GS-R24F
2 A DC-DC converter modules
Features
MTBF 1 000 000 hours (TA = 25C) 2 A max output current 35 V max input voltage 1.5 V max drop-out voltage Remote logic inhibit/enable Synchronization Not-latching overload and short circuit protection Thermal shutdown Fixed or adjustable output No heatsink required Operating temperature range -25 C ÷ 85 C
Description
The GS-R24F series is a family of high efficiency step down switching voltage regulator, designed to replace linear regulators. Based on ST L5973 device, these non isolated regulators are suitable for various applications, including telecom, industry, computer and distributed power supply system having a wide range input voltage. Table 1. Device summary
Output voltage [V] 1.8 4% 2.5 4% 3.3 4% 5.0 4% 1.235 ÷ 5.5 12 4% 3.3 ÷ 24 Input voltage [V] 16 ÷ 35 16 ÷ 35 16 ÷ 35 16 ÷ 35 16 ÷ 35 16 ÷ 35 16 ÷ 35 Output ripple [mVpp] 25 25 25 25 25 100 100 ÷ 250 Efficiency [%] 72 76 82 85 68 ÷ 85 91 78 ÷ 96 Notes Fixed output voltage Fixed output voltage Fixed output voltage Fixed output voltage Progr. output voltage Fixed output voltage Progr. output voltage
Order codes GS-R24F0182.0 GS-R24F0252.0 GS-R24F0332.0 GS-R24F0502.0 GS-R24F0002.0 GS-R24F1201.5 GS-R24F0001.0
February 2008
Rev 2
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Contents
GS-R24F
Contents
1 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 1.2 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 2.2 2.3 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Thermal de-rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Inhibit function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Multiple units synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Current limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Thermal shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Output voltage programming (GS-R24F0002.0 and GS-R24F0001.0) 7 Loop compensation (GS-R24F0002.0 and GS-R24F0001.0) . . . . . . . . . . 7 Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5
Additional features and protections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1 Output overvoltage protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 7
Ordering scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
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GS-R24F
Pin settings
1
1.1
Pin settings
Pin connection
Figure 1. Pin connection and mechanical data (dimensions in mm)
1.2
Pin description
Table 2.
Name 1 2 3 4 5 6 7 8 9 10 11 12
Pin description
Function INH Vref Input + Input + Input GND Input GND Output GND Output GND Vout Vout FB Sync Description A logic high level disables the device. When the pin is open, an internal pull up disables the device 3.3 V reference voltage DC input voltage DC input voltage Return for input voltage source Return for input voltage source Return for output voltage source Return for output voltage source Regulated power output Regulated power output Feedback input, available on adjustable device and on request for additional compensation Master/Slave synchronization
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Maximum ratings
GS-R24F
2
2.1
Maximum ratings
Absolute maximum ratings
Table 3.
Symbol VI IOUT V1 V12 V11 DC input voltage Maximum output current INH Sync FB
Absolute maximum ratings
Parameter Value 36 internally limit -0.3 to VI -0.3 to 4 4 V V V Unit V
2.2
Thermal data
Table 4.
Symbol Tstg Top
Absolute maximum ratings
Parameter Storage temperature range Operating ambient temperature Value -40 ÷ 105 -25 ÷ 85 Unit C C
2.3
Thermal de-rating
Table 5.
Symbol
Thermal de-rating for free air condition (all versions)
Parameter Test condition VI = 16 ÷ 35 V --------TA = 60 C VI = 16 ÷ 35 V---------TA = 65 C Value 1.95 1.85 1.75 A 1.65 1.55 1.40 Unit
Io
Output current
VI = 16 ÷ 35 V ---------TA = 70 C VI = 16 ÷ 35 V ---------TA = 75 C VI = 16 ÷ 35 V ---------TA = 80 C VI = 16 ÷ 35 V ------ --TA = 85 C
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GS-R24F
Electrical characteristics
3
Electrical characteristics
TA = 25 C, unless otherwise specified Table 6.
Symbol Vr Vr Vr
Electrical characteristics (all version)
Parameter Ripple voltage Ripple voltage Ripple voltage Temperature stability Test condition VI =24 V Io = 2A for GS-R24Fyyy2.0 VI =24 V Io = 1.5 A for GS-R24F1201.5 VI =24V Io = 1 A for GS-R24F0001.0 VI =Vo + 1.5 V Io = 2 A VI =16 ÷ 35 V for GS-R24Fyyy2.0 VI =16 ÷ 35 V for GS-R24F1201.5 VI =16 ÷ 35 V for GS-R24F0001.0 VI =16 ÷ 35 V VI =24 V Io = 0 A 0 0 0 2.5 1.8 80 225 3.234 8 Device ON 250 3.3 10 2.5 150 275 3.366 30 0.8 2.2 1.22 1.235 1.25 2 1.5 1 100 Min Typ 25 Max 35 100 250 Unit mVpp mVpp mVpp mV/C A A A A mA A kHz V mA V V V
Io Io Io IoL Iq Iqst-by fs Vref
Output current Output current Output current Current limit Quiescent current
Total stand-by quiescent Vinh>2.2 V Vi = 35 V current Switching frequency Reference voltage Shor t circuit current INH threshold voltage Device OFF Feedback voltage Vi=16 ÷ 35 V IO=0 ÷ 2 A VI = 24 V Io = 2 A VI = 16 ÷ 35 V Iref = 0 ÷ 5 mA
INH VFB
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Application information
GS-R24F
4
4.1
Application information
Input voltage
The recommended maximum operating Dc input voltage is 35 V including ripple voltage.
4.2
Reference voltage
No capacitor is required for stability.
4.3
Inhibit function
The inhibit feature allows to put the device in stand-by mode. With INH pin 1 is higher than 2.2 V the device is disabled and the current consumption is reduced to less than 150 A for VI = 35 V. With INH pin lower than 0.8 V, the device is enabled. If the INH pin is left floating, an internal pull up ensures that the voltage at the pin reaches the inhibit threshold and the device is disabled. The pin can be pulled to VI to disable the device.
4.4
Multiple units synchronization
Using more than one unit on the same circuit, it is possible to synchronize the switching frequency, connecting all pin 12 together (see Figure 5). The unit with higher frequency becomes the master.
4.5
Current limitation
The device has two current limit protections, pulse by pulse and frequency fold back. The current is sensed through a resistor and if it reaches the threshold, the on time is reduced and consequently the output voltage, too. Since the minimum switch ON time (necessary to avoid false overcurrent signal) is not enough to obtain a sufficiently low duty cycle at 250 Hz, the output current could increase again, in strong overcurrent or short circuit conditions. For this reason the switching frequency is also reduced to keep the inductor current within its maximum threshold limit. The frequency depends on the feedback voltage. As the feedback voltage decreases (due to the reduced duty cycle), the switching frequency decrease too.
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GS-R24F
Application information
4.6
Thermal shutdown
The shutdown block generates a signal that turns off the power stage if the temperature of the internal chip goes higher than a fixed internal threshold (150C min). The sensing element of the chip is very close to the PDMOS area, so ensuring an accurate and fast temperature detection. An hysteresis of approximately 20 C avoids that the devices turns on and off continuously.
4.7
Output voltage programming (GS-R24F0002.0 and GSR24F0001.0)
The GS-R24F0002.0 output voltage is 5.54 V 4 %, the GS-R24F0001.0 output voltage is 24.44 V 4 %, to reduce these values connect a resistor between pin 11 (FB) and pin 10 (Vout). The resistor must be located very close to the proper pins, to minimize the injected noise (see figure 2). The resistor value is calculated using the following formula: for GS-R24F0002.0 Rv = [(Vout - 1.235) * 11.3] / (5.54 - Vout) --[k]; for GS-R24F0001.0 Rv = [(Vout - 1.235) * 62] / (24.44 - Vout) --[k]. Vout can be adjusted between 1.235 V (Rv = 0 ) and 5.54 V/24.44 V (Rv = open).
4.8
Loop compensation (GS-R24F0002.0 and GS-R24F0001.0)
If required by particular load conditions, it is possible to change the feedback loop compensation, adding an external capacitor between pin 11 (FB) and pin 10 (Vout), which will act as speed up (see Figure 4).
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Application information
GS-R24F
4.9
Soldering
Soldering phase has to be execute with care : in order to avoid undesired melting phenomenon, particular attention has to be take on the set up of the peak temperature. Here following some suggestions for the temperature profile based on IPC/JEDEC J-STD-020C ,July 2004 recommendations. Table 7. Soldering
Profile feature Average ramp up rate ( TSMAX to TP) Preheat Temperature min ( TS MIN) Temperature max ( TS MAX) Time (TS MIN to TS MAX) ( tS ) Time maintained above : Temperature TL Time tL Peak temperature (TP) Time within 5 C of actual peak temperature (tP) Ramp down rate Time from 25 C to peak temperature PB free assembly 3 C / sec max 150 C 200 C 60 100 sec 217 C 40 70 sec 240 + 0 C 10 20 sec 6 C / sec 8 minutes max
Figure 2.
Soldering
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GS-R24F
Additional features and protections
5
5.1
Additional features and protections
Output overvoltage protection
The overvoltage protection, OVP, is realized by using an internal comparator, whose input is connected to the feedback. It turns off the power stage when the OVP threshold is reached. This threshold is typically 30 % higher than the feedback voltage. Figure 3. Output voltage programming Figure 4. Loop compensation
Figure 5.
Multiple units synchronization
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Additional features and protections Figure 6. PCB footprint (dimensions in mm)
GS-R24F
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GS-R24F
Ordering scheme
6
Ordering scheme
Table 8. Ordering information scheme
GSR24 F018 2.0
Input voltage 24 = 24 V
Output voltage 018 = 1.8 V 025 = 2.5 V 033 = 3.3 V 050 = 5.0 V 120 = 12 V 000 = 1.235 ÷ 5.5 V / 3.3 ÷ 24 V
Output current 2.0 = 2 A 1.5 = 1.5 A 1.0 = 1 A
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Revision history
GS-R24F
7
Revision history
Table 9.
Date 13-Oct-2006 27-Feb-2008
Document revision history
Revision 1 2 Initial release Added: Section 4.9: Soldering on page 8 Changes
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GS-R24F
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