LT1307/LT1307B
Single Cell Micropower
600kHz PWM DC/DC Converters
FEATURES
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DESCRIPTION
The LT
®
1307/LT1307B are micropower, fixed frequency
DC/DC converters that operate from an input voltage as
low as 1V. First in the industry to achieve true current
mode PWM performance from a single cell supply, the
LT1307 features automatic shifting to power saving Burst
Mode operation at light loads. High efficiency is main-
tained over a broad 100µA to 100mA load range. The
LT1307B does not shift into Burst Mode operation at light
loads, eliminating low frequency output ripple at the
expense of light load efficiency. The devices contain a low-
battery detector with a 200mV reference and shut down to
less than 5µA. No load quiescent current of the LT1307 is
50µA and the internal NPN power switch handles a 500mA
current with a voltage drop of just 295mV.
Unlike competitive devices, large electrolytic capacitors
are
not required
with the LT1307/LT1307B in single cell
applications. The high frequency (600kHz) switching al-
lows the use of tiny surface mount multilayer ceramic
(MLC) capacitors along with small surface mount induc-
tors. The devices work with just 10µF of output capaci-
tance and require only 1µF of input bypassing.
The LT1307/LT1307B are available in 8-lead MSOP, PDIP
and SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
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Uses Small Ceramic Capacitors
50µA Quiescent Current (LT1307)
1mA Quiescent Current (LT1307B)
Operates with V
IN
as Low as 1V
600kHz Fixed Frequency Operation
Starts into Full Load
Low Shutdown Current: 3µA
Low-Battery Detector
3.3V at 75mA from a Single Cell
Automatic Burst Mode
TM
Operation at
Light Load (LT1307)
Continuous Switching at Light Load (LT1307B)
Low V
CESAT
Switch: 295mV at 500mA
APPLICATIONS
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Pagers
Cordless Telephones
GPS Receivers
Battery Backup
Portable Electronic Equipment
Glucose Meters
Diagnostic Medical Instrumentation
TYPICAL APPLICATION
L1
10µH
D1
C1: MURATA-ERIE GRM235Y5V105Z01
MARCON THCS50E1E105Z
TOKIN 1E105ZY5U-C103-F
3.3V
C2: MURATA-ERIE GRM235Y5V106Z01
75mA
MARCON THCS50E1E105Z
TOKIN 1E106ZY5U-C304-F
D1: MOTOROLA MBR0520L
C2
L1: COILCRAFT D01608C-103
10µF
SUMIDA CD43-100
MURATA ERIE LQH3C100
FOR 5V OUTPUT: R1 = 1M, R2 = 329k
1307 F01
Single Cell to 3.3V Converter Efficiency
90
C1
1µF
1.5V
CELL
SHUTDOWN
V
IN
LBI
SW
FB
R1
1.02M
1%
R2
604k
1%
EFFICIENCY (%)
LT1307
SHDN
LBO
GND
V
C
100k
680pF
Figure 1. Single Cell to 3.3V Boost Converter
U
80
70
60
U
U
V
IN
= 1.5V
V
IN
= 1V
V
IN
= 1.25V
50
0.1
1
10
LOAD CURRENT (mA)
100
1307 TA01
1
LT1307/LT1307B
ABSOLUTE
AXI U
RATI GS
Junction Temperature........................................... 125°C
Operating Temperature Range
Commercial (Note 1) ......................... – 20°C to 70°C
Industrial ........................................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
V
IN
, SHDN, LBO Voltage ......................................... 12V
SW Voltage ............................................................. 30V
FB Voltage ....................................................... V
IN
+ 1V
V
C
Voltage ................................................................ 2V
LBI Voltage ............................................ 0V
≤
V
LBI
≤
1V
Current into FB Pin ..............................................
±1mA
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
V
C
FB
SHDN
GND
1
2
3
4
8
7
6
5
LBO
LBI
V
IN
SW
LT1307CMS8
LT1307BCMS8
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 160°C/W
MS8 PART MARKING
BU
BF
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
Commercial Grade 0°C to 70°C. V
IN
= 1.1V, V
SHDN
= V
IN
, T
A
= 25°C, LT1307/LT1307B unless otherwise noted.
SYMBOL
I
Q
PARAMETER
Quiescent Current
CONDITIONS
Not Switching (LT1307)
Not Switching (LT1307B)
V
SHDN
= 0V
V
FB
= V
REF
1V
≤
V
IN
≤
2V (25°C, 0°C)
1V
≤
V
IN
≤
2V (70°C)
2V
≤
V
IN
≤
5V
q
q
q
q
q
V
FB
I
B
Feedback Voltage
FB Pin Bias Current (Note 2)
Reference Line Regulation
Minimum Input Voltage
Input Voltage Range
g
m
A
V
f
OSC
Error Amp Transconductance
Error Amp Voltage Gain
Switching Frequency
∆I
= 5µA
25°C, 0°C
70°C
q
q
q
2
U
U
W
W W
U
W
TOP VIEW
V
C
1
FB 2
SHDN 3
GND 4
N8 PACKAGE
8-LEAD PDIP
8
7
6
5
LBO
LBI
V
IN
SW
ORDER PART
NUMBER
LT1307CN8
LT1307CS8
LT1307IS8
LT1307BCS8
LT1307BIS8
S8 PART MARKING
1307
1307I
1307B
1307BI
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 100°C/W (N8)
T
JMAX
= 125°C,
θ
JA
= 120°C/W (S8)
MIN
TYP
50
1.0
1
MAX
90
1.5
3
1.24
60
1.1
1.5
0.8
1
5
65
UNITS
µA
mA
µA
V
nA
%/V
%/V
%/V
V
V
µmhos
V/V
V/V
1.20
1.22
27
0.6
q
0.3
0.92
1
25
35
30
550
35
100
600
750
kHz
LT1307/LT1307B
ELECTRICAL CHARACTERISTICS
Commercial Grade 0°C to 70°C. V
IN
= 1.1V, V
SHDN
= V
IN
, T
A
= 25°C unless otherwise noted.
SYMBOL
PARAMETER
Maximum Duty Cycle
Switch Current Limit (Note 3)
Switch V
CESAT
Burst Mode Operation Switch Current Limit
(LT1307 Only)
Shutdown Pin Current
LBI Threshold Voltage
LBO Output Low
LBO Leakage Current
LBI Input Bias Current (Note 4)
Low-Battery Detector Gain
Switch Leakage Current
Reverse Battery Current
I
SINK
= 10µA
V
LBI
= 250mV, V
LBO
= 5V
V
LBI
= 150mV
1MΩ Load (25°C, 0°C)
1MΩ Load (70°C)
V
SW
= 5V
(Note 5)
q
CONDITIONS
25°C, 0°C
70°C
DC = 40%
DC = 75%
I
SW
= 500mA (25°C, 0°C)
I
SW
= 500mA (70°C)
L = 10µH
L = 22µH
V
SHDN
= V
IN
V
SHDN
= 0V
q
q
q
q
q
q
q
MIN
80
76
TYP
84
0.6
0.5
295
100
50
2.5
– 1.5
MAX
UNITS
%
%
1.25
350
400
A
A
mV
mV
mA
mA
4.0
– 2.5
210
0.25
0.1
25
µA
µA
mV
V
µA
nA
V/V
V/V
190
200
0.1
0.01
5
1000
500
3000
0.01
750
3
µA
mA
Commercial Grade T
A
= – 20°C, V
IN
= 1.1V, V
SHDN
= V
IN
, unless otherwise noted (Note 1).
SYMBOL
I
Q
PARAMETER
Quiescent Current
CONDITIONS
V
FB
= 1.3V, Not Switching (LT1307)
V
FB
= 1.3V, Not Switching (LT1307B)
V
SHDN
= 0V
1.195
∆I
= 5µA
25
35
500
80
I
SW
= 500mA, V
IN
= 1.2V
V
SHDN
= V
IN
V
SHDN
= 0V
186
MIN
TYP
50
1.1
1
1.22
35
100
600
84
250
2.5
– 1.5
200
350
4.0
– 2.5
210
750
MAX
100
1.6
3
1.245
65
UNITS
µA
mA
µA
V
µmhos
V/V
kHz
%
mV
µA
µA
mV
V
FB
g
m
A
V
f
OSC
Feedback Voltage
Error Amp Transconductance
Error Amp Voltage Gain
Switching Frequency
Maximum Duty Cycle
Switch V
CESAT
Shutdown Pin Current
LBI Threshold Voltage
3
LT1307/LT1307B
ELECTRICAL CHARACTERISTICS
Industrial Grade – 40°C to 85°C. V
IN
= 1.1V, V
SHDN
= V
IN
, LT1307/LT1307B unless otherwise noted.
SYMBOL
I
Q
PARAMETER
Quiescent Current
CONDITIONS
V
FB
= 1.3V, Not Switching (LT1307)
V
FB
= 1.3V, Not Switching (LT1307B)
V
SHDN
= 0V
V
FB
= V
REF
1V
≤
V
IN
≤
2V (– 40°C)
1V
≤
V
IN
≤
2V (85°C)
2V
≤
V
IN
≤
5V
– 40°C
85°C
q
q
q
q
q
q
MIN
TYP
50
1
1
MAX
100
1.8
3
1.245
100
1.1
3.2
0.8
1.2
1.0
5
65
UNITS
µA
mA
µA
V
nA
%/V
%/V
%/V
V
V
V
µmhos
V/V
V/V
V
FB
I
B
Feedback Voltage
FB Pin Bias Current (Note 2)
Reference Line Regulation
1.195
10
1.22
27
0.6
q
0.3
1.1
0.8
Minimum Input Voltage
Input Voltage Range
g
m
A
V
f
OSC
Error Amp Transconductance
Error Amp Voltage Gain
Switching Frequency
Maximum Duty Cycle
Switch Current Limit (Note 3)
Switch V
CESAT
Burst Mode Operation Switch Current Limit
(LT1307 Only)
Shutdown Pin Current
LBI Threshold Voltage
LBO Output Low
LBO Leakage Current
LBI Input Bias Current (Note 4)
Low-Battery Detector Gain
Switch Leakage Current
∆I
= 5µA
– 40°C
85°C
q
25
35
30
35
q
500
80
75
600
84
80
0.6
0.5
250
330
100
50
750
kHz
%
%
– 40°C
85°C
DC = 40%
DC = 75%
I
SW
= 500mA, V
IN
= 1.2V (– 40°C)
I
SW
= 500mA (85°C)
L = 10µH
L = 22µH
V
SHDN
= V
IN
V
SHDN
= 0V
I
SINK
= 10µA
V
LBI
= 250mV, V
LBO
= 5V
V
LBI
= 150mV
1MΩ Load (– 40°C)
1MΩ Load (85°C)
V
SW
= 5V
q
q
q
q
q
q
q
q
1.25
350
400
A
A
mV
mV
mA
mA
2.5
– 1.5
186
200
0.1
0.1
5
1000
400
6000
0.01
4.0
– 2.5
210
0.25
0.3
30
µA
µA
mV
V
µA
nA
V/V
V/V
3
µA
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
Specifications for commercial (C) grade devices are guaranteed
but not tested at – 20°C. MS8 package devices are designed for and
intended to meet commercial temperature range specifications but are not
tested at – 20°C or 0°C.
Note 2:
Bias current flows into FB pin.
Note 3:
Switch current limit guaranteed by design and/or correlation to
static tests. Duty cycle affects current limit due to ramp generator.
Note 4:
Bias current flows out of LBI pin.
Note 5:
The LT1307 will withstand continuous application of 1.6V applied
to the GND pin while V
IN
and SW are grounded.
4
LT1307/LT1307B
TYPICAL PERFORMANCE CHARACTERISTICS
5V Output Efficiency, Circuit of
Figure 1 (LT1307)
90
90
80
80
EFFICIENCY (%)
EFFICIENCY (%)
60
50
40
30
20
EFFICIENCY (%)
70
V
IN
= 1.00V
V
IN
= 1.25V
V
IN
= 1.5V
60
50
0.1
10
1
LOAD CURRENT (mA)
Quiescent Current vs Temperature
80
70
FEEDBACK BIAS CURRENT (nA)
QUIESCENT CURRENT (µA)
50
40
30
20
10
0
–50
–25
50
25
TEMPERATURE (°C)
0
75
100
LBI BIAS CURRENT (nA)
60
Quiescent Current in Shutdown
10
10
QUIESCENT CURRENT (µA)
8
SHUTDOWN PIN CURRENT (µA)
6
12
V
CESAT
(mV)
4
2
0
0
1
3
2
INPUT VOLTAGE (V)
4
5
U W
LT1307 • G01
LT1307 • TPC04
LT1307 • TPC07
3.3V Output Efficiency, Circuit of
Figure 1 (LT1307B)
90
80
70
V
IN
= 1.25V
V
IN
= 1V
5V Output Efficiency, Circuit of
Figure 1 (LT1307B)
V
IN
= 1.5V
70
V
IN
= 1V
60
50
40
30
20
10
V
IN
= 1.25V
V
IN
= 1.5V
100 200
10
0.1
1
10
LOAD CURRENT (mA)
100
1307 G02
0.1
1
10
LOAD CURRENT (mA)
100
LT1307 • TPC03
Feedback Bias Current vs
Temperature
50
V
IN
= 1.1V
40
LBI Bias Current vs Temperature
16
14
12
10
8
6
4
2
30
20
10
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
0
–50
–25
50
25
TEMPERATURE (°C)
0
75
100
LTC1307 • TPC05
LT1307 • TPC06
Shutdown Pin Bias Current vs
Input Voltage
500
Switch V
CESAT
vs Current
T
A
= 25°C
16
400
300
8
200
4
100
0
0
1
3
2
INPUT VOLTAGE (V)
4
5
0
0
100
500
200
300
400
SWITCH CURRENT (mA)
600
LT1307 • TPC08
LT1307 • TPC09
5
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