R1234D Datasheet, PDF (7/26 Pages) RICOH electronics devices division – PWM/VFM Step-Down DC/DC CONVERTER with Synchronous Rectifier

• R1234DxxxC
Symbol
VIN
VFB
∆VFB/∆Topt
fosc
IDD
Istandby
RONP
RONN
ILXleak
IVFBleak
ICE
IMODE
VCEH
VCEL
VMODEH
VMODEL
Maxduty
tstart
VLXlim
Tprot
VUVLO1
VUVLO2
VFMduty
Item
Operating Input Voltage
Feedback Voltage
Feedback Voltage
Temperature Coefficient
Oscillator Frequency
Supply Current
Standby Current
ON Resistance of Pch Transistor
ON Resistance of Nch Transistor
LX Leakage Current
VFB Leakage Current
CE Input Current
MODE Pin Input Current
CE "H" Input Voltage
CE "L" Input Voltage
MODE "H" Input Voltage
MODE "L" Input Voltage
Oscillator Maximum Duty Cycle
LX Limit Voltage
Delay Time by Soft-Start function
Delay Time for protection circuit
UVLO Threshold Voltage
UVLO Released Voltage
VFM Duty Cycle
Conditions
VIN=VCE=VSET+1.5V,
VMODE=0V, IOUT=10mA
−40°C ^<= Topt ^<= 85°C
VIN=VCE=VSET+1.5V
VIN=VCE=VSET+1.5V,
VFB =VMODE=0V
VIN=5.5V, VCE=VFB=0V
VIN=5.0V
VIN=5.0V
VIN=5.5V, VCE=0V,
VLX=0V or 5.5V
VIN=5.5V, VCE=0V,
VFB=0V or 5.5V
VIN=5.5V, VMODE=0V,
VCE=5.5V or 0V
VIN=5.5V, VCE=0V,
VMODE=5.5V or 0V
VIN=5.5V, VFB=0V
VIN=2.4V, VFB=0V
VIN=VCE=5.5V, VFB=0V
VIN=VCE=2.4V, VFB=0V
VMODE=0V
at no load,
VIN=VCE=VSET+1.5V
VMODE=VFB=0V,
VIN=VCE=3.0V
VIN=VCE=3.6V,
VMODE=0V
VIN=VCE=2.5V→1.5V,
VMODE=0V
VIN=VCE=1.5V→2.7V,
VFB=0V
VIN=VCE=VMODE=2.4V,
VFB=0V
R1234D
Min.
2.7
Typ.
Topt=25°C
Max. Unit
5.5
V
0.776 0.800 0.824 _V
±300
ppm/
°C
425 500 575 kHz
230 300 µA
0
5
µA
0.2 0.4 0.9 Ω
0.2 0.6 0.9 Ω
−5.0 0.0 5.0 µA
−0.1 0.0 0.1 µA
−0.1 0.0 0.1 µA
−0.1
0.1 µA
1.5
V
0.3
V
1.5
V
0.3
V
100
%
0.5 1.5 2.5 ms
VIN
VIN
VIN
−0.15 −0.35 −0.65
V
0.5 1.5 2.5 ms
1.95 2.20 2.45 V
2.20 2.40 2.65 V
55
65
85
%
7