XRP7674 Datasheet, PDF (10/12 Pages) Exar Corporation – 2A 18V Synchronous PFM/PWM Step-Down Regulator

XRP7 6 7 4
2 A 1 8 V Sy n ch r on ou s PFM/ PW M St ep - Dow n Reg u lat or
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w here R _load is the output load resistance .
The uncompensated regulator has a constant
gain up to its pole frequency, beyond which
the gain decreases at - 20dB/decade. The zero
arising from the output capacitor ¶s ESR is
inconsequential if ceramic C _OUT is used. This
simplifies the compensation. The RC and CC,
which are placed between the output of
XRP7674 ¶V (UURU $PSOLILHU
constitute a zero. The frequency of this
compensating zero is given by:
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For the typical application circuit,
RC= 13 NŸ
and CC= 4.7 nF provide a satisfactory
compensation . The XRP7674 can also be used
as a pin to pin upgrade replacement for
XRP7664 based designs; in this instance, the
recommended RC network for XRP7664,
RC=5.6k and CC=3.3nF , can be used with
satisfactory results with the XRP7674 . Please
contact EXAR if you need assistance with the
c^Do^Qmp^Gen^sati^Jon^Uof^Ry^Xou^Qr p^Gar^tic^ular circuit.
TYPICAL APPLICATIONS
Fig. 18 : XRP7674 Typical Application Diagram - 12V to 3.3V Conversion
© 2013 Exar Corporation
10 / 12
Rev. 1.0.0