BD6934FV

Technical Note

10/12

www.rohm.com

2009.09 - Rev.B

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●Operating explanation

Driving current adjustment function.

This IC control the duty of output pulse in response to supply voltage(Vcc).

This function is allowed to control driving current and adjust the arrival range of radio frequency. The relationship

between supply voltage(Vcc) and output(OUTN) is as shown in the following figure.

This data is typical , refer to the electrical characteristics in regard to variation.

External FET

Connect

PchMOS to OUTP and Nch MOS to OUTN

Vds＞VCC, Vgs＞VCC, Allowable current ＞ Output current

There is a possibility that upper and lower FET turn on at the same time. It is recommended to use 1000pF or smaller

at input capacitor of external FET. However , these characteristics change in the layout pattern and parts variation and

so on. Make evaluations with using board in mass production.

Oscillation precision and condition

The oscillation precision depends on the condition of ceramic resonator. This IC is evaluated with the ceramic

resonator (Product No.CSTCR4M00G55B-R0) of MURATA manufacturing. In the range of

Vcc 2.2~2.7V, this IC

stops its oscillation without disenabling the ceramic resonator.

● OPERATING NOTES

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 specialmode

where the absolute maximum ratings may be exceeded is anticipated.

2)

GND potential

Ensure a minimum GND pin potential in all operating conditions.

3)

Thermal design

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 mounting

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 and the power supply and GND pins caused by the presence of a foreign

object may result in damage to the IC. Ensure a minimum GND pin potential in all operating conditions.

5)

Actions in strong magnetic field

Keep in mind that the IC may malfunction in strong magnetic fields.

Vcc(v)

3.5 4

7

8

9.17

15

49

(%)

Duty

Fig.36 Supply voltage (Vcc) - Output (OUTN) Duty