LA70011 Datasheet, PDF (9/11 Pages) Sanyo Semicon Device – Recording/Playback Amplifier for VHS VCRs

LA70011, 70011M
Envelope Detector Characteristic: Pin 6
The LA70011 includes a built-in playback signal envelope detector circuit for use in automating tracking adjustment.
Envelope detector voltage characteristic
Pin 6 level - detector
DC level (V)
EP, with 18kΩ resistor on pin 6
SP, with 18kΩ resistor on pin 6
Pin 7 level - playback output level (mVp-p)
REC AMP Gain Control
The LA70011 eliminates recording current adjustment by adding an automatic gain control circuit to the recording
amplifier. It is also possible to change the recording current with the following methods.
REC-CURRENT-ADJ2 Open
The internal bias forces the DC level at pin 12 to 1/2 V_CC (that is, approximately 2.5 V), and R_O1 determines the
recording current.
Design values
R_O1 = 1.5 kΩ = 16.0 mA (SP) (per channel)
R_O1 = 1.5 kΩ =12.7 mA (EP)
REC-CURRENT-ADJ2 Used
Applying a DC control voltage between 1 and 4 V to pin 12 adjusts the figure determined by R_O1 between –6.0 dB and
+3.5 dB.
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