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N4E-A1-110356 Datasheet situation where the designer has generated the external clock frequency using TTL logic, the addition ofa 10k pull- up resistor to V supply is required. Note that the pump frequency with external clocking, as with internal clocking, will be l/2 0f the clock frequency. Output transitions occur on the positive-going edge of the clock. It is also possible to increase the conversion efficiency ofthe TC1044S at low load levels by lowering the oscillator frequency.This reducesthe switching losses,and isachieved by connecting an additional capacitor, Cosc, as shown in Figure 7. Lowering the oscillator frequency will cause an undesirable increase in the impedance ofthe pump (Ci) and the reservoir (C2) capacitors. To overcome this, increase the values of Ci and C2 by the same factor that the frequency has been reduced. For example, the addition of a 100pF capacitor between pin 7 (OSC) and pin 8 (V+) will lower the oscillator frequency t0 1kHz from its nominal frequency of 10kHz (a multiple of 10), and necessitate a corresponding increase in the values of Ci and C2 (from 10ccF t0 100ccF). N4E-A1-110356 on stock band.The bump size and pitch of these filters are selected such that the device can be placed directly on a FR4 printed circuit board using conventional assembly techniques. Ground-bounce and cross-talk are mini- mized by a die design that provides eight solder bump contacts to the common supply connection.The solder bump contacts are a 63/37 Sn/Pb alloy and are nomi- nally 0.30 mm in diameter.
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