PWM STEP-UP DC/DC CONVERTER WITH
VOLTAGE REGULATOR AND DETECTOR
RS5RM SERIES
OUTLINE
NO. EA-018-0311
The RS5RM Series are CMOS-based step-up DC/DC converter ICs equipped with a voltage regulator (VR) and
a voltage detector (VD). Each of these step-up DC/DC converter ICs consists of a PWM DC/DC converter, a linear
regulator and a voltage detector. These ICs are output-voltage-fixed type regulators which function as a linear
regulator when input voltage is high, and as step-up DC/DC converter+linear regulator when input voltage is low,
by using an inductor, a diode and a capacitor as external parts for the ICs.
Since a voltage detector is built in these ICs, the potentials such as the output voltage of DC/DC converters can
be monitored.
In addition, these step-up DC/DC converter ICs are suitable for battery-powered and hand-held instruments
because internal circuits can be turned off by the chip enable function so that the standby current can be mini-
mized.
FEATURES
• Low Supply Current ..........................................Typ. 55µA (RS5RM3624A : V
IN
=3.0V,at no load)
• Standby Mode.....................................................Istandby=Max. 1.0µA (RS5RMxxxxA)
Istandby=Max. 10.0µA (RS5RMxxxxB)
• Low Voltage Operation Possible .......................Operating Voltage V
IN
=1.2V to 10V
• High Output Voltage Accuracy .........................Fixed Output Voltage Accuracy±2.5%
• High Voltage Detection Accuracy .....................±2.5%
• Output Voltage can be set at User's request (refer to Selection Guide).
• Voltage close to battery's voltage can be output because these ICs are of a step-up / step-down type
(Ex. a fixed voltage of 3V can be output by a 3V battery).
• Soft Start Function, built-in Protection Circuits for Lx Driver
• Phase Compensation Circuits built in
• Pin for External Driver is equipped, and a large current output can be obtained.
• Small Packages ..................................................8pin SOP
APPLICATIONS
• Power source for cameras, camcorders, and hand-held audio equipment.
• Power source for small OA apparatus such as note book personal computers,and word processors.
• Power source for hand-held communication appliances such as pagers,cordless telephones, and cellular phones.
1
RS5RM
BLOCK DIAGRAM
OSC
V
SS
1
PWM
V
LX
Limiter
8
L
X
CE
2
–
+
7
Soft Start
Vref1
EXT
VD
OUT
3
+
–
–
+
6
Vref2
V
DD
VD
IN
4
5
V
OUT
SELECTION GUIDE
In the RS5RM Series, the output voltage, the detector threshold, the version symbols, and the taping type for
the ICs can be selected at the user's request.
The selection can be made by designating the part number as shown below:
RS5RMxxxxx
–xx
←
Part Number
↑ ↑↑ ↑
a bc d
}
}
}
Code
Contents
a
Setting Output Voltage (V
OUT
):
Stepwise setting with a step of 0.1V in the range of 1.5V to 6.0V is possible.
Setting Detector Threshold (–V
DET
):
Stepwise setting with a step of 0.1V in the range of 1.2V to 5.0V is possible.
Designation of Version Symbols:
A:
Operation of all the internal circuits is stopped by setting CE pin at V
DD
level.
B:
Operation of only Step-up DC/DC converter is stopped by setting CE pin atV
DD
level.
Designation of Taping Type:
Ex. 8pin SOP : T1, T2
(refer to Taping Specification)
“T2” is prescribed as a standard.
b
c
d
For example, the product with Output Voltage 5.0V, Detector Threshold 4.5V, Version A, and Taping Type T1,
is designated by Part Number RS5RM5045A-T1.
2
RS5RM
PIN CONFIGURATION
•
8pin SOP
1
2
3
4
8
7
6
5
PIN DESCRIPTION
Pin No.
Symbol
Pin Description
1
2
3
4
5
6
7
8
V
SS
CE
VD
OUT
VD
IN
V
OUT
V
DD
EXT
L
X
Ground Pin
Chip Enable Pin
Voltage Detector Output Pin.Nch Open Drain Output
Detection Input Pin of Voltage Detector
Output Pin for Regulator
Step-up Output Pin.Power Supply Pin
External Transistor Drive Pin
External Inductor Drive Pin.
3
RS5RM
ABSOLUTE MAXIMUM RATINGS
Symbol
Item
Rating
Topt=25˚C,Vss=0V
Unit
V
DD
V
LX
V
EXT
V
OUT
VD
OUT
V
CE
Supply Voltage
L
X
Pin Voltage
Output Voltage
EXT Pin Voltage
V
OUT
Pin Voltage
VD
OUT
Pin Voltage
CE Pin Voltage
Input Voltage
VD
IN
Pin Voltage
A Version
B Version
– 0.3 to +12
Vss–0.3 to +12
Vss–0.3 to V
DD
+0.3
Vss–0.3 to V
DD
+0.3
Vss–0.3 to +12
Vss–0.3 to V
DD
+0.3
Vss–0.3 to V
DD
+0.3
Vss– 0.3 to +12
250
50
300
–30 to +80
–55 to +125
260˚C, 10s
V
V
V
V
V
V
V
mA
mA
mW
˚C
˚C
VD
IN
I
LX
I
EXT
P
D
Topt
Tstg
Tsolder
Power Dissipation
Inductor Drive Output Current
Lx Pin Current
EXT Pin Current
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering)
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under any
conditions. Moreover, such values for any two items must not be reached simultaneously. Operation above
these absolute maximum ratings may cause degradation or permanent damage to the device. These are stress
ratings only and do not necessarily imply functional operation below these limits.
4
RS5RM
ELECTRICAL CHARACTERISTICS
•
RS5RM3624A,B
Symbol
Item
Conditions
Min.
Typ.
Max.
Unit
Topt=25˚C
Note
V
IN
V
DD
Voscst
Vhold
fosc
Maxdty
V
OL
1
I
OH
1
V
LX
lim
V
OH
V
OL
2
V
OUT
V
DIF
Operation Input Voltage
Step-up Output Voltage
Oscillator Start-up Voltage
Hold-on Voltage
Oscillator Frequency
Oscillator Maximum Duty Cycle
Lx Output Voltage
Lx Leakage Current
Lx Voltage Limit
EXT Output Pch ON Voltage
EXT Output Nch ON Voltage
Output Voltage
Dropout Voltage
No load
No load
No load
I
OUT
=1mA
1.2
3.99
4.10
0.9
0.7
40
65
50
80
10
4.21
1.2
V
V
V
V
60
90
0.5
kHz
%
V
µA
V
V
I
OL
=50mA
0.01
L
X
Pin On
I
EXT
=–3mA,V
DD
=4.1V
I
EXT
=5mA,V
DD
=4.1V
I
RL
=–5mA
I
RL
=–30mA
–30mA≤I
RL
≤0mA
2.34
60
I
OL
=5mA
0.01
VD
IN
=V
DD
VD
IN
=Vss
–0.5
V
DD
–0.3
0
CE=V
DD
CE=Vss
V
IN
=3V, L=100µH,
–0.5
–0.5
2.40
120
3.51
3.60
0.3
3.6
0.9
10.00
0.5
3.69
V
V
V
∆V
OUT
/∆I
OUT
Load Regulation
–V
DET
V
HYS
V
OL
3
I
OH
2
I
VDINH
I
VDINL
V
CEH
V
CEL
I
CEH
I
CEL
I
DD
Detector Threshold
Detector Threshold Hysteresis
VD
OUT
ON Voltage
VD
OUT
Leakage Current
VD
IN
“H” Input Current
VD
IN
“L” Input Current
CE “H” Input Voltage
CE “L” Input Voltage
CE “H” Input Current
CE “L” Input Current
Supply Current
100
2.46
240
0.5
5.00
5
0.5
V
DD
0.2V
DD
0.5
0.5
mV
V
mV
V
µA
µA
µA
V
V
µA
µA
C=22µF, CE=Vss,
No load
V
IN
=3V, L=100µH,
55
120
µA
1.0
10.0
µA
µA
Note1
Note2
Istandby
Standby Current
C=22µF, CE=V
DD
,
No load
(Note 1) Standby current of Version A
(Note 2) Standby current of Version B
Please refer to Basic Circuit for Test Circuit.
5
PCB Design
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