SI9140 Datasheet, PDF (8/15 Pages) Vishay Siliconix – SMP Controller For High Performance Process Power Supplies

Si9140
Vishay Siliconix
Pin 10: R_OSC
A resistor connected from this pin to ground sets the
oscillator’s capacitor C_OSC, charge and discharge current.
See the oscillator section of the description of operation.
Pin 11: C_OSC
An external capacitor is connected to this pin to set the
oscillator frequency.
f
O
S
C
≅
-------------⁰---^.--⁷---⁵--------------
R_OSC × C_OSC
(at V_DD = 5.0 V)
Pin 12: UVLO_SET
This pin will place the chip in the standby mode if the
UVLO_SET voltage drops below 1.2 V. Once the UVLO_SET
voltage exceeds 1.2 V, the chip operates normally. There is a
built-in hysteresis of 165 mV.
Pin 13: P_GND
The negative return for the V_S supply.
Pin 14: D_S
This CMOS push-pull output pin drives the external p-channel
MOSFET. This pin will be high in the standby mode. A
break-before-make function between D_S and D_R is built-in.
Pin 15: D_R
This CMOS push-pull output pin drives the external n-channel
MOSFET. This pin will be low in the standby mode. A
break-before-make function between the D_S and D_R is built-in.
Pin 16: V_S
The positive terminal of the power supply which powers the
CMOS output drivers. A bypass capacitor is required.
FUNCTIONAL BLOCK DIAGRAM
S-58034—Rev. G, 15-Mar-99
8
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