ENPIRION EP5357LUI-E 600ma synchronous buck regulator with integrated inductor Datasheet

EP5357LUI/EP5357HUI
600mA Synchronous Buck Regulator
with Integrated Inductor
RoHS Compliant; Halogen Free
Description
Features
The EP5357xUI (x = L or H) is a 600mA
PowerSOC. The EP5357xUI integrates MOSFET
switches, control, compensation, and the
magnetics in an advanced 2.5mm x 2.25mm
QFN Package.
•
Integrated Inductor Technology
•
2.5mm x 2.25mm x 1.1mm package
•
Total Solution Footprint 10mm2
•
Low VOUT ripple for RF compatibility
Integrated magnetics enables a tiny solution
footprint, low output ripple, low part-count, and
high reliability, while maintaining high efficiency.
The complete solution can be implemented in as
little as 10mm2.
•
High efficiency, up to 93%
•
600mA continuous output current
•
55µA quiescent current
•
Less than 1µA standby current
A proprietary light load mode (LLM) provides high
efficiency in light load conditions.
•
5 MHz switching frequency
•
3 pin VID for glitch free voltage scaling
The EP5357xUI uses a 3-pin VID to easily select
the output voltage setting.
Output voltage
settings are available in 2 optimized ranges
providing coverage for typical VOUT settings.
•
VOUT Range 0.6V to VIN – 0.25V
•
Short circuit and over current protection
•
UVLO and thermal protection
•
IC level reliability in a PowerSOC solution
The VID pins can be changed on the fly for fast
dynamic voltage scaling. EP5357LUI further has
the option to use an external voltage divider.
•
Wireless and RF applications
•
Wireless broad band data cards
•
Smart phone and portable media players
•
Advanced Low Power Processors, DSP, IO,
Memory, Video, Multimedia Engines
EP5357xUI
10uF
AVIN
4.7uF
2.25mm
Application
VOUT
PVIN
EP5357LUI
4.7uF
VSO
VS1
VS2
ENABLE
LLM
10uF
VSENSE
VFB
AGND
PGND
4.75mm
Figure 1: Total Solution Footprint.
Figure 2: Typical Application Schematic.
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September 12, 2012
Rev: D
EP5357LUI/EP5357HUI
LOW VID Range
16-pin QFN T&R
EP5357HUI
HIGH VID Range
16-pin QFN T&R
EP5357LUI-E
EP5357LUI Evaluation Board
NC(SW)
1
EP5357HUI-E
EP5357HUI Evaluation Board
PGND
2
LLM
3
VFB
4
VSENSE
5
AGND
6
NC(SW)
EP5357LUI
16
15
7
8
VOUT
Package
NC(SW)
Comment
EP5357LUI
Part Number
Pin Assignments (Top View)
VOUT
Ordering Information
14
PVIN
13
AVIN
12
ENABLE
11
VS0
10
VS1
9
VS2
2
LLM
3
NC
4
VSENSE
5
AGND
6
NC(SW)
7
8
VOUT
PGND
15
EP5357HUI
1
16
VOUT
NC(SW)
NC(SW)
Figure 3: EP5357LUI Pin Out Diagram (Top View)
14
PVIN
13
AVIN
12
ENABLE
11
VS0
10
VS1
9
VS2
Figure 4: EP5357HUI Pin Out Diagram (Top View)
Pin Description
PIN
NAME
1, 15,
16
NC(SW)
2
PGND
3
LLM
4
VFB/NC
5
VSENSE
FUNCTION
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.
Power ground. Connect this pin to the ground electrode of the Input and output filter
capacitors.
LLM (Light Load Mode – “LLM”) pin. Logic-High enables automatic LLM/PWM and logiclow places the device in fixed PWM operation. LLM pin should be connected to ENABLE,
or should be disabled before ENABLE is pulled low.
EP5357LUI: Feed back pin for external divider option.
EP5357HUI: No Connect
Sense pin for preset output voltages. Refer to application section for proper configuration.
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Rev: D
EP5357LUI/EP5357HUI
PIN
NAME
6
AGND
7, 8
VOUT
9, 10,
11
VS2, VS1,
VS0
12
13
14
ENABLE
AVIN
PVIN
FUNCTION
Analog ground. This is the quiet ground for the internal control circuitry, and the ground
return for external feedback voltage divider
Regulated Output Voltage. Refer to application section for proper layout and decoupling.
Output voltage select. VS2 = pin 9, VS1 = pin 10, VS0 = pin 11.
EP5357LUI: Selects one of seven preset output voltages or an external resistor divider.
EP5357HUI: Selects one of eight preset output voltages.
(Refer to section on output voltage select for more details.)
Output Enable. Enable = logic high; Disable = logic low
Input power supply for the controller circuitry.
Input Voltage for the MOSFET switches.
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
VIN
-0.3
6.0
V
Voltages on: ENABLE, VSENSE, VSO – VS2
-0.3
VIN+ 0.3
V
Voltages on: VFB (EP5357LUI)
-0.3
2.7
V
150
°C
150
°C
Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020C
260
°C
ESD Rating (based on Human Body Mode)
2000
V
Input Supply Voltage
Maximum Operating Junction Temperature
TJ-ABS
Storage Temperature Range
TSTG
-65
Recommended Operating Conditions
PARAMETER
SYMBOL
MIN
MAX
UNITS
Input Voltage Range
VIN
2.4
5.5
V
Operating Ambient Temperature
TA
-40
+85
°C
Operating Junction Temperature
TJ
-40
+125
°C
Thermal Characteristics
PARAMETER
Thermal Resistance: Junction to Ambient –0 LFM (Note 1)
Thermal Overload Trip Point
Thermal Overload Trip Point Hysteresis
SYMBOL
TYP
UNITS
θJA
85
°C/W
TJ-TP
+155
°C
25
°C
Note 1: Based on a four layer copper board and proper thermal design per JEDEC EIJ/JESD51 standards
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Rev: D
EP5357LUI/EP5357HUI
Electrical Characteristics
NOTE: TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C, VIN = 3.6V.
CIN = 4.7µF MLCC, COUT = 10µF MLCC
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
Operating Input Voltage
Range
VIN
Under Voltage Lock-out –
VIN Rising
VUVLO_R
2.0
V
Under Voltage Lock-out –
VIN Falling
VUVLO_F
1.9
V
Drop Out Resistance
RDO
Input to Output Resistance
Output Voltage Range
VOUT
EP5357LUI (VDO = ILOAD X RDO)
EP5357HUI
Dynamic Voltage Slew
Rate
VSLEW
EP5357LUI (VID MODE)
EP5357HUI (VID MODE)
VID Preset VOUT Initial
Accuracy
ΔVOUT
TA = 25°C, VIN = 3.6V;
ILOAD = 100mA ;
0.8V ≤ VOUT ≤ 3.3V
Line Regulation
ΔVOUT_LINE
2.4V ≤ VIN ≤ 5.5V
0.03
%/V
Load Regulation
ΔVOUT_LOAD
0A ≤ ILOAD ≤ 600mA
0.48
%/A
Temperature Variation
ΔVOUT_TEMPL
-40°C ≤ TA ≤ +85°C
24
ppm/°C
Output Current
IOUT
Shut-down Current
ISD
Enable = Low
EP5357HUI Operating
Quiescent Current
IQ
EP5357LUI Operating
Quiescent Current
2.4
350
0.6
1.8
MAX
UNITS
5.5
V
500
VIN-VDO
3.3
4
8
mΩ
V
V/mS
-2
+2
600
%
mA
0.75
µA
ILOAD=0; Preset Output Voltages,
LLM=High
55
µA
IQ
ILOAD=0; Preset Output Voltages,
LLM=High
65
µA
OCP Threshold
ILIM
2.4V ≤ VIN ≤ 5.5V
0.6V ≤ VOUT ≤ 3.3V
1.25
1.4
A
Feedback Pin Voltage
Initial Accuracy
VFB
TA = 25°C, VIN = 3.6V;
ILOAD = 100mA ;
0.8V ≤ VOUT ≤ 3.3V
.588
0.6
0.612
V
.582
0.6
0.618.
V
-40°C ≤ TA ≤ +85°C;
2.4V ≤ VIN ≤ 5.5V
Feedback Pin Voltage
variation over Line, Load,
and Temperature
VFB
Feedback Pin Input
Current
IFB
VS0-VS2, Pin Logic Low
VVSLO
0.0
0.3
V
VS0-VS2, Pin Logic High
VVSHI
1.4
VIN
V
VS0-VS2, Pin Input
Current
IVSX
Enable Pin Logic Low
VENLO
Enable Pin Logic High
VENHI
Enable Pin Current
IENABLE
0mA ≤ ILOAD ≤ 600mA
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03409
Note 1
<100
Note 1
nA
<100
nA
0.3
1.4
Note 1
V
<100
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September 12, 2012
V
nA
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Rev: D
EP5357LUI/EP5357HUI
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
Minimum VIN-VOUT to ensure
proper LLM operation
LLM Engage Headroom
TYP
MAX
600
UNITS
mV
LLM Pin Logic Low
VLLMLO
0.3
LLM Pin Logic High
VLLMHI
LLM Pin Current
ILLM
<100
nA
Operating Frequency
FOSC
5
MHz
8
4
V/mS
250
uSec
1.4
V
V
Soft Start Operation
Soft Start Slew Rate
ΔVSS
EP5357HUI (VID MODE)
EP5357LUI (VID MODE)
VOUT Rise Time
TRISE
Time to 90% VOUT (VFB MODE)
180
Note 1: Parameter guaranteed by design
95
90
85
80
75
70
65
60
55
50
45
LLM
Efficiency (%)
Efficiency (%)
Typical Performance Characteristics
PWM
10
100
Load Current (mA)
1000
Efficiency (%)
LLM
PWM
10
Efficiency vs. Load Current: VIN = 5.0V, VOUT (from
top to bottom) = 3.3, 2.5, 1.8, 1.2V
95
90
85
80
75
70
65
60
55
50
45
95
90
85
80
75
70
65
60
55
50
45
100
Load Current (mA)
1000
Efficiency vs. Load Current: VIN = 3.7V, VOUT (from
top to bottom) = 2.5, 1.8, 1.2V
LLM
PWM
10
100
Load Current (mA)
1000
Efficiency vs. Load Current: VIN = 3.3V, VOUT (from
top to bottom) = 2.5, 1.8, 1.2V
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EP5357LUI/EP5357HUI
Start Up Waveform: VIN = 5.0V, VOUT = 3.3V;
ILOAD = 10mA (VID MODE)
Start Up Waveform: VIN = 5.0V, VOUT = 3.3V;
ILOAD = 1000mA (VID MODE)
Shut-down Waveform: VIN = 5.0V, VOUT = 3.3V;
ILOAD = 10mA, PWM
Shut-down Waveform: VIN = 5.0V, VOUT = 3.3V;
ILOAD = 500mA, PWM
5mV/Div
50mV/Div
Output Ripple: VIN = 5.0V, VOUT = 1.2V,
Load = 500mA
Output Ripple: VIN = 5.0V, VOUT = 1.2V, Load = 10mA
LLM enabled
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EP5357LUI/EP5357HUI
50mV/Div
5mV/Div
Output Ripple: VIN = 5.0V, VOUT = 3.3V, Load = 10mA
LLM enabled
Output Ripple: VIN = 5.0V, VOUT = 3.3V,
Load = 500mA
50mV/Div
5mV/Div
Output Ripple: VIN = 3.3V, VOUT = 1.8V
Load = 500mA
Output Ripple: VIN = 3.3V, VOUT = 1.8V, Load = 10mA
LLM enabled
5mV/Div
50mV/Div
Output Ripple: VIN = 3.3V, VOUT = 1.2V, Load = 10mA
LLM enabled
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03409
Output Ripple: VIN = 3.3V, VOUT = 1.2V,
Load = 500mA
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Rev: D
EP5357LUI/EP5357HUI
Load Transient: VIN = 5.0V, VOUT = 1.2V
Load stepped from 0mA to 500mA, LLM enabled
Load Transient: VIN = 5.0V, VOUT = 1.2V
Load stepped from 10mA to 500mA
Load Transient: VIN = 3.3V, VOUT = 1.8V
Load stepped from 0mA to 500mA, LLM enabled
Load Transient: VIN = 3.3V, VOUT = 1.8V
Load stepped from 10mA to 500mA
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Rev: D
EP5357LUI/EP5357HUI
Functional Block Diagram
LLM
PVIN
UVLO
Mode Logic
Thermal Limit
Current Limit
ENABLE
NC(SW)
Soft Start
P-Drive
(-)
Logic
VOUT
PWM
Comp
(+)
N-Drive
PGND
VSENSE
Sawtooth
Generator
Compensation
Network
(-)
Switch
VFB
Error
Amp
(+)
DAC
Voltage
Select
VREF
Package Boundry
AVIN
VS0 VS1 VS2
AGND
Figure 5: Functional Block Diagram
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EP5357LUI/EP5357HUI
Detailed Description
Functional Overview
Integrated Inductor
The EP5357xUI requires only 2 small MLCC
capacitors for a complete DC-DC converter
solution.
The device integrates MOSFET
switches,
PWM
controller,
Gate-drive,
compensation, and inductor into a tiny 2.5mm x
2.25mm x 1.1mm QFN package. Advanced
package design, along with the high level of
integration, provides very low output ripple and
noise. The EP5357xUI uses voltage mode
control for high noise immunity and load
matching to advanced ≤90nm loads. A 3-pin
VID allows the user to choose from one of 8
output voltage settings.
The EP5357xUI
comes with two VID output voltage ranges.
The EP5357HUI provides VOUT settings from
1.8V to 3.3V, the EP5357LUI provides VID
settings from 0.8V to 1.5V, and also has an
external resistor divider option to program
output setting over the 0.6V to VIN-0.25V
range. The EP5357xUI provides the industry’s
highest power density of any 600mA DCDC
converter solution.
The EP5357xUI 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 conducted and radiated 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 input AC ripple currents that
are a major source of radiated emissions from
DC-DC converters. The integrated inductor
provides the optimal solution to the complexity,
output ripple, and noise that plague low power
DCDC converter design.
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 seem-less 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 lockout (UVLO), over-current protection (OCP),
short circuit protection, and thermal overload
protection.
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03409
Voltage Mode Control
The EP5357xUI utilizes an integrated 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.
Light Load Mode (LLM) Operation
The EP5357xUI uses a proprietary light load
mode to provide high efficiency in the low load
operating condition. When the LLM pin is high,
the device is in automatic LLM/PWM mode.
When the LLM pin is low, the device is in PWM
mode. In automatic LLM/PWM mode, when a
light load condition is detected, the device will
(1) step VOUT up by approximately 1.5% above
the nominal operating output voltage setting,
VNOM, and then (2) shut down unnecessary
circuitry, and (3) monitor VOUT. When VOUT falls
below VNOM, the device will repeat (1), (2), and
(3). The voltage step up, or pre-positioning,
improves transient droop when a load transient
causes a transition from LLM mode to PWM
mode. If a load transient occurs, causing VOUT
to fall below the threshold VMIN, the device will
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Rev: D
EP5357LUI/EP5357HUI
exit LLM operation and begin normal PWM
operation. Figure 6 demonstrates VOUT
behavior during transition into and out of LLM
operation.
LLM Threshold Current vs. VOUT
LLM Threshold (mA)
250
LLM
Ripple
VMAX
PWM
Ripple
VNOM
VMIN
200
150
VIN=5V (top curve)
100
VIN=4.2V
VIN=3.7V
50
VIN=3.3V (bottom curve)
VOUT
0
0.8
1.1
1.4
1.7
2.0
2.3
2.6
2.9
3.2
VOUT (V)
Load
Step
IOUT
Figure 6: VOUT Behavior in LLM Operation
Figure 8: Typical load current for LLM engage and
disengage versus VOUT for selected input voltages
Table 1: Load current below which the device can be
certain to be in LLM operation. These values are
guaranteed by design
VIN
Device exits LLM,
tests load current
Figure 7: VOUT Droop during Periodic LLM Exit
Many multi-mode DCDC converters suffer from
a condition that occurs when the load current
increases only slowly so that there is no load
transient driving VOUT below the VMIN threshold.
In this condition, the device would never exit
LLM operation. This could adversely affect
efficiency and cause unwanted ripple. To
prevent this from occurring, the EP5357xUI
periodically exits LLM mode into PWM mode
and measures the load current. If the load
current is above the LLM threshold current, the
device will remain in PWM mode. If the load
current is below the LLM threshold, the device
will re-enter LLM operation. There will be a
small droop in VOUT at the point where the
device exits and re-enters LLM, as shown in
Figure 7.
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03409
VOUT
3.30
3.00
2.90
2.60
2.50
2.20
2.10
1.80
1.50
1.45
1.20
1.15
1.10
1.05
0.80
3.3
3.7
56
69
101
105
111
111
111
105
103
101
99
87
62
89
106
111
120
122
124
120
119
111
108
106
104
89
4.3
105
122
126
136
138
141
141
138
130
128
117
114
111
108
92
5.0
147
156
158
162
162
160
158
150
138
136
122
119
116
113
94
The load current at which the device will enter
LLM mode is a function of input and output
voltage. Figure 8 shows the typical value at
which the device will enter LLM operation. The
actual load current at which the device will
enter LLM operation can vary by +/-30%. Table
1 shows the minimum load current below which
the device is guaranteed to be in LLM
operating mode.
To ensure normal LLM operation, LLM mode
should be enabled/disabled with specific
sequencing. For applications with explicit LLM
pin control, enable LLM after VIN ramp up is
complete; disable LLM before VIN ramp down.
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EP5357LUI/EP5357HUI
For applications with ENABLE control, tie LLM
to ENABLE; enable device after VIN ramp up is
complete and disable device before VIN ramp
down begins. For devices with ENABLE and
LLM tied to VIN, contact Enpirion Applications
engineering for specific recommendations
Increased output filter capacitance and/or
increased bulk capacitance at the load will
decrease the magnitude of the LLM ripple.
Refer to the section on output filter capacitance
for maximum values of output filter capacitance
and the Soft-Start section for maximum bulk
capacitance at the load.
NOTE: For proper LLM operation the
EP5357xUI requires a minimum difference
between VIN and VOUT of 600mV. If this
condition is not met, the device cannot be
assured proper LLM operation.
NOTE: Automatic LLM/PWM is not available
when using the external resistor divider option
for VOUT programming.
Soft Start
Internal soft start circuits limit in-rush current
when the device starts up from a power down
condition or when the “ENABLE” pin is
asserted “high”. Digital control circuitry limits
the VOUT ramp rate to levels that are safe for
the Power MOSFETS and the integrated
inductor.
The EP5357HUI has a soft-start slew rate that
is twice that of the EP5357LUI.
When the EP5357LUI is configured in external
resistor divider mode, the device has a fixed
VOUT ramp time. Therefore, the ramp rate will
vary with the output voltage setting. Output
voltage ramp 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:
EP5357LUI:
COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 200uF
COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 100uF
EP5357LUI in external divider mode:
COUT_TOTAL_MAX = 2.25x10-4/VOUT Farads
The nominal value for COUT 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 PMOSFET which is compared to a reference
current. When this level is exceeded the PFET 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 insure proper operation. If
the voltage drops below the UVLO threshold
the lockout circuitry will again 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 temperature 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.
EP5357HUI:
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EP5357LUI/EP5357HUI
Application Information
VIN
4.7μF
PVIN
VOUT
AVIN
VSENSE
ENABLE
LLM
VOUT
10μF
VS0
VS1
VS2
PGND AGND
Internally, the output of the VID multiplexer
sets the value for the voltage reference DAC,
which in turn is connected to the non-inverting
input of the error amplifier. This allows the use
of a single feedback divider with constant loop
gain and optimum compensation, independent
of the output voltage selected.
NOTE: The VID pins must not be left floating.
EP5357L Low VID Range Programming
Figure 9: Application Circuit, EP5357HUI, configured
for LLM Enabled. Note that all control signals should
be connected to AVIN or AGND.
VIN
μF
PVIN
VOUT
AVIN
VSENSE
ENABLE
LLM
VS0
VFB
VOUT
10μF
VS1
VS2
The EP5357LUI is designed to provide a high
degree of flexibility in powering applications
that require low VOUT settings and dynamic
voltage scaling (DVS). The device employs a
3-pin VID architecture that allows the user to
choose one of seven (7) preset output voltage
settings, or the user can select an external
voltage divider option. The VID pin settings
can be changed on the fly to implement glitchfree voltage scaling.
PGND AGND
Table 2: EP5357LUI VID Voltage Select Settings
VS2
0
0
0
0
1
1
1
1
Figure 10: Application Circuit, EP5357LUI,
configured for LLM Enabled, showing the VFB
function.
Output Voltage Programming
The EP5357xUI utilizes a 3-pin VID to program
the output voltage value. The VID is available
in two sets of output VID programming ranges.
The VID pins should be connected either to
AVIN or to AGND to avoid noise coupling into
the device.
The “Low” range is optimized for low voltage
applications. It comes with preset VID settings
ranging from 0.80V and 1.5V. This VID set
also has an external divider option.
To specify this VID range, order part number
EP5357LUI.
The “High” VID set provides output voltage
settings ranging from 1.8V to 3.3V. This
version does not have an external divider
option. To specify this VID range, order part
number EP5357HUI.
©Enpirion 2012 all rights reserved, E&OE
03409
VS1
0
0
1
1
0
0
1
1
VS0
0
1
0
1
0
1
0
1
VOUT
1.50
1.45
1.20
1.15
1.10
1.05
0.8
EXT
Table 2 shows the VS2-VS0 pin logic states for
the EP5357LUI and the associated output
voltage levels.
A logic “1” indicates a
connection to AVIN or to a “high” logic voltage
level. A logic “0” indicates a connection to
AGND or to a “low” logic voltage level. These
pins can be either hardwired to AVIN or AGND
or alternatively can be driven by standard logic
levels. Logic levels are defined in the electrical
characteristics table. Any level between the
logic high and logic low is indeterminate.
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EP5357LUI/EP5357HUI
connection to AVIN or to a “high” logic voltage
level. A logic “0” indicates a connection to
AGND or to a “low” logic voltage level. These
pins can be either hardwired to AVIN or AGND
or alternatively can be driven by standard logic
levels. Logic levels are defined in the electrical
characteristics table. Any level between the
logic high and logic low is indeterminate.
These pins must not be left floating.
EP5357LUI External Voltage Divider
The external divider option is chosen by
connecting VID pins VS2-VS0 to VIN or a logic
“1” or “high”. The EP5357LUI uses a separate
feedback pin, VFB, when using the external
divider. VSENSE must be connected to VOUT as
indicated in Figure 11. The output voltage is
selected by the following formula:
VOUT = 0.6V (1 +
Ra
Rb
)
Ra must be chosen as 237KΩ to maintain loop
gain. Then Rb is given as:
Rb =
Table 3: EP5357HUI VID Voltage Select Settings
VS2
0
0
0
0
1
1
1
1
142.2 x10 3
Ω
VOUT − 0.6
VOUT can be programmed over the range of
0.6V to (VIN – 0.25V).
NOTE: Dynamic Voltage Scaling is not allowed
between internal preset voltages and external
divider.
NOTE: LLM is not functional when using the
external divider option. Tie the LLM pin to
AGND.
VIN
VSense
AVIN
ENABLE
VS0
VS1
VS2
EP5357L
4.7uF
PVIN
VS0
0
1
0
1
0
1
0
1
VOUT
3.3
3.0
2.9
2.6
2.5
2.2
2.1
1.8
Power-Up/Down Sequencing
VOUT
VOUT
Ra
VS1
0
0
1
1
0
0
1
1
10μF
VFB
Rb
PGND AGND
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
Figure 11: EP5357LUI using external divider
EP5357HUI High VID Range Programming
The EP5357HUI VOUT settings are optimized
for higher nominal voltages such as those
required to power IO, RF, or IC memory. The
preset voltages range from 1.8V to 3.3V.
There are eight (8) preset output voltage
settings. The EP5357HUI does not have an
external divider option.
As with the
EP5357LUI, the VID pin settings can be
changed while the device is enabled.
Table 3 shows the VS0-VS2 pin logic states for
the EP5357HUI and the associated output
voltage levels.
A logic “1” indicates a
©Enpirion 2012 all rights reserved, E&OE
03409
The EP5357xUI does not support startup into a
pre-biased condition. Be sure the output
capacitors are not charged or the output of the
EP5357xUI is not pre-biased when the
EP5357xUI is first enabled.
Input Filter Capacitor
For ILOAD ≤ 500mA, CIN = 2.2uF
For ILOAD > 500mA CIN = 4.7uF.
0402 capacitor case size is acceptable.
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
14
September 12, 2012
www.enpirion.com
Rev: D
EP5357LUI/EP5357HUI
temperature, and are not suitable for switchmode DC-DC converter input filter applications.
Output Filter Capacitor
For VIN ≤ 4.3V, COUT_MIN = 10uF 0603 MLCC.
For VIN > 4.3V, COUT_MIN = 10uF 0805 MLCC.
Ripple performance can be improved by using
2x10µF 0603 MLCC capacitors (for any
allowed VIN).
The maximum output filter capacitance next to
the output pins of the device is 60µF low ESR
MLCC capacitance. VOUT has to be sensed at
the last output filter capacitor next to the
EP5357xUI.
Additional bulk capacitance for decoupling and
bypass can be placed at the load as long as
there is sufficient separation between the VOUT
Sense point and the bulk capacitance.
Excess total capacitance on the output (Output
Filter + Bulk) can cause an over-current
condition at startup. Refer to the section on
Soft-Start for the maximum total capacitance
on the output.
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 switchmode
DC-DC
converter
output
filter
applications.
Recommended PCB Footprint
Figure 12: EP5357 Package PCB Footprint
©Enpirion 2012 all rights reserved, E&OE
03409
15
September 12, 2012
www.enpirion.com
Rev: D
EP5357LUI/EP5357HUI
Package and Mechanical
Figure 13: EP5357xUI Package Dimensions
©Enpirion 2012 all rights reserved, E&OE
03409
16
September 12, 2012
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Rev: D
EP5357LUI/EP5357HUI
Contact Information
Enpirion, Inc.
Perryville III
53 Frontage Road Suite 210
Hampton, NJ 08827
Phone: +1 908-894-6000
Fax: +1 908-894-6090
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
03409
17
September 12, 2012
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Rev: D
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