Linear Technology LT1309 Datasheet
LT1309
, LTC and LT are registered trademarks of Linear Technology Corporation.
500kHz Micropower
DC/DC Converter
for Flash Memory
EATU
F
■
60mA Output Current at 12V from 3V or 5V Supply
■
Shutdown to 9µA
■
VPP VALID Comparator
■
Up to 85% Efficiency
■
Switching Frequency: 500kHz (Typical)
■
Quiescent Current: 650µA
■
Low V
■
Soft Start Reduces Supply Current Transients
■
Uses Low Value, Small Size,
S
RE
Switch: 300mV at 0.5A (Typical)
CESAT
Surface Mount Inductors
■
Available in 8-Lead SO Package
U
O
PPLICATI
A
■
Flash Memory VPP Generators
■
Type II and III PCMCIA Card DC/DC Converters
■
3V to 12V, 5V to 12V Converters
■
Portable Computers and Instruments
■
Cellular Telephones
■
DC/DC Converter Module Replacements
S
DUESCRIPTIO
The LT®1309 is a 500kHz micropower DC/DC converter
for Flash Memory. The regulator features Burst Mode
operation with a 0.5A, 300mV switch, enabling 85%
efficiency at the fixed 12V output. High frequency operation permits the use of small value, and therefore small
size, surface mount inductors and capacitors. The LT1309
comes in an 8-lead SO package allowing extremely
compact PC board layouts. These features make the
device attractive for PCMCIA cards, cellular phones and
other applications where PC board space is limited.
Quiescent current is 650µA decreasing to 9µA when the
part shuts down. The device includes a soft start feature
which limits supply current transients during turn-on.
The LT1309 contains a VPP VALID comparator with a
logic output that goes low when the output voltage is
ready to program 12V Flash Memory. This comparator
simplifies the interface to external control logic.
Burst Mode is a trademark of Linear Technology Corporation.
TM
A
PPLICATITYPICAL
12V, 60mA Flash Memory Programming Supply 12V Output Efficiency
L1*
V
IN
3.3V TO 5V
VPP VALID
+
*
**
†
ON/OFF
C1
4.7µF
MURATA ERIE LQH3C100K0YM00
CERAMIC
MOTOROLA MBR0530
10µH
V
IN
VPP VALID
LT1309
ON/OFF
PGND GND
O
V
SENSE
SOFT
START
U
SW
R1
1M
D1
†
VPP 12V, 60mA
C3
0.1µF
LT1309 • TA01
C2
1µF**
86
84
82
80
78
76
EFFICIENCY (%)
74
72
70
1
VIN = 5V
VIN = 3.3V
10 100
LOAD CURRENT (mA)
LT1309 • TA02
1
LT13 09
WU
U
PACKAGE
/
O
RDER I FOR ATIO
W
O
A
LUTEXI T
S
VCC Voltage............................................................... 7V
VSW Voltage............................................................ 20V
V
V
V
I
Voltage ....................................................... 20V
SENSE
Voltage......................................................... 7V
ON/OFF
Voltage ............................................................. 7V
SEL
Voltage .............................................................. 7V
LIM
Maximum Power Dissipation ............................ 500mW
Operating Temperature Range .....................0°C to 70°C
Storage Temperature Range ................. –65°C to 150°C
A
WUW
ARB
U
G
I
S
SOFT START
V
PGND
V
TOP VIEW
1
2
CC
3
4
SW
S8 PACKAGE
8-LEAD PLASTIC SO
T
= 150°C, θJA = 150°C/W
JMAX
8
7
6
5
ON/OFF
SENSE
VPP VALID
GND
ORDER PART
NUMBER
LT1309CS8
S8 PART MARKING
1309
Lead Temperature (Soldering, 10 sec)..................300°C
Consult factory for Industrial and Military grade parts.
LECTRICAL C CHARA TERIST
E
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
Q
f
OSC
DC Maximum Duty Cycle ● 80 85 92 %
t
ON
V
CESAT
Quiescent Current V
Quiescent Current, Shutdown V
Input Voltage Range 2 6 V
Output Sense Voltage ● 11.5 12 12.6 V
Output Referred Comparator Hysteresis 35 mV
Oscillator Frequency Current Limit Not Asserted 400 500 700 kHz
Switch ON Time 1.7 µs
Reference Line Regulation 2V < VIN < 6V 0.06 0.15 %/V
Switch Saturation Voltage ISW = 0.5A 230 350 mV
Switch Leakage Current VSW = 12V, Switch Off 0.1 10 µA
Switch Current Limit VIN = 5V, Soft Start Floating 400 600 900 mA
Soft Start Current Soft Start Grounded 80 120 µA
ON/OFF Input Voltage Low 0.8 V
ON/OFF Input Voltage High 1.6 V
ON/OFF Bias Current V
Sense Pin Input Current 50.0 90 µA
VPP VALID Threshold V
VPP VALID Output Voltage Low I
VPP VALID Output Voltage High I
ICS
TA = 25°C, VCC = 5V, V
= 12V 650 900 µA
SENSE
= 0.2V 9 15 µA
ON/OFF
= 3V, Soft Start Floating 450 650 950 mA
V
IN
= 5V 16.0 24.0 µA
ON/OFF
= 3V 8.0 14.0 µA
V
ON/OFF
= 0V 0.1 1.0 µA
V
ON/OFF
= 0.2V 0.1 1 µA
V
ON/OFF
Rising (High to Low Transition) V
SENSE
= 100µA 0.13 0.3 V
SINK
= 2.5µA 4 4.5 V
SOURCE
= 3V, unless otherwise noted.
ON/OFF
SENSE
– 200mV
The ● denotes specifications which apply over the full operating
temperature range.
2
W
TEMPERATURE (°C)
–50
100
SWITCH SATURATION VOLTAGE (mV)
125
150
175
200
250
–25
02550
1309 G03
75 100
225
ISW = 500mA
TEMPERATURE (°C)
–50
300
SUPPLY CURRENT (µA)
400
500
600
700
800
–25
02550
1309 G05
75 100
VCC = 5V
V
CC
= 3V
U
TYPICAL PERFORMANCE CHARACTERISTICS
LT1309
Oscillator Frequency
800
700
600
500
400
OSCILLATOR FREQUENCY (kHz)
300
–50
02550
–25
TEMPERATURE (°C)
Sense Voltage
12.20
12.15
12.10
12.05
12.00
11.95
SENSE VOLTAGE (V)
11.90
11.85
11.80
–25 0 50
–50
75 100
1309 G01
25
TEMPERATURE (°C)
Switch Current Limit
1000
900
800
700
600
SWITCH CURRENT (mA)
500
400
–50
–25
75
100
1309 G04
VCC = 3V
VCC = 5V
02550
TEMPERATURE (°C)
Switch Saturation Voltage
75 100
1309 G02
Supply Current
14
12
10
8
SUPPLY CURRENT (µA)
6
4
2
0
–50
Supply Current in Shutdown
VCC = 5V
VCC = 3V
50 100
–25 0
25 75
TEMPERATURE (°C)
1309 G06
Maximum Duty Cycle
95
90
85
80
MAXIMUM DUTY CYCLE (%)
75
70
–50
02550
–25
TEMPERATURE (°C)
75 100
1309 G07
3
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