NJM2352
- 1
-
Ver.2003-07-18
■ MINIMUM OPERATING VOLTAGE
Minimum operating voltage is V
+
≥ 2.6V at 25°C and its temperature coefficient is negative. Be careful when you
design. Less than this minimum operating voltage, internal switching transistor becomes on, and the surge-like high
current flows into it especially in Step-Up or Inverting application.
■ OSCILLATOR
Oscillator frequency is decided by putting a capacitor into PIN 2. The amplitude of both square wave A and triangular
wave B is between 1 V
BE
and 3V
BE
.
■ AMPLIFIER
AMP source current it 20 µA max. and so the feedback resistor R
1
to be connected to PIN 6 and PIN 7 are
recommended more than 100kΩ.
■ SWITCHING TRANSISTOR
When the negative voltage more than 0.5V absolute value based on ground level is applied, the NJM2352 may
operate unordinary by reason of parasitic effect in it. And so put SBD in between PIN 3 and ground when you drive
directory coil with internal switching transistor.
NJM2352
■ DETECTION CIRCUIT OF INPUT VOLTAGE DROP
When input voltage becomes lower than specified voltage, transistor Q
56
switches on and indicative device like LED
turns on. The specified voltage is decided by internal reference voltage and outer resistors ratio.
V
TH
= V
REF
(1+R2/R5) + R2 x 0.5µA
When - input voltage becomes lower than + input voltage, PIN 1 of COMP-3 sinks about 1µA and thus prevents
chattering. Transistor Q56 becomes off condition when PIN 1 voltage is lower than about 0.2V. It is recommendable to
put about 1µF to PIN 1 in actual application to avoid switching noise.
