ENPIRION EN5339QI-E

EN5339QI
3A Low Profile Synchronous Buck DC-DC
Converter with Integrated Inductor
RoHS Compliant
Halogen Free
Description
Features
The EN5339QI is a highly integrated, low profile,
highly efficient, 3A synchronous buck power system
on a chip (PowerSoC). The device features an
advance integrated inductor, integrated MOSFETs, a
PWM voltage-mode
controller,
and
internal
compensation providing the smallest possible solution
size.
The EN5339QI PowerSoC is designed specifically to
meet the driving demand for higher power density by
providing a fully integrated buck converter into a tiny
4x6x1.1mm 24-pin QFN package. It features high
efficiency, excellent line and load regulation and
guarantees the full 3A output current over
temperature.
The EN5339QI operates at high switching frequency
and allows for the use of tiny MLCC capacitors. It also
enables a very wide control loop bandwidth providing
excellent transient performance and reduced output
impedance. The internal compensation is designed
for unconditional stability across all operating
conditions.
The Enpirion integrated inductor solution significantly
helps to reduce noise. The complete power converter
solution enhances productivity by offering greatly
simplified board design, layout and manufacturing
requirements. All Enpirion products are RoHS
compliant and lead-free manufacturing environment
compatible.
• Integrated Inductor
• Solution Footprint as Small as 55 mm2
• Low Profile, 1.1mm
• High Reliability Solution: 35,700 Years MTBF
• High Efficiency, up to 95 %
• Low Output Ripple Voltage; <5mVP-P Typical
• ±3% Output Variation Over Line, Load, Temp
• 2.4 V to 5.5 V Input Voltage Range
• 3A Continuous Output Current Capability
• Output Enable and Power OK Signal
• Under Voltage Lockout, Over Current, Short Circuit,
and Thermal Protection
• RoHS Compliant; Halogen Free; 260°C Reflow
Applications
• Applications with Low Profile Requirement such as
SSD and Embedded Computing
• SAN/NAS Accelerator Appliance
• Controllers, Raid, Processors, Network Processors,
DSPs’ FPGAs, and ASICs
• Noise Sensitive Applications
Efficiency vs. Output Current
100
EFFICIENCY (%)
90
80
70
60
50
CONDITIONS
VIN = 3.3V
40
30
Actual Solution Size
55mm2
VOUT = 2.5V
20
VOUT = 1.2V
10
0
0
Figure 1. Simplified Applications Circuit
0.5
1
1.5
2
OUTPUT CURRENT (A)
2.5
3
Figure 2. Highest Efficiency in Smallest Solution Size
www.enpirion.com
06903
September 12, 2012
Rev: B
EN5339QI
Ordering Information
Part Number
EN5339QI
EN5339QI-E
Package Markings
EN5339
EN5339
Temp Rating (°C)
-40 to +85
Package Description
24-pin (4mm x 6mm x 1.1mm) QFN T&R
QFN Evaluation Board
Packing and Marking Information: http://www.enpirion.com/resource-center-packing-and-marking-information.htm
Pin Assignments (Top View)
Figure 3: Pin Out Diagram (Top View)
NOTE A: NC pins are not to be electrically connected to each other or to any external signal, ground, or voltage.
However, they must be soldered to the PCB. Failure to follow this guideline may result in part malfunction or damage.
NOTE B: Grey area highlights exposed metal on the bottom of the package that is not to be mechanically or electrically
connected to the PCB. There should be no traces on PCB top layer under these keep out areas.
NOTE C: White ‘dot’ on top left is pin 1 indicator on top of the device package.
Pin Description
PIN
NAME
1, 21-24
NC(SW)
2-3, 8-9
PGND
4-7
VOUT
10
11
TST2
TST1
FUNCTION
NO CONNECT: These pins are internally connected to the common switching node of the
internal MOSFETs. They must be soldered to PCB but not be electrically connected to any
external signal, ground, or voltage. Failure to follow this guideline may result in device
damage.
Input and output power ground. Connect these pins to the ground electrode of the input and
output filter capacitors. See VOUT, PVIN descriptions and Layout Recommendation for more
details.
Regulated converter output. Connect to the load and place output filter capacitor(s) between
these pins and PGND pins 8 and 9. See layout recommendation for details
Test Pin. For Enpirion internal use only. Connect to AVIN at all times.
Test Pin. For Enpirion internal use only. Connect to AVIN at all times.
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06903
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September 12, 2012
Rev: B
EN5339QI
PIN
12
NAME
TST0
13
NC
14
VFB
15
AGND
16
AVIN
17
POK
18
ENABLE
19-20
PVIN
25,26
PGND
FUNCTION
Test Pin. For Enpirion internal use only. Connect to AVIN at all times.
NO CONNECT: This pin must be soldered to PCB but not electrically connected to any other
pin or to any external signal, voltage, or ground. This pin may be connected internally. Failure
to follow this guideline may result in device damage.
This is the external feedback input pin. A resistor divider connects from the output to AGND.
The mid-point of the resistor divider is connected to VFB. A feed-forward capacitor is
required parallel to the upper feedback resistor (RA). The output voltage regulation is based
on the VFB node voltage equal to 0.600V.
The quiet ground for the control circuits. Connect to the ground plane with a via right next to
the pin.
Analog input voltage for the control circuits. Connect this pin to the input power supply (PVIN)
at a quiet point. Decouple with a 1uF capacitor to AGND.
POK is an open drain output. Refer to Power OK section for details. Leave POK open if
unused.
Output Enable. A logic high level on this pin enables the output and initiates a soft-start. A
logic low signal disables the output and discharges the output to GND. This pin must not be
left floating.
Input power supply. Connect to input power supply and place input filter capacitor(s) between
these pins and PGND pins 2 to 3.
Not a perimeter pin. Device thermal pad to be connected to the system GND plane for heatsinking purposes. See Layout Recommendation section.
Enpirion 2012 all rights reserved, E&OE
06903
www.enpirion.com, Page 3
September 12, 2012
Rev: B
EN5339QI
Absolute Maximum Ratings
CAUTION: Absolute Maximum ratings are stress ratings only. Functional operation beyond the recommended operating
conditions is not implied. Stress beyond the absolute maximum ratings may impair device life. Exposure to absolute
maximum rated conditions for extended periods may affect device reliability.
PARAMETER
SYMBOL
MIN
MAX
UNITS
Voltages on : PVIN, AVIN, VOUT
-0.3
6.5
V
Voltages on: ENABLE, POK, TST0, TST1, TST2
-0.3
VIN+0.3
V
Voltages on: VFB
-0.3
2.7
V
-65
150
°C
150
°C
Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020A
260
°C
ESD Rating (Human Body Model)
2000
V
ESD Rating (Charge Device Model)
500
V
Storage Temperature Range
TSTG
Maximum Operating Junction Temperature
TJ-ABS Max
Recommended Operating Conditions
PARAMETER
SYMBOL
MIN
MAX
UNITS
VIN
2.4
5.5
V
Output Voltage Range (Note 1)
VOUT
0.6
VIN – VDO
V
Output Current
IOUT
0
3
A
Operating Ambient Temperature
TA
-40
+85
°C
Operating Junction Temperature
TJ
-40
+125
°C
Input Voltage Range
Thermal Characteristics
PARAMETER
SYMBOL
TYP
UNITS
Thermal Resistance: Junction to Ambient (0 LFM) (Note 2)
θJA
36
°C/W
Thermal Resistance: Junction to Case (0 LFM)
θJC
6
°C/W
Thermal Shutdown
TSD
150
°C
Thermal Shutdown Hysteresis
TSDH
15
°C
Note 1: VDO (dropout voltage) is defined as (ILOAD x Dropout Resistance). Please see Electrical Characteristics Table.
Note 2: Based on 2oz. external copper layers and proper thermal design in line with EIJ/JEDEC JESD51-7 standard for
high thermal conductivity boards.
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06903
www.enpirion.com, Page 4
September 12, 2012
Rev: B
EN5339QI
Electrical Characteristics
NOTE: VIN = 5V, Minimum and Maximum values are over operating ambient temperature range unless otherwise noted.
Typical values are at TA = 25°C.
PARAMETER
Operating Input Voltage
Feedback Node Initial
Accuracy
Output Variation (Note 3)
(Line, Load, Temperature)
VFB, ENABLE, TST0/1/2
Pin Input Current (Note 4)
Shutdown Current
Under Voltage Lock-out –
VIN Rising
Under Voltage Lock-out –
tVIN Falling
Soft-start Time
SYMBOL
VIN
VVFB
VOUT
VUVLOR
VUVLOF
TEST CONDITIONS
TA = 25°C; VIN = 5V
ILOAD = 100 mA
2.4V ≤ VIN ≤ 5.5V
0 ≤ ILOAD ≤ 3A
ENABLE Low
Voltage Above Which UVLO is
Not Asserted
Voltage Below Which UVLO is
Asserted
Time from Enable High (Note 4)
MIN
2.4
0.588
Output Ripple Voltage
Logic Low
Logic High
VOUT Rising
VOUT Falling
ISINK = 1 mA
0.91
2.4V ≤ VIN ≤ 5.5V
VRIPPLE
COUT = 3 x 22 µF 0805 X5R
MLCC, VOUT = 3.3 V, ILOAD = 3A
COUT = 3 x 22 µF 0805 X5R
MLCC, VOUT = 1.8 V, ILOAD = 3A
3.5
MAX
5.5
UNITS
V
0.612
V
+3
%
+/-40
nA
20
µA
2.2
V
2.1
V
1.40
1.89
ms
150
300
mΩ
0.4
VIN
V
0.0
1.4
POK High
FOSC
0.600
-3
Dropout Resistance
ENABLE Voltage
Threshold
POK Threshold
POK Threshold
POK Low Voltage
POK Pin VOH Leakage
Current
Current Limit Threshold
Operating Frequency
TYP
92
90
0.15
0.4
%
%
V
0.5
2
µA
5
3.2
A
MHz
4.2
mVP-P
5.5
mVP-P
Note 3: Output voltage variation is based on using 0.1% accuracy resistor values.
Note 4: Parameter not production tested but is guaranteed by design.
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September 12, 2012
Rev: B
EN5339QI
Typical Performance Curves
Efficiency vs. Output Current
Efficiency vs. Output Current
100
100
90
80
EFFICIENCY (%)
EFFICIENCY (%)
90
70
60
50
VOUT = 2.5V
40
VOUT = 1.8V
30
VOUT = 1.2V
20
CONDITIONS
VIN = 3.3V
VOUT = 1.0V
10
0
0
0.5
1
1.5
2
2.5
80
70
60
50
VOUT = 3.3V
40
VOUT = 2.5V
30
VOUT = 1.8V
20
VOUT = 1.2V
10
VOUT = 1.0V
0
3
0
OUTPUT CURRENT (A)
1.5
2
2.5
3
3.36
IOUT = 1A
3.5
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1
Output Voltage vs. Output Current
Dropout Voltage
IOUT = 2A
3.4
IOUT = 3A
3.3
3.2
3.1
3
CONDITIONS
VOUT = 3.3V
2.9
2.8
VOUT = 3.3V
3.34
3.32
3.3
3.28
CONDITIONS
VIN = 5V
3.26
3.24
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
0
4
0.5
1
1.5
2
2.5
INPUT VOLTAGE(V)
OUTPUT CURRENT (A)
Output Voltage vs. Output Current
Output Voltage vs. Output Current
2.56
3
1.86
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
0.5
OUTPUT CURRENT (A)
3.6
VOUT = 2.5V
2.54
2.52
2.5
2.48
CONDITIONS
VIN = 5V
2.46
2.44
VOUT = 1.8V
1.84
1.82
1.8
1.78
CONDITIONS
VIN = 5V
1.76
1.74
0
0.5
1
1.5
2
2.5
3
0
OUTPUT CURRENT (A)
0.5
1
1.5
2
2.5
3
OUTPUT CURRENT (A)
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CONDITIONS
VIN = 5V
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September 12, 2012
Rev: B
EN5339QI
Typical Performance Curves (Continued)
Output Voltage vs. Output Current
Output Voltage vs. Output Current
2.56
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.26
VOUT = 1.2V
1.24
1.22
1.2
1.18
CONDITIONS
VIN = 5V
1.16
VOUT = 2.5V
2.54
2.52
2.5
2.48
CONDITIONS
VIN = 3.3V
2.46
2.44
1.14
0
0.5
1
1.5
2
2.5
0
3
0.5
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
2
2.5
3
1.26
VOUT = 1.8V
1.84
1.82
1.8
1.78
CONDITIONS
VIN = 3.3V
1.76
1.74
VOUT = 1.2V
1.24
1.22
1.2
1.18
CONDITIONS
VIN = 3.3V
1.16
1.14
0
0.5
1
1.5
2
2.5
3
0
0.5
OUTPUT CURRENT (A)
1.815
1.815
OUTPUT VOLTAGE (V)
1.820
1.810
1.805
1.800
1.795
CONDITIONS
Load = 5mA
1.785
1.5
2
2.5
3
Output Voltage vs. Input Voltage
1.820
1.790
1
OUTPUT CURRENT (A)
Output Voltage vs. Input Voltage
OUTPUT VOLTAGE (V)
1.5
Output Voltage vs. Output Current
Output Voltage vs. Output Current
1.86
1.810
1.805
1.800
1.795
1.790
CONDITIONS
Load = 500mA
1.785
1.780
1.780
2.5
3.1
3.7
4.3
INPUT VOLTAGE (V)
4.9
5.5
2.5
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1
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
3.1
3.7
4.3
INPUT VOLTAGE (V)
4.9
5.5
www.enpirion.com, Page 7
September 12, 2012
Rev: B
EN5339QI
Typical Performance Curves (Continued)
Output Voltage vs. Input Voltage
1.820
1.815
1.815
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
Output Voltage vs. Input Voltage
1.820
1.810
1.805
1.800
1.795
1.790
CONDITIONS
Load = 2A
1.785
1.810
1.805
1.800
1.795
1.790
CONDITIONS
Load = 3A
1.785
1.780
1.780
2.5
3.1
3.7
4.3
INPUT VOLTAGE (V)
4.9
2.5
5.5
1.030
1.830
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.840
1.020
1.010
1.000
0.990
LOAD = 3A
0.970
LOAD = 100mA
CONDITIONS
VIN = 5V
VOUT_NOM = 1.0V
5.5
1.810
1.800
1.790
1.780
1.770
LOAD = 100mA
CONDITIONS
V IN = 5V
V OUT_NOM = 1.8V
1.760
-40
-15
10
35
60
AMBIENT TEMPERATURE ( C)
85
-40
4.5
4
3.5
3
2.5
2
1.5
CONDITIONS
Conditions
VINVIN
= 5.0V
= 5.0V
VOUT
VOUT
= 1.0V
= 3.3V
1
0.5
0
-40
-15
10
35
60
AMBIENT TEMPERATURE( C)
-15
10
35
60
AMBIENT TEMPERATURE ( C)
85
No Thermal Derating
5
85
GUARANTEED OUTPUT CURRENT (A)
No Thermal Derating
GUARANTEED OUTPUT CURRENT (A)
4.9
1.820
LOAD = 3A
0.960
5
4.5
4
3.5
3
2.5
2
1.5
CONDITIONS
Conditions
VIN
V IN
= 5.0V
= 5.0V
VOUT
V OUT
= 3.3V
= 3.3V
1
0.5
0
-40
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06903
3.7
4.3
INPUT VOLTAGE (V)
Output Voltage vs. Temperature
Output Voltage vs. Temperature
1.040
0.980
3.1
-15
10
35
60
AMBIENT TEMPERATURE( C)
85
www.enpirion.com, Page 8
September 12, 2012
Rev: B
EN5339QI
Typical Performance Characteristics (Continued)
Output Ripple at 20MHz
Output Ripple at 20MHz
VOUT
(AC Coupled)
VOUT
(AC Coupled)
CONDITIONS
VIN = 5V
VOUT = 1.8V
IOUT = 3A
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
CONDITIONS
VIN = 5V
VOUT = 3.3V
IOUT = 3A
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
Output Ripple at 500MHz
Output Ripple at 500MHz
VOUT
(AC Coupled)
CONDITIONS
VIN = 3.3V
VOUT = 1.8V
IOUT = 3A
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
VOUT
(AC Coupled)
CONDITIONS
VIN = 5V
VOUT = 3.3V
IOUT = 3A
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
Startup Waveforms at 0A
Startup Waveforms at 3A
ENABLE
ENABLE
VOUT
VOUT
POK
POK
LOAD
LOAD
VIN = 5V, VOUT = 1.8V
CIN = 1 X 22µF (0805), COUT = 3 x 22µF (0805), IOUT = 3A
VIN = 5V, VOUT = 1.8V
CIN = 1 X 22µF (0805), COUT = 3 x 22µF (0805), IOUT = 0A
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September 12, 2012
Rev: B
EN5339QI
Typical Performance Characteristics (Continued)
Load Transient from 0 to 1A
VOUT
(AC Coupled)
Load Transient from 0 to 3A
VOUT
(AC Coupled)
CONDITIONS
VIN = 3.3V
VOUT = 1.8V
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
LOAD
LOAD
Load Transient from 0 to 1A
VOUT
(AC Coupled)
Load Transient from 0 to 3A
VOUT
(AC Coupled)
CONDITIONS
VIN = 5V
VOUT = 2.5V
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
LOAD
CONDITIONS
VIN = 5V
VOUT = 2.5V
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
LOAD
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06903
CONDITIONS
VIN = 3.3V
VOUT = 1.8V
CIN = 1 X 22µF (0805)
COUT = 3 x 22µF (0805)
www.enpirion.com, Page 10
September 12, 2012
Rev: B
EN5339QI
Functional Block Diagram
Figure 4: Functional Block Diagram
Functional Description
Overview
Stability and Compensation
The EN5339QI is a highly integrated synchronous
buck converter with an internal inductor utilizing
advanced CMOS technology to provide high
switching frequency, while also maintaining high
efficiency. The EN5339QI is a high power density
device packaged in a tiny 4x6x1.1mm 24-pin QFN
package. Its high switching frequency allows for the
use of very small MLCC input and output filter
capacitors and results in a total solution size as
small as 55mm2.
The EN5339QI buck converter uses Type III
voltage mode control to provide pin-point output
voltage accuracy, high noise immunity, low output
impedance and excellent load transient response.
The EN5339QI features include Power OK, under
voltage lockout (UVLO), over current protection,
short circuit protection, and thermal overload
protection.
The EN5339QI utilizes an internal compensation
network that is designed to provide stable operation
over a wide range of operating conditions. The
output compensation circuit may be customized to
improve transient performance or reduce output
voltage ripple with dynamic loads.
Soft-Start
The EN5339QI has an internal soft-start circuit that
controls the ramp of the output voltage. The control
circuitry limits the VOUT ramp rate to levels that are
safe for the Power MOSFETs and the integrated
inductor.
The EN5339QI has a constant startup up time
which is independent of the VOUT setting. The
output rising slew rate is proportional to the output
voltage. The startup time is approximately 1.4ms
from when the ENABLE is first pulled high until
VOUT reaches the regulated voltage level.
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September 12, 2012
Rev: B
EN5339QI
Excess bulk capacitance on the output of the
device can cause an over-current condition at
startup. Since the slew rate varies with the output
voltage setting, the maximum capacitance is a
function of the VOUT setting.
The maximum capacitance on the output power
rail, including the output filter capacitors and all
decoupling and bulk capacitors on the supply rail is
given by:
COUT_TOTAL_MAX [µF] = 3.41x103 / VOUT
NOTE: The above number and formula assume a
no load condition at startup.
Over Current/Short Circuit Protection
When an over current condition occurs, VOUT is
pulled low and the device disables switching
internally. This condition is maintained for a period
of 1.2 ms and then a normal soft-start cycle is
initiated. If the over current condition still persists,
this cycle will repeat.
Under Voltage Lockout
An under voltage lockout circuit will hold off
switching during initial power up until the input
voltage reaches sufficient level to ensure proper
operation. If the voltage drops below the UVLO
threshold the lockout circuitry will again disable
switching. Hysteresis is included to prevent
chattering between UVLO high and low states.
Enable
The ENABLE pin provides means to shut down the
converter or initiate normal operation. A logic high
on the ENABLE pin will initiate the converter to start
the soft-start cycle and regulate the output voltage
to the desired value. A logic low will allow the
device to discharge the output and go into
shutdown mode for minimal power consumption.
When the output is discharged, an auxiliary NFET
turns on and limits the discharge current to 300 mA
or below. The ENABLE pin should not be left
floating.
turns off the converter, allowing the device to cool.
When the junction temperature drops 15°C, the
device will be re-enabled and go through a normal
startup process.
Power OK
The Power OK (POK) feature is an open drain
output signal used to indicate if the output voltage
is within 92% of the set value. Within this range, the
POK output is allowed to be pulled high. Outside
this range, the POK output is maintained low.
During transitions such as power up and power
down, the POK output will not change state until the
transition is complete for enhanced noise immunity.
The POK has 1mA sink capability. When POK is
pulled high, the worst case pin leakage current is
as low as 500nA over temperature. This allows a
large pull up resistor such as 100kΩ to be used for
minimal current consumption in shutdown mode.
The POK output can also be conveniently used as
an enable input of the next stage for power
sequencing of multiple converters.
Power-Up/Down Sequencing
During power-up, ENABLE should not be asserted
before PVIN, and PVIN should not be asserted
before AVIN. The PVIN should never be powered
when AVIN is off. During power down, the AVIN
should not be powered down before the PVIN.
Tying PVIN and AVIN or all three pins (AVIN, PVIN,
ENABLE) together during power up or power down
meets these requirements.
Pre-Bias Start-up
The EN5339QI does not support startup into a prebiased condition. Be sure the output capacitors are
not charged or the output of the EN5339QI is not
pre-biased when the EN5339QI is first enabled.
Thermal Shutdown
When excessive power is dissipated in the device,
its junction temperature rises. Once the junction
temperature exceeds the thermal shutdown
temperature of 150°C, the thermal shutdown circuit
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September 12, 2012
Rev: B
EN5339QI
Application Information
Setting the Output Voltage
The EN5339 uses a simple and flexible resistor
divider network to program the output voltage. A
feed-forward capacitor (Ca) is used to improve
transient response. Table 3 shows the
recommended component values for the feedback
network as a function of VOUT. It is recommended
to use 1% or better feedback resistors to ensure
output voltage accuracy. The Ra resistor value is
fixed at 348k as shown in Table 3. Based on that
value, the bottom resistor Rb can be calculated
below as:
Rb =
Ra × 0.6 V
VOUT − 0.6 V
The VOUT is the nominal output voltage. The Rb
and Ra resistors have the same units based on the
above equation.
Low ESR MLCC capacitors with X5R or X7R or
equivalent dielectric should be used for the input
capacitors. Y5V or equivalent dielectrics lose too
much capacitance with frequency, DC bias, and
temperature. Therefore, they are not suitable for
switch-mode DC-DC converter filtering, and must
be avoided.
Table 1: Recommended Input Capacitors
Description
22µF, 10V,
X5R, 0805
MFG
P/N
Taiyo
Yuden
LMK212BBJ226MG-T
Murata
GRM21BR61A226ME
51
Output Filter Capacitor Selection
The EN5339QI output capacitor selection may be
determined based on two configurations. Table 3
provides the recommended output capacitor
configurations based on operating conditions. For
lower output ripple, choose 3 x 22µF for the output
capacitors. For smaller solution size, use two 47µF
output
capacitors.
Table
2
shows
the
recommended type and brand of output capacitors
to use. For details regarding other configurations,
contact Enpirion ([email protected]).
Table 2: Recommended Output Capacitors
Description
MFG
47µF, 6.3V,
X5R, 0805
Figure 5. Typical Application Circuit.
(NOTE: Enable can be separated from PVIN if the
application requires it)
AVIN Filter Capacitor
A 1.0 µF, 10V, 0402 MLCC capacitor should be
placed between AVIN and AGND as close to the
pins as possible. This will provide high frequency
bypass to ensure clean chip supply for optimal
performance.
Input Filter Capacitor Selection
A single 22µF, 0805 MLCC capacitor is needed on
PVIN for all applications. Connect the input
capacitor between PVIN and PGND as close to the
pins as possible. Placement of the input capacitor
is critical to ensure low conducted and radiated
EMI.
22µF, 10V,
X5R, 0805
JMK212BBJ476MG-T
GRM21BR60J476ME15
LMK212BBJ226MG-T
GRM21BR61A226ME51
Table 3. Typical Recommended Components
(Note: Follow Layout Recommendations)
VIN (V)
IOUT
VOUT
COUT
Ra
(kΩ)
Ca
(pF)
0.9V
1V
1.2V
2.5
to
5.5
3A
1.5V
1.8V
2.5
2.85V
3x 22µF
(0805)
Or
10
348
2x 47µF
(0805)
8.2
3.3V
Enpirion 2012 all rights reserved, E&OE
06903
P/N
Taiyo
Yuden
Murata
Taiyo
Yuden
Murata
www.enpirion.com, Page 13
September 12, 2012
Rev: B
EN5339QI
Thermal Considerations
Thermal considerations are important power supply
design facts that cannot be avoided in the real
world. Whenever there are power losses in a
system, the heat that is generated by the power
dissipation needs to be accounted for. The Enpirion
PowerSoC helps alleviate some of those concerns.
The Enpirion EN5339QI DC-DC converter is
packaged in a 4x6x1.1mm 24-pin QFN package.
The QFN package is constructed with exposed
thermal pads on the bottom of the package. The
exposed thermal pad should be soldered directly on
to a copper ground pad on the printed circuit board
(PCB) to act as a heat sink. The recommended
maximum junction temperature for continuous
operation is 125°C. Continuous operation above
125°C may reduce long-term reliability. The device
has a thermal overload protection circuit designed
to turn off the device at an approximate junction
temperature value of 150°C.
The EN5339QI is guaranteed to support the full 3A
output current up to 85°C ambient temperature.
The following example and calculations illustrate
the thermal performance of the EN5339QI.
Example:
For VIN = 5V, VOUT = 3.3V at 3A, η ≈ 90%
η = POUT / PIN = 90% = 0.90
PIN = POUT / η
PIN ≈ 9.9W / 0.9 ≈ 11W
The power dissipation (PD) is the power loss in the
system and can be calculated by subtracting the
output power from the input power.
PD = PIN – POUT
≈ 11W – 9.9W ≈ 1.1W
With the power dissipation known, the temperature
rise in the device may be estimated based on the
theta JA value (θJA). The θJA parameter estimates
how much the temperature will rise in the device for
every watt of power dissipation. The EN5339QI has
a θJA value of 36 ºC/W without airflow.
Determine the change in die temperature (∆T)
based on PD and θJA.
∆T = PD x θJA
∆T ≈ 1.1W x 36°C/W = 39.6°C ≈ 40°C
VOUT = 3.3V
The junction temperature (TJ) of the device is
approximately the ambient temperature (TA) plus
the change in temperature. We assume the initial
ambient temperature to be 25°C.
IOUT = 3A
TJ = TA + ∆T
First calculate the output power.
TJ ≈ 25°C + 40°C ≈ 65°C
POUT = 3.3V x 3A = 9.9W
The maximum operating junction temperature
(TJMAX) of the device is 125°C, so the device can
operate at a higher ambient temperature. The
maximum ambient temperature (TAMAX) allowed can
be calculated.
VIN = 5V
Next, determine the input power based on the
efficiency (η) shown in Figure 6.
100
90
TAMAX = TJMAX – PD x θJA
EFFICIENCY (%)
80
70
≈ 125°C – 40°C ≈ 85°C
~90%
60
50
40
30
20
CONDITIONS
VIN = 5V
VOUT = 3.3V
10
0
0
0.5
1
1.5
2
2.5
3
The ambient temperature can actually rise by
another 60°C, bringing it to 85°C before the device
will reach TJMAX. This indicates that the EN5339QI
can support the full 3A output current range up to
approximately 85°C ambient temperature given the
input and output voltage conditions. Note that the
efficiency will be slightly lower at higher
temperatures and these calculations are estimates.
OUTPUT CURRENT (A)
Figure 6: Efficiency vs. Output Current
Enpirion 2012 all rights reserved, E&OE
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www.enpirion.com, Page 14
September 12, 2012
Rev: B
EN5339QI
Engineering Schematic
Figure 7. Engineering Schematic with Critical Components
Enpirion 2012 all rights reserved, E&OE
06903
www.enpirion.com, Page 15
September 12, 2012
Rev: B
EN5339QI
Layout Recommendations
Figure 8. Optimized Layout Recommendations
Recommendation 1: Input and output filter
capacitors should be placed on the same side of
the PCB, and as close to the EN5339QI package
as possible. They should be connected to the
device with very short and wide traces. Do not use
thermal reliefs or spokes when connecting the
capacitor pads to the respective nodes. The +V and
GND traces between the capacitors and the
EN5339QI should be as close to each other as
possible so that the gap between the two nodes is
minimized, even under the capacitors.
Recommendation 2: The system ground plane
should be the first layer immediately below the
surface layer. This ground plane should be
continuous and un-interrupted below the converter
and the input/output capacitors.
Recommendation 3: The thermal pad underneath
the component must be connected to the system
ground plane through as many vias as possible.
The drill diameter of the vias should be 0.33mm,
and the vias must have at least 1 oz. copper plating
on the inside wall, making the finished hole size
around 0.20-0.26mm. Do not use thermal reliefs or
spokes to connect the vias to the ground plane.
This connection provides the path for heat
dissipation from the converter.
Recommendation 4: Multiple small vias (the same
size as the thermal vias discussed in
recommendation 3) should be used to connect
ground terminal of the input capacitor and output
capacitors to the system ground plane. It is
preferred to put these vias along the edge of the
GND copper closest to the +V copper. These vias
connect the input/output filter capacitors to the
GND plane, and help reduce parasitic inductances
in the input and output current loops.
Recommendation 5: AVIN is the power supply for
the small-signal control circuits. It should be
connected to the input voltage at a quiet point. In
Figure 8 this connection is made at the input
capacitor. Connect a 1µF capacitor from the AVIN
pin to AGND.
Recommendation 6: The layer 1 metal under the
device must not be more than shown in Figure 8.
See the section regarding exposed metal on bottom
of package. As with any switch-mode DC/DC
converter, try not to run sensitive signal or control
lines underneath the converter package on other
layers.
Recommendation 7: The VOUT sense point should
be just after the last output filter capacitor. Keep the
sense trace short in order to avoid noise coupling
into the node.
Recommendation 8: Keep RA, CA, RB close to the
VFB pin (See Figures 6). The VFB pin is a highimpedance, sensitive node. Keep the trace to this
pin as short as possible. Whenever possible,
connect RB directly to the AGND pin instead of
going through the GND plane.
Recommendation 13: Enpirion provides schematic
and layout reviews for all customer designs. Please
contact local sales representatives for references to
Enpirion
Applications
Engineering
support
([email protected]).
Enpirion 2012 all rights reserved, E&OE
06903
www.enpirion.com, Page 16
September 12, 2012
Rev: B
EN5339QI
Design Considerations for Lead-Frame Based Modules
Exposed Metal Pads on Package Bottom
QFN lead-frame based package technology utilizes exposed metal pads on the bottom of the package that
provide improved thermal dissipation, lower package thermal resistance, smaller package footprint and
thickness, larger lead size and pitch, and excellent lead co-planarity. As the EN5339 package is a fully
integrated module consisting of multiple internal devices, the lead-frame provides circuit interconnection and
mechanical support of these devices result
resulting
ing in multiple exposed metal pads on the package bottom.
Only the two large thermal pads and the perimeter leads are to be mechanically/electrically connected to the
PCB through a SMT soldering process. All other exposed metal is to remain free of any interconnection to the
PCB. Figure 9 shows the recommended PCB metal layout for the EN5339 package. A GND pad with a solder
mask "bridge" to separate into two pads and 24 signal pads are to be used to match the metal on the package.
The PCB should be clear of any other metal, including trace
traces,
s, vias, etc., under the package to avoid electrical
shorting.
The Solder Stencil Aperture should be smaller than the PCB ground pad. This will prevent excess solder from
causing bridging between adjacent pins or other exposed metal under the package. Please consult the
Enpirion Manufacturing Application Note for more details and recommendations.
Figure 9. Recommended Footprint for PCB (Top View)
Note: Grey area highlights exposed metal that is not to be mechanically or electrically connected to the PCB.
Enpirion 2012 all rights reserved, E&OE
06903
www
ww.enpirion.com, Page 17
September 12, 2012
Rev: B
EN5339QI
Recommended PCB Footprint
Figure 10. Recommended PCB Footprint (Top View)
Enpirion 2012 all rights reserved, E&OE
06903
www.enpirion.com, Page 18
September 12, 2012
Rev: B
EN5339QI
Package Mechanical
Figure 11. EN5339QI Package Dimensions (Bottom View)
Packing and Marking Information: http://www.enpirion.com/resource-center-packing-and-marking-information.htm
Contact Information
Enpirion, Inc.
Perryville III Corporate Park
53 Frontage Road, Suite 210
Hampton, NJ 08827
USA
Phone: 908-894-6000
Fax: 908-894-6090
Enpirion reserves the right to make changes in circuit design and/or specifications at any time without notice. Information furnished by Enpirion is
believed to be accurate and reliable. Enpirion assumes no responsibility for its use or for infringement of patents or other third party rights, which may
result from its use. Enpirion products are not authorized for use in nuclear control systems, as critical components in life support systems or equipment
used in hazardous environment without the express written authority from Enpirion.
Enpirion 2012 all rights reserved, E&OE
06903
www.enpirion.com, Page 19
September 12, 2012
Rev: B