XC9141/XC9142
Series
■NOTE ON USE
1)
For the phenomenon of temporal and transitional voltage decrease or voltage increase, the IC may be damaged or deteriorated if IC is used
beyond the absolute maximum ratings.
2)
Spike noise and ripple voltage arise in a switching regulator as with a DC/DC converter. These are greatly influenced by external component
selection, such as the coil inductance, capacitance values, and board layout of external components. Once the design has been completed,
verification with actual components should be done.
3)
The DC/DC converter performance is greatly influenced by not only the ICs' characteristics, but also by those of the external components.
Care must be taken when selecting the external components. Especially for CL load capacitor, it is recommended to use type B capacitors
(JIS regulation) or X7R, X5R capacitors (EIA regulation).
4)
5)
6)
7)
Use a ground wire of sufficient strength. Ground potential fluctuation caused by the ground current during switching could cause the IC
operation to become unstable, so reinforce the area around the GND pin of the IC in particular.
Please mount each external component as close to the IC as possible. Also, please make traces thick and short to reduce the circuit
impedance.
With regard to the current limiting value (ILIM), the actual coil current may at times exceed the electrical characteristics due to propagation
delay inside the product.
The CE pin is a CMOS input pin. Do not use with the pin open. If connecting to the BAT pin or ground pin, use the resistor which is 1MΩ or
less. To prevent malfunctioning of the device connected to this product or the input/output due to short circuiting between pins, it is
recommended that a resistor be connected.
8)
9)
In case of connecting to another power supply as shown in below circuit diagram, please use the XC9142C/F type. Connecting another
external power supply to the output of any other type may destroy the IC.
The maximum current limiter controls the limit of the N-channel driver transistor by monitoring current flow. This function does not limit the
current flow of the P-channel synchronous transistor. When used with the condition VBAT > VOUT (input voltage higher than the output voltage),
the IC may be destroyed if overcurrent flows to the P-channel synchronous switching transistor due to short-circuiting of the load or other
reason.
10) When the device is used in high step-up ratio, the current limit function may not work during excessive load current. In this case, the
maximum duty cycle limits maximum current. In this event, latching may not take place on XC9141D/E types and XC9142D/E/F types (“latch
types” below) because the maximum current limit cannot be detected.
11) On latch types, some board conditions may cause release from the maximum current limit, and the integrated latch time may become longer
or latching may not take place.
12) If the status heavy load and large output capacitor is connected or the input voltage is low, the output voltage may overshoot, on XC9141A/B
types and XC9142A/B/C types(“non-latch types” below). On a latch type, the maximum current limit may be detected, and this will cause
the latch function to activate and stop operation after the soft start time elapses. In particular, note that the soft start time becomes shorter
when the IC is used at high temperatures.
13) When the step-up voltage difference is small, the XC9141 series for PWM control may oscillate intermittently.
14) When the voltage boost difference is small, the current limiting function may not operate if the on time of the N-channel driver transistor is
shorter than the propagation delay time of the current limit circuit. In this case, latching may not take place on a latch type because the
maximum current limit is not detected.
15) When an XC9142C/F type is used with VBAT > VOUT(T) (input voltage higher than the set output voltage), the P-channel synchronous switching
transistor turns off but current flows to the parasitic diode. This causes excessive heat generation in the IC. Test using the actual equipment
and note the power dissipation and heat dissipation of the package. During voltage boosting with a voltage drop due to VF of the parasitic
diode, the output voltage may become unstable. On the XC9141 series and XC9142A/B/D/E types, the P-channel synchronous switching
transistor turns on and the output voltage becomes equal to the input voltage. In environments where VBAT > VOUT（T）, the XC9141 series and
XC9142A/B/D/E types are recommended.
16) When input voltage and output voltage are low, integral latch function and short-circuit protection may not operate.
We recommend that you fully check actual performance.
17) TOREX places an importance on improving our products and its reliability. However, by any possibility, we would request user fail-safe
design and post-aging treatment on system or equipment.
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