SS6642G
3-Pin Simple Step-Up DC/DC Converter
FEATURES
A guaranteed start-up from less than 0.9 V.
High efficiency.
Low quiescent current.
Fewer external components needed.
Low ripple and low noise.
Fixed output voltage: 2.7V, 3.0V, 3.3V, 3.7V,
4.5V and 5V.
Space-saving packages: SOT-23, SOT-89 and
TO-92.
DESCRIPTION
The SS6642G is a high efficiency step-up DC/DC
converter for applications using 1 to 4 NiMH bat-
tery cells. Only three external components are re-
quired to deliver a fixed output voltage of 2.7V,
3.0V, 3.3V, 3.7V, 4.5V or 5V. The SS6642G starts
up from less than 0.9V input with 1mA load. A
Pulse Frequency Modulation scheme optimizes
performance for applications with light output
loading and low input voltages. The output ripple
and noise are lower when compared with circuits
operating in PSM mode.
Pb-free, RoHS compliant.
APPLICATIONS
Pagers.
Cameras.
Wireless Microphones.
Pocket Organizers.
Battery Backup Suppliers.
Portable Instruments.
The PFM control circuit operating at a 100KHz
(max.) switching rate results in smaller passive
components. The space saving SOT-23, SOT-
89 and TO-92 packages make the SS6642G an
ideal choice for DC/DC converter for space con-
scious applications, such as pagers, electronic
cameras, and wireless microphones.
TYPICAL APPLICATION CIRCUIT
V
IN
L1
100µH
D1
SS12
V
OUT
SS6642-xxG
+
C1
SW
22µF
GND
+
VOUT
C2
47µF
One Cell Step-Up DC/DC Converter
1/15/2005 Rev.2.10
www.SiliconStandard.com
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SS6642G
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VOUT pin)
SW pin Voltage
SW pin Switch Current
Operating Temperature Range
Maximum Junction Temperature
Storage Temperature Range
Lead Temperature (Soldering 10 Sec.)
.6V
6V
0.6A
-40°C to 85°C
125°C
-65°C to 150°C
260°C
Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.
TEST CIRCUIT
V
IN
I
IN
L1
100µH
D1
SS12
V
OUT
IS
SS6642
VOUT
GND
SW
VSW
SS6642-xxG
+ C2
22µF SW
GND
VOUT
+ C1
47µF
VS
Fig. 1 Test Circuit 1
Fig. 2 Test Circuit 2
SS6642
100W
V
S
VOUT
GND
SW
F
OSC
Fig. 3 Test Circuit 3
1/15/2005 Rev.2.10
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SS6642G
ELECTRICAL CHARACTERISTICS
PARAMETER
TEST CONDITIONS
SS6642-27G
SS6642-30G
SS6642-33G
SW Switch-On Resis-
tance
SS6642-37G
SS6642-45G
SS6642-50G
V
S
=V
OUT
x 0.95,
V
SW
=0.4V
V
S
=V
OUT
x 0.95
Oscillator Duty Cycle
Measurement of the SW
pin waveform
V
S
=V
OUT
x 0.95
Max. Oscillator Freq.
Efficiency
Measurement of the SW
pin waveform
3
1
F
OSC
η
80
105
85
130
KHz
%
3
DUTY
65
75
85
%
2
R
ON
(Continued)
TEST
CKT
SYMBOL
MIN.
TYP.
2.2
2.1
2.0
2.0
1.9
1.9
MAX.
UNIT
Ω
Note 1:
Specifications are production tested at T
A
=25°C. Specifications over the -40°C to 85°C operating
temperature range are assured by design, characterization and correlation with Statistical Quality
Controls (SQC).
TYPICAL PERFORMANCE CHARACTERISTICS
Test circuit refer to typical application circuit
Capacitor (C2) : 47
µ
F (Tantalum Type)
Diode (D1) : 1N5819 Schottky Type
2.8
85
80
2.7
Output Voltage (V)
V
IN
=1.5V
V
IN
=1.2V
2.5
Efficiency (%)
2.6
V
IN
=1.8V
V
IN
=2.
0V
75
70
V
IN
=1.8V
V
IN
=2.0V
2.4
65
V
IN
=0.9V
2.3
60
V
IN
=1.5V
V
IN
=0.9V
2.2
0
55
V
IN
=1.2V
40
60
80
100
120
140
160
180
20
40
60
80
100
120
140
160
180
0
20
Output Current (mA)
Fig. 4 SS6642-27 Load Regulation
(L=100µH CD54)
Output current (mA)
Fig. 5 SS6642-27 Efficiency (L=100µH CD54)
1/15/2005 Rev.2.10
www.SiliconStandard.com
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