CYStech Electronics Corp.
Simple Switcher 3A Step- Down Voltage Regulator
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 1/10
PL2576-XXXF5
Features
3.3V, 5V, 12V, 15V, and adjustable output versions. Adjustable version output voltage range, 1.23V to 37V±4% max over line and load conditions. Guaranteed 3A output current. Wide input voltage range. Requires only 4 external components 52 kHz fixed frequency oscillator TTL shutdown capability, low power standby mode. High efficiency Uses readily available standard inductors. Thermal shutdown and current limit protection.
TO-263-5L
Description
The PL2576-XXXF5 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving 3A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation and a fixed-frequency oscillator. The PL2576-XXXF5 series offers a high-efficiency replacement for popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in some cases no heat sink is required. A standard series if inductors optimized for use with the PL2576 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies. Other features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring 50µA (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault conditions.
Applications
Simple high-efficiency step-down (buck) regulator. Efficient pre-regulator for linear regulators. On-card switching regulators. Positive to negative converter (Buck-Boost).
PL2576-XXXF5
CYStek Product Specification
CYStech Electronics Corp.
Typical Application (Fixed Output Voltage Version)
7V-40V unregulated DC input Feedback 4 Output 2
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 2/10
+VIN 1
PL2576-5.0
L1 100μH D1 1N5822
+
+5V regulated output 3A load Cout 1000μF
+
Cin 100μF
3 GND 5 ON/OFF
Figure. 1
Block Diagram
Unregulated DC Input
Vin
1
Internal Regulator
ON / OFF
5
ON/OFF
Feedback Cin
+
4 R2
Fixed Gain Error Amp
Comparator Driver
1.0k
R1
3 Amp Switch
2
Output GND
L1
Vout Cout
1.23V band-gap reference
52kHz Oscillator
Reset
Thermal Current Shutdown Limit
3
+
D1
L O A D
3.3V, R2=1.7k 5V, R2=3.1k 12V, R2=8.84k 15V, R2=11.3k For Adjustable version, R1=open, R2=0
Ordering Information
Temperature Range -40℃≤TA≤125℃ Output Voltage
3.3
5.0
12
15
ADJ
Package Type
PL2576-3.3F5 PL2576-5.0F5 PL2576-12F5 PL2576-15F5 PL2576-ADJF5 TO-263-5L
PL2576-XXXF5
CYStek Product Specification
CYStech Electronics Corp.
Absolute Maximum Ratings (Note 1)
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 3/10
Maximum supply voltage ………………………………………………………………………………………………45V ON/OFF pin input voltage …………………………………………………………………………………-0.3V≤V≤+VIN Output voltage to ground (steady state)…………………………………………………………………………………-1V Power dissipation ………………………………………………………………………………………. Internally limited Storage temperature range…………………………….…………………………………………………..-65°C to +150°C Maximum junction temperature……. ……………………………………………………………………………….150°C Minimum ESD rating (C=100pF, R=1.5kΩ)……………………………………………………………………2kV Lead temperature (Soldering, 10 seconds)……………………………………………………………….. …………260°C
Operating Ratings
Temperature range…………………………………………………………………………………. .-40°C ≤ TJ ≤ +125°C Supply voltage…………………………………………………………………………………………………………40V
PL2576-3.3 Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range Symbol Parameter Conditions Typ 3.3 3.3 75 Min 3.234 3.168/3.135 Max 3.336 3.432/3.465 Units V V %
System Parameters (Note 3) Test Circuit Figure 2
VOUT VOUT η Output Voltage VIN=12V, ILOAD=0.5A Circuit of Figure 2 6V≤VIN≤40V, 0.5A≤ILOAD≤3A Output Voltage Circuit of Figure 2 Efficiency VIN=12V, ILOAD=3A
PL2576-5.0 Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range Symbol Parameter Conditions Typ 5.0 3.3 77 Min 4.9 4.800/4.750 Max 5.1 5.200/5.250 Units V V %
CYStek Product Specification
System Parameters (Note 3) Test Circuit Figure 2
VOUT VOUT η
PL2576-XXXF5
Output Voltage VIN=12V, ILOAD=0.5A Circuit of Figure 2 8V≤VIN≤40V, 0.5A≤ILOAD≤3A Output Voltage Circuit of Figure 2 Efficiency VIN=12V, ILOAD=3A
CYStech Electronics Corp.
PL2576-12 Electrical Characteristics
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 4/10
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range Symbol Parameter Conditions Typ 12 12 88 Min 11.76 11.52/11.40 Max 12.24 12.48/12.60 Units V V %
System Parameters (Note 3) Test Circuit Figure 2
VOUT VOUT η Output Voltage VIN=25V, ILOAD=0.5A Circuit of Figure 2 15V≤VIN≤40V, 0.5A≤ILOAD≤3A Output Voltage Circuit of Figure 2 Efficiency VIN=15V, ILOAD=3A
PL2576-15 Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range Symbol Parameter Conditions Typ 15 3.3 88 Min 14.7 14.40/14.25 Max 15.3 15.60/15.75 Units V V %
System Parameters (Note 3) Test Circuit Figure 2
VOUT VOUT η Output Voltage VIN=25V, ILOAD=0.5A Circuit of Figure 2 18V≤VIN≤40V, 0.5A≤ILOAD≤3A Output Voltage Circuit of Figure 2 Efficiency VIN=18V, ILOAD=3A
PL2576-ADJ Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range Symbol Parameter Feedback Voltage Feedback Voltage Efficiency Conditions VIN=12V, ILOAD=0.5A, VOUT=5V, Circuit of Figure 2 8V≤VIN≤40V, 0.5A≤ILOAD≤3A VOUT=5V, Circuit of Figure 2 VIN=12V, ILOAD=3A, VOUT=5V Typ 1.230 1.230 77 Min 1.217 1.193/1.180 Max 1.243 1.267/1.280 Units V V %
System Parameters (Note 3) Test Circuit Figure 2
VOUT VOUT η
PL2576-XXXF5
CYStek Product Specification
CYStech Electronics Corp.
All Output Voltage Versions Electrical Characteristics
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 5/10
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range. Unless otherwise specified, VIN=12V for the 3.3V, 5.0V, and adjustable versions, VIN=25V for the 12V version, and VIN=30V for the 15V version. ILOAD=500mA. Symbol Ib fO VSAT DC ICL IL IQ ISTBY Parameter Conditions Typ Min 47/42 93 4.2/3.5 Max 100/500 58/63 1.8/2.0 6.9/7.5 2 30 10 200 Units nA kHz V % A mA mA µA
Feedback bias current VOUT=5V (adjustable version only) 50 Oscillator frequency (Note 8) 52 Saturation voltage IOUT=3A (Note 4) 1.4 Maximum duty cycle (Note 5) 98 (ON) (Notes 4, 8) Current limit 5.8 (Notes 6, 7) Output = 0V Output leakage current Output = -1V 7.5 (Note 6) Quiescent current 5 Standby quiescent 50 ON/OFF pin=5V (OFF) current
ON/OFF Control
VIH VIL IIH IIL ON/OFF pin logic input level ON/OFF pin input current VOUT=0V VOUT=Nominal output voltage ON/OFF pin=5V (OFF) ON/OFF pin=0V (ON) 1.4 1.2 12 0 2.2/2.4 1.0/0.8 30 10 V V µA µA
Note 1 : Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. 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. Note 2 : All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). Note 3 : External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the PL2576 is used as shown in the figure 2 test circuit, system performance will be as shown in system parameters section of Electrical Characteristics. Note 4 : Output pin sourcing current. No diode, inductor or capacitor connected to output. Note 5 : Feedback pin removed from output and connected to 0V. Note 6 : Feedback pin removed from output and connected to +12V for the Adjustable, 3.3V, and 5V versions, and +25V for the 12V and 15V versions, to force the output transistor OFF. Note 7 : VIN=40V. Note 8 : The oscillator frequency reduces to approximately 11 kHz in the event of an output short or an overload which causes the regulated output voltage to drop approximately 40% from the nominal output voltage. This self protection feature lowers the average power dissipation of the IC by lowering the minimum duty cycle from 5% down to approximately 2%.
PL2576-XXXF5
CYStek Product Specification
CYStech Electronics Corp.
Typical Performance Characteristics (circuit of Figure 2)
N orm alized Output Voltage
1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 -50 -25 0 25 50 75 100 125 Junction Temperature(℃)
1.4
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 6/10
L ine Regulation
VIN = 20V,ILOAD = 500mA Normalized at TJ = 25℃
1.2 1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 0
ILOAD = 500mA, TJ = 25℃
3.3V, 5V & ADJ 12V & 15V
10
20
30
40
50
Input Voltage(V)
D ropout Voltage
1.75 1.5 1.25 200
S tandby Quiescent Current
175 150 VIN=40V
ILOAD=3A ILOAD=1A
1 0.75 0.5 0.25 0 -75 -50 -25 0 25 50 75 100 125 150 Junction Temperature(℃)
125 100 75
VON/OFF = 5V
L1 = 150μH Rind = 0.1Ω
ILOAD=0.2A
50 25 0 -50 -25 0 25 50 75 100 125 Junction Temperature(℃) VIN=12V
Q uiescent Current
20 18 16 14 12 10 8 6 4 0 10 20 30 Input Voltage (V) 40 50 6.5
C urrent Lim it
VOUT = 5V, measured at ground pin, TJ = 25℃
VIN =25V
6 5.5 5 4.5
ILOAD=3A
ILOAD=0.2A
4 -75 -50 -25 0 25 50 75 100 125 150 Junction Temperature (℃)
PL2576-XXXF5
CYStek Product Specification
CYStech Electronics Corp.
S witch Saturation Voltage
1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 2 Switch Current (A) 2.5 3 95
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 7/10
E fficiency
-55℃
90 85 80
ILOAD = 3A 15V OUT ILOAD = 0.2A 5V ILOAD = 3A ILOAD = 0.2A TJ = 25℃
0 10 20 30 40 50
25℃ 150℃
75 70 65 60
Input Voltage (V)
O scillator Frequency
8 6 4 2 0 -2 -4 -6 -8 -75 -50 -25 0 25 50 75 100 125 150 Junction Temperature (℃) 5
M inim um Operating Voltage
Normalized at 25℃
4.5 4 3.5 3 2.5
Adjustable version only
VIN = 40V
2 1.5 1
VIN = 12V
VOUT ≒1.23V ILOAD = 0.5A
0.5 0 -50 -25 0 25 50 75 100 125 Junction Temperature (℃)
Q uiescent Current vs Duty Cycle
20 17.5 15 12.5 10 7.5 5 2.5 0 0 20 40 60 80 100 Duty Cycle (%)
PL2576-XXXF5
F eedback Voltage vs Duty Cycle
20
Adjustable version only ILOAD = 0.5A VIN=7V
15 10 5 0
Adjustable version only ILOAD = 0.5A VIN=40V
VIN=40V
-5 -10 -15 -20 0 20 40 60 80 100 Duty Cycle (%)
CYStek Product Specification
VIN=7V
CYStech Electronics Corp.
M inim um Power Dissipation
5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 0 10 20 30 40 50 60 70 80 90 100 Ambient Temperature (℃) 100
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 8/10
F eedback Pin Current
θJA = 32℃/W θJA = 37℃/W θJA = 50℃/W
75 50 25 0 -25 -50
Adjustable version only
θJA = 73℃/W
-75 -100 -75 -50 -25 0 25 50 75 100 125 150 Junction Temperature (℃)
Switching Waveforms
A 50V 0 4A B 2A 0 4A C D 2A 0 5μs/ div Load Current
Load Transient Response
100mV Output 0 Voltage Change -100mV
3A 2A 1A 0 100 μs / div
VOUT=15V A : Output Pin Voltage, 50 V / div B : Output Pin Current, 2A / div C : Inductor Current, 2A / div D : Output Ripple Voltage, 50mV / div AC Coupled Horizontal Time Base : 5μs / div
PL2576-XXXF5
CYStek Product Specification
CYStech Electronics Corp.
Test Circuit and Layout Guidelines
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 9/10
As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring inductance generate voltage transients which can cause problems. For minimal inductance and ground loops, the length of the leads indicated by heavy lines should be kept as short as possible. Single-point grounding (as indicated) or ground plane construction should be used for best results. When using the Adjustable version, physically locate the programming resistors near the regulator, to keep the sensitive feedback wiring short.
Fixed Output Voltage Versions
+Vin 1 Vin Unregulated DC Input
PL2576 Fixed Output
Feedback 4 Output 2 L1 100μH
+
Vout
+
Cin 100μF
GND
3
ON / OFF
5
D1 MBR360
Cout 1000μF
L O A D
Cin--100μF, 75V, Aluminum Electrolytic Cout--1000μF, 25V, Aluminum Electrolytic D1--Schottky, MBR360 L1--100μH, Pulse Eng, PE92108 R1--2k, 0.1% R2--6.12k, 0.1%
Adjustable Output Voltage Version
+Vin 1 7V-40V Unregulated DC Input
Feedback 4
PL2576-ADJ
Output 2 L1 100μH
+
Vout 5.00V R2 L O A D
+
Cin 100μF
GND 3
ON / OFF 5
D1 MBR360
Cout 1000μF
R1
Vout=VREF(1+ R2=R1( Vout VREF
R2 ) R1 -1)
where VREF=1.23V, R1 between 1k and 5k
Figure 2
PL2576-XXXF5 CYStek Product Specification
CYStech Electronics Corp.
TO-263-5L Dimension
Spec. No. : C543F5 Issued Date : 2004.02.27 Revised Date : Page No. : 10/10
Marking:
2576-XXX
Style: Pin 1.Vin 2.Vout 3.GND 4.Feedback 5.ON/OFF 5-Lead TO-263-5L Plastic Package CYStek Package Code: F5
*: Typical
DIM A A1 B b c c1 D
Inches Min. Max. 0.176 0.184 0 0.006 0.061 0.069 0.028 0.036 0.012 0.021 0.046 0.054 0.389 0.401
Millimeters Min. Max. 4.47 4.67 0 0.150 1.560 1.760 0.710 0.910 0.310 0.530 1.170 1.370 9.880 10.180
DIM E e e1 L L1 L2 V
Inches Min. Max. 0.323 0.339 0.067(typical) 0.264 0.272 0.596 0.612 0.200 0.216 0.092 0.108 0.220REF
Millimeters Min. Max. 0.820 0.860 1.700(typical) 0.670 0.690 15.140 15.540 5.080 5.480 2.340 2.740 5.600REF
Notes: 1.Controlling dimension: inch
2.Maximum lead thickness includes lead finish thickness, and minimum lead thickness is the minimum thickness of base material. 3.If there is any question with packing specification or packing method, please contact your local CYStek sales office.
Material:
• Lead: 42 Alloy ; solder plating • Mold Compound: Epoxy resin family, flammability solid burning class: UL94V-0
Important Notice:
• All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of CYStek. • CYStek reserves the right to make changes to its products without notice. • CYStek semiconductor products are not warranted to be suitable for use in Life-Support Applications, or systems. • CYStek assumes no liability for any consequence of customer product design, infringement of patents, or application assistance.
PL2576-XXXF5
CYStek Product Specification