ENPIRION EP53F8QI

EP53F8QI
1500 mA Synchronous Buck PWM
DC-DC Converter with Integrated Inductor
RoHS Compliant; Halogen Free
Description
Application
The EP53F8QI provides high efficiency in a very
small footprint. Featuring integrated inductor, the
device delivers up to 1500mA of continuous
output current. Total solution footprint can be as
little as 40mm2.
•
Wireless wide area networking data cards.
•
Replacement of inefficient LDOs
•
Noise Sensitive Applications such as RF,
Audio and Video, and high speed IO
Output voltage is programmed via an external
resistor divider providing a wide range of
flexibility while maintaining a very small footprint.
•
Computing, Computer Peripherals, Storage,
Networking, and Instrumentation
•
USB, DSL, STB, DVR, DTV, and iPC
Integration of the inductor reduces conducted
and
radiated
noise
providing
excellent
compatibility with sensitive RF and high speed
data applications.
Features
Integrated Inductor Technology
•
Total Solution Footprint as Small as 40 mm2
•
3 mm x 3 mm x 1.1 mm QFN Package
•
Solution Power Density up to 140mW/mm2
•
1500 mA Continuous Output Current
•
High Efficiency, up to 94 %
•
Low Ripple Voltage; 8 mVP-P Typical
•
Power OK Signal with 5 mA Sink Capability
•
2.4V to 5.5V Input Voltage Range
•
Fast Transient Response
•
4 MHz Fixed Switching Frequency
•
Low Dropout Operation: 100 % Duty Cycle
•
Under Voltage Lockout, Over Current, Short
Circuit, and Thermal Protection
•
Figure 1: Typical Application Circuit
Product Performance
95
85
75
Efficiency (%)
•
65
55
45
35
25
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5
Load Current (A)
RoHS Compliant; MSL 3 260 °C Reflow
Figure 2: Efficiency, VIN=5V, VOUT=3.7V
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01542
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Rev:A
EP53F8QI
Ordering Information
Pin Assignments (Top View)
Temp Rating
Package
(°C)
-40 to +85
16-pin QFN T&R
QFN Evaluation Board
Part Number
EP53F8QI-T
EP53F8QI-E
Figure 3: Pin Diagram (Top View)
Pin Description
PIN
NAME
FUNCTION
1,
15,16
NC(SW)
No Connect. These pins are internally connected to the common drain output of the internal
MOSFETs. NC(SW) pins are not to be electrically connected 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.
2-3,
PGND
Input/Output Power Ground. Connect these pins to the ground electrode of the input and
output filter capacitors. Refer to Layout Considerations section for details.
4
AVIN2
Analog input voltage. Connect to AVIN1 only.
5
VFB
Feedback Pin for External Voltage Divider Network. Connect a resistor divider to this pin to
set the output voltage. Use 100 kΩ, 1% or better for the upper resistor.
6
NC
No Connect.
7,8
VOUT
Voltage and Power Output. Connect these pins to output capacitor(s).
9
AGND
Analog Ground for the Controller Circuits
10
AVIN1
Analog Voltage Input for the Controller Circuits. Connect this pin to PVIN with a 10Ω
resistor. Connect a 1 uF capacitor between this pin and AGND. Connect AVIN2 to this pin.
11
POK
12
ENABLE
13-14
PVIN
Power OK with an Open Drain Outp t. Refer to Power OK section.
Input Enable. A logic high signal 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 supply. Decouple with input capacitor(s) to PGND.
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EP53F8QI
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
cause permanent damage to the device. Exposure to absolute maximum rated conditions for
extended periods may affect device reliability.
Absolute Maximum Electrical Ratings
MIN
MAX
Voltages on: PVIN, AVIN, VOUT
-0.3 V
6.5 V
Voltages on: ENABLE, POK
-0.3 V
VIN
Voltage on: VFB
-0.3 V
2.7 V
ESD Rating (Human Body Model)
2 kV
ESD Rating (Charge Device Model)
500 V
Absolute Maximum Thermal Ratings
MIN
MAX
Ambient Operating Range
-40 °C
+85 °C
Storage Temperature Range
-65 °C
+150 °C
Reflow Peak Body Temperature MSL3 (10 s)
+260 °C
Recommended Operating Conditions
PARAMETER
SYMBOL
MIN
MAX
VIN
2.4
5.5
Input Voltage Range
†
UNITS
V
†
Output Voltage Range
VOUT
0.6
VIN - VDROPOUT
V
Output Current
ILOAD
0
1500
mA
Operating Junction Temperature
TJ
-40
+125
°C
Operating Ambient Temperature
TA
-40
+85
°C
VDROPOUT is defined as (ILOAD x Dropout Resistance) including temperature effect
Thermal Characteristics
PARAMETER
SYMBOL
Thermal Shutdown (Junction Temperature)
Thermal Shutdown Hysteresis
Thermal Resistance: Junction to Ambient (0 LFM)
††
TYP
MAX
UNITS
TSD
155
°C
TSDH
15
°C
θJA
55
°C/W
Based on a 2 oz. copper board and proper thermal design in line with JEDEC EIJ/JESD51 standards
©Enpirion 2009 all rights reserved, E&OE
01542
††
MIN
3
4/3/2009
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EP53F8QI
Electrical Characteristics
Typical values for VIN = 5V and TA =25°C, unless otherwise noted.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
UNITS
5.5
V
Operating Input Voltage
VIN
Under Voltage Lockout
VUVLO
VIN going low to high
2.2
V
Under Voltage Lockout
VUVLO
VIN going high to low
2.1
V
VFB
TA = 25 °C; VIN = 5V
ILOAD = 100 mA
VFB Voltage Initial
Accuracy
2.4
MAX
0.588
0.600
0.612
V
Line Regulation
2.4 V ≤ VIN ≤ 5.5V
0.0031
%/V
Load Regulation
ILOAD = 0 to 1.5A
0.420
%/A
Temperature Variation
-40°C ≤ TA ≤ +85°C
0.0012
%/°C
Soft Start Slew Rate
0.975
VFB, ENABLE, Pin Input
Current (Note 1)
1.5
2.025
V/ms
-40°C ≤ TA ≤ +85°C
-40
+40
nA
ENABLE Voltage
Threshold
Logic Low
0.0
0.4
V
Logic High
1.4
VIN
V
POK Upper Threshold
VOUT Rising
111
%
POK Upper Threshold
VOUT Falling
102
%
POK Lower Threshold
VOUT Rising;
percent of VOUT Nominal
92
%
POK Lower Threshold
VOUT Falling;
percent of VOUT Nominal
90
%
POK Low Voltage
ISINK = 5 mA, -40°C ≤ TA ≤ +85°C
POK Pin VOH Leakage
Current
POK High, -40°C ≤ TA ≤ +85°C
Shutdown Current
ENABLE Low
Current Limit Threshold
2.4 V ≤ VIN ≤ 5.5 V,
-40°C ≤ TA ≤ +85°C
2.0
Dropout Resistance
Operating Frequency
0.15
V
500
nA
14
μA
3.2
A
250
FOSC
0.4
4
360
mΩ
MHz
Note 1: VFB, ENABLE pin input current specification is guaranteed by design.
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EP53F8QI
95
95
85
85
75
75
Efficiency (%)
Efficiency (%)
Typical Performance Characteristics†††
65
55
65
55
45
45
35
35
25
25
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
Load Current (A)
Load Current (A)
Efficiency vs. Load Current: VIN = 5.0V, VOUT (from
top to bottom) = 3.7, 2.5V, 1.8V, 1.2V
Efficiency vs. Load Current: VIN = 3.3V, VOUT (from
top to bottom) = 2.5V, 1.8V, 1.2V
20 MHz BW limit
500 MHz BW
Output Ripple: VIN = 5V, VOUT = 3.7V, ILOAD = 900mA
Output Ripple: VIN = 5V, VOUT = 3.7V, ILOAD = 900mA
20 MHz BW limit
500 MHz BW
Output Ripple: VIN = 3.3V, VOUT = 1.8V, ILOAD = 900mA
Output Ripple: VIN = 3.3V, VOUT = 1.8V, ILOAD = 900mA
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EP53F8QI
Transient Response: VIN = 3.3V, VOUT = 1.8V
Load Step 0 to 1.5A
Transient Response: VIN = 5.0V, VOUT = 1.2V
Load Step 0 to 1.5A
ENABLE
ENABLE
VOUT
VOUT
POK
POK
Startup and Shutdown Waveform
VIN = 5.0V, VOUT = 3.7V, ILOAD = 0mA
Startup and Shutdown Waveform
VIN = 5.0V, VOUT = 3.7V, ILOAD = 900mA
†††
Application Circuit in Figure 1 used for
typical performance characteristics.
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EP53F8QI
Functional Block Diagram
PVIN
POK
UVLO
POK
Thermal Limit
Current Limit
ENABLE
NC (SW)
Soft Start
P-Drive
(-)
Logic
VOUT
PWM
Comp
(+)
N-Drive
PGND
Sawtooth
Generator
Compensation
Network
(-)
VFB
Error
Amp
(+)
DAC
VREF
BIAS
Package Boundary
AVIN
Figure 4: Functional Block Diagram
Functional Description
The EP53F8QI leverages advanced CMOS
technology
to
provide
high
switching
frequency, while also maintaining high
efficiency.
it is within ±10% of nominal. Protection
features include under voltage lockout (UVLO),
over current protection, short circuit protection,
and thermal overload protection.
Packaged in a 3 mm x 3 mm x 1.1 mm QFN,
the EP53F8QI provides a high degree of
flexibility in circuit design while maintaining a
very small footprint. High switching frequency
allows for the use of very small MLCC input
and output filter capacitors.
Stability over Wide Range of Operating
Conditions
The converter uses voltage mode control to
provide high noise immunity, low output
impedance and excellent load transient
response. Most compensation components are
integrated into the device, requiring only a
single external compensation capacitor.
Output voltage is programmed via an external
resistor divider.
Output voltage can be
programmed from 0.6V to VIN-VDROPOUT.
POK monitors the output voltage and signals if
©Enpirion 2009 all rights reserved, E&OE
01542
The
EP53F8QI
utilizes
an
internal
compensation network and is designed to
provide stable operation over a wide range of
operating conditions. To improve transient
performance or reduce output voltage ripple
with dynamic loads you have the option to add
supplementary capacitance to the output. The
EP53F8QI is stable with up to 60 µF of output
capacitance without compensation adjustment.
Additional output capacitance above 60 µF can
be
accommodated
with
compensation
adjustment depending on the application. The
high switching frequency allows for a wide
control loop bandwidth.
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EP53F8QI
Soft Start
The internal soft start circuit limits inrush
current when the device starts up from a power
down condition or when the ENABLE pin is
asserted “high”. Digital control circuitry sets the
VOUT ramp rate to minimize input voltage ripple
and inrush current to ensure a glitch-free start
up. The soft start ramp rate can be found in the
electrical characteristics table.
Over Current/Short Circuit Protection
When an over current condition occurs, VOUT is
pulled low. 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.
shutdown junction temperature and hysteresis
can be found in the thermal characteristics
table
Power OK
The EP53F8QI provides an open drain output
to indicate if the output voltage stays within
92% to 111% of the set value. Within this
range, the POK output is allowed to be pulled
high. Outside this range, POK remains low.
However, during transitions such as power up,
power down, and dynamic voltage scaling, the
POK output will not change state until the
transition is complete for enhanced noise
immunity.
The POK has 5 mA sink capability for events
where it needs to feed a digital controller with
standard CMOS inputs. When POK is pulled
high, the pin leakage current is as low as 500
nA maximum over temperature. This allows a
large pull up resistor such as 100 kΩ 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.
Enable
The ENABLE pin provides means to shut down
the converter or initiate normal operation. A
logic high will enable the converter to go
through 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 must not be left floating.
Thermal Shutdown
When excessive power is dissipated in the
device, its junction temperature rises. Once the
junction temperature exceeds the thermal
shutdown temperature, the thermal shutdown
circuit turns off the converter, allowing the
device to cool. When the junction temperature
decreases to a safe operating level, the device
will be re-enabled and go through a normal
startup process.
The specific thermal
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EP53F8QI
Application Information
Setting the Output Voltage
AVIN Decoupling
AVIN should be connected to PVIN using a
10Ω resistor. An 0402 or smaller case size is
recommended for this resistor. A 1 µF, 10 V,
0402 MLC capacitor should be connected from
AVIN to AGND to provide high frequency
decoupling for the control circuitry supply for
optimal performance.
POK Pull Up Resistor Selection
Figure 5: Typical Application Circuit
The EP53F8QI uses a simple resistor divider to
program the output voltage.
Referring to Figure 5, use 237 kΩ, 1% or better
for the upper resistor (Ra). The value of the
bottom resistor (Rb) in kΩ is given as:
Rb =
142.2
kΩ
VOUT − 0.6
Where VOUT is the output voltage. Rb should
also be a 1% or better resistor.
A 5.0pF MLCC capacitor is required in parallel
with Ra for compensation.
If the POK signal is required for the application.
The POK pin must be pulled up through a
resistor to any voltage source that can be as
high as VIN. The simplest way is to connect
POK to the power input of the converter
through a resistor. A 100 kΩ pull up resistor is
recommended for most applications for
minimal current drain from the voltage source
and good noise immunity. POK can sink up to
5mA.
Layout Recommendation
Please refer to the EP53F8QI product page at
www.enpirion.com for the most current device
layout recommendation, Gerber files, and other
manufacturing guidelines.
Input and Output Capacitor Selection
Low ESR MLC capacitors with X5R or X7R or
equivalent dielectric should be used for input
and output capacitors. Y5V or equivalent
dielectrics lose too much capacitance with
frequency, DC bias, and temperature.
Therefore, they are not suitable for switchmode DC-DC converter filtering, and must be
avoided.
The input filter capacitor requirement is a 10
µF, 10V 0805 MLCC capacitor in parallel with a
680pF MLCC capacitor. The 680pF capacitor
provides additional high frequency decoupling
and is manditory. The 680pF capacitor must
be placed closest to the EP53F8QI as shown
in Figure 5.
The output filter capacitor requirement is a
22 µF, 6.3V, 0805 MLCC for most applications.
The output ripple can be reduced by using 2 x
22 µF, 6.3V, 0805 MLC capacitors.
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EP53F8QI
Recommended PCB Footprint
Figure 6: EP53F8QI Package PCB Footprint
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Rev:A
EP53F8QI
Package and Mechanical
Figure 7: EP53F8QI Package Dimensions
Contact Information
Enpirion, Inc.
685 Route 202/206
Suite 305
Bridgewater, NJ 08807
Phone: 908-575-7550
Fax: 908-575-0775
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.
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