78SR 2 Amp Series

78SR 2 Amp Series
www.murata-ps.com
2 Amp, 3.3V & 5V Output, High Efficiency,
Synchronous Switching Regulators
FEATURES
„„
Up to 95% efficiency– no costly heat sinks or fans
required
„„
3.3V/2A & 5V/2A models; pin compatible with 1.5A 78xx
regulators
„„
Wide 8– 32Vdc input voltage range
„„
Two package options:
3-pin vertical mount SIP
Low profile, horizontal mount SIP
„„
No external Input/Output filter capacitors required
„„
–40 to +70°C full load operation at 24Vin with no
derating
„„
Excellent load (±0.25%) and line (±0.35%) regulation
„„
Low-cost upgrade for 78HT2, 78SR1, 78ST1, and
PT5100 switchers
„„
Open frame design minimizes self-heating & pc-board
footprint
„„
Includes output short-circuit protection and thermal
shutdown
„„
Low noise output for powering sensitive instrumentation
Murata’s 78SR-3.3/2 (3.3V, 2 Amp output) and 78SR-5/2 (5V, 2 Amp output) step-down,
switching regulators are ultra high-efficiency, modern replacements for LM78xx series
1.5Amp linear regulators. They are pin- and size-compatible, drop-in replacements for
TO-220 style, 3-pin SIP or modular packages which require heat sinks. And, to ensure the
lowest installed cost, no messy thermal grease, no mounting hardware and no external
components are required for full operation.
A 200KHz switching frequency, combined with a synchronous rectifier buck regulator
topology, provides for efficiencies exceeding 95%. 78SR switchers can easily drive 2A loads
from 12V or 24Vsupplies—at ambient temperatures up to +70°C—without heat sinks,
fans, or thermal derating. A thermally efficient 3-pin vertical mount SIP occupies less than
0.09in.2 (58mm2) of pc-board real estate, while a horizontal mount option has an installed
height of less than 0.290in. (7.4mm).
78SR Series 2A switching regulators are lower cost, improved-efficiency upgrades for
many 78HT2, 78SR1, 78ST1, and PT5100 series switchers. Their higher efficiency ensures
significantly lower heat generation and provides increased run time in battery-powered
applications, making these regulators ideal for today’s low power “green” applications.
TECHNICAL NOTES
1. Input/Output (I/O) Filtering: As shown in the accompanying noise and ripple graphs,
78SR Series regulators exhibit excellent low noise performance with no additional I/O filter
components. 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 input voltage and ambient temperatures. Adding external output capacitors
will improve the unit’s load-transient response.
Ordering Information
Part No.
Output Output Input
Voltage CurrentVoltage
78SR-3.3/2-C
78SR-5/2-C
78SRH-3.3/2-C
78SRH-5/2-C
3.3Vdc2.0A
5.0Vdc2.0A
3.3Vdc2.0A
5.0Vdc2.0A
8.0-32Vdc
8.0-32Vdc
8.0-32Vdc
8.0-32Vdc
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 potentially 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
select an appropriate slow-blow fuse.
For full details go to
www.murata-ps.com/rohs
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MPM_78SR-2A_B03 Page 1 of 5
78SR 2 Amp Series
2 Amp, 3.3V & 5V Output, High Efficiency,
Synchronous Switching Regulators
Performance/Functional Specifications
TECHNICAL NOTES (continued)
Typical at TA = +25°C & VIN = 12V, unless otherwise noted
Input/Output
Models
78SR-3.3/2
78SR-5/2
Output Voltage
3.3Vdc5.0Vdc
Rated Output Current2.0A 2.0A
Output Voltage Accuracy
±2%
Input Voltage Range
8.0-32Vdc8.0-32Vdc
Line Regulation (100% load)
±0.35%
±0.35%
Load Regulation (0-100% load)
±0.2%
±0.2%
Quiescent Current (mAdc)
25 typ., 30 max
Input Current vs. Input Voltage
±2%
20 typ., 35max
See Efficiency Curves
Efficiency
See Efficiency Curves
Transient Response
See Performance Curves
Input & Output Noise
See Performance Curves
Output Short Circuit Protection ➀
Continuous
Input/Output Isolation
None
Overvoltage Protection
None
Undervoltage Protection
None
Environmental
Models
78SR-3.3/2
Operating Temperature 78SR-5/2
–40 to +70°C
Storage Temperature
3. Input-Output Isolation: 78SR regulators’ internal input and output circuits share a common connection (GND, pin 2), there is no electrical
isolation between their 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
where a catastrophic failure occurs, the output voltage may rise to
excessively high levels. If the load circuit must be protected against
all possible overvoltage situations, voltage-limiting circuitry must be
provided externally.
5. Soldering & Handling Precautions: All units are designed to be hand
soldered to pc-boards, using lead-free no-clean solders (+260°C, 5
seconds max.). See the Mechanical Specifications section for pin 1
orientation and recommended pc-board hole dimensions.
78SR series regulators have limited built-in ESD protection; therefore
they should always be treated as ESD susceptible devices.
6. Horizontal-Pin Models (78SRH): 78SRH switching regulators are pincompatible replacements for TO-220 style LM78xx linear regulators
which are installed with their metal tabs or heat sinks laying flat on
the surface of the pc-board. In replacement applications, 78SRH units
must be soldered to the pc-board such that the insulating body of
diode D1 lies flat and in contact with the pc-board’s surface.
–40 to +85°C
Cooling ③
Free Air Convection
Humidity (Non-condensing)
0 to 85%
Physical
Mechanical
See Mechanical Specifications
Package
Pins
Weight
Pin Soldering
Open-frame SIP
0.025” (0.64mm) square,
tin-plated bronze
0.15 ounces (4.2g)
+260°C for 5 seconds
Absolute Maximum Ratings ➁
Input Voltage:
+36Vdc
Operating Temperature
+85°C
Output Current
3.0 Amps
➀78SR Series regulators can withstand a continuous short-circuit across their
output terminals. However, extended short-circuit operation will decrease the
unit’s long-term reliability.
➁These are stress ratings only; Exposure of devices to any of these conditions
may adversely affect long-term reliability. Proper operation under conditions
other than those listed in the Performance/Functional Specifications Table is not
implied.
③See derating chart for more information.
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MPM_78SR-2A_B03 Page 2 of 5
78SR 2 Amp Series
2 Amp, 3.3V & 5V Output, High Efficiency,
Synchronous Switching Regulators
Typical Performance Curves TA = +25°C, VIN as indicated
Noise and Ripple - 10% and 100% Load, 20 MHz Bandwidth
78SR-3.3/2
78SR-5/2
Vin = 12V, ILOAD = 0.2A
Vin = 12V, ILOAD = 0.2A
78SR-3.3/2
78SR-5/2
Vin = 12V, ILOAD = 2.0A
Vin = 12V, ILOAD = 2.0A
78SR-3.3/2
78SR-5/2
Vin = 24V, ILOAD = 2.0A
Vin = 24V, ILOAD = 2.0A
Transient Response - 50% Load Step
78SR-3.3/2 25% to 75% Load Step
78SR-3.3/2 25% to 75% Load Step
Vin = 12V
78SR-3.3/2 75% to 25% Load Step
Vin = 24V
CH1: Vout, 50mV/div.
Vin = 12V
CH1: Vout, 50mV/div.
CH1: Vout, 50mV/div.
CH2: Load Current 1A/div.
CH2: Load Current 1A/div.
CH2: Load Current 1A/div.
25%75%
25%75%
75%25%
78SR-5/2
40µsec/div.
25% to 75% Load Step
40µsec/div.
78SR-5/2 25% to 75% Load Step
Vin = 12V
78SR-5/2
40µsec/div.
75% to 25% Load Step
Vin = 24V
CH1: Vout, 50mV/div.
Vin = 12V
CH1: Vout, 50mV/div.
CH1: Vout, 50mV/div.
CH2: Load Current 1A/div.
CH2: Load Current 1A/div.
CH2: Load Current 1A/div.
25%75%
25%75%
75%25%
40µsec/div.
40µsec/div.
40µsec/div.
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MPM_78SR-2A_B03 Page 3 of 5
78SR 2 Amp Series
2 Amp, 3.3V & 5V Output, High Efficiency,
Synchronous Switching Regulators
78SR-3.3/2-C Input Current
78SR-5/2-C Input Current
1.0
1.4
2.0A LOAD
2.0A LOAD
1.2
INPUT CURRENT (AMPS)
INPUT CURRENT (AMPS)
0.8
0.6
1.0A LOAD
0.4
1.0
0.8
0.6
1.0A LOAD
0.4
0.5A LOAD
0.2
0.5A LOAD
0.2
0.0
0.0
0
5
10
15
20
25
30
35
0
5
10
INPUT VOLTAGE
78SR-3.3/2-C Efficiency
95
90
90
85
85
EFFICIENCY (%)
95
EFFICIENCY (%)
100
Vin = 8V
75
Vin = 12V
70
Vin = 15V
65
Vin = 24V
Vin = 28V
60
80
0.50
0.75
1.00
1.25
25
30
35
Vin = 8V
75
Vin = 12V
70
Vin = 15V
65
Vin = 24V
Vin = 28V
60
Vin = 32V
55
0.25
20
78SR-5/2-C Efficiency
100
80
15
INPUT VOLTAGE
Vin = 32V
1.50
1.75
2.00
LOAD CURRENT (AMPS)
55
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
LOAD CURRENT (AMPS)
Thermal Derating Curve
OUTPUT CURRENT (AMPS)
2.00
60ºC
65ºC
1.75
70ºC
1.50
1.25
8
12
15
24
28
INPUT VOLTAGE
32
36
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MPM_78SR-2A_B03 Page 4 of 5
78SR 2 Amp Series
2 Amp, 3.3V & 5V Output, High Efficiency,
Synchronous Switching Regulators
MECHANICAL DIMENSIONS: Inches (mm)
TOLERANCES:
2 PL DEC ±0.02 (±0.51)
3 PL DEC ±0.010 (±0.254)
Standard Package
0.16
(4.1)
0.80
(20.3)
D1
103
L1
Pins: 0.025 (0.64) sq.
0.100 (2.54)
centers
L1
0.85
(21.6)
PC-Board Hole:
0.037 - 0.043
(0.94 - 1.09) Dia.
DATEL 78SR-5/2-C
0.095
(2.4)
1
0.15
(3.8) Min.
3
OUTPUT (+VOUT)
GND
INPUT (+VIN)
0.23
(5.7)
2
Horizontal Package
(H Pin Option)
0.07
(1.8)
L1
L1
L1
1
0.280
(7.1)
D1
3
OUTPUT (+VOUT)
ISO 9001 and 14001 REGISTERED
GND
INPUT (+VIN)
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
2
0.30 (7.6) min.
Pins: 0.025 (0.64) sq.
0.100 (2.54)
centers
PC-Board Hole:
0.037 - 0.043
(0.94 - 1.09) Dia.
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
Murata Power Solutions, Inc. 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. © 2015 Murata Power Solutions, Inc.
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MPM_78SR-2A_B03 Page 5 of 5