HA12155 データシートの表示（PDF） - Hitachi -> Renesas Electronics

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HA12155

Audio Signal Processor for Cassette Deck (Dolby B/C-type NR with Recording System)

Hitachi -> Renesas Electronics 

HA12155NT/HA12157NT

Table 2 Threshold Voltage (VTH)

Pin No.

Lo

Hi

Unit

1, 2, 3

–0.2 to 1.0

3.5 to 5.3

V

62, 63, 64

–0.2 to 1.0

3.5 to 5.3

V

Notes: 1. Voltages shown above are determined by internal circuits of LSI when take pin 55 (DGND pin) as

reference pin. On split supply use, same V can be offered by connecting DGND pin to GND

TH

pin.

This means that it can be controlled directly by micro processor.

2. Each pins are on pulled down with 100 kΩ internal resistor.

Therefore, it will be low-level when each pins ar open.

3. Note on serial data inputting

(a) The clock frequency on CLK must be less than 500 kHz.

(b) Over shoot level and under shoot level of input signal must be the value shown below.

(c) The serial input pins (pins 62, 63, and 64) are extremely sensitive to undershoot, overshoot,

ringing, and noise. This can result in malfunctions due to problems with the wiring pattern.

We recommend attaching capacitors in parallel with the serial input pins to ameliorate this

problem.

Figure 2-b shows an example of this circuit appropriate when the clock frequency is 500

kHz. The value of the capacitor should be set in accordance with the clock frequency

actually used.

4. NR Mode Switching

In actual use, pop noises may accompany NR on/off switching in C mode. To avoid these

noises, use the following sequences to turn NR on and off.

From C mode NR off to C mode NR on:

(C mode, NR off) → (B mode, NR off) → (B mode, NR on) → (C mode, NR on).

From C mode NR on to C mode NR off:

(C mode, NR on) → (B mode, NR on) → (B mode, NR off) → (C mode, NR off).

Table 3 Switching Truth Table

Pin No.

Lo

Hi

1

NR-OFF

NR-ON

2

B-NR

C-NR

3

MPX-ON

MPX-OFF

Notes: 1. Low level will be offered when each pins are open.

2. Please refer to next term as for the serial data for formatting.

When connecting microcomputer or Logic-IC with HA12155NT/HA12157NT directly, there is

apprehension of rash-current under some transition timming of raising voltage or falling voltage at VCC

ON/OFF.

For this countermeasure, connect 10 kΩ to 20 kΩ resistor with each pins. It is shown in test circuit.

Rev.4, Jun. 1997, page 15 of 57

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