LINER LT1109A_03

LT1109A
Micropower
DC/DC Converter
Flash Memory VPP Generator
Adjustable and Fixed 5V, 12V
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DESCRIPTIO
FEATURES
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Uses Off-the-Shelf Inductors
Low Cost
8-Pin DIP or SO Package
Fixed 5V or 12V Output or Adjustable Version
Only Four External Components Required
360µA Standby Current
Logic-Controlled Shutdown
The LT1109A is a simple step-up DC/DC converter. The 8pin DIP or SOIC devices require only four external components to construct a complete DC/DC converter. Current
drain is just 360µA at no load, making the device ideal for
cost-sensitive applications where standby current must
be kept to a minimum.
The LT1109A-12 can deliver 12V at over 150mA from a 5V
supply, enough power to program four flash memory
chips simultaneously. The LT1109A-5 can deliver 5V at up
to 110mA from a 2V input. The devices feature a shutdown
pin that turns off the oscillator when taken low. The gatedoscillator design requires no frequency compensation
components. High frequency 120kHz operation permits
the use of small surface mount inductors and capacitors.
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APPLICATI
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S
Flash Memory VPP Generators
5V to 12V Converters
3.3V to 12V Converters
Disk Drives
PC Plug-In Cards
Peripherals
Battery-Powered Equipment
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TYPICAL APPLICATI
All Surface Mount
Flash Memory VPP Generator
1
+VIN
5V
C1
22µF
10V
3
SW
VIN
SENSE
LT1109ACS8-12
+
7
**
13.0
MBRS130T3
SHUTDOWN
PGND
GND
4
5
12V
12.5
8
+
VOUT
12V
C2
47µF
20V
OUTPUT VOLTAGE (V)
L1*
33µH
Output Voltage
Output Current
VIN = 5V
12.0
11.5
VOUT
2V/DIV
SHUTDOWN
5V/DIV
VIN = 4.5V
500µs/DIV
11.0
1109A TA03
10.5
* COILTRONICS CTX33-2
SUMIDA CD54-330LC
** 1 = PROGRAM
0 = SHUTDOWN
10.0
1109A TA01
0
50
250
100
150
200
OUTPUT CURRENT (mA)
300
1109A TA02
1
LT1109A
W W
W
AXI U
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ABSOLUTE
RATI GS
(Voltages Referred to GND Pin)
Supply Voltage (VIN) ................................ – 0.4V to 20V
SW Pin Voltage ........................................ – 0.4V to 50V
Feedback Pin Voltage (LT1109A) ........................... 5.5V
Shutdown Pin Voltage ........................................... 5.5V
Switch Current .......................................................... 2A
Maximum Power Dissipation ............................ 300mW
Operating Temperature Range .................... 0°C to 70°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
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PACKAGE/ORDER I FOR ATIO
TOP VIEW
VIN 1
8
FB (SENSE)*
NC 2
7
SHUTDOWN
SW 3
6
NC
PGND 4
5
GND
N8 PACKAGE
8-LEAD PLASTIC DIP
*FIXED VERSIONS
ORDER PART
NUMBER
LT1109ACN8
LT1109ACN8-5
LT1109ACN8-12
TOP VIEW
VIN 1
8 FB (SENSE)*
NC 2
7 SHUTDOWN
SW 3
6 NC
PGND 4
1109A
1109A5
1109A1
TA = 25°C, VIN = 3V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
IQ
Quiescent Current
Switch Off
VIN
Input Voltage
tON
LT1109ACS8
LT1109ACS8-5
LT1109ACS8-12
TJMAX = 90°C, θJA = 150°C/W
ELECTRICAL CHARACTERISTICS
fOSC
S8 PART
MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
*FIXED VERSIONS
TJMAX = 90°C, θJA = 130°C/W
VOUT
5 GND
ORDER PART
NUMBER
MIN
●
●
2
TYP
MAX
UNITS
360
500
µA
9
V
Comparator Trip Point Voltage
LT1109A
●
1.20
1.25
1.30
V
Output Sense Voltage
LT1109A-5; 2V ≤ VIN ≤ 5V
LT1109A-12; 2V ≤ VIN ≤ 12V
●
●
4.75
11.52
5.00
12.00
5.25
12.55
V
V
Comparator Hysteresis
LT1109A
●
8
12.5
mV
Output Voltage Ripple
LT1109A-5
LT1109A-12
●
●
25
60
50
120
mV
mV
Oscillator Frequency
105
95
120
●
135
155
kHz
kHz
4.1
3.8
5.5
●
6.9
7.4
µs
µs
60
68
77
%
0.5
0.7
0.65
1.00
V
V
1
10
µA
Switch On Time
DC
Duty Cycle
Full Load
●
VCESAT
Switch Saturation Voltage
VIN = 3V, ISW = 650mA
VIN = 5V, ISW = 1A
●
Switch Leakage Current
VSW = 12V
VIH
SHUTDOWN Pin High
●
VIL
SHUTDOWN Pin Low
●
0.8
V
IIH
SHUTDOWN Pin Input Current
VSHUTDOWN ≥ 2.0V
●
10
µA
IL
SHUTDOWN Pin Input Current
0V ≤ VSHUTDOWN ≤ 0.8V
●
20
µA
The ● denotes specifications which apply over the full operating
temperature range.
2
2.0
V
LT1109A
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TYPICAL PERFOR A CE CHARACTERISTICS
Efficiency
Oscillator Frequency
VIN = 5V
VOUT = 12V
LOAD = 120mA
L = 29µH
75
80
75
DUTY CYCLE (%)
140
FREQUENCY (kHz)
85
EFFICIENCY (%)
Duty Cycle
80
160
90
120
100
80
70
4.2
4.4 4.6
4.8 5.0 5.2 5.4
INPUT VOLTAGE (V)
5.6
–25
0
25
50
TEMPERATURE (°C)
75
Switch Saturation Voltage
50
–50
100
–25
0
25
50
TEMPERATURE (°C)
75
100
1109A G03
Switch Saturation Voltage
Switch On Time
8
0.7
1.4
ISW = 650mA
VIN = 3V
0.6
VIN = 2V
SWITCH ON TIME (µs)
7
0.5
0.8
VIN = 5V
0.6
VCESAT (V)
1.0
0.4
0.3
0.4
0.2
0.2
0.1
6
5
4
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0
–50
–25
ISWITCH (A)
0
25
50
TEMPERATURE (°C)
75
3
–50
100
–25
0
25
50
TEMPERATURE (°C)
Quiescent Current
75
100
1109A G06
1109A G05
1109A G04
Quiescent Current
500
500
TA = 25°C
450
QUIESCENT CURRENT (µA)
0
QUIESCENT CURRENT (µA)
VCESAT (V)
60
1109A G02
1109A G01
1.2
65
55
60
–50
5.8
70
400
350
300
250
200
–50
450
400
350
300
250
–25
0
25
50
TEMPERATURE (°C)
75
100
1109A G07
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
1109A G08
3
LT1109A
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TYPICAL PERFOR A CE CHARACTERISTICS
Minimum/Maximum
Oscillator Frequency vs tON
LT1109A-12
Output Voltage
160
12.3
OSCILLATOR FREQUENCY (kHz)
150
OUTPUT VOLTAGE (V)
12.2
12.1
12.0
11.9
11.8
0°C ≤ TA ≤ 70°C
140
130
TA= 25°C
120
110
100
90
11.7
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
80
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0
tON (µs)
125
1109A G10
1109A G09
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BLOCK DIAGRA S
LT1109A-5, LT1109A-12
VIN
LT1109A (Adjustable)
SENSE
VIN
SW
FB
SW
R2
250k
1.25V
REF
1.25V
REF
+
COMP
A1
120kHz
OSC
–
+
COMP
A1
Q1
120kHz
OSC
–
DRIVER
Q1
DRIVER
R1*
GND
SHUTDOWN
PGND
GND
SHUTDOWN
PGND
1109A BD
*LT1109A-5: R1 = 83k
LT1109A-12: R1 = 29k
4
LT1109A
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OPERATIO
The LT1109A is a micropower step-up DC/DC converter.
It uses Burst ModeTM operation to achieve micropower
operation yet still deliver more than 2W of output power
from a 5V supply. Circuit operation can be best understood by referring to the LT1109A block diagram. With
SHUTDOWN high, comparator A1 compares the feedback
(FB) pin voltage with the 1.25V reference signal. When FB
Burst ModeTM is a trademark of Linear Technology Corporation
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UO
APPLICATI
drops below 1.25V, A1 switches on the 120kHz oscillator.
The driver amplifier boosts the signal level to drive the
output NPN power switch. When the FB voltage is sufficient
to trip A1, the oscillator is turned off. A low signal on the
shutdown pin gates off the oscillator, overriding A1. With
SHUTDOWN low, quiescent current remains at 360µA.
S I FOR ATIO
Inductor Selection
A DC/DC converter operates by storing energy as magnetic flux in an inductor core, and then switching this
energy into the load. To operate as an efficient energy
transfer element, the inductor must fulfill three requirements: inductance value, saturation current and DC resistance. A fourth requirement is physical size. The inductors
recommended with the LT1109A circuits are small, surface-mountable and are designed for switch-mode applications. Avoid using RF chokes or air core units since they
have very low peak current ratings. The LT1109A works
best in situations where the input voltage does not vary
much since the device has no internal switch current limit
function. For situations where the input voltage varies,
such as battery inputs, the LT1107 or LT1111 is suggested
instead.
Capacitor Selection
The output capacitor should be chosen on the basis of its
equivalent series resistance (ESR) and capacitance value.
Low ESR tantalum surface-mountable capacitors such as
those made by AVX are well-suited for DC/DC converter
applications. Inexpensive aluminum electrolytics may have
excessive ESR, resulting in high output ripple. These
should be avoided.
Diode Selection
Speed, forward drop, and leakage current are the three
main considerations in selecting a diode for LT1109A
converters. General purpose rectifiers such as the 1N4001
are unsuitable for use in any switching regulator application. Although they are rated at 1A, the switching time of
a 1N4001 is in the 10µs to 50µs range. At best, efficiency
will be severely compromised if this diode is used; at
worst, the circuit may not work at all. The 1N5818 is an
ideal choice for LT1109A circuits. Surface-mountable
versions, such as the MBRS130T3, are available as well.
Table 1. Inductor Manufacturers
MANUFACTURER
PART NUMBERS
Coiltronics International
984 S.W. 13th Court
Pompano Beach, FL 33069
305-781-8900
Surface Mount
OCTA-PACTM Series
Sumida Electric Co., Ltd.
637 E. Golf Road, Suite 209
Arlington Heights, IL 60005
708-956-0666
CD54
CD105
Surface Mount
OCTA-PACTM is a trademark of Coiltronics International
Table 2. Capacitor Manufacturers
MANUFACTURER
PART NUMBERS
AVX
Myrtle Beach, SC 29578
803-946-0690
TPS Series
Philips Components
2001 W. Blue Heron Blvd.
P.O. Box 10330
Riviera Beach, FL 33404
407-881-3200
49MC Series
Sanyo Video Components
1201 Sanyo Avenue
San Diego, CA 92073
619-661-6322
OS-CON Series
5
LT1109A
UO
TYPICAL APPLICATI
S
3.3V Powered Flash Memory VPP Generator
VIN
3.3V
20µH*
MBRS130T3
12V
60mA
+
22µF
1
VIN
3
SW
8
SENSE
LT1109A-12
7
SHUTDOWN
GND
PGND
4
5
+
33µF**
25V
SHUTDOWN
* COILTRONICS CTX20-1
SUMIDA CD54-220LC
** AVX TPS SERIES
1109A TA04
2V Powered Flash Memory VPP Generator
VIN
2V
10µH*
MBRS130T3
12V
35mA
+
22µF
1
VIN
3
SW
8
SENSE
LT1109A-12
7
SHUTDOWN
GND
PGND
4
5
+
33µF**
25V
SHUTDOWN
* COILTRONICS CTX10-1
SUMIDA CD54-100LC
** AVX TPS SERIES
6
1109A TA05
LT1109A
UO
TYPICAL APPLICATI
S
2V to 5V Converter
MBRS130T3
10µH*
VIN
2V
5V
110mA
+
22µF
1
3
SW
8
SENSE
VIN
LT1109A-12
7
SHUTDOWN
GND
PGND
4
5
+
33µF**
10V
SHUTDOWN
* COILTRONICS CTX10-1
SUMIDA CD54-100LC
** AVX TPS SERIES
1109A TA06
5V to 12V Converter with Shutdown to 0V at Output
2k
VIN
5V
10µH*
MBRS130T3
+
2N4403
22µF
1
VIN
3
SW
8
SENSE
VOUT
12V
110mA
LT1109A-12
7
SHUTDOWN
GND
PGND
4
5
+
47µF**
20V
+
1µF
SHUTDOWN
* COILTRONICS CTX33-2
SUMIDA CD54-330LC
1109A TA07
** AVX TPS SERIES
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
7
LT1109A
U
PACKAGE DESCRIPTIO
Dimensions are in inches (millimeters) unless otherwise noted.
N8 Package
8-Lead Plastic DIP
0.300 – 0.320
(7.620 – 8.128)
0.045 – 0.065
(1.143 – 1.651)
+0.025
0.325 –0.015
8.255
+0.635
–0.381
0.130 ± 0.005
(3.302 ± 0.127)
8
7
6
5
0.065
(1.651)
TYP
0.009 – 0.015
(0.229 – 0.381)
(
0.400
(10.160)
MAX
0.250 ± 0.010
(6.350 ± 0.254)
0.045 ± 0.015
(1.143 ± 0.381)
)
0.100 ± 0.010
(2.540 ± 0.254)
0.125
(3.175)
MIN
0.020
(0.508)
MIN
1
2
3
4
0.018 ± 0.003
(0.457 ± 0.076)
N8 0392
S8 Package
8-Lead Plastic SOIC
0.189 – 0.197
(4.801 – 5.004)
8
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.016 – 0.050
0.406 – 1.270
6
5
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
7
0.014 – 0.019
(0.355 – 0.483)
0.228 – 0.244
(5.791 – 6.197)
0.150 – 0.157
(3.810 – 3.988)
0.050
(1.270)
BSC
1
2
3
4
SO8 0392
8
Linear Technology Corporation
sn1109A 1109afs LT/GP 0493 10K REV 0
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977
 LINEAR TECHNOLOGY CORPORATION 1993