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LTC1504AIS8#TRPBF

P1-P3P4-P6P7-P9P10-P12
1
LTC1504A
500mA Low Voltage
Step-Down Synchronous
Switching Regulator
Daisy-Chained Control Outputs
FEATURES
The LTC
®
1504A is a self-contained, high efficiency syn-
chronous buck switching regulator. It includes a pair of
on-chip 1.3Ω power switches, enabling it to supply up to
500mA of load current. Efficiency peaks at 92%, minimiz-
ing heat and wasted power. The synchronous buck archi-
tecture allows the output to source or sink current as
required to keep the output voltage in regulation. 100%
duty cycle operation minimizes dropout voltage.
The LTC1504A is available in adjustable and fixed 3.3V
output versions. An adjustable current limit circuit pro-
vides protection from overloads. The internal 1% refer-
ence combined with a sophisticated voltage feedback loop
provides optimum output voltage accuracy and fast load
transient response. The LTC1504A is specified to operate
with input voltages between 4V and 10V. Contact the LTC
factory for guaranteed specifications at 2.7V supply.
The LTC1504A is a pin-compatible, functional upgrade to
the LTC1504.
The LTC1504A is available in a plastic SO-8 package.
DESCRIPTION
U
■
500mA Output Current at 3.3V Output
■
Up to 92% Peak Efficiency
■
100% Maximum Duty Cycle
■
Internal Reference Trimmed to 1%
■
Output Can Source or Sink Current
■
Requires as Few as Four External Components
■
Input Voltage Range: 4V to 10V
■
Adjustable Current Limit
■
Small SO-8 Package
■
200kHz Switching Frequency Can Typically be
Synchronized Up to 500kHz
Minimum Part Count 5V to 3.3V Regulator 5V to 3.3V Efficiency
LOAD CURRENT (mA)
10
EFFICIENCY (%)
100
90
80
70
60
50
40
30
20
10
0
100 500
1504 • TA02
I
MAX
SHDN
SS COMP
V
CC
GND
SW
SENSE
+
5V
SHUTDOWNNC
NC
1000pF
+
3.3V AT 500mA
L
EXT
50µH
C
IN
: AVX TPSC226M016R0375
C
OUT
: AVX TAJC476M010
L
EXT
: COILTRONICS CTX50-1P
1504A • TA01
LTC1504A-3.3
C
IN
22µF
C
OUT
47µF
APPLICATIONS
U
■
Small Portable Digital Systems
■
Active Termination
■
Auxiliary Output Voltage Supplies
■
Minimum Part Count/Size Switchers
TYPICAL APPLICATION
U
, LTC and LT are registered trademarks of Linear Technology Corporation.
2
LTC1504A
ABSOLUTE MAXIMUM RATINGS
W
WW
U
WU
U
PACKAGE
/
O
RDER I FOR ATIO
ELECTRICAL CHARACTERISTICS
V
CC
= 5V, T
A
= 25°C unless otherwise specified. (Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CC
Minimum Supply Voltage (Note 7) ● 4V
V
FB
Feedback Voltage LTC1504ACS8 ● 1.25 1.265 1.28 V
LTC1504AIS8
● 1.23 1.265 1.29 V
∆V
FB
Feedback Voltage PSRR Figure 1, 4V ≤ V
CC
≤ 10V, LTC1504ACS8 ● 1.1 1.6 %
Figure 1, 4V ≤ V
CC
≤ 10V, LTC1504AIS8 ● 1.1 1.8 %
V
SENSE
Sense Pin Voltage LTC1504ACS8-3.3 ● 3.20 3.30 3.40 V
∆V
SENSE
Sense Voltage PSRR Figure 1, 4V ≤ V
CC
≤ 10V, LTC1504ACS8-3.3 ● 1.2 1.8 %
Figure 1, 4V ≤ V
CC
≤ 10V, LTC1504AIS8-3.3 ● 1.2 2.0 %
I
CC
Supply Current Figure 1, V
SHDN
= V
CC
, I
OUT
= 0 (Note 4) 3 mA
Figure 1, V
SHDN
= V
CC
, I
OUT
= 0, V
FB
/V
SENSE
= V
CC
(Note 4) ● 0.3 0.6 mA
V
SHDN
= 0V ● 1.0 20 µA
f
OSC
Internal Oscillator Frequency Commercial ● 150 200 250 kHz
Industrial
● 130 200 300 kHz
R
SW
Internal Switch Resistance Commercial ● 1.3 2.0 Ω
Industrial
● 1.3 2.2 Ω
V
IH
SHDN Input High Voltage ● 2.4 V
V
IL
SHDN Input Low Voltage ● 0.8 V
I
IN
SHDN Input Current ● ±0.1 ±1 µA
V
OH
Error Amplifier Positive Swing Figure 2 ● 4.5 4.95 V
V
OL
Error Amplifier Negative Swing Figure 2 ● 0.05 0.5 V
I
OH
, I
OL
Error Amplifier Output Current Figure 2 ● ±50 ±100 ±200 µA
g
mV
Error Amplifier Transconductance Commercial (Note 5) ● 350 600 1100 µmho
Industrial (Note 5)
● 300 600 1200 µmho
A
V
Error Amplifier DC Gain (Note 5) ● 40 48 dB
g
mI
I
LIM
Amplifier Transconductance (Note 6) 2000 µmho
I
MAX
I
MAX
Sink Current V
IMAX
= V
CC
, Commercial ● 81216 µA
V
IMAX
= V
CC
, Industrial ● 81217 µA
ORDER PART
NUMBER
S8 PART MARKING
Consult factory for Military grade parts.
1504AI
04AI33
T
JMAX
= 125°C, θ
JA
= 90°C/W
1
2
3
4
8
7
6
5
TOP VIEW
COMP
SS
SHDN
FB/SENSE*
I
MAX
V
CC
SW
GND
S8 PACKAGE
8-LEAD PLASTIC SO
*FB FOR LTC1504A, SENSE FOR LTC1504A-3.3
LTC1504ACS8
LTC1504ACS8-3.3
LTC1504AIS8
LTC1504AIS8-3.3
(Note 1)
Supply Voltage (V
CC
to GND)................................... 10V
Peak Output Current (SW) .......................................±1A
Input Voltage (All Other Pins)...... –0.3V to (V
CC
+ 0.3V)
Operating Temperature Range
LTC1504AC .............................................0°C to 70°C
LTC1504AI ......................................... –40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
1504A
1504A33
3
LTC1504A
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3: This parameter is guaranteed by correlation and is not tested
directly.
Note 4: LTC1504A quiescent current is dominated by the gate drive
current drawn by the onboard power switches. With FB or SENSE pulled to
V
CC
the output stage will stop switching and the static quiescent current
can be observed. With FB or SENSE hooked up normally, the output stage
will be switching and total dynamic supply current can be measured.
Note 5: Fixed output parts will appear to have g
mV
and A
V
values 2.6 times
lower than the specified values, due to the internal divider resistors.
Note 6: The I
LIM
amplifier can sink but not source current. Under normal
(not current limited) operation, the I
LIM
output current will be zero.
Note 7: Contact factory for guaranteed specifications at 2.7V supply.
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
TEMPERATURE (°C)
–50
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
25 75
1504A • TPC03
–25 0
50 100 125
SWITCH ON-RESISTANCE (Ω)
V
CC
= 10V
V
CC
= 5V
V
CC
= 3.3V
Switch On-Resistance vs
TemperatureSupply Current vs Supply Voltage
SUPPLY VOLTAGE (V)
2.5
1504A • TPC01
5
7.5 10
SUPPLY CURRENT (mA)
14
12
10
8
6
4
2
0
V
FB
= V
OUT
V
FB
= V
CC
T
A
= 25°C
I
OUT
= 0
Current Limit Threshold vs R
IMAX
R
IMAX
(Ω)
10k
CURRENT LIMIT THRESHOLD (mA)
700
600
500
400
300
200
100
0
100k
1504A • TPC04
T
A
= 25°C
V
CC
= 5V
TEMPERATURE (°C)
–50 –25 0 25 50 75 100 125
SUPPLY CURRENT (mA)
10
1
0.1
1504A • TPC02
V
FB
= V
OUT
V
FB
= V
CC
V
CC
= 5V
I
OUT
= 0
Supply Current vs Temperature
Shutdown Threshold vs
Supply Voltage
SUPPLY VOLTAGE (V)
357
SHUTDOWN PIN THRESHOLD (V)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
10
1504A • TPC07
Current Limit Threshold vs
Temperature
TEMPERATURE (°C)
–50
CURRENT LIMIT THRESHOLD (mA)
–25 0 25 50 75
1504A • TPC05
125
500
450
400
350
300
250
200
150
100
50
0
100
V
CC
= 5V
R
IMAX
= 47k
R
IMAX
= 22k
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
SS
Soft Start Source Current V
SS
= 0V, Commercial ● –8 –12 –16 µA
V
SS
= 0V, Industrial ● –8 –12 –17 µA
t
r
, t
f
Output Switch Rise/Fall Time 10% to 90% Ouput Swing ● 550 ns
DC
MAX
Maximum Duty Cycle V
COMP
= V
CC
● 100 %
V
CC
= 5V, T
A
= 25°C unless otherwise specified. (Note 2)
P1-P3P4-P6P7-P9P10-P12

LTC1504AIS8#TRPBF

Mfr. #:
Buy LTC1504AIS8#TRPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 500mA L V Buck Sync Sw Reg
Lifecycle:
New from this manufacturer.
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