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L5973D
2.5A SWITCH STEP DOWN SWITCHING REGULATOR
s s s s s
s s s s s s s s
2.5A INTERNAL SWITCH OPERATING INPUT VOLTAGE FROM 4.4V TO 36V 3.3V / (2%) REFERENCE VOLTAGE OUTPUT VOLTAGE ADJUSTABLE FROM 1.235V TO 35V LOW DROPOUT OPERATION: 100% DUTY CYCLE 250KHz INTERNALLY FIXED FREQUENCY VOLTAGE FEEDFORWARD ZERO LOAD CURRENT OPERATION INTERNAL CURRENT LIMITING INHIBIT FOR ZERO CURRENT CONSUMPTION SYNCHRONIZATION PROTECTION AGAINST FEEDBACK DISCONNECTION THERMAL SHUTDOWN
HSOP8 - EXPOSED PAD ORDERING NUMBERS: L5973D (Tube) L5973D013TR (T & R)
DESCRIPTION The L5973D is a step down monolithic power switching regulator with a minimum switch current limit of 2.5A so it is able to deliver more than 2A DC current to the load depending on the application conditions. The output voltage can be set from 1.235V to 35V. The high current level is also achieved thanks to an SO8 package with exposed frame, that allows to reduce the Rth(j-amb) down to approximately 40C/W The device uses an internal P-Channel D-MOS transistor (with a typical Rdson of 250m) as switching element to minimize the size of the external components. An internal oscillator fixes the switching frequency at 250KHz. Having a minimum input voltage of 4.4V only, it is particularly suitable for 5V bus, available in all computer related applications. Pulse by pulse current limit with the internal frequency modulation offers an effective constant current short circuit protection.
APPLICATIONS: s CONSUMER: STB, DVD, TV, VCR,CAR RADIO, LCD MONITORS s NETWORKING: XDSL, MODEMS,DC-DC MODULES s COMPUTER: PRINTERS, AUDIO/GRAPHIC CARDS, OPTICAL STORAGE, HARD DISK DRIVE s INDUSTRIAL: CHARGERS, CAR BATTERY DC-DC CONVERTERS TEST APPLICATION CIRCUIT
3.3V VIN = 4.4V to 35V VREF VCC SYNC. C1 10F 35V CERAMIC COMP C4 22nF C3 220pF R3 4.7K 6 8 2 4 INH
1
OUT
L1 15H D1 STPS340U
VOUT=3.3V
L5973D
3 7 5 FB GND
R1 5.6K
C2 330F 10V
R2 3.3K
D03IN1439
September 2003
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L5973D
PIN CONNECTION
OUT SYNC INH COMP
1 2 3 4
D98IN955
8 7 6 5
VCC GND VREF FB
PIN DESCRIPTION
N 1 2 3 4 5 6 7 8 Pin OUT SYNC INH COMP FB VREF GND VCC Regulator Output. Master/slave synchronization. A logical signal (active high) disables the device. If INH not used the pin must be grounded. When it is open an internal pull-up disable the device. E/A output for frequency compensation. Feedback input. Connecting directly to this pin results in an output voltage of 1.23V. An external resistive divider is required for higher output voltages. 3.3V VREF. No cap is requested for stability. Ground. Unregulated DC input voltage. Function
THERMAL DATA
Symbol Rth (j-amb) Parameter Thermal Resistance Junction to ambient Max. Value 40 (*) Unit C/W
(*) Package mounted on board
ABSOLUTE MAXIMUM RATINGS
Symbol V8 V1 I1 V4, V5 V3 V2 Ptot Tj Tstg Input Voltage Output DC voltage Output peak voltage at t = 0.1s Maximum output current Analog pins INH SYNC Power dissipation at Tamb 60C Operating junction temperature range Storage temperature range Parameter Value 40 -1 to 40 -5 to 40 int. limit. 4 -0.3V to VCC -0.3 to 4 2.25 -40 to 150 -55 to 150 V W C C V Unit V V V
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L5973D
ELECTRICAL CHARACTERISTICS (Tj = 25C, VCC = 12V, unless otherwise specified.) (*) Specification Referred to Tj from -40 to 125C (1).
Symbol VCC RDSON Il fs Parameter Operating input voltage range Mosfet on Resistance Maximum limiting current Switching frequency VCC = 4.4V to 36V * Test Condition Vo = 1.235V; Io = 2A * * 2.5 212 225 0 1.220 1.198 Min. 4.4 Typ. 0.250 3 250 250 Max. 36 0.5 3.5 280 275 100 1.25 1.272 Unit V A KHz KHz % V V % 5 2.5 * * 50 80 100 150 0.8 2.2 3.5 0.4 200 1 50 300 1.5 2.5 RL = Icomp = -0.1mA to 0.1mA VCOMP = 1.9V VCC = 4.4V to 36V VCC = 4.4V to 36V Vsync = 0.74V (2) Vsync = 2.33V Isource = 3mA no load, Vsync = 1.65V 0.11 0.21 2.75 0.20 3.234 3.2 3 0.35 3.3 3.3 5 8 10 18 3.366 3.399 10 15 30 2.5 57 2.3 4 mA mA A A V V V V A mA A dB mS
Duty cycle DYNAMIC CHARACTERISTICS (see test circuit ). V5 Voltage feedback 4.4V < VCC < 36V, 20mA < IO < 2A Efficiency VO = 5V, VCC = 12V DC CHARACTERISTICS Total Operating Quiescent Iqop Current Quiescent current Iq Iqst-by INHIBIT INH Threshold Voltage ERROR AMPLIFIER VOH VOL Io source Io sink Ib gm High level output voltage Low level output voltage Source output current Sink output current Source bias current DC open loop gain Transconductance VFB = 1V VFB = 1.5V VCOMP = 1.9V; VFB = 1V VCOMP = 1.9V; VFB = 1.5V Device ON Device OFF Total stand-by quiescent current
*
1.235 1.235 90
* Duty Cycle = 0; VFB = 1.5V Vinh > 2.2V VCC = 36V; Vinh > 2.2V
3
SYNC FUNCTION High Input Voltage Low Input Voltage Slave Sink Current Master Output Amplitude Output Pulse Width REFERENCE SECTION Reference Voltage
VREF 0.74 0.25 0.45
V V mA mA V s V V mV mV mA
IREF = 0 to 5mA VCC = 4.4V to 36V Line Regulation Load Regulation Short Circuit Current IREF = 0mA VCC = 4.4V to 36V IREF = 0 to 5mA
*
Notes: 1. Specification over the -40 to +125 Tj Temperature range are assured by design, characterization and statistical correlation. 2. Guaranteed by design.
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L5973D
Figure 1. Line Regulation
Vo (V) 3.312 3.308 3.304 3.3 3.296 3.292 3.288 3.284 3.28 3.276 0 10 20 Vcc (V) 30 40 Tj = 125C Vcc = 12V Vo = 3.3V Tj = 25C
Figure 4. Shutdown Current vs.Junction Temperature
Ishd (A) 70
60
Vcc = 12V
50
40
30 -50 0 50 Tj (C) 100 150
Figure 2. Output Voltage vs. Junction Temperature
Vo (V) 1.25 1.24 1.23 1.22 Vcc = 12V 1.21 1.2 -50 0 50 Tj (C) 100 150 Vcc=12V
Figure 5. Switching Frequency vs.Junction Temperature
Fsw (KHz) 260
250
240
230
Vcc = 12V Vo = 3.3V
220 -50 0 50 Tj (C) 100 150
Figure 3. Quiescent Current vs. Junction Temperature
Iq (mA)
2
1.8
1.6 Vcc = 12V DC = 0%
1.4
1.2 -50 0 50 Tj (C) 100 150
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L5973D
APPLICATION CIRCUIT In figure 6 is shown the demo board application circuit, where the input supply voltage, Vcc, can range from 4.4V to 25V due to the rated voltage of the input capacitor and the output voltage is adjustable from 1.235V to Vcc. Figure 6. Demo board Application Circuit
3.3V VIN = 4.4V to 25V
VREF VCC SYNC.
6 8 2 4 INH
1
OUT
L1 15H D1 STPS2L25U
VOUT=3.3V
L5973D
3 7 5 FB GND
R1 5.6K
C1 10F 25V CERAMIC
COMP C4 22nF C3 220pF R3 4.7K
C2 330F 6.3V
R2 3.3K
D03IN1440
Table 1. Component List
Reference C1 C2 C3 C4 R1 R2 R3 D1 L1 STPS2L25U DO3316P-153 POSCAP 6TPB330M C1206C221J5GAC C1206C223K5RAC Part Number Description 10F, 25V 330F, 6.3V 220pF, 5%, 50V 22nF, 10%, 50V 5.6K, 1%, 0.1W 0603 3.3K, 1%, 0.1W 0603 4.7K, 1%, 0.1W 0603 2A, 25V 15H, 3A Manufacturer TOKIN Sanyo KEMET KEMET Neohm Neohm Neohm ST COILCRAFT
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L5973D
Figure 7. PCB layout (component side)
42mm
34mm
Figure 8. PCB layout (bottom side)
Figure 9. PCB layout (front side)
Below some graphs show the Tj versus output current in different conditions of the input and output voltage and some efficiency measurements.
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L5973D
Figure 10. Junction Temperature vs. Output Current
Tj(C) 120 110 Vin=5V 100 Tamb=25C 90 80 70 60 50 40 30 20 0.2 0.4 0.6 0.8 1
Figure 12. Efficiency vs. Output Current
Vo=3.3V
Vo=2.5V
Vo=1.8V
1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 Io(A)
95 93 91 89 87 85 83 81 79 77 75 73 71 69 67
Vo=3.3V
Efficiency (%)
Vo=2.5V Vo=1.8V
Vin=5V
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 Io (A)
Figure 11. Junction Temperature vs. Output Current
Tj (C) 120 110 100 90 80 70 60 50 40 30 20 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Io (A) 2 2.2 2.4 2.6
Vo=2.5V
Figure 13. Efficiency vs. Output Current
Vin=12V Tamb=25C
Vo=5V
Vo=3.3V
91 89 87 85 83 81 79 77 75 73 71 69 67 65
Vo=5V Vo=3.3V Vo=2.5V
Efficiency (%)
Vin=12V
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 Io (A)
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L5973D
APPLICATION IDEAS Figure 14. Positive Buck-Boost regulator
L1 15uH
D2 STPS2L25U
VIN=5V
Vcc
OUT
VOUT=12V/0.6A
8
COMP C1 10uF 10V Ceramic
1 L5973D
D1 STPS2L25U FB 24k
4 2 6
VREF GND
7
5 3
C2 220pF
C3 22nF R3 4.7k
M1 STN4NE03L
2.7k
C4 100uF 16V
SYNC
INH
3.3V
Figure 15. Buck-Boost regulator
VIN=5V OUT
Vcc
L1 15uH
8
COMP C1 10uF 10V Ceramic C2 10uF C3 25V Ceramic 220pF
1 L5973D
FB D1 STPS2L25U 2.7k VOUT=-12V/0.6A
4 2 6
GND
7
5 3
INH
C4 22nF R3 4.7k
SYNC VREF
24k
C5 100uF 16V
3.3V
Figure 16. Dual output voltage with auxiliary winding
N1/N2=2 D2 1N4148 VOUT1=5V 50mA
VIN=12V
VCC
8
COMP C1 10uF 25V Ceramic
OUT
Lp=22uH
D1 STPS25L25U
1 L5973D
FB
VOUT=3.3V 0.5A C4 100uF 10V C5 47uF 10V
4 2 6
GND
7
5 3
C2 220pF
C3 22nF R3 4.7k
SYNC VREF
INH
3.3V
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L5973D
mm DIM. MIN. A A1 A2 B C D E e H h L k ddd 5.800 0.250 0.400 1.350 0.100 1.100 0.330 0.190 4.800 3.800 1.270 6.200 0.500 1.270 0.228 0.010 0.016 TYP. MAX. 1.750 0.250 1.650 0.510 0.250 5.000 4.000 MIN. 0.531 0.004 0.043 0.013 0.07 0.189 0.150
inch TYP. MAX. 0.069 0.010 0.065 0.020 0.010 0.197 0.157 0.05 0.244 0.020 0.05
OUTLINE AND MECHANICAL DATA
0 (min), 8 (max) 0.100 0.010
(1) Dimension D does not include mold flash, protusions or gate burrs shall not exeed 0.15mm (both side).
HSOP8 (Exposed Pad)
Exposed Pad: D1 = 3.1mm E1 = 2.41mm
7195016
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L5973D
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners (c) 2003 STMicroelectronics - All rights reserved STMicroelectronics GROUP OF COMPANIES Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States www.st.com
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