UTC UT2306/UT2306-3.3V/UT2306-5.0V
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
1
QW-R103-029,A
MICROPOWER DC/DC
CONVERTERS WITH
LOW-BATTERY DETECTOR
ACTIVE IN SHUTDOWN
DESCRIPTION
The UTC UT2306 is a micropower step-up DC/DC
converter ideal for use in small, low voltage,
battery-operated systems. The devices operate from a
wide input supply range of 1.5V to 8V.
The UTC UT2306-3.3 and UT2306-5.0 generate
regulated outputs of 3.3V and 5V and the adjustable
UT2306 can deliver output voltages up to
25V.Quiescent current,120 A in active mode,
decreases to just 10 A in shutdown with the
low-battery detector still active. Peak switch current,
internally set at 1A,can be reduced by adding a single
resistor from the I
LIM
pin to ground. The high speed
operation of the UTC UT2306 allows the use of small,
surface-mountable inductors and capacitors.
FEATURES
*5V at 200mA from two cells.
*10A quiescent current in shutdown.
*Operates with V
IN
as low as1.5V
*Low battery detector active in shutdown
*Low switch V
CESAT
:370mV at 1A typical.
*120A quiescent current in active mode.
*Switching frequency up to 300kHz
*Programmable peak current with one resistor.
.
DIP-8
SOP-8
*Pb-free plating product number:
UT2306L/UT2306L-3.3V/UT2306L-5.0V
APPLICATIONS
*2-,3-,or 4-cell to 5V or 3.3V step-up
*Portable instruments
*Bar code scanners
*Palmtop computers
*Diagnostic medical instrumentation.
*Personal data communicators/computers.
PIN CONFIGURATION
1
2
3
4
8
7
6
5
LBI
SW
V
IN
LBO
GND
I
L I M
SHDN
FB(SENSE)*
UTC UT2306/UT2306-3.3V/UT2306-5.0V
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
2
QW-R103-029,A
ABSOLUTE MAXIMUM RATINGS
PARAMETER SYMBOL RATING
UNIT
Input Voltage
V
IN
8
V
SW Voltage
-0.4 ~ +25
V
FB Voltage(UT2306)
V
IN
+0.3 V
I
LIM
Voltage(UT2306-3.3/UT2306-5.0)
5
V
SHDN Voltage
6 V
LBI Voltage
V
IN
V
LBO Voltage
8
V
Maximum Power Dissipation
P
D
500
mW
Junction Temperature
Tj
125
C
Operating Temperature Range
Topr
0 ~ 70
C
Storage Temperature Range
Tstg
-65 ~ +150
C
Lead Temperature (soldering,10sec)
300
C
ELECTRICAL CHARACTERISTICS
(V
IN
=2V,V
SHDN
=2V Unless otherwise noted.)
PARAMETER TEST
CONDITIONS
MIN
TYP
MAX
UNIT
Minimum Operating Voltage
*
1.5
1.65
V
Operating Voltage Range
*
8
V
Quiescent Current
*
V
SHDN
=2V,Not switching
120
200 A
*
V
SHDN
=0V,V
IN
=2V
7 15 A
Quiescent Current In Shutdown
*
V
SHDN
=0V,V
IN
=5V
27 50 A
Comparator Trip Point
*
1.22
1.24 1.26 V
FB Pin Bias Current
*
10 25 nA
Sense Pin Leakage in Shutdown
*
V
SHDN
=0V,Fixed Output Versions
0.002 1 A
Line Regulation
*
1.8VV
IN
8V
0.04
0.15
%/V
LBI Input Threshold
*
Falling Edge
1.10
1.17
1.25
V
LBI Bias Current
*
6
20
nA
LBI Input Hysteresis
*
35
65
mV
LBO Output Voltage Low
*
I
SINK
=500A
0.2
0.4
V
LBO Output Leakage Current
*
LBI=1.5V,LBO=5V
0.01
0.1
A
SHDN Input Voltage High
*
1.4
V
SHDN Input Voltage Low
*
0.4
V
*
V
SHDN
=5V
5 8 A
SHDN Pin Bias Current
*
V
SHDN
=0V
-5
-2 A
Switching Off Time
*
1
1.5
2
s
Switch On Time
*
Current Limit Not Asserted
4
6
8
s
Maximum Duty Cycle
*
Current Limit Not Asserted
76
80
88
%
I
LIM
Pin Open,V
IN
=5V 0.8
1
1.2
A
Peak Switch Current
20K from I
LIM
to GND
500
mA
Isw=1A
0.37
V
Switch Saturation Voltage
* Isw=700mA
0.26 0.35
V
Switch Leakage
Switch off, Vsw=5V
0.01
7
A
UTC UT2306/UT2306-3.3V/UT2306-5.0V
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
3
QW-R103-029,A
The * denotes specifications which apply over the 0
C to 70C operating temperature range.
PIN FUNCTIONS
PIN No.
SYMBOL
DESCRIPTION
1
LBI
Low Battery Detector Input. When voltage on this pin is less than
1.17V,detector output is low
2
LBO
Low Battery Detector Output. Open collector can sink up to 500A.Low
battery detector remains active when device is shut down.
3
V
IN
Input Supply. Must be bypassed close (<0.2") to the pin. See required layout
in the Typical Applications
4
SW
Collector of Power NPN. Keep copper traces on this pin short and direct to
minimize RFI
5
GND
Device Ground. Must be low impedance; solder directly to ground plane
6
I
LIM
Current Limit Set Pin. Float for 1A peak switch current; a resistor to ground
will lower peak current
7
SHDN
Shutdown Input. When low, switching regulator is turned off. The
low-battery detector remains active. The SHDN input should not be left
floating. If SHDN is not used, tie the pin to V
IN
8
FB/SENSE
On the UT2306 (adjustable) this pin goes to the comparator input. On the
fixed-output versions, the pin connects to the resistor divider which sets output
voltage. The divider is disconnected from the pin during shutdown.
TYPICAL APPLICATION
+
VIN
SW
LBI
SENSE
ILIM
IBO
SHDN
GND
7
100F
5V
200mA
2 CELLS
22H
UT2306-5.0
2-Cell to 5V Step-Up Converter with Low-Battery Detect
499K
604K
SHUTDOWN
1
6
NC
3
4
5
8
2
100K
100F
+
LBO
LOW WHEN
VBAT2.2V
D1
90
LOAD CURRENT(mA)
Efficiency
E
F
F
I
C
I
E
N
C
Y
(
%
)
1
10
100 500
0.01
80
70
60
50
40
V IN =3.3V
V IN =2.5V
V IN =1.8V
1N5817
UTC UT2306/UT2306-3.3V/UT2306-5.0V
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
4
QW-R103-029,A
TYPICAL PERFORMANCE CHARACTERISTICS
S
a
tu
r
a
ti
on
V
o
lta
g
e
(
m
V
)
0
200
300
400
500
1.2
0
0.2
0.4
0.6
100
0.8
1.0
1.2
Switch Saturation Voltage
Switch Current (A)
Ta =25
P
e
ak
C
u
r
r
e
n
t
(
A
)
-50
0.8
0.9
1.0
1.1
100
0.6
-25
0
25
0.7
50
75
Peak Switch Current Limit
Temperature(
)
1.3
6
Ti
m
e
(
s)
-50
2
3
4
5
100
0
-25
0
25
1
50
75
Temperature(
)
7
On-and Off-times
8
Maximum On-Time
Off-Time
1.240
F
e
ed
b
a
c
k
V
o
l
t
ag
e (
V
)
-50
1.220
1.225
1.230
1.235
100
1.210
-25
0
25
1.215
50
75
1.245
1.250
Temperature(
)
Feedback Voltage
1.205
1.200
16
B
i
as
C
u
r
r
en
t
(
n
A
)
-50
8
10
12
14
100
4
-25
0
25
6
50
75
18
20
Temperature(
)
Feedback Pin Bias Current
2
0
S
u
ppl
y
C
u
r
r
e
nt
s)
0
150
200
250
300
6
50
1
2
3
100
4
5
Input Voltage (V)
Supply Current
0
7
8
VSHDN=VN
NOT SW ITCHING
VSHDN= 0 V
Ta =25
UTC UT2306/UT2306-3.3V/UT2306-5.0V
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
5
QW-R103-029,A
V
OUT
100mV / DIV
AC COUPLED
Load Transient
Response
100 s / DIV
I
LOAD
200mA
0
V
OUT
100mV/DIV
AC COUPLED
Burst Mode
Operation
20 s/DIV
I
L
500mA/DIV
Vs w
5V/DIV
VIN=2.5V
VOUT=5V
ILOAD=185mA
L=22 H
0
BLOCK DIAGRAMS
2
4
3
1
8
5
6
7
TIMERS
6s ON
1.5s OFF
1.5V
UNDERVOLTA
GELOCKOUT
+
-
-
+
A1
A2
+
-
ENABLE
DRIVER
GND
ILIM
SHDN
SHUTDOWN
1.24V
VREF
Q2
1
Q1
200
1K
Q3
BIAS
-1V
R2
36mV
R1
7.2
VIN
SW
C1
+
C2
+
D1
L1
VIN
VOUT
LBO
LBI
A3
1.17V
R3
R4
FB
OFF
1K
Figure 1. UT2306 Block Diagram. Independent Low-Battery Detector A3 Remains Alive When Device Is in Shutdown
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