EP5348UI - Enpirion - Product.Network

05721 6/15/2011 Rev: B

EP5348UI

400mA Synchronous Buck Regulator

with Integrated Inductor

RoHS Compliant; Halogen Free

www.enpirion.com

Description

The EP5348UI delivers the optimal trade-off

between footprint and efficiency. It is a perfect

alternative to replace less efficient LDOs in space

constrained applications that require improved

efficiency.

The EP5348UI is a 400mA PowerSoC which

integrates MOSFET switches, control,

compensation, and the magnetics in a micro-

QFN Package. This highly integrated DCDC

solution offers up to 46-points better efficiency

than the comparable LDO. A significant

reduction in power loss and improved thermals

are achieved. It enables extended battery life

and helps Meet Energy Star requirements.

Integrated magnetics enables a tiny solution

footprint, low output ripple, and high reliability,

while maintaining high efficiency. The complete

solution size is similar to an LDO and much

smaller than a comparable DCDC.

Features

• Integrated Inductor Technology

• 400mA continuous output current

• 2.0mm x 1.75mm x 0.9mm uQFN package

• Small Solution Footprint

• Efficiency, up to 90%

• V

OUT Range 0.6V to VIN – VDROP_OUT

• Short circuit and over current protection

• UVLO and thermal protection

• IC level reliability in a PowerSoC solution

Applications

• Applications where poor LDO efficiency

creates:

o Thermal challenges

o Battery Life challenges

o Failure to meet Energy Star

requirements

• Space-constrained applications

• Portable media players and USB peripherals

Figure 1: Typical Application Schematic

0.0 0.1 0.2 0.3

Efficiency (%)

Load Current (A)

EP5348UI

LDO

Δ = 46-points

VIN = 5.0V

VOUT = 1.2V

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EP5348UI

Ordering Information

Part Number Package

EP5348UI 14-pin μQFN T&R

EP5348UI-E EP5348UI Evaluation Board

Pin Assignments (Top View)

PVIN

AVIN

ENABLE

VOUT

NC(SW)

EP5348UI

14 13

NC(SW)

PGND

VFB

AGND

Figure 2: EP5348UI Pin Out Diagram (Top View)

Pin Description

PIN NAME FUNCTION

1, 13,

14 NC(SW)

NO CONNECT – These pins are internally connected to the common switching node 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 to the device.

2 PGND

Power ground. Connect this pin to the ground electrode of the Input and output filter

capacitors.

3, 8, 9 NC

NO CONNECT: These pins may already be connected inside the device. Therefore, they

cannot be electrically connected to each other or to any external signal, voltage, or ground.

They must however be soldered to the PCB. Failure to follow this guideline may result in

device damage.

4 VFB Feedback pin for external voltage divider network.

5 AGND

Analog ground. This is the quiet ground for the internal control circuitry, and the ground

return for external feedback voltage divider

6, 7 VOUT Regulated Output Voltage. Refer to application section for proper layout and decoupling.

10 ENABLE Output Enable. Enable = logic high; Disable = logic low

11 AVIN Input power supply for the controller circuitry. Connect to VIN at a quiet point.

12 PVIN Input Voltage for the MOSFET switches.

05721 6/15/2011 Rev: B

EP5348UI

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.

PARAMETER SYMBOL MIN MAX UNITS

Absolute Maximum Electrical Ratings

Supply Voltage – PVIN, AVIN, VOUT VIN -0.3 6.0 V

Voltage on ENABLE -0.3 VIN+ 0.3 V

Voltage on VFB -0.3 2.7 V

ESD Rating (based on Human Body Mode) 2000 V

ESD Rating (Charge Device Model) 500 V

Absolute Maximum Thermal Ratings

Maximum Operating Junction Temperature TJ-ABS 150 °C

Storage Temperature Range TSTG -65 150 °C

Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020C 260 °C

Recommended Operating Conditions

PARAMETER SYMBOL MIN MAX UNITS

Input Voltage Range VIN 2.5 5.5 V

Output Voltage Range VOUT 0.6 VIN-VDO

†V

Operating Ambient Temperature TA -40 +85 °C

Operating Junction Temperature TJ -40 +125 °C

† VDO (drop-out voltage) is defined as (ILOAD x Dropout Resistance). Please see the EC Table.

Thermal Characteristics

PARAMETER SYMBOL TYP UNITS

Thermal Shutdown Trip Point TJ-TP +155 °C

Thermal Shutdown Trip Point Hysteresis 15 °C

Thermal Resistance: Junction to Ambient –0 LFM (Note 1) θJA 105 °C/W

Note 1: Based on 2 oz. external copper layers and proper thermal design in line with

EIA/JEDEC JESD51-7 standard for high effective thermal conductivity boards.

05721 6/15/2011 Rev: B

EP5348UI

Electrical Characteristics

NOTE: TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C, VIN = 3.6V.

CIN = 2.2µF 0603 MLCC, COUT = 10µF 0603.

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Operating Input Voltage

Range VIN 2.5 5.5 V

Under Voltage Lock-out –

VIN Rising VUVLO_R 2.3 V

Under Voltage Lock-out –

VIN Falling VUVLO_F 2.2 V

Shut-down Supply Current ISD Enable = Low 3 µA

VFB Voltage Initial

Accuracy VFB

TA = 25°C, VIN = 3.6V;

ILOAD = 100mA ;

0.8V ≤ VOUT ≤ 3.3V

0.588 0.600 0.612 V

Line Regulation ΔVOUT_LINE 2.5V ≤ VIN ≤ 5.5V 0.03 %/V

Load Regulation ΔVOUT_LOAD 0A ≤ ILOAD ≤ 400Ma 0.48 %/A

Temperature Variation ΔVOUT_TEMPL -40°C ≤ TA ≤ +85°C 24

ppm/°C

Feedback Pin Input

Current IFB Note 1 <300 nA

Output Current IOUT 0 400 mA

OCP Threshold ILIM 2.5V ≤ VIN ≤ 5.5V

0.6V ≤ VOUT ≤ 3.3V 1.4 A

Output Dropout

Resistance (Note 1)

Voltage (Note 1,2)

RDO

VDO_FL

Input to Output Resistance

VINMIN - VOUT at Full load

520

208

780

312

mΩ

Operating Output Voltage

Range VOUT V

DO = IOUT * RDO 0.6

VIN-VDO V

Enable Pin Logic Low VENLO 0.3 V

Enable Pin Logic High VENHI 1.4 V

Enable Pin Current IENABLE Note 1 <200 nA

Operating Frequency FOSC 9 MHz

Soft Start Operation

VOUT Rise Time TRISE From 0 to full output voltage 1.17 1.8 2.43 mSec

Notes: 1 - Parameter guaranteed by design

2 - VDO_FL (full-load drop-out voltage) is defined as (Maximum IOUT x Dropout Resistance)

05721 6/15/2011 Rev: B

EP5348UI

Typical Performance Characteristics

Efficiency vs. Load Current: VIN = 3.3V, VOUT (from

top to bottom) = 2.5, 1.8, 1.2V

Efficiency vs. Load Current: VIN = 5.0V, VOUT (from

top to bottom) = 3.3, 2.5, 1.8, 1.2V

Output Ripple: VIN = 3.3V, VOUT = 1.0V, Iout = 400mA

CIN = 2.2μF/0603, COUT = 10μF/0603 + 2.2uF/0603

Output Ripple: VIN = 3.3V, VOUT = 1.0V, Iout = 400mA

CIN = 2.2μF/0603, COUT = 10μF/0603 + 2.2uF/0603

Output Ripple: VIN = 5V, VOUT = 1.0V, Iout = 400mA

CIN = 2.2μF/0603, COUT = 10μF/0603 + 2.2uF/0603

Output Ripple: VIN = 5V, VOUT = 1.0V, Iout = 400mA

CIN = 2.2μF/0603, COUT = 10μF/0603 + 2.2uF/0603

0.00.10.20.30.4

Efficiency (%)

Load Current (A)

VIN = 3.3V

VOUT=2.5

VOUT=1.8

VOUT=1.2

Top to Bottom :

0.00.10.20.30.4

Efficiency (%)

Load Current (A)

VIN = 5.0V

VOUT=3.3V

VOUT=2.5V

VOUT=1.8V

VOUT=1.2V

Top to Bottom :

20 MHz BW limit 500 MHz B

05721 6/15/2011 Rev: B

EP5348UI

Load Transient: VIN = 3.3V, VOUT = 1.0V

Ch.1: VOUT, Ch.2: ILOAD 0↔400mA

CIN = 2.2μF/0603, COUT = 10μF/0603 + 2.2uF/0603

Load Transient: VIN = 5V, VOUT = 1.0V

Ch.1: VOUT, Ch.2: ILOAD 0↔400mA

CIN = 2.2μF/0603, COUT = 10μF/0603 + 2.2uF/0603

Power Up/Down at No Load: VIN/VOUT = 5.0V/1.2V,

Cout ≈ 10µF, Ch.1: ENABLE, Ch. 2: VOUT, Ch.4: IOUT

Power Up/Down into 3Ω load: VIN/VOUT = 5.5V/3.3V,

Cout ≈ 10µF, Ch.1: ENABLE, Ch. 2: VOUT, Ch.4: IOUT

05721 6/15/2011 Rev: B

EP5348UI

Detailed Description

Functional Overview

The EP5348UI requires only 2 small MLCC

capacitors and a few small-signal components

for a complete DC-DC converter solution. The

device integrates MOSFET switches, PWM

controller, Gate-drive, part of the loop

compensation, and inductor into a tiny 2.0mm x

1.75mm x 0.9mm micro-QFN package.

Advanced package design, along with the high

level of integration, provides very low output

ripple and noise. The EP5348UI uses voltage

mode control for high noise immunity and load

matching to advanced ≤90nm loads. An

external resistor divider is used to program

output setting over the 0.6V to VIN-VDROPOUT as

specified in the Electrical Characteristics Table.

The EP5348UI provides the industry’s highest

power density of any 400mA DC-DC converter

solution.

The key enabler of this revolutionary

integration is Enpirion’s proprietary power

MOSFET technology. The advanced MOSFET

switches are implemented in deep-submicron

CMOS to supply very low switching loss at high

switching frequencies and to allow a high level

of integration. The semiconductor process

allows seamless integration of all switching,

control, and compensation circuitry.

The proprietary magnetics design provides

high-density/high-value magnetics in a very

small footprint. Enpirion magnetics are

carefully matched to the control and

compensation circuitry yielding an optimal

solution with assured performance over the

entire operating range.

Protection features include under-voltage lock-

out (UVLO), over-current protection (OCP),

short circuit protection, and thermal overload

protection.

Integrated Inductor

The EP5348UI utilizes a proprietary low loss

integrated inductor. The integration of the

inductor greatly simplifies the power supply

design process. The inherent shielding and

compact construction of the integrated inductor

reduces the noise that can couple into the

traces of the printed circuit board. Further, the

package layout is optimized to reduce the

electrical path length for the high di/dT currents

that are always present in DC-DC converters.

The integrated inductor provides the optimal

solution to the complexity, output ripple, and

noise that plague low power DC-DC converter

design.

Control Matched to sub 90nm Loads

The EP5348UI utilizes a type III compensation

network. Voltage mode control is inherently

impedance matched to the sub 90nm process

technology that is used in today’s advanced

ICs. Voltage mode control also provides a high

degree of noise immunity at light load currents

so that low ripple and high accuracy are

maintained over the entire load range. The

very high switching frequency allows for a very

wide control loop bandwidth and hence

excellent transient performance.

Soft Start

Internal soft start circuits limit the rate of output

voltage rise when the device starts up from a

power down condition, or when the “ENABLE”

pin is asserted “high”. Digital control circuitry

controls the VOUT rise time to ensure a smooth

turn-on ramp.

The EP5348UI has a fixed VOUT turn-on time.

Therefore, the ramp rate will vary with the

output voltage setting. Output voltage rise time

is given in the Electrical Characteristics Table.

Excess bulk capacitance on the output of the

device can cause an over-current condition at

startup. The maximum total capacitance on

the output, including the output filter capacitor,

and bulk and decoupling capacitance at the

load, is given as:

COUT_TOTAL_MAX = 9.333 x 10-4 / VOUT

The nominal value for the output filter capacitor

is 10uF. See the applications section for more

details.

Over Current/Short Circuit Protection

The current limit function is achieved by

sensing the current flowing through a sense P-

05721 6/15/2011 Rev: B

EP5348UI

MOSFET which is compared to a reference

current. When this level is exceeded the P-

FET is turned off and the N-FET is turned on,

pulling VOUT low. This condition is maintained

for approximately 0.5mS and then a normal

soft start is initiated. If the over current

condition still persists, this cycle will repeat.

Under Voltage Lockout

During initial power up an under voltage

lockout circuit will hold-off the switching

circuitry until the input voltage reaches a

sufficient level to ensure proper operation. If

the voltage drops below the UVLO threshold,

the lockout circuitry will disable the switching.

Hysteresis is included to prevent chattering

between states.

Enable

The ENABLE pin provides a means to shut

down the converter or enable normal

operation. A logic low will disable the

converter and cause it to shut down. A logic

high will enable the converter into normal

operation.

NOTE: The ENABLE pin must not be left

floating.

Thermal Shutdown

When excessive power is dissipated in the

chip, the junction temperature rises. Once the

junction temperature exceeds the thermal

shutdown threshold, the thermal shutdown

circuit turns off the converter output voltage

thus allowing the device to cool. When the

junction temperature decreases by 15C°, the

device will go through the normal startup

process.

Application Information

Output Voltage Programming

Figure 3: Typical Application Circuit

The EP5348UI uses a simple resistor divider to

program the output voltage.

Referring to Figure 3, use 200 kΩ, 1% or better

for the upper resistor (RA). The value of the

bottom resistor (RB) in kΩ is given as:

nominal6.0

)( *VVFB

VFBV RVFB

OUT

−

A 5pF MLCC capacitor CA is also required in

parallel with RA for compensation.

Input Filter Capacitor

CIN_MIN = 2.2µF 0603 case size or larger.

The input capacitor must use a X5R or X7R or

equivalent dielectric formulation. Y5V or

equivalent dielectric formulations lose

capacitance with frequency, bias, and with

temperature, and are not suitable for switch-

mode DC-DC converter input filter applications.

Output Filter Capacitor

COUT_MIN = 10uF 0603 + 2.2uF 0603 MLCC

when 4.5V ≤ VIN ≤ 5.5V, AND IOUT > 300mA.

COUT_MIN = 10uF 0603 MLCC for all other use

cases. However, ripple performance can

always be improved by adding a second 2.2uF

or 1uF output capacitor for any operating

condition.

VOUT has to be sensed at the last output filter

capacitor next to the EP5348UI. Any additional

bulk capacitance for load decoupling and

byass has to be far enough from the VOUT

05721 6/15/2011 Rev: B

EP5348UI

sensing point so that it does not interfere with

the control loop operation. Excess total

capacitance on the output (Output Filter + Bulk)

can cause an over-current condition at startup.

Please see the Soft Start section under

Functional Overview for the maximum

allowable bulk capacitance on the output rail.

The output capacitor must use a X5R or X7R

or equivalent dielectric formulation. Y5V or

equivalent dielectric formulations lose

capacitance with frequency, bias, and

temperature and are not suitable for switch-

mode DC-DC converter output filter

applications.

LDO Replacement

The Enpirion EP5348UI is a suitable

replacement for inefficient LDOs and can be

used to augment the LDOs in a PMU with

minimum footprint impact. This integrated

DCDC solution offers significantly better

efficiency, and significant reduction in power

loss. The resulting improved thermals and

extended battery life helps meet Energy Star

requirements. The total solution size is 25%

smaller than a comparable LDO and half the

footprint of a comparable DCDC.

As the table below shows, EP5348UI provides

the optimal trade-off between footprint and

efficiency when compared to a traditional LDO:

Power-Up Sequencing

During power-up, ENABLE should not be

asserted before PVIN, and PVIN should not be

asserted before AVIN. Tying all three pins

together meets these requirements.

Layout Recommendations

Figure 4: Top PCB Layer Critical Components and

Copper for Minimum Footprint

Figure 5: Bottom PCB Layer Critical Components

(RA, RB, CA) & Copper for Minimum Footprint

VIN

(V)

VOUT

(V)

LOAD

(mA)

EFF

DCDC

EFF

LDO

PLOSS

DCDC

(mW)

PLOSS

LDO

(mW)

Power Saved

(mW)

5.0 1.2 400 70.4% 24.0% 202 1520 1318

5.0 1.8 400 76.4% 36.0% 222 1280 1058

5.0 2.5 400 81.6% 50.0% 225 1000 775

5.0 3.3 400 87.7% 66.0% 185 680 495

3.3 1.2 400 77.1% 36.4% 143 840 697

3.3 1.8 400 83.3% 54.5% 144 600 456

3.3 2.5 400 88.2% 75.8% 134 320 186

05721 6/15/2011 Rev: B

EP5348UI

Figures 4 and 5 show critical PCB top and

bottom layer components and traces for a

minimum-footpint recommended EP5348

layout with ENABLE tied to VIN. Alternate

ENABLE configurations need to be connected

and routed according to specific customer

application. This layout consists of four layers.

For the other 2 layers and the exact

dimensions, please see the Gerber files at

www.enpirion.com. The recommendations

given below are general guidelines. Customers

may need to adjust these according to their

own layout and manufacturing rules.

Recommendation 1: Input and output filter

capacitors should be placed on the same side

of the PCB, and as close to the EP5348UI

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 EP5348UI

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.

Please the Gerber files at www.enpirion.com.

Recommendation 3: Multiple small vias

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. See Figure

4. If the two vias cannot be put under CIN or

COUT, then put two vias right after the

capacitors next the VIN and VOUT vias.

Recommendation 4: As Figure 5 shows, RA,

RB, and CA have been placed on the back side

to minimize the footprint. These components

also need to be close to the VFB pin (see

Figures 3, 4 and 5). The VFB pin is a high-

impedance, sensitive node. Keep any trace

connected to this node as short and thin as

possible. Whenever possible, connect RB

directly to the AGND pin instead of going

through the GND plane. In the layout shown

above, RB goes to the via next to AGND pin

using a dedicated trace on layer 3 not shown

here. See Gerber files at www.enpirion.com.

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 4 this connection is made at the vias

just before CIN. There is an additional

decoupling capacitor CAVIN for AVIN which is

connected between the device pin and the

GND plane.

Recommendation 6: The via to the right of pin

2 underneath the device helps to minimize the

parasitic inductances in the input and output

loop ground connections.

Recommendation 7: The top layer 1 metal

under the device must not be more than shown

in Figure 4. 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 8: 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.

05721 6/15/2011 Rev: B

EP5348UI

Recommended PCB Footprint

Figure 6: EN5348UI Package PCB Footprint

Package and Mechanical

Figure 7 EN5348UI Package Dimensions

Dimensions in mm

05721 6/15/2011 Rev: B

EP5348UI

Contact Information

Enpirion, Inc.

Perryville III Corporate Park

53 Frontage Road, Suite 210

Hampton, NJ 08827

Phone: +1 908-894-6000

Fax: +1 908-894-6090

www.enpirion.com

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.