R1151N Datasheet, PDF (25/26 Pages) RICOH electronics devices division – Boost type Voltage Regulator with Reset

R1151N
Calculation of Output Delay Time of Release
tPLH(s)=1.83×C/(300×10^-9)
tPHL vs. Capacitance
30
25
20
15
10
5
Measured value
Calculated value
0
0
1000 2000 3000 4000 5000
External Capacitance for CD pin (pF)
For Stable Operation
Phase Compensation
In these ICs, phase compensation is externally made for securing stable operation even if the load current is varied.
For this purpose, be sure to use a capacitor for the output pin with good frequency characteristics and ESR (Equivalent
Series Resistance) of which is in the range described as follows:
Ceramic
Capacitor
VIN
4.7µF
VDET
CD
EXT
VIN R1151NxxxxC
VOUT
GND
Ceramic
Capacitance
10µF
ESR
IOUT
Spectrum
Analyser
S.A.
Measuring Circuit for white noise; R1151NxxxC
The relations between IOUT (Output Current) and ESR of Output Capacitor are shown below. The conditions when the
white noise level is under 40µV (Avg.) are marked as the hatched area in the graph.
<Measurement conditions>
(1) VIN=VOUT+1V
(2) Frequency band: 10Hz to 1MHz
(3) Temperature: 25°C
(4) COUT: Ceramic 10µF; ESR=0.075Ω (10kHz)
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