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A SUBSIDIARY OF C&D TECHNOLOGIES
78SR Series
NEW
low-profile package
Order online at www.datel.com
Features
* 3.3V/0.5A, 5V/0.5A or 12V/0.4A outputs; Pin and size-compatible with LM7805 & LM7812 regulators * Up to 95% efficiency - no heat sinks or thermal derating required! * Two SIP-packages fit existing TO-220 footprints: Vertical-pin models occupy less than 0.1 square in. Optional horizontal pins provide 0.350 in. installed height * +7.5-36Vdc operating input range; Low 3mA quiescent current * Built-in filter capacitors - no external components required * -40 to +70C operation at full load; Short-circuit protection * Excellent load (0.2%) and line (0.3%) regulation * Ideal for powering instrumentation from 9V/12V/24V/28V supplies or batteries * Can be used with unregulated dc supplies
3.3V/5V/12V Outputs High-Efficiency Switching Regulators with LM78XX Pinouts
DATEL's 7805SR (5V output), 7812SR (12V output) and 7803SR (3.3V output) step-down switching regulators are modern drop-in replacements for older, inefficient, LM7805 and LM7812 linear regulators. The 78XXSR's are pin- and sizecompatible with industry-standard TO-220 SIP packages. A 260kHz switching frequency provides for efficiencies as high as 95%. Full-load (up to 0.5A) operation from 9V, 12V, 24V, or 36V supplies at ambient temperatures up to +70C requires no heat sinks, no temperature derating, no forced-air cooling, and no external capacitors. 78SR switching regulators provide many significant improvements over their linear counterparts: lower quiescent current (3mA vs. 5 mA), higher input voltage (40V vs. 32V), and better output accuracy (1.5% vs. 5%). All these features combine to make 78SR regulators ideal for new or existing LM7805 & LM7812 applications requiring full-load operation at elevated voltages.
Technical Notes
1. Input/Output (I/O) Filtering: As shown in the noise and ripple graphs, 78SR switching regulators exhibit excellent low-noise performance with no external I/O capacitors. However, if additional noise reduction is required, be sure to use low-ESR capacitors that are rated for continuous operation (with an additional 20% safety margin) at the highest system voltages and temperatures. Adding external output capacitors will also improve the unit's load-transient response. Applications in which 78SR regulators are located more than 24 inches (61cm) from the input power supply should include an external 47uF/50V (or greater) aluminum electrolytic capacitor, connected as close as possible to the regulator's +Vin and GND terminals (pins 1 and 2). An external input capacitor is particularly important if the input voltage is applied to the regulator via a mechanical switch or relay. Contact bounce at turn-on can produce large inductive current-spikes, and these current spikes can generate damaging voltage transients at the regulator's input terminals. 2. Input Fusing: 78SR switching regulators are not internally fused. If fusing their input and/or output terminals is required, use the data shown in the Efficiency Curves as a guide to selecting an appropriate slow-blow fuse. 3. Input-Output Isolation: 78SR regulators' internal input and output circuits share a common connection (GND, pin 2); there is no electrical isolation between the INPUT (pin 1) and OUTPUT (pin 3) terminals. 4. Overvoltage Protection: 78SR switching regulators do not provide input or output overvoltage protection. In the extremely rare situation in which a catastrophic failure occurs, the output voltage may rise to excessively high levels. If your load must be protected against all possible overvoltage situations, external voltage-limiting circuitry must be provided. 5. Operation at 40Vdc: Operating with inputs up to 40Vdc is permissible if, for inputs between 36 and 40Vdc, the maximum load current is reduced to 0.35A for 7805SR and 7803SR, and to 0.3A for 7812SR. Under no circumstances should the input voltage be allowed to exceed 45Vdc. 6. Soldering & Handling Precautions: All units are designed to be hand soldered to pc-boards using no-clean solders (+260C, 5 seconds max.). Water-soluble solders can also be used, but the units must be washed and dried using processes appropriate to the type of solder employed. See the Mechanical Specifications section for pin 1 orientation and recommended plated-through hole dimensions. While 78SR regulators easily withstand a 2kV ESD discharge to any terminal (using human body model), they should always be treated as ESD sensitive devices. 7. Horizontal-Pin Models (78XXSRH): 78XXSRH switching regulators are pin-compatible replacements for TO-220 style LM78XX linear regulators that are installed with their metal tabs lying flat on the surface
DATEL, Inc., Mansfield, MA 02048 (USA) * Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 * E-mail: sales@datel.com * Internet: www.datel.com
78SR Series
H I G H - E F F I C I E N C Y S W I T C H I N G R E G U L ATO R S
Technical Notes (continued)
of the pc-board. However, because the surface of inductor L1 on 78XXSRH models is electrically conductive, it must not be allowed to come in contact with any exposed pc-board traces, other than power ground (GND). While the 2-mil-thick (0.05mm) polyester label attached to L1 provides some degree of electrical insulation (only if L1 sits perfectly flat on the pc-board), it is recommended that a 0.020" (0.5mm) clearance be maintained between L1 and all exposed pc-board traces. 8. Dropout Voltage: 78SR series regulators described in this data sheet specify a minimum input voltage at which full-load accuracy and output regulation are guaranteed (7.5V for 7803SR and 7805SR, and 15.0V for 7812SR). However, these devices will stay in regulation at lower input voltages if they are operated at less than their rated loads. The following dropout-voltage data, derived from sample testing performed at an ambient temperature of +25C with resistive loads, should be used for information purposes only. For these tests, a unit was considered to be out of regulation when its output changed by more +/-0.005Vdc from its nominal value. All voltages were measured directly at the regulator's I/O pins.
Typical Dropout Voltage 0% Load 7803SR 7805SR 7812SR 6.0V 6.3V 12.8V 25% Load 6.2V 6.2V 13.0V 50% Load 6.2V 6.2V 12.8V 100% Load 6.3V 6.8V 13.0V
Performance/Functional Specifications
Typical at TA = +25C Input/Output Models Output Voltage Rated Output Current Output Voltage Accuracy Input Voltage Range Line Regulation (100% load) Load Regulation (0-100% load) Quiescent Current Input Current Efficiency Transient Response Input & Output Noise Short Circuit Protection Isolation Overvoltage Protection Undervoltage Protection Environmental Models Operating Temperature Storage Temperature Cooling Humidity (Non-condensing) Physical Mechanical Package Pins Weight Pin Soldering See Technical Note 5. While these regulators can withstand a continuous short-circuit across their output terminals, they will experience a significant temperature rise. Extended short-circuit operation will adversely affect the unit's reliability. See Mechanical Specifications Open-frame SIP 0.025" (0.64mm) square, tin-plated bronze 0.08 ounces (2.2g) +260C for 5 seconds 7803SR 7805SR -40 to +70C -40 to +85C Free Air Convection 0 to 85% 7812SR 7803SR +3.3Vdc 0.5A 2% +7.5-36Vdc 0.3% 0.2% 7805SR +5.0Vdc 0.5A 1.5% +7.5-36Vdc 0.3% 0.2% 7812SR +12.0Vdc 0.4A 2% +15-36Vdc 0.3% 0.2%
3mA typ., 5mA max. See Performance Curves See Performance Curves See Performance Curves See Performance Curves Continuous None None None
Ordering Information
DATEL Part No. Output Voltage Output Current 0.5A 0.5A 0.4A 0.5A 0.5A 0.4A Input Voltage +7.5-36Vdc +7.5-36Vdc +15-36Vdc +7.5-36Vdc +7.5-36Vdc +15-36Vdc
Standard Pin Package 7803SR +3.3Vdc 7805SR +5.0Vdc 7812SR +12.0Vdc Horizontal Pin Package 7803SRH +3.3Vdc 7805SRH +5.0Vdc 7812SRH +12.0Vdc
DATEL, Inc., Mansfield, MA 02048 (USA) * Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 * E-mail: sales@datel.com * Internet: www.datel.com
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H I G H - E F F I C I E N C Y S W I T C H I N G R E G U L ATO R S
78SR Series
Typical Performance Curves
7803SR
TA = +25C, VIN as indicated
Noise and Ripple - 10% and 100% Load, 20MHz Bandwidth
Vin = 12V, ILOAD = 50mA 7805SR Vin = 12V, ILOAD = 50mA 7812SR Vin = 24V, ILOAD = 40mA
7803SR
Vin = 12V, ILOAD = 500mA
7805SR
Vin = 12V, ILOAD = 500mA
7812SR
Vin = 24V, ILOAD = 400mA
Transient Response - 90% Load Step
7803SR 10% to 100% Load Step Vin = 9V 7805SR 10% to 100% Load Step Vin = 9V 7812SR 10% to 100% Load Step Vin = 18V
7803SR
100% to 10% Load Step Vin = 9V
7805SR
100% to 10% Load Step Vin = 9V
7812SR
100% to 10% Load Step Vin = 18V
DATEL, Inc., Mansfield, MA 02048 (USA) * Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 * E-mail: sales@datel.com * Internet: www.datel.com
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78SR Series
7803SR Efficiency
90 85
H I G H - E F F I C I E N C Y S W I T C H I N G R E G U L ATO R S
7803SR Input Current
0.25 0.20 0.15 0.10 0.05
100% LOAD 50% LOAD 25% LOAD
EFFICIENCY
75 70 65 60 55 50 8 10 12 14 16 18 20 22 24
INPUT CURRENT (AMPS)
80
100% LOAD
50% LOAD
25% LOAD
0.00 26 28 30 32 34 36 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 INPUT VOLTAGE INPUT VOLTAGE
7805SR Efficiency
95
NPUT CURRENT (AMPS)
0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 8 10 12 14
7805SR Input Current
90 85
EFFICIENCY
100% LOAD 50% LOAD 25% LOAD
80 75 70 65 60 8 10 12 14 16 18 20 22 24
100% LOAD 50% LOAD
25% LOAD
16 18 20 22 24 26 28 30 32 34 36
26
28
30
32
34
36
INPUT VOLTAGE
INPUT VOLTAGE
7812SR Efficiency
100 INPUT CURRENT (AMPS) 95 EFFICIENCY 90 85 80 75 70 14 16 18 20 22 24 26 28 30 32 34 36 INPUT VOLTAGE 0.40 0.35
7812SR Input Current
100% LOAD 50% LOAD 25% LOAD
0.30 0.25 0.20 0.15 0.10 0.05 0.00 14 16 18
100% LOAD
50% LOAD
25% LOAD
20 22 24 26 28 30 32 34 36
INPUT VOLTAGE
DATEL, Inc., Mansfield, MA 02048 (USA) * Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 * E-mail: sales@datel.com * Internet: www.datel.com
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H I G H E F F I C I E N C Y S W I T C H I N G R E G U L ATO R S
78SR Series
Mechanical Specifications
MECHANICAL DIMENSIONS: Inches (mm) TOLERANCES: 2 PL DEC 0.02 (0.51) 3 PL DEC 0.010 (0.254)
Standard Package
0.41 (10.4) 0.19 (4.8)
L1
0.75 (19.1)
1
0.15 (3.8) Min.
1
2
3
Pins: 0.025 (0.64) sq. 0.100 (2.54) centers 0.21 (5.3) PC-Board Hole: 0.037 - 0.043 (0.94 - 1.09) Dia. OUTPUT (+VOUT)
INPUT (+VIN)
Horizontal Package (H Pin Option)
0.35 (8.9) max. 0.15 (3.8) min. INPUT (+VIN) OUTPUT (+VOUT) GND
GND
L1
1
2
3 Pins: 0.025 (0.64) sq. 0.100 (2.54) centers PC-Board Hole: 0.037 - 0.043 (0.94 - 1.09) Dia.
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DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 Internet: www.datel-europe.com E-mail: datel.ltd@datel.com DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01 Internet: www.datel-europe.com E-mail: datel.sarl@datel.com DATEL GmbH Munchen, Germany Tel: 89-544334-0 Internet: www.datel-europe.com E-mail: datel.gmbh@datel.com DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025 Internet: www.datel-co.jp E-mail: salestko@datel.co.jp, salesosa@datel.co.jp DATEL China Shanghai, China Tel: 011-86-51317131 E-mail: davidx@datel.com
A SUBSIDIARY OF C&D TECHNOLOGIES
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 ww.datel.com E-mail: sales@datel.com www.cdpowerelectronics.com ISO 9001:2000 REGISTERED
DS-0540D 11/04
DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.

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