R1155 Datasheet, PDF (10/26 Pages) RICOH electronics devices division – 150 mA 24 V Input High Voltage Regulator

R1155x
NO.EA-270-150702
APPLICATION INFORMATION
V IN
V IN
V DD
R11 5 5x x xxB
V OUT
CIN
CE
V OUT
CIN
GND
COUT
V DD
R115 5x00 1C
V _OUT
CE
GND
VFB
V OUT
R1
COU T
R2
R1155xxxxB Typical Application
(Fixed Output Voltage Type)
R1155x001C Typical Application
(Adjustable Output Voltage Type)
Technical Notes on the Components Selection
 In the R1155x, phase compensation is provided to secure stable operation even when the load current is
varied. For this purpose, use a 4.7 μF or more output capacitor (COUT) with good frequency
characteristics and proper ESR (Equivalent Series Resistance). In case of using a tantalum type
capacitor and the ESR value of the capacitor is large, the output might be unstable. Evaluate the circuit
including consideration of frequency characteristics.
 Ensure the VDD and GND lines are sufficiently robust. If their impedance is too high, noise pickup or
unstable operation may result. Connect COUT with suitable values between the VOUT and GND pins, and
as close as possible to the pins. Please refer to Figure 5 and Figure 6 below.
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