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LTC1574CS#TRPBF

P1-P3P4-P6P7-P8
1
LTC1574
LTC1574-3.3/LTC1574-5
High Efficiency Step-Down
DC/DC Converters
with Internal Schottky Diode
The LTC
®
1574 is a family of easy-to-use current mode
DC/DC converters ideally suited for 9V to 5V, 5V to 3.3V
and inverting operation. With an internal 0.9Ω switch (at
a supply voltage of 12V) and a low forward drop Schottky
diode (0.450V typ at 200mA, T
A
= 25°C), the LTC1574
requires only three external components to construct a
complete high efficiency DC/DC converter.
Under no load condition, the LTC1574 draws only 130µA.
In shutdown, it draws a mere 2µA making this converter
ideal for battery-powered applications. In dropout, the
internal P-channel MOSFET switch is turned on continu-
ously allowing the user to maximize the life of the battery
source.
The maximum inductor current of the LTC1574 family is
pin selectable to either 340mA or 600mA, optimizing
efficiency for a wide range of applications. Operation up to
200kHz permits the use of small surface mount inductors
and capacitors.
For applications requiring higher output current or ultra-
high efficiency, see the LTC1148 or LTC1265 data sheets.
For detailed applications information, see the LTC1174
data sheet.
High Efficiency Step-Down Converter
LTC1574-5 Efficiency
■
Inverting Converters
■
Step-Down Converters
■
Memory Backup Supply
■
Portable Instruments
■
Battery-Powered Equipment
■
Distributed Power Systems
■
High Efficiency: Up to 94%
■
Usable in Noise-Sensitive Products
■
Peak Inductor Current Independent of Inductor Value
■
Short-Circuit Protection
■
Internal Low Forward Drop Schottky Diode
■
Only Three External Components Required
■
Wide V
IN
Range: 4V to 18.5V (Absolute Maximum)
■
Low Dropout Operation
■
Low-Battery Detector
■
Pin Selectable Current Limit
■
Internal 0.9Ω Power Switch: V
IN
< 11V
■
Standby Current: 130µA
■
Active Low Micropower Shutdown
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.
V
IN
100µH
†
22µF*
35V
100µF*
10V
1574 TA01
5V
175mA
5
2, 4, 13, 15
7
10
3, 14
12
11
6
V
IN
5.5V to
16V
GND
LTC1574-5
LB
IN
LB
OUT
I
PGM
SHDN
V
OUT
SW
* AVX TPSD226K035
** AVX TPSD107K010
†
COILTRONICS CTX100-4
+
+
LOAD CURRENT (mA)
1
EFFICIENCY (%)
100
95
90
85
80
75
70
10 100
1574 TA02
200
V
IN
= 6V
V
IN
= 9V
L = 100µH
V
OUT
= 5V
I
PGM
= 0V
2
LTC1574
LTC1574-3.3/LTC1574-5
ORDER PART
NUMBER
LTC1574CS
LTC1574CS-3.3
LTC1574CS-5
Consult factory for Industrial and Military grade parts.
(Note 1)
(Voltage Referred to GND Pin)
Input Supply Voltage (Pin 5) ................. –0.3V to 18.5V
Switch Current (Pin 3, 14) ........................................ 1A
Switch Voltage (Pin 3, 14) .......................... V
IN
– 18.5V
Operating Temperature Range .................... 0°C to 70°C
Junction Temperature (Note 2)............................ 125°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
FB
Feedback Current into Pin 10 LTC1574 1 µA
V
FB
Feedback Voltage LTC1574 ● 1.20 1.25 1.30 V
V
OUT
Regulated Output Voltage LTC1574-3.3 ● 3.14 3.30 3.46 V
LTC1574-5 ● 4.75 5.00 5.25 V
∆V
OUT
Output Voltage Line V
IN
= 6V to 12V, I
LOAD
= 100mA, I
PGM
= V
IN
(Note 3) 10 70 mV
Regulation
Output Voltage Load LTC1574-3.3 (Note 3) 20mA < I
LOAD
< 175mA, I
PGM
= 0V –5 –70 mV
Regulation 20mA < I
LOAD
< 400mA, I
PGM
= V
IN
–45 –70 mV
LTC1574-5 (Note 3) 20mA < I
LOAD
< 175mA, I
PGM
= 0V –5 –70 mV
20mA < I
LOAD
< 400mA, I
PGM
= V
IN
–50 –70 mV
I
Q
Input DC Supply Current (Note 4)
Active Mode 4V < V
IN
< 16V, I
PGM
= 0V 450 600 µA
Sleep Mode 4V < V
IN
< 16V 130 180 µA
Shutdown (Note 5) SHDN = 0V, 4V < V
IN
< 16V 2 25 µA
V
LBTRIP
Low-Battery Trip Point 1.25 1.4 V
I
LBIN
Current into Pin 12 0.5 µA
I
LBOUT
Current Sunk by Pin 11 V
LBOUT
= 0.4V, V
LBIN
= 0V 0.5 1.0 1.5 mA
V
LBOUT
= 5V, V
LBIN
= 10V 1.0 µA
V
HYST
Comparator Hysteresis 7.5 15 30 mV
I
PEAK
Current Limit I
PGM
= V
IN
, V
OUT
= 0V ● 0.54 0.60 0.83 A
I
PGM
= 0V, V
OUT
= 0V ● 0.27 0.34 0.53 A
R
ON
ON Resistance of Switch ● 0.9 1.55 Ω
t
OFF
Switch Off Time V
OUT
at Regulated Value 3 4 5 µs
V
IH
SHDN Pin High Minimum Voltage at Pin 7 for Device to Be Active 1.2 V
V
IL
SHDN Pin Low Maximum Voltage at Pin 7 for Device to Be in Shutdown 0.75 V
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
TOP VIEW
S PACKAGE
16-LEAD PLASTIC SO
*ADJUSTABLE OUTPUT VERSION
T
JMAX
= 125°C, θ
JA
= 110°C/W
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
NC
GND
SW
GND
V
IN
I
PGM
SHDN
NC
NC
GND
SW
GND
LB
IN
LB
OUT
V
OUT
(V
FB
*)
NC
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 9V, SHDN = V
IN
, I
PGM
= 0V, unless otherwise specified.
3
LTC1574
LTC1574-3.3/LTC1574-5
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 9V, SHDN = V
IN
, I
PGM
= 0V, unless otherwise specified.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
IH
SHDN Pin Input Current SHDN = 16V 2 µA
I
IL
SHDN Pin Input Current 0 ≤ SHDN ≤ 0.8V 0.5 µA
V
F
Schottky Diode Forward Voltage Forward Current = 200mA 0.450 0.570 V
I
R
Schottky Reverse Current Reverse Voltage = 5V 10 25 µA
Reverse Voltage = 18.5V 100 250 µA
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a 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:
T
J
= T
A
+ (P
D
• 110°C/W)
Note 3: Guaranteed by design.
Note 4: Does not include Schottky reverse current. Dynamic supply
current is higher due to the gate charge being delivered at the switching
frequency.
Note 5: Current into Pin 5 only, measured without electrolytic input
capacitor.
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
Efficiency vs Input VoltageEfficiency vs Load CurrentEfficiency vs Load Current
Switch Resistance vs
Input Voltage
Switch Leakage Current
vs Temperature
Efficiency Using Different Types
of Inductor Core Material
ELECTRICAL CHARACTERISTICS
LOAD CURRENT (mA)
1
EFFICIENCY (%)
10 100
1574 • TPC01
500
100
90
80
70
60
50
L = 50µH
V
OUT
= 3.3V
I
PGM
= V
IN
COIL = CTX50-4
V
IN
= 5V
V
IN
= 9V
LOAD CURRENT (mA)
1
EFFICIENCY (%)
10 100
1574 • TPC02
400
100
95
90
85
80
75
70
L = 50µH
V
OUT
= 5V
I
PGM
= V
IN
COIL = CTX50-4
V
IN
= 6V
V
IN
= 9V
INPUT VOLTAGE (V)
5
EFFICIENCY (%)
7
9
10 14
1574 • TPC03
68
11
12
13
95
94
93
92
91
90
89
V
OUT
= 5V
L = 100µH
COIL = CTX100-4
I
LOAD
= 300mA
I
PGM
= V
IN
I
LOAD
= 100mA
I
PGM
= 0V
LOAD CURRENT (mA)
1
EFFICIENCY (%)
10 100 500
100
90
80
70
60
50
V
IN
= 5V
V
OUT
= 3.3V
I
PGM
= V
IN
CTX50-4
CTX50-4P
1574 • TPC04
TEMPERATURE (°C)
0
LEAKAGE CURRENT (nA)
180
160
140
120
100
80
60
40
20
0
40
80
100
1574 • TPC05
20 60
V
IN
= 13.5V
INPUT VOLTAGE (V)
4
RDS
(ON)
(Ω)
12
1574 • TPC06
6
8
10
14 16 18 20
T
A
= 25°C
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
P1-P3P4-P6P7-P8

LTC1574CS#TRPBF

Mfr. #:
Buy LTC1574CS#TRPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Adj CMOS Stepdn 425mA,DC/DC Converter
Lifecycle:
New from this manufacturer.
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