BA8400FV ROHM

Document overview

  • Manufacturer or author: Provided By www.digicamel.com(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 9

Technical content

CTL recording / playback amplifier for VHS VCRs BA8400FV The BA8400FV is a CTL recording / playback amplifier developed for VHS VCRs. The playback amplifier has an AGC circuit that can handle large input signal fluctuations, and a recording / playback switching circuit is provided to allow high-speed switching.

  • Applications VHS-format VCRs
  • Features 1) Can be operated off low power supply voltage (2.7V to 3.5V). 2) Playback amplifier with AGC. 3) Fast switching between recording and playback.
  • Block diagram SW P R P R P R Ref REC AMP AGC AMP DET 141 132 123 114 105 CTL OUT VCC FILTER HysBIAS AGC MONI OUT IN – BIAS RECHPB RECIN GND CTL + CTL – RECPBGND
  • Pin descriptions Pin No. Pin name Function CTL OUT (CTL pulse output) RECHPB (record / play switch) RECIN (REC CTL pulse input) GND CTL + (CTL head “+” input) CTL – (CTL head “–” input) RECPBGND BIAS (bias) IN – (playback amplifier input) MONIOUT (playback amplifier output) AGC (AGC time constant) HysBIAS (hysteresis amplifier center level) FILTER (high-frequency noise filter) V CC CTL pulse output. High output level approx. VCC – 0.05V, IO = + 0.5mA Low output level approx. 0.05V, IO = – 0.5mA Switch input pin for the record / playback amplifiers. High input: REC mode Low input: PB mode Threshold voltage: approx. 1 / 2V CC CTL pulse input pin for recording. Threshold voltage: approx. 1 / 2V CC Power, REC / PB SW, CTL output buffer ground pin. Ground pin for the REC and playback amplifiers. Feedback input pin for the playback amplifier. Playback amplifier output monitor pin. Output dynamic range is the DC level – Vf. Set the time constant after considering the transient response of the playback mode switching. AGC detect level VdetAGC = 0.47V CC [V] (approx.) Playback amplifier output amplitude VAGC = 2 · (VdetAGC – HysVcent) [VP-P] Connection pin for the bypass capacitor for the hysteresis amplifier center level. Connect a decoupling capacitor close to the pin. Pin for connection of high-frequency noise filter for AGC amplifier output for playback CTL pulse. Also, input pin for the hysteresis amplifier. Hysteresis amplifier center voltage HysVcent = 0.27Vcc [V] approx. High-side hysteresis width DHysVH = 0.367V CC – HysVcent [V] Low-side hysteresis width DHysVL = 0.173VCC – HysVcent [V] Bias pin for the playback amplifier. Bias voltage: VIB8 = 0.15VCC + 1.3V (approx.) When recording: CTL head positive-side recording current. When playing: input pin for the playback CTL pulse. When recording: CTL head negative-side recording current. When playing: bias pin for the playback CTL pulse input.
  • Absolute maximum ratings (Ta = 25°C) Parameter Symbol Limits Unit Power supply voltage Power dissipation Operating temperature Storage temperature V CC Pd Topr Tstg 8.0 450* – 25 ~ + 75 – 55 ~ + 125 V mW * Reduced by 4.5mW for each increase in Ta of 1 °C over 25°C.
  • Recommended operating conditions (Ta = 25°C) Parameter Symbol Limits Unit Applied voltage V CC 2.7 ~ 3.5 V sNot designed for radiation resistance.
  • Input / output circuits Vcc 25k 30k 25k CTLOUT

1 RECPB

CTL – 30k 25k 25k RECIN 22k 45k 30k BIAS Vcc Vcc Vcc Vcc Fig.1 Fig.2 Fig.3 Fig.5 Fig.4

IN – MONIOUT CTL + 22k 45k 30k 1.7V 1.7V 100 5.6k 15.9k 19k 2.9k 2.9k 5.2k 14.1k 100 AGC HysBIAS FILTER Vcc Vcc Vcc Fig.6 Fig.7 Fig.8

Parameter Symbol Min. Typ. Max. Unit Conditions Circuit current ÆAGC amplifieræ AGC amplifier gain Input bias voltage Pin 5 input resistance AGC control sensitivity Output amplitude ÆHysteresis amplifieræ Hysteresis width CTLOUT output high level voltage CTLOUT output low level voltage ÆREC amplifieræ Recording current Max. output high level voltage Max. output low level voltage Threshold voltage Input resistance ÆREC / PB switchæ Threshold voltage REC to PB switching time ICC GVagc VIB8 ZIN5 DAGC / V VAGC DHysV VOHP VOLP Irec VOHR VOLR Vth3 ZIN3 Vth2 TR – P 2.5 1.35 1.6 – 2 0.88 – 250 2.0 – 1.3 2.0 1.0 1.0 3.5 4.5 1.7 2.0 1.1 – 290 2.8 0.2 – 2.5 2.8 0.2 1.5 1.5 7.0 6.5 2.05 2.4 + 2 1.32 – 330 1.0 – 3.7 1.0 2.0 2.0 100 mA dB V kW dB V P-P mV V V mA V V V kW V ms No signal, CTLOUT: High V IN = 0.15fi 1.0VP-P f = 300Hz, VIN = 300mVP-P IO = – 0.5mA IO = + 0.5mA R O = 400 W IO = – 0.5mA IO = + 0.5mA *See note below * Note: The switching time from REC to PB is the time until CTLOUT is output.

  • Electrical characteristics (unless otherwise noted, Ta = 25°C and VCC = 3V)

P R P R P R Ref + – REC AMP AGC AMP DET VCC VCC 132 123 114 105 A Am14 SW13a V 1000p Vm13 270k 4.7k 1M1m 10m Vm10 SW10 12k330k 820910 + V V ab ab SW9 10m 1m Vm8 SW12 Vs13 SW13b V A V Is2 abc SW2 OSC abc abc SW5 SW1 Am2 Am3 VCC A V Vm3 Vm1 Is1 Vm5 400 Am56 Vm6 abc Vs3 d SW3 Is5 10m A V V Fig.9

  • Measurement circuit

Parameter Symbol Monitor Notes Switch position SW SW SW SW SW SW SW SW 13a SW 13b Circuit current ÆAGC amplifieræ AGC amplifier gain Input bias voltage Pin 5 input resistance AGC control sensitivity Output amplitude ÆHysteresis amplifieræ Hysteresis width CTLOUT output voltage H CTLOUT output voltage L ÆREC amplifieræ Recording current 5 Recording current 6 Max. output voltage "H" Max. output voltage "L" Input threshold voltage Input resistance ÆREC / PB switchæ Threshold voltage REC to PB switching time Am14 Vm13 Vm8 Vm5 13pin 13pin Vm1 Vm1 Vm1 Am56 Am56 Vm1 Vm1 Vm3 Vm3 Vm2 1pin a a a a a a a c c a a c c a a a a a a a b a a a a a b b b b b b c ba a a a b a a a a a b a b a c d a a a c a b c c a a a a a a a a a a c a b a a a a a a a a a a a a a a a a b a a b b a a a a a a a a a a a ON OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF ON OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF b b b OFF OFF OFF OFF OFF OFF OFF OFF *1. f = 300Hz, VIN = 50mVP-P *3. f = 300Hz, VIN = 0.15 / 1.0VP-P *4. f = 300Hz, VIN = 300mVP-P *2. *5. IO = – 0.5mA, Vs13 = 1.5V IO = + 0.5mA, Vs13 = 0V *6. *6. IO = – 0.5mA IO = + 0.5mA ICC GVagc VIB8 ZIN5 DAGC / V VAGC DHysV VOHP VOLP Irec5 Irec6 VOHR VOLR Vth3 ZIN3 Vth2 TR-P

  • Measurement conditions (unless otherwise noted, Ta = 25°C and VCC = 3V) Measurement method *1 Input a sine wave of f = 300Hz to pin 5, and measure the output amplitudes on pins 10 and 13 (Vo10 and Vo13). The AGC gain is given by: Gvagc = 20log (Vo13 / Vo10) [dB]. *2 Measure the output voltages Vo0 and Vo.5 on pin 5 when currents of Is5 = 0, and Is5 = 0.5mA are applied. The input resistance is given by: ZIN5 = {0.0005 / (Vo.5 Vo0) 1 / 400} –1 [W ] *3 Input a sine wave of f = 300Hz to pin 5. Adjust the input level until the output amplitude on pin 10 is 0.15VP-P and 1.0VP-P, and measure the correspond- ing output amplitudes on pin 13 (Vo0.15 and Vo1.0). The AGC control sensitivity is given by: DAGC / V = 20log (Vo1.0 / Vo0.15) [dB]. *4 Input a sine wave of f = 300Hz to pin 5. Adjust the input level until the output amplitude on pin 10 is 300mV P-P. Measure the output amplitude on pin 13. *5 With pin 13 floating, measure the output voltage Vocent. Increase Vs13 from 0V, and record VINH as the Vs13 voltage when the pin 1 output exceeds 2.8V. Decrease Vs13 from 1.5V, and record VINL as the Vs13 voltage when the pin 1 output goes below 0.2V. High-side hysteresis width DHysVH = VINH Vocent [VP-P] Low-side hysteresis width DHysVL = VINL Vocent [VP-P] The input resistance is given by: ZIN3 = 0.3 / (IIN3.0 IIN2.7) [W ] *7 Input a square wave of 300Hz, VIN = 20mVP-P to pin 5, and measure the time that it takes CTLOUT to be output after pin 2 goes from VCC to 0V.

P R P R P R Ref + – REC AMP AGC AMP DET 141 132 123 114 105 CTL OUT VCC 3.0V FILTER HysBIAS AGC MONI OUT IN – BIAS RECHPB RECIN GND CTL + CTL – RECPBGND 1mF 10mF 1M W 910W 1mF 330kW 22mF 33mF 1000pF Fig.10

  • Application example

0.1 0.22 – 0.10.65 6.4 – 0.3 4.4 – 0.2 5.0 – 0.2 1.15 – 0.1 0.15 – 0.1 0.3Min. 0.1

  • External dimensions (Units: mm)