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Details, datasheet, quote on part number:LM2574-12
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Datasheet text preview:
LM2574 0.5 A, Adjustable Output Voltage, Step-Down Switching Regulator
The LM2574 series of regulators are monolithic integrated circuits ideally suited for easy and convenient design of a stepdown switching regulator (buck converter). All circuits of this series are capable of driving a 0.5 A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5.0 V, 12 V, 15 V, and an adjustable output version. These regulators were designed to minimize the number of external components to simplify the power supply design. Standard series of inductors optimized for use with the LM2574 are offered by several different inductor manufacturers. Since the LM2574 converter is a switchmode power supply, its efficiency is significantly higher in comparison with popular threeterminal linear regulators, especially with higher input voltages. In most cases, the power dissipated by the LM2574 regulator is so low, that the copper traces on the printed circuit board are normally the only heatsink needed and no additional heatsinking is required. The LM2574 features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency (±2% over 0°C to +125°C). External shutdown is included, featuring 60 µA (typical) standby current. The output switch includes cyclebycycle current limiting, as well as thermal shutdown for full protection under fault conditions.
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16 1
SO16W DW SUFFIX CASE 751G
8 1
PDIP8 N SUFFIX CASE 626
PIN CONNECTIONS
* * FB Sig Gnd ON/OFF Pwr Gnd * *
1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9
· 3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions · Adjustable Version Output Voltage Range, 1.23 to 37 V ±4% max · · · · · · · · · · · · · ·
over Line and Load Conditions Guaranteed 0.5 A Output Current Wide Input Voltage Range: 4.75 to 40 V Requires Only 4 External Components 52 kHz Fixed Frequency Internal Oscillator TTL Shutdown Capability, Low Power Standby Mode High Efficiency Uses Readily Available Standard Inductors Thermal Shutdown and Current Limit Protection Simple and HighEfficiency StepDown (Buck) Regulators Efficient Preregulator for Linear Regulators OnCard Switching Regulators Positive to Negative Converters (BuckBoost) Negative StepUp Converters Power Supply for Battery Chargers
* * Output * Vin * * *
(Top View)
FB Sig Gnd ON/OFF Pwr Gnd
1 2 3 4
8 7 6 5
* Output * Vin
(Top View)
* No internal connection, but should be soldered to * PC board for best heat transfer.
Applications ORDERING INFORMATION
See detailed ordering and shipping information in the package dimensions section on page 24 of this data sheet.
DEVICE MARKING INFORMATION
See general marking information in the device marking section on page 24 of this data sheet.
© Semiconductor Components Industries, LLC, 2002
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February, 2002 Rev. 5
Publication Order Number: LM2574/D
LM2574
Typical Application (Fixed Output Voltage Versions)
7.0 - 40 V Unregulated DC Input (3) LM2574 (14) 2 (4) Sig Gnd 4 (6) Pwr 3 Gnd (5) Feedback 1 Output L1 330 µH D1 1N5819 Cout 220 µF
+Vin Cin 22 µF 5 (12)
7 ON/OFF
5.0 V Regulated Output 0.5 A Load
Representative Block Diagram and Typical Application
+Vin Cin 5 1 Feedback R2 Fixed Gain Error Amplifier Comparator Freq Shift 18 kHz 52 kHz Oscillator (12) (3) Current Limit Driver Latch 1.0 Amp Switch Output 7 (14) Pwr Gnd 4 (6) D1 L1 Cout Load Vout ON/OFF 3 (5)
Unregulated DC Input
3.1 V Internal Regulator
ON/OFF
Output Voltage Versions 3.3 V 5.0 V 12 V 15 V For adjustable version R1 = open, R2 = 0
R2 () 1.7 k 3.1 k 8.84 k 11.3 k
R1 1.0 k Sig Gnd 2 (4)
1.235 V Band-Gap Reference
Reset
Thermal Shutdown
NOTE: Pin numbers in ( ) are for the SO16W package.
Figure 1. Block Diagram and Typical Application
ABSOLUTE MAXIMUM RATINGS (Absolute Maximum Ratings indicate limits beyond which damage to the device may occur).
Rating Maximum Supply Voltage ON/OFF Pin Input Voltage Output Voltage to Ground (Steady State) DW Suffix, Plastic Package Case 751G Max Power Dissipation Thermal Resistance, JunctiontoAir N Suffix, Plastic Package Case 626 Max Power Dissipation Thermal Resistance, JunctiontoAmbient Thermal Resistance, JunctiontoCase Storage Temperature Range Minimum ESD Rating (Human Body Model: C = 100 pF, R = 1.5 k) Lead Temperature (Soldering, 10 seconds) Maximum Junction Temperature NOTE: ESD data available upon request. TJ 260 150 °C °C Symbol Vin PD R J A PD R J A R J C Tstg Value 45 0.3 V V +Vin 1.0 Internally Limited 145 Internally Limited 100 5.0 65°C to +150°C 2.0 Unit V V V W °C/W W °C/W °C/W °C kV
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LM2574
OPERATING RATINGS (Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee
specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics). Rating Operating Junction Temperature Range Supply Voltage Symbol TJ Vin Value 40 to +125 40 Unit °C V
SYSTEM PARAMETERS ([Note 1] Test Circuit Figure 16)
ELECTRICAL CHARACTERISTICS (Unless otherwise specified, Vin = 12 V for the 3.3 V, 5.0 V, and Adjustable
version, Vin = 25 V for the 12 V version, Vin = 30 V for the 15 V version. ILoad = 100 mA. For typical values TJ = 25°C, for min/max values TJ is the operating junction temperature range that applies [Note 2], unless otherwise noted). Characteristic LM25743.3 ([Note 1] Test Circuit Figure 16) Output Voltage (Vin = 12 V, ILoad = 100 mA, TJ = 25°C) Output Voltage (4.75 V Vin 40 V, 0.1 A ILoad 0.5 A) TJ = 25°C TJ = 40 to +125°C Efficiency (Vin = 12 V, ILoad = 0.5 A) LM25745 ([Note 1] Test Circuit Figure 16) Output Voltage (Vin = 12 V, ILoad = 100 mA, TJ = 25°C) Output Voltage (7.0 V Vin 40 V, 0.1 A ILoad 0.5 A) TJ = 25°C TJ = 40 to +125°C Efficiency (Vin = 12 V, ILoad = 0.5 A) LM257412 ([Note 1] Test Circuit Figure 16) Output Voltage (Vin = 25 V, ILoad = 100 mA, TJ = 25°C) Output Voltage (15 V Vin 40 V, 0.1 A ILoad 0.5 A) TJ = 25°C TJ = 40 to +125°C Efficiency (Vin = 15 V, ILoad = 0.5 A) LM257415 ([Note 1] Test Circuit Figure 16) Output Voltage (Vin = 30 V, ILoad = 100 mA, TJ = 25°C) Output Voltage (18 V < Vin < 40 V, 0.1 A < ILoad < 0.5 A) TJ = 25°C TJ = 40 to +125°C Efficiency (Vin = 18 V, ILoad = 0.5 A) LM2574 ADJUSTABLE VERSION ([Note 1] Test Circuit Figure 16) Feedback Voltage Vin = 12 V, ILoad = 100 mA, Vout = 5.0 V, TJ = 25°C Feedback Voltage 7.0 V Vin 40 V, 0.1 A ILoad 0.5 A, Vout = 5.0 V TJ = 25°C TJ = 40 to +125°C Efficiency (Vin = 12 V, ILoad = 0.5 A, Vout = 5.0 V) VFB VFBT 1.193 1.18 1.23 77 1.267 1.28 % 1.217 1.23 1.243 V V Vout Vout 14.4 14.25 15 88 15.6 15.75 % 14.7 15 15.3 V V Vout Vout 11.52 11.4 12 88 12.48 12.6 % 11.76 10 12.24 V V Vout Vout 4.8 4.75 5.0 77 5.2 5.25 % 4.9 5.0 5.1 V V Vout Vout 3.168 3.135 3.3 72 3.432 3.465 % 3.234 3.3 3.366 V V Symbol Min Typ Max Unit
1. External components such as the catch diode, inductor, input and output capacitors can affect the switching regulator system performance. When the LM2574 is used as shown in the Figure 16 test circuit, the system performance will be as shown in the system parameters section of the Electrical Characteristics. 2. Tested junction temperature range for the LM2574: Tlow = 40°C Thigh = +125°C.
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