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LTC1265CS-3.3#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16
1
LTC1265/LTC1265-3.3/LTC1265-5
V
IN
5.4V TO
12V
L1*
33µH
R
SENSE
**
0.1Ω
V
OUT
5V
1A
C
OUT
††
220µF
10V
1000pF
130pF
3900pF
1k
0.1µF
C
IN
†††
68µF
20V
D1
†
PWR V
IN
V
IN
SW
PGND
SENSE
+
SENSE
–
SGND
I
TH
C
T
LTC1265-FO1
SHDN
*
**
†
††
†††
COILTRONICS CTX33-4
IRC LRC2010-01-R100-J
MBRS130LT3
AVX TPSE227K010
AVX TPSE686K020
LTC1265-5
+
+
Figure 1. High Efficiency Step-Down Converter
1.2A, High Efficiency
Step-Down DC/DC Converter
■
High Efficiency: Up to 95%
■
Current Mode Operation for Excellent Line and Load
Transient Response
■
Internal 0.3
Ω
Power Switch (V
IN
= 10V)
■
Short-Circuit Protection
■
Low Dropout Operation: 100% Duty Cycle
■
Low-Battery Detector
■
Low 160µA Standby Current at Light Loads
■
Active-High Micropower Shutdown: I
Q
< 15µA
■
Peak Inductor Current Independent of Inductor Value
■
Available in 14-pin SO Package
The LTC
®
1265 is a monolithic step-down current mode
DC/DC converter featuring Burst Mode
TM
operation at low
output current. The LTC1265 incorporates a 0.3Ω switch
(V
IN
=10V) allowing up to 1.2A of output current.
Under no load condition, the converter draws only 160µA.
In shutdown it typically draws a mere 5µA making this
converter ideal for current sensitive applications. In drop-
out the internal P-channel MOSFET switch is turned on
continuously maximizing the life of the battery source. The
LTC1265 incorporates automatic power saving Burst Mode
operation to reduce gate charge losses when the load
currents drop below the level required for continuous
operation.
The inductor current is user-programmable via an external
current sense resistor. Operation up to 700kHz permits
the use of small surface mount inductors and capacitors.
■
5V to 3.3V Conversion
■
Distributed Power Systems
■
Step-Down Converters
■
Inverting Converters
■
Memory Backup Supply
■
Portable Instruments
■
Battery-Powered Equipment
■
Cellular Telephones
LTC1265-5 Efficiency
Burst Mode is a trademark of Linear Technology Corporation.
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
LOAD CURRENT (A)
0.01
70
EFFICIENCY (%)
75
80
85
90
100
0.10 1.00
LTC1265 TA01
95
V
IN
= 6V
V
IN
= 9V
V
IN
= 12V
L = 33µH
V
OUT
= 5V
R
SENSE
= 0.1Ω
C
T
= 130pF
, LTC and LT are registered trademarks of Linear Technology Corporation.
2
LTC1265/LTC1265-3.3/LTC1265-5
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 10V, V
SHDN
= 0V, unless otherwise specified.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
FB
Feedback Current into Pin 9 LTC1265 0.2 1 µA
V
FB
Feedback Voltage LTC1265C ● 1.22 1.25 1.28 V
V
IN
= 9V, LTC1265I ● 1.20 1.25 1.30 V
V
OUT
Regulator Output Voltage LTC1265-3.3: I
LOAD
= 800mA ● 3.22 3.3 3.40 V
LTC1265-5: I
LOAD
= 800mA ● 4.9 5 5.2 V
∆V
OUT
Output Voltage Line Regulation V
IN
= 6.5V to 10V, I
LOAD
= 800mA –40 0 40 mV
Output Voltage Load Regulation LTC1265-3.3: 10mA < I
LOAD
< 800mA 40 65 mV
LTC1265-5: 10mA < I
LOAD
< 800mA 60 100 mV
Burst Mode Operation Output Ripple I
LOAD
= 0mA 50 mV
P-P
I
Q
Input DC Supply Current (Note 3) Active Mode: 3.5V < V
IN
< 10V 1.8 2.4 mA
Sleep Mode: 3.5V < V
IN
< 10V 160 230 µA
Sleep Mode: 5V < V
IN
< 10V (LTC1265-5) 160 230 µA
Shutdown: V
SHDN
= V
IN
, 3.5V < V
IN
< 10V 5 15 µA
V
LBTRIP
Low-Battery Trip Point 1.15 1.25 1.35 V
I
LBIN
Current into Pin 4 0.5 µA
I
LBOUT
Current Sunk by Pin 3 V
LBOUT
= 0.4V, V
LBIN
= 0V 0.5 1.0 1.5 mA
V
LBOUT
= 5V, V
LBIN
= 10V 1.0 µA
V
8
– V
7
Current Sense Threshold Voltage LTC1265: V
SENSE
–
= 5V, V
9
= V
OUT
/4 + 25mV (Forced) 25 mV
V
SENSE
–
= 5V, V
9
= V
OUT
/4 – 25mV (Forced) 130 150 180 mV
LTC1265-3.3: V
SENSE
–
= V
OUT
+ 100mV (Forced) 25 mV
V
SENSE
–
= V
OUT
– 100mV (Forced) 130 150 180 mV
LTC1265-5: V
SENSE
–
= V
OUT
+ 100mV (Forced) 25 mV
V
SENSE
–
= V
OUT
– 100mV (Forced) 130 150 180 mV
R
ON
ON Resistance of Switch LTC1265C ● 0.3 0.60 Ω
LTC1265I 0.3 0.70 Ω
I
5
C
T
Pin Discharge Current V
OUT
in Regulation, V
SENSE
–
= V
OUT
40 60 100 µA
V
OUT
= 0V 2 10 µA
t
OFF
Switch Off Time (Note 4) C
T
= 390pF, I
LOAD
= 800mA (LTC1265C) ● 456 µs
C
T
= 390pF, I
LOAD
= 800mA (LTC1265I) ● 3.5 5 7 µs
Input Supply Voltage (Pins 1, 2, 13)..........–0.3V to 13V
DC Switch Current (Pin 14) .................................... 1.2A
Peak Switch Current (Pin 14) ................................. 1.6A
Switch Voltage (Pin 14) ..................................V
IN
– 13.0
Operating Temperature Range
LTC1265C ............................................... 0° to 70°C
LTC1265I ........................................ –40°C to 85°C
Junction Temperature (Note 2).............................125°C
Storage Temperature Range ....................–65° to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
(Voltages Refer to GND Pin) (Note 1)
ORDER PART
NUMBER
LTC1265CS
LTC1265CS-5
LTC1265CS-3.3
LTC1265IS
Consult factory for Military grade parts.
TOP VIEW
S PACKAGE
14-LEAD PLASTIC SO
*ADJUSTABLE OUTPUT VERSION
T
JMAX
= 125°C, θ
JA
= 110°C/W
1
2
3
4
5
6
7
14
13
12
11
10
9
8
PWR V
IN
V
IN
LB
OUT
LB
IN
C
T
I
TH
SENSE
–
SW
PWR V
IN
PGND
SGND
SHDN
N/C (V
FB
*)
SENSE
+
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
ELECTRICAL CHARACTERISTICS
3
LTC1265/LTC1265-3.3/LTC1265-5
Note 3: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 4: In applications where R
SENSE
is placed at ground potential, the
off time increases by approximately 40%.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC1265CS, LTC1265CS-3.3, LTC1265CS-5:
T
J
= T
A
+ (P
D
• 110°C/W)
LOAD CURRENT (A)
0.01
70
EFFICIENCY (%)
75
80
85
90
100
0.10 1.00
1265 G01
95
V
IN
= 5V
V
IN
= 9V
V
IN
= 12V
LTC1265-3.3
V
OUT
= 3.3V
R
SENSE
= 0.1Ω
C
T
= 130pF
COIL = CTX33-4
INPUT VOLTAGE (V)
4
80
EFFICIENCY (%)
82
86
88
90
100
94
6
8
913
LTC1265 G03
84
96
98
92
57
10
11
12
I
LOAD
= 250mA
I
LOAD
= 800mA
LTC1265-3.3
R
SENSE
= 0.1Ω
C
T
= 130pF
COIL = CTX33-4
INPUT VOLTAGE (V)
4
80
EFFICIENCY (%)
82
86
88
90
100
94
6
8
913
1265 G02
84
96
98
92
57
10
11
12
I
LOAD
= 250mA
I
LOAD
= 800mA
LTC1265-5
R
SENSE
= 0.1Ω
C
T
= 130pF
COIL = CTX33-4
Switch Resistance
INPUT VOLTAGE (V)
3
0
RDS
(ON)
(Ω)
0.1
0.3
0.4
0.5
7
11
13
0.9
1265 G05
0.2
59
6
10
12
48
0.6
0.7
0.8
T
J
= 70°C
T
J
= 125°C
T
J
= 25°C
T
J
= 0°C
(V
IN
–
V
OUT
) VOLTAGE (V)
0
NORMALIZED FREQUENCY
0.4
0.8
1.2
1.0
0.6
0.2
21468
1265 G04
1003579
0°C
25°C
70°C
Operating Frequency
vs (V
IN
– V
OUT
)
Efficiency vs Input Voltage
(V
OUT
= 3.3V)
Efficiency vs Input Voltage
(V
OUT
= 5V)
Efficiency vs Load Current
Switch Leakage Current
TEMPERATURE (°C)
0
LEAKAGE CURRENT (nA)
180
240
300
270
210
150
90
30
80
1265 G06
120
60
0
20
40
60
100
V
IN
= 12V
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IH
Shutdown Pin High Min Voltage at Pin 10 for Device to be in Shutdown 1.2 V
V
IL
Shutdown Pin Low Max Voltage at Pin 10 for Device to be Active 0.6 V
I
10
Shutdown Pin Input Current V
SHDN
= 8V 0.5 µA
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 10V, V
SHDN
= 0V, unless otherwise specified.
ELECTRICAL CHARACTERISTICS
TYPICAL PERFOR A CE CHARACTERISTICS
UW
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16

LTC1265CS-3.3#PBF

Mfr. #:
Buy LTC1265CS-3.3#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Adj Hi Eff 1A Stepdn Converter
Lifecycle:
New from this manufacturer.
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