (flying
capacitor and load capacitor), generating a negative voltage. When +3 V is applied to this IC, approximately -2.83 V of
negative voltage is obtained.
As is shown in Figure 6, in the BH768xxFVM Series, a dual power supply amplifier is integrated with a charge pump circuit
in the same IC. This enables operation using a + 3V single power supply while also using a dual power supply amplifier,
which eliminates the need for an output coupling capacitor.
1μF
AMP
VCC
Dual power supply amp
ンプ H768xxFVM
75Ω
150k
VCC
75Ω
Single chip
integration
Output capacitor not required
for single power supply either.
Charge Pump
-VCC
3.3μF
Charge pump
768xxFVM
1μF
Fig. 6 BH768xxFVM Configuration Diagram
2) Input terminal type and sag characteristics
BH768xxFVM Series devices provide both a low-voltage video driver and a large dynamic range (approximately 5.2 Vpp).
A resistance termination method (150 k termination) is used instead of the clamp method, which only supports video
signals, since it supports various signal types.
The BH768xxFVM series supports a wide range of devices such as, video signals, chroma signals, and RGB signals that
can operate normally even without a synchronization signal.
In addition, input terminating resistance (150 k) can use a small input capacitor without reducing the sag low-band
It is recommended to use a H-bar signal when evaluating sag characteristics, since it makes sag more noticeable. (See
Figures 7 to 10.)
※Although ROHM is confident that the example application circuit reflects the best possible
recommendations, be sure to verify circuit characteristics for your particular application.
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 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/(2π× C3 × 150 k) (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 ) in the VCC line to improve the power
supply's ripple effects. Although inserting a 10 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.)
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Examples of application circuits, circuit constants and any other information contained herein
illustrate the standard usage and operations of the Products. The peripheral conditions must
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