E-CMOS EC9301A 3a 150khz pwm buck dc/dc converter Datasheet

3A 150KHz PWM Buck DC/DC Converter
EC9301A
General Description
Features
The EC9301A is a series of easy to use fixed and

3.3V,5V and adjustable output Versions
adjustable step-down (buck) switch-mode voltage

Output adjustable from 1.23V to 43V
regulators. These devices are available in fixed output

Fixed 150KHz frequency internal oscillator
voltage of 3.3V, 5V, and an adjustable output version.

Guaranteed 3A output load current
Both versions are capable of driving a 3A load with

Input voltage range up to 45V
excellent line and load regulation.

Low power standby mode, IQ typically 80 μA

TTL shutdown capability
Requiring a minimum number of external components,

Excellent line and load regulation
these regulators are simple to use and include internal

Requires only 4 external components
frequency

High efficiency

Thermal shutdown and current limit protection

Available in TO-220B/TO220 and TO-263
packages
compensation,
and
a
fixed-frequency
oscillator.
The output voltage is guaranteed to ±3% tolerance
under
specified
input
voltage
and
output
load
conditions. The oscillator frequency is guaranteed to
±15%. External shutdown is included, featuring typically
Applications

Simple High-efficiency step-down regulator
a two stage frequency reducing current limit for the

On-card switching regulators
output switch and an over temperature shutdown for

Positive to negative converter
complete protection under fault conditions.

LCD monitor and LCD TV

DVD recorder and PDP TV

Battery charger

Step-down to 3.3V for microprocessors
80 μA standby current. Self protection features include
The EC9301A is available in TO-220B-5L ,TO220-5L
and TO-263-5L packages.
Package Types
Figure 1. Package Types of EC9301A
E-CMOS Corp. (www.ecmos.com.tw)
Page 1 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Pin Assignment (Top-View)
TO220B-5L/TO220-5L
TO263-5L
Figure 2. Pin Configuration of EC9301A
Pin Descriptions
Name
Description
Vin
Input supply voltage
Output
Switching output
GND
Ground
Feedback
Output voltage feedback
ON/OFF
ON/OFF shutdown
Active is “Low” or floating
E-CMOS Corp. (www.ecmos.com.tw)
Page 2 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Ordering/ Marking Information
Package type
TO220B-5L
Part Number
Marking
Marking Information
EC9301AXXXA1R
1. VV is the Output Voltage
(XXX:Output Voltage)
(33=3.3V;50=5.0V;AJ=Adjustable)
TO263-5L
TO220-5L
EC9301AXXXAAR
(XXX:Output Voltage)
9301A
VVLLL
YYWWT
2. LLL:last three number of lot no.
3. YYWW:Date Code
4. T:Internal tracking Code
EC9301AXXXABR
(XXX:Output Voltage)
Function Block Diagram
Figure 3 Function Block Diagram of EC9301A
E-CMOS Corp. (www.ecmos.com.tw)
Page 3 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Absolute Maximum Ratings
Parameter
Symbol
Value
Unit
Input Voltage
VIN
-0.3 ~ 45
V
Feedback
VFB
-0.3 ~ VIN +0.3
V
ON/OFF Pin voltage
VEN
-0.3~ VIN +0.3
V
Output pin voltage
VSW
-0.3 ~ VIN +0.3
V
Power Dissipation
PD
Internally limited
mW
Operating Junction Temperature
TJ
150
o
-65~+150
o
260
o
pin voltage
Storage Temperature
Lead Temperature (Soldering, 10 sec)
Tstg
TLead
ESD(HBM)
C
C
C
2000
MSL
V
Level 3
Thermal Resistance-Junction to Ambient
RθJA
23
℃/W
Thermal Resistance-Junction to Case
RθJA
3.5
℃/W
Note1: Stresses greater than those listed under Maximum Ratings may cause permanent damage to the device. This is a stress rating only and
functional operation of the device at these or any other conditions above those indicated in the operation is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect reliability.
Recommended Operating Conditions
Parameter
Symbol
Min.
Max.
Unit
Input Voltage
VIN
3.6
45
V
Operating Junction Temperature
TJ
-40
125
℃
Operating Ambient Temperature
TA
-40
85
℃
E-CMOS Corp. (www.ecmos.com.tw)
Page 4 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Electrical Characteristics
Specifications with boldface type are for full operationg temperature range, the other type are for TJ=25℃.
Note1: Thermal resistance with copper area of approximately 3 in
Symbol
Parameter
2.
Conditions
Min.
Typ.
Max.
Unit
Ib
Feedback bias current
Adjustable only, VFB=1.3V
10
50/100
nA
IQ
Quiescent current
VFB=12V force driver off
5
10
mA
ISTBY
Standby quiescent current
ON/OFF=5V, VIN=36V
-
80
200/250
uA
FOSC
Oscillator frequency
127
150
173
KHz
VSAT
Saturation voltage
IOUT=3A
1.2
1.4/1.5
V
ICL
Current Limit
Peak Current (VFB=0V)
4.5
5.5/6.5
A
IL
Output leakage current
Output=0V (VFB=12V)
50
uA
IL
Output leakage current
Output=-1V (VIN=36V)
2
30
mA
VIL
ON/OFF pin logic input
Low (Regulator ON)
1.3
0.6
V
VIH
Threshold voltage
High (Regulator OFF)
IH
ON/OFF pin input current
VLOGIC=2.5V(Regulator OFF)
5
15
uA
IL
ON/OFF pin input current
VLOGIC=0.5V(Regulator ON)
0.02
5
uA
Thermal Resistance Junction
TO220B-5L/TO220-5L
2.5
to Case
TO263-5L
3.5
Thermal Resistance Junction
TO220B-5L/TO220-5L
28
to Ambient (Note1)
TO263-5L
23
θJC
θJA
2.0
1.3
V
℃/W
℃ /W
Electrical Characteristics (Continued)
Specifications with boldface type are for full operationg temperature range, the other type are for TJ=25℃.
Note1: Thermal resistance with copper area of approximately 3 in
2.
11V≤VIN≤45V, 0.2A≤ILOAD ≤3A
1.193/
Vout: Output Voltage
1.180
Vout for 9V
ADJ
η: Efficiency
Vout: Output Voltage
3.3V
1.267/
VIN=12V,VOUT=9V,ILOAD=3A
-
4.75V≤VIN≤45V, 0.2A≤ILOAD
3.168/
1.280
88
≤3A
Vout: Output Voltage
7V≤VIN ≤45V, 0.2A≤ILOAD ≤ 3A
-
VIN=12V, ILOAD=3A
Page 5 of 16
V
3.465
76
4.800/
-
-
%
5.200/
5.0
4.750
5V
%
3.432/
3.135
VIN=12V, ILOAD=3A
E-CMOS Corp. (www.ecmos.com.tw)
-
3.3
η: Efficiency
η: Efficiency
V
1.23
V
5.250
83
-
%
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Typical Performance Characteristics
Figure 4. Output Voltage vs. Temperature
Figure 5. Switching Frequency vs. Temperature
Figure 6. Output Saturation Characteristics
E-CMOS Corp. (www.ecmos.com.tw)
Figure 7. Quiescent Current vs. Temperature
Page 6 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Typical Performance Characteristics (Continued)
Figure 8. ON/OFF Pin Voltage
Figure 9. ON/OFF Pin Sink Current
Figure 10. Output Saturation Characteristics
E-CMOS Corp. (www.ecmos.com.tw)
Page 7 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Typical Application Circuit
Figure 11. Typical Application of EC9301A For 3.3V
Input Voltage
Inductor (L1)
6V ~ 18V
6V ~ 45V
47uh
68uh
Output Capacitor (Cout)
Through Hole Electrolytic
Surface Mount Tantalum
470uf/25V
330uf/6.3V
560uf/25V
330uf/6.3V
Table 1. EC9301A Series Buck Regulator Design Procedure For 3.3V
Figure 12. Typical Application of EC9301A For 5V
Input Voltage
Inductor (L1)
8V ~ 18V
8V ~ 45V
33uh
47uh
Output Capacitor (Cout)
Through Hole Electrolytic
Surface Mount Tantalum
330uf/25V
220uf/10V
470uf/25V
330uf/10V
Table 2. EC9301A Series Buck Regulator Design Procedure For 5V
E-CMOS Corp. (www.ecmos.com.tw)
Page 8 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Figure 13. Typical Application of EC9301A For ADJ
Note:In PCB layout. Reserved an area for CFF
Vout
3.3V
5V
9V
12V
R1
1.6K
3.6K
6.8K
1.5K
R2
2.7K
11K
43K
13K
Cf (Operational)
33nf
10nf
1.5nf
1nf
Table 3. Vout VS. R1, R2, Cf Select Table
Output
Voltage
3.3V
5V
9V
12V
Input
Voltage
6V ~ 18V
6V ~45V
8V ~ 18V
8V ~45V
12V ~18V
12V ~45V
15V ~ 18V
15V ~45V
Inductor (L1)
47uh
68uh
33uh
47uh
47uh
47uh
47uh
47uh
Output Capacitor (Cout)
Through Hole Electrolytic
470uf/25V
560uf/25V
330uf/25V
470uf/25V
330uf/25V
470uf/25V
220uf/25V
330uf/25V
Table 4. Typical Application Buck Regulator Design Procedure
E-CMOS Corp. (www.ecmos.com.tw)
Page 9 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Function Description
Pin Functions
temperature rises above ambient temperature for a 3A
load and different input and output voltages.
+VIN
This is the positive input supply for the IC switching
regulator. A suitable input bypass capacitor must be
present at this pin to minimize voltage transients and to
supply the switching currents needed by the regulator
Ground
Circuit ground.
Output
Internal switch. The voltage at this pin switches
between (+VIN – VSAT) and approximately – 0.5V, with a
duty cycle of approximately VOUT / VIN. To minimize
coupling to sensitive circuitry, the PC board copper area
connected to this pin should be kept a minimum.
Feedback
Senses the regulated output voltage to complete the
feedback loop.
ON/OFF
Allows the switching regulator circuit to be shutdown
using logic level signals thus dropping the total input
supply current to approximately 80uA. Pulling this pin
below a threshold voltage of approximately 1.3V turns
the regulator on, and pulling this pin above 1.3V (up to a
maximum of 25V) shuts the regulator down. If this
shutdown feature is not needed, the ON /OFF pin can
be wired to the ground pin or it can be left open, in
either case the regulator will be in the ON condition.
for
these
curves
was
(TO-220B/TO-220
taken
with
package) operating
The data
the
EC9301A
as
a
buck
switching regulator in an ambient temperature of 25℃
(still
air).
These
temperature
rise
numbers
are
all
approximate and there are many factors that can affect
these
temperatures.
Higher ambient
temperatures
require more heat sinking.
The TO-263 surface mount package tab is designed to
be soldered to the copper on a printed circuit board. The
copper and the board are the heat sink for this package
and the other heat producing components, such as the
catch diode and inductor. The PC board copper area that
2,
the package is soldered to should be at least 0.4 in and
ideally should have 2 or more square inches of 2 oz.
Additional
copper
characteristics,
but
area
with
improves
copper
areas
the
thermal
greater
than
2
approximately 6 in , only small improvements in heat
dissipation are realized. If further thermal improvements
are needed, double sided, multilayer PC board with large
copper areas and/or airflow are recommended.
The EC9301A (TO-263 package) junction temperature rise
above ambient temperature with a 3A load for various
input and output voltages. This data was taken with the
circuit operating as a buck switching regulator with all
components mounted on a PC board to simulate the
junction temperature under actual operating conditions.
This curve can be used for a quick check for the
approximate junction temperature for various conditions,
Thermal Considerations
but be aware that there are many factors that can affect
the junction temperature. When load currents higher
The EC9301A is available in two packages, a 5-pin
than 3A are used, double sided or multilayer PC boards
TO-220B/TO-220 and a 5-pin surface mount TO-263.
with large copper areas and/or airflow might be needed,
The TO-220B/TO-220 package needs a heat sink under
especially for high ambient temperatures and high output
most conditions. The size of the heatsink depends on
voltages.
the input voltage, the output voltage, the load current
For the best thermal performance, wide copper traces
and the ambient temperature. The EC9301A junction
and generous amounts of printed circuit board copper
should be used in the board layout. (Once exception to
E-CMOS Corp. (www.ecmos.com.tw)
Page 10 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Function Description(Cont.)
this is the output (switch) pin, which should not have
L = (VOUT) * (VIN-VOUT) / VIN * f * ∆I
large areas of copper.) Large areas of copper provide the
Where VOUT is the output voltage, VIN is the input
best transfer of heat (lower thermal resistance) to the
voltage, f is the switching frequency, and ∆I is the
surrounding air, and moving air lowers the thermal
peak-to-peak inductor ripple current.
resistance even further.
Input Capacitor
Setting the Output Voltage
The input current to the step-down converter is
The output voltage is set using a resistive voltage divider
discontinuous, and so a capacitor is required to supply
from the output voltage to FB(EC9301A-ADJ) The voltage
the AC current to the step-down converter while
divider divides the output voltage down by the ratio:
maintaining the DC input voltage. A low ESR capacitor is
VFB = VOUT * R1 / (R1 + R2)
required to keep the noise at the IC to a minimum.
Thus the output voltage is:
Ceramic capacitors are preferred, but tantalum or
VOUT = 1.235 * (R1 + R2) / R1
low-ESR electrolytic capacitors may also suffice.
R1 can be as high as 100KΩ, but a typical value is 10KΩ.
The input capacitor value should be greater than 10μF.
Using that value, R2 is determined by:
The capacitor can be electrolytic, tantalum or ceramic.
R2 ~= 8.18 * (VOUT – 1.235) (KΩ)
However since it absorbs the input switching current it
For example, for a 3.3V output voltage, R1 is 10KΩ, and
requires an adequate ripple current rating. Its RMS
R2is 17KΩ.
current rating should be greater than approximately
1/2 of the DC load current.
Inductor
For insuring stable operation should be placed as close
to the IC as possible. Alternately a smaller high quality
The inductor is required to supply constant current to the
output load while being driven by the switched input
voltage. A larger value inductor results in less ripple
current that in turn results in lower output ripple voltage.
However, the larger value inductor has a larger physical
size, higher series resistance, and/or lower saturation
current. Choose an inductor that does not saturate under
ceramic 0.1μF capacitor may be placed closer to the IC
and a larger capacitor placed further away. If using this
technique, it is recommended that the larger capacitor be
a tantalum or electrolytic type. All ceramic capacitors
should be places close to the EC9301A.
Output Capacitor
the worst-case load conditions. A good rule for
determining the inductance is to allow the peak-to-peak
The output capacitor is required to maintain the DC
ripple current in the inductor to be approximately 30% of
output voltage. Low ESR capacitors are preferred to
the maximum load current. Also, make sure that the peak
keep the output voltage ripple low. The characteristics of
inductor current (the load current plus half the peak to
the output capacitor also affect the stability of the
peak inductor ripple current) is below the TBDA minimum
regulation control system. Ceramic, tantalum, or low
current limit. The inductance value can be calculated by
ESR electrolytic capacitors are recommended. In the
the equation:
case of ceramic capacitors, the impedance at the
switching frequency is dominated by the capacitance,
E-CMOS Corp. (www.ecmos.com.tw)
Page 11 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Function Description(Cont.)
and so the output voltage ripple is mostly
output capacitors, such as solid tantalum capacitors.
independent of the ESR. The output voltage
ripple is estimated to be:
VRIPPLE ~= 1.4 * VIN * (fLC/fSW)^2
Where VRIPPLE is the output ripple voltage, VIN
This capacitor type can be ceramic, plastic, silver mica,
is the input voltage, fLC is the resonant
etc.(Because of the unstable characteristics of ceramic
frequency of the LC filter, fSW is the switching
capacitors made with Z5U material, they are not
frequency. In the case of tanatalum or low-
recommended.)
ESR electrolytic capacitors, the ESR
Note:In PCB layout. Reserved an area for CFF.
dominates the impedance at the switching
frequency, and so the output ripple is
Over Current Protection (OCP)
calculated as:
VRIPPLE ~= ∆I * RESR
Where VRIPPLE is the output voltage ripple, ∆I is
The cycle by cycle current limit threshold is set between
the inductor ripple current, and RESR is the
4A and 5A. When the load current reaches the current
equivalent series resistance of the output
limit threshold, the cycle by cycle current limit circuit
capacitors.
turns off the high side switch immediately to terminate
the current duty cycle. The inductor current stops rising.
Output Rectifier Diode
The cycle by cycle current limit protection directly limits
inductor peak current. The average inductor current is
also limited due to the limitation on peak inductor current.
The output rectifier diode supplies the current to the
When the cycle by cycle current limit circuit is triggered,
inductor when the high-side switch is off. To reduce
the output voltage drops as the duty cycle is decreasing.
losses due to the diode forward voltage and recovery
times, use a Schottky rectifier.
Thermal Management and Layout
Table 1 provides the Schottky rectifier part numbers
based on the maximum input voltage and current rating.
Consideration
Choose a rectifier who’s maximum reverse voltage rating
is greater than the maximum input voltage, and who’s
current rating is greater than the maximum load current.
In the EC9301A buck regulator circuit, high pulsing current
flows through two circuit loops. The first loop starts from
Feedforward Capacitor (CFF)
the input capacitors, to the VIN pin, to the VOUT pins, to
the filter inductor, to the output capacitor and load, and
then returns to the input capacitor through ground.
For output voltages greater than approximately 8V, an
Current flows in the first loop when the high side switch is
additional capacitor is required. The compensation
on. The second loop starts from the inductor, to the
capacitor is typically between 100 pF and 33 nF, and is
output capacitors and load, to the GND pin of the
wired in parallel with the output voltage setting resistor,
EC9301A, and to the VOUT pins of the EC9301A. Current
R2. It provides additional stability for high output
flows in the second loop when the low side diode is on.
voltages, low input-output voltages, and/or very low ESR
In PCB layout, minimizing the two loops area reduces the
E-CMOS Corp. (www.ecmos.com.tw)
Page 12 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
Function Description(Cont.)
noise of this circuit and improves efficiency. A ground
Several layout tips are listed below for the best electric
plane is recommended to connect input capacitor, output
and thermal performance.
capacitor, and GND pin of the EC9301A.
1. Do not use thermal relief connection to the VIN and
In the EC9301A buck regulator circuit, the two major
the GND pin. Pour a maximized copper area to the GND
power dissipating components are the EC9301A and
pin and the VIN pin to help thermal dissipation.
output inductor. The total power dissipation of converter
2. Input capacitor should be connected to the VIN pin
circuit can be measured by input power minus output
and the GND pin as close as possible.
power.
3. Make the current trace from VOUT pins to L to the
Ptotal _loss = V IN × IIN – V O × IO
GND as short as possible.
The power dissipation of inductor can be approximately
4. Pour copper plane on all unused board area and
calculated by output current and DCR of inductor.
Pinductor _loss= IO 2 × Rinductor × 1.1
connect it to stable DC nodes, like VIN, GND, or VOUT.
The junction to ambient temperature can be got from
FB pin away from the VOUT pins.
5. Keep sensitive signal traces such as trace connecting
power dissipation in the EC9301A and thermal impedance
from junction to ambient.
T (jun-amb) =(Ptotalloss–Pinductorloss)× ΘJA
The maximum junction temperature of EC9301A is 145°C,
which limits the maximum load current capability. Please
see the thermal de-rating curves for the maximum load
current of the EC9301A under different ambient
temperatures.
The thermal performance of the EC9301A is trongly
affected by the PCB layout. Extra care should be taken
by users during the design process to nsure that the IC
will operate under the recommended environmental
conditions.
E-CMOS Corp. (www.ecmos.com.tw)
Page 13 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
OUTLINE DRAWING FOR TO-220B-5L
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min.
Max.
Min.
Max.
A
4.40
4.70
0.175
0.185
b
0.69
0.94
0.027
0.037
D
8.38
8.90
0.330
0.350
d1
1.0
0.039
d2
6.3
0.248
E
9.91
10.41
0.390
0.410
e
1.58
1.83
0.062
0.072
F
1.22
1.32
0.048
0.052
H1
6.40
0.250
H2
20.83
22.35
0.820
0.880
H3
23.93
25.45
0942
1.002
J1
J2
2.66
3.73
J3
Q
0.105
5.26
0.147
8.40
2.55
E-CMOS Corp. (www.ecmos.com.tw)
0.207
0.331
3.05
0.100
Page 14 of 16
0.120
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
OUTLINE DRAWING FOR TO-220-5L
E-CMOS Corp. (www.ecmos.com.tw)
Page 15 of 16
5J22N Rev. F001
3A 150KHz PWM Buck DC/DC Converter
EC9301A
OUTLINE DRAWING FOR TO-263-5L
E-CMOS Corp. (www.ecmos.com.tw)
Page 16 of 16
5J22N Rev. F001
Similar pages