NTE7138 データシートの表示（PDF） - NTE Electronics

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NTE7138

Integrated Circuit Advanced Monitor Video Controller for OSD

NTE Electronics 

Notes to the Characteristics (Cont’d):

Note 8. ∆Gtrack = 20 x maximum of

log

A1

A10

x

A20

A2

; log

A1

A10

x

A30

A3

; log

A2

A20

x

A30

A3

dB

Ax: signal output amplitude in channel x at any contrast sertting between 1 and 6V.

Ax0: signal output amplitude in channel x at nominal contrast and same gain setting.

Note 9. Typical step in contrast voltage and response at signal outputs for nominal input signal

Vi(b–w) = 0.7V (OSD fast blanking input/output).

Note10. Linear control range is 1 to 6V for Vi(GC), independent of supply voltage.

Note 11. The internal reference voltage can be measured at Pin18, Pin15 and Pin12 (channel feed-

back inputs) during output clamping (Vi(HBL) = 2V) in closed feedback loop.

Note12. Slow variations of video supply VCRT will be suppressed at CRT cathode by cut–off stabiliza-

tion. Change of VCRT by 5V leads to specified cghange of cut–off voltage.

Note13. The test mode allows testing without input and output clamping pulses. The signal inputs

have to be biased via resistors to the previously measured clamp voltages of approximately

3V (artificial black level + VBE). Signal and brightness blanking is not possible during test

mode. The current outputs should be adjusted by resistors >> R0 from voltage outputs to a

positive voltage (e.g. VP).

Note14. The signal–to–noise ratio is calculated by the formula (frequency range 1 to 70MHz):

S

N

= 20 x log

peak–to–peak value of the nominal signal output voltage

RMS value of the noise output voltage

dB

Note15. Large output swing e.g. Io(b–w) = 50mA leads to signal–dependent power dissipation in output

transistors. Thermal VBE variation is compensated.

Note16. Composite signals will not disturb normal operation because an internal clipping circuit cuts

all signal parts below black level.

Note17. The output current approximately follows the equation Io = Vo

1

RO

+

1

2.2kΩ

–500µA for

Vo > Vb(SO) and with RO = external resistor at voltage output to GND. The external RC com-

bination at Pin19, Pin16 and Pin13 (voltage outputs) enables peak currents during tran-

sients.

Note18. Frequency responses, crosstalk aznd pulse response have been measured at voltage out-

puts on a special printed–circuit board with 50Ω line in/out connections and without peaking.

Note19. Crosstalk between any two voltage outputs (e.g. channels 1 and 2).

a) Input conditions: one channel (channel1 ) with nominal input signal and minimum

rise time. The inputs of the other channels capacitively coupled to GND (channels 2

and 3). Gain Pin3 and Pin11 open–circuit.

b) Output conditions: output signal of channel 1 is set by contrast control voltage, to

Vo(b–w) = Vo(VOUT1) = 0.7V, the rise time should be 5ns. Output signal of channel 2 then

is Vo(b–w) = Vo(VOUT2).

c) Transient crosstalk: αct(tr) = 20 x log

Vo(VOUT2)

Vo(VOUT1)

db

d) Crosstalk as a function of frequency has been measured without peaking circuit, with

nominal input signal and nominla settings.

Note20. The internal threshold voltages are derived from a stabilized voltage. The internal pulses are

generated while the input pulses are higher than the thresholds. Voltages less than –0.1V

at Pin9 and Pin10 can influence black–level control and should be avoided.

Note21. The delay between HBL input pulse (horizontakl blanking) and output signal blanking pulse

and also brightness blanking (∆Vbl), at the voltage outputs, depends on the input rise time

of the HBL pulse. The specified values for td(Hblank) are valid for HBL rise times greater than

100ns only.

Note22. For 75ns/V < tf(CL) < 240ns/V, generation of internal input clamping and blanking pulse is not

defined. Pulses not exceeding the threshold of input clamping (typical 3V) will be detected

as blanking pulses.

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