ELM91xxxxA
CMOS PFM Step-up DC/DC converter and controller
■General description
ELM91xx1xA is CMOS PFM control step-up DC-DC converter; ELM91xx3xA is CMOS PFM control step-
up DC-DC controller, which has large output current capacity by using an external FET switch. ELM91 series
consists of reference voltage source, error amplifier, oscillation circuit, start-up circuit, PFM-control circuit,
switching current limit circuit (ELM91xx1xA only), switching transistor (ELM91xx1xA only) and output
voltage setting resistor. For external parts, coil, diode, MOSFET and capacitor are possible choices. The
standard output voltages are 1.8V,3.0V,3.3V,5.0V; ELM91 series can also be designed as semi-custom IC within
the range of 1.8V to 5.5V by 0.1V step.
■Features
•
•
•
•
•
•
•
Output voltage range
Low voltage operation
Oscillating frequency
Low power operation
High efficiency
Output current(e.g.)
Package
■Application
: 1.8V to 5.5V (by 0.1V)
• Constant voltage source for battery-
: 0.9V(ELM91xx1xA: Iout=1mA)
operated devices
: Typ.100kHz
• Portable communication equipments
: Typ.40µW(ELM91301xA: Typ.100kHz)
and video recorders
: 85%(ELM9130xxA: Vin=1.5V, Iout=10mA)
: 100mA(Vin=1.5V, Vout=3.0V)
: SOT-89, SOT-23, SC-70(SOT-323)
■Maximum absolute ratings
Parameter
Apply voltage to LX pin
Apply voltage to VOUT pin
Output current of LX pin
Output current of EXT pin
Power dissipation
Operationg temperature
Storage temperature
Symbol
Vlx
Vout
Ilx
Iext
Pd
Top
Tstg
Limit
Vss-0.3 to 7.0
Vss-0.3 to 7.0
500
20
500 (SOT-89)
250 (SOT-23)
150 (SC-70)
-40 to +85
-55 to +125
Unit
V
V
mA
mA
mW
°C
°C
■Selection guide
ELM91xxxxA-x
Symbol
a, b
c
d
e
f
e.g. :
Output voltage
18: Vout=1.8V 30: Vout=3.0V
33: Vout=3.3V 50: Vout=5.0V
1: Internal switch
Switching transistor
3: External switch
A: SOT-89
Package
B: SOT-23
C: SC-70(SOT-323)
Product version
A
Taping direction
S , N: Refer to PKG file
ELM91 x x x x A - x
↑ ↑ ↑ ↑ ↑ ↑
a b c d e f
22 - 1