ENPIRION EP53A7LQ 1000ma synchronous buck regulator with integrated inductor Datasheet

EP53A7LQI/EP53A7HQI
1000mA Synchronous Buck Regulator
with Integrated Inductor
RoHS Compliant; Halogen Free
Description
Features
The EP53A7xQI (x = L or H) is a 1000mA
PowerSOC. The EP53A7xQI integrates MOSFET
switches, control, compensation, and the
magnetics in an advanced 3mm x 3mm QFN
Package.
•
Integrated Inductor Technology
•
3mm x 3mm x 1.1mm QFN package
•
Total Solution Footprint < 21mm2
•
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 21mm2.
•
High efficiency, up to 94%
•
1000mA 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 EP53A7xQI 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 – 0.5V
•
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. EP53A7LQI further has
the option to use an external voltage divider.
The EP53A7xQI offers the optimal combination
of very small solution footprint and advanced
performance features.
3.5mm
Application
•
Portable wireless and RF applications
•
Solid state storage applications
•
Space constrained applications requiring high
efficiency and very small solution size
100 ohm
4.7uF
100 Ohm
VIN
6mm
4.7μF
EP53A7xQI
PVIN
VOUT
AVIN
VSENSE
ENABLE
LLM
VS0
VFB
VOUT
10μF
VS1
VS2
PGND AGND
10uF
Figure 2: Typical Application Schematic
Figure 1: Total Solution Footprint
www.enpirion.com
01543
11/11/2009
Rev:B
EP53A7LQI/EP53A7HQI
Ordering Information
Part Number
Pin Assignments (Top View)
Comment
Package
EP53A7LQI
LOW VID Range
16-pin QFN T&R
EP53A7HQI
HIGH VID Range
16-pin QFN T&R
EP53A7LQI-E
EP53A7LQI Evaluation Board
EP53A7HQI-E
EP53A7HQI Evaluation Board
Figure 3: EP53A7LQI Pin Out Diagram (Top View)
Figure 4: EP53A7HQI Pin Out Diagram (Top View)
Pin Description
PIN
NAME
1, 15,
16
NC(SW)
2
PGND
3
LLM
5
VFB
NC
VSENSE
6
AGND
7, 8
VOUT
4
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.
EP53A7LQI: Feed back pin for external resistor divider option.
EP53A7HQI: No Connect
Sense pin for preset output voltages. Refer to application section for proper configuration.
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.
©Enpirion 2009 all rights reserved, E&OE
01543
2
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
PIN
NAME
9, 10,
11
VS2, VS1,
VS0
12
13
14
ENABLE
AVIN
PVIN
FUNCTION
Output voltage select. VS2 = pin 9, VS1 = pin 10, VS0 = pin 11.
EP53A7LQI: Selects one of seven preset output voltages or an external resistor divider.
EP53A7HQI: 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. Connect to PVIN through a 100 Ohm resistor.
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 (EP53A7LQI)
-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
©Enpirion 2009 all rights reserved, E&OE
01543
3
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
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
Operating Input Voltage
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
EP53A7LQI (VDO = ILOAD X RDO)
EP53A7HQI
Dynamic Voltage Slew
Rate
VSLEW
EP53A7LQI
EP53A7HQI
ΔVOUT
TA = 25°C, VIN = 3.6V;
ILOAD = 100mA ;
0.8V ≤ VOUT ≤ 3.3V
-2
Feedback Pin Voltage
Initial Accuracy
VFB
TA = 25°C, VIN = 3.6V;
ILOAD = 100mA ;
0.8V ≤ VOUT ≤ 3.3V
.588
Line Regulation
ΔVOUT_LINE
2.4V ≤ VIN ≤ 5.5V
0.03
%/V
Load Regulation
ΔVOUT_LOAD
0A ≤ ILOAD ≤ 1000mA
0.6
%/A
Temperature Variation
ΔVOUT_TEMPL
-40°C ≤ TA ≤ +85°C
30
ppm/°C
Output Current
IOUT
Shut-down Current
ISD
Enable = Low
EP53A7HQI Operating
Quiescent Current
IQ
EP53A7LQI Operating
Quiescent Current
VID Preset VOUT Initial
Accuracy
TEST CONDITIONS
MIN
TYP
2.4
350
0.6
1.8
MAX
UNITS
5.5
V
500
VIN-VDO
3.3
4
8
mΩ
V
V/mS
0.6
+2
%
0.612
V
1000
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
1.4
A
Feedback Pin Input
Current
IFB
Note 1
<100
nA
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
Note 1
<100
LLM Pin Logic Low
VLLMLO
LLM Pin Logic High
VLLMHI
©Enpirion 2009 all rights reserved, E&OE
nA
0.3
1.4
Note 1
nA
700
mV
0.3
1.4
4
11/11/2009
V
V
<100
Minimum difference between VIN
and VOUT to ensure proper LLM
operation
LLM Engage Headroom
01543
1.25
V
V
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
LLM Pin Current
ILLM
<100
nA
Operating Frequency
FOSC
5
MHz
4
8
V/mS
Soft Start Operation
Soft Start Slew Rate
ΔVSS
EP53A7LQI (VID only)
EP53A7HQI (VID only)
Soft Start Rise Time
ΔTSS
EP53A7LQI (VFB mode); Note 2
170
225
280
μS
Note 1: Parameter guaranteed by design
Note 2: Measured from when VIN ≥ VUVLO_R & ENABLE pin crosses its logic High threshold.
95
90
85
80
75
70
65
60
55
50
45
LLM
Efficiency (%)
Efficiency (%)
Typical Performance Characteristics
VOUT=1.2V
PWM
10
100
Load Current (mA)
Efficiency (%)
Efficiency (%)
VOUT=2.5V
PWM
100
Load Current (mA)
01543
PWM
95
90
85
80
75
70
65
60
55
50
45
100
Load Current (mA)
1000
LLM
VOUT=3.3V
PWM
10
1000
Efficiency vs. Load Current: VOUT = 2.5V, VIN (from
top to bottom) = 3.3, 3.7, 4.3, 5.0V
©Enpirion 2009 all rights reserved, E&OE
VOUT=1.8V
Efficiency vs. Load Current: VOUT = 1.8V, VIN (from
top to bottom) = 2.5, 3.3, 3.7, 4.3, 5.0V
LLM
10
LLM
10
1000
Efficiency vs. Load Current: VOUT = 1.2V, VIN (from
top to bottom) = 2.5, 3.3, 3.7, 4.3, 5.0V
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: VOUT = 3.3V, VIN (from
top to bottom) = 3.7, 4.3, 5.0V
5
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
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 = 1000mA, PWM
5mV/Div
50mV/Div
Output Ripple: VIN = 5.0V, VOUT = 1.2V, Load = 10mA
LLM enabled
©Enpirion 2009 all rights reserved, E&OE
01543
Output Ripple: VIN = 5.0V, VOUT = 1.2V,
Load = 1A
6
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
50mV/Div
5mV/Div
Output Ripple: VIN = 5.0V, VOUT = 3.3V,
Load = 1A
Output Ripple: VIN = 5.0V, VOUT = 3.3V, Load = 10mA
LLM enabled
50mV/Div
5mV/Div
Output Ripple: VIN = 3.3V, VOUT = 1.8V, Load = 10mA
LLM enabled
Output Ripple: VIN = 3.3V, VOUT = 1.8V
Load = 1A
5mV/Div
50mV/Div
Output Ripple: VIN = 3.3V, VOUT = 1.2V,
Load = 1A
Output Ripple: VIN = 3.3V, VOUT = 1.2V, Load = 10mA
LLM enabled
©Enpirion 2009 all rights reserved, E&OE
01543
7
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
Load Transient: VIN = 5.0V, VOUT = 3.3V
Load stepped from 0mA to 1000mA
Load Transient: VIN = 5.0V, VOUT = 3.3V
Load stepped from 10mA to 1000mA, LLM enabled
Load Transient: VIN = 5.0V, VOUT = 1.2V
Load stepped from 0mA to 1000mA
Load Transient: VIN = 5.0V, VOUT = 1.2V
Load stepped from 10mA to 1000mA, LLM enabled
©Enpirion 2009 all rights reserved, E&OE
01543
8
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
Load Transient: VIN = 3.7V, VOUT = 1.2V
Load stepped from 0mA to 1000mA
Load Transient: VIN = 3.7V, VOUT = 1.2V
Load stepped from 10mA to 1000mA, LLM enabled
Load Transient: VIN = 3.3V, VOUT = 1.8V
Load stepped from 0mA to 1000mA
Load Transient: VIN = 3.3V, VOUT = 1.8V
Load stepped from 10mA to 1000mA, LLM enabled
©Enpirion 2009 all rights reserved, E&OE
01543
9
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
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
©Enpirion 2009 all rights reserved, E&OE
01543
10
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
Detailed Description
Functional Overview
Integrated Inductor
The EP53A7xQI requires only 2 small MLCC
capacitors and an 0201 resistor for a complete
DC-DC converter solution.
The device
integrates MOSFET switches, PWM controller,
Gate-drive, compensation, and inductor into a
tiny 3mm x 3mm x 1.1mm QFN package.
Advanced package design, along with the high
level of integration, provides very low output
ripple and noise.
The EP53A7xQI 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 EP53A7xQI
comes with two VID output voltage ranges.
The EP53A7HQI provides VOUT settings from
1.8V to 3.3V, the EP53A7LQI 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-0.5V range.
The EP53A7xQI provides the industry’s highest
power density of any 1A DCDC converter
solution.
The EP53A7xQI utilizes a proprietary low loss
integrated inductor. The integration of the
inductor greatly simplifies the power supply
design process. 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 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 lockout (UVLO), over-current protection (OCP),
short circuit protection, and thermal overload
protection.
©Enpirion 2009 all rights reserved, E&OE
01543
Voltage Mode Control
The EP53A7xQI 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 EP53A7xQI 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
exit LLM operation and begin normal PWM
operation. Figure 6 demonstrates VOUT
behavior during transition into and out of LLM
operation.
11
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
LLM
Ripple
VMAX
LLM Threshold Current vs. VOUT
250
VNOM
VMIN
LLM Threshold (mA)
PWM
Ripple
VOUT
Load
Step
200
150
VIN=5V (top curve)
100
VIN=4.2V
VIN=3.7V
50
VIN=3.3V (bottom curve)
0
IOUT
0.8
1.1
1.4
1.7
2.0
2.3
2.6
2.9
3.2
VOUT (V)
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
(shown in Figure 6). 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 EP53A7xQI 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 reenters LLM, as shown in Figure 7.
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
©Enpirion 2009 all rights reserved, E&OE
01543
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
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
complete; disable LLM before VIN ramp down.
For applications with ENABLE control, tie LLM
to ENABLE; enable device after VIN ramp up
complete and disable device before VIN ramp
12
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
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
EP53A7xQI requires a minimum difference
between VIN and VOUT of 700mV. 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 EP53A7HQI has a soft-start slew rate that
is twice that of the EP53A7LQI.
When the EP53A7LUI 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:
EP53A7LQI:
COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 200uF
EP53A7HQI:
EP53A7LUI 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 25C°, the
device will go through the normal startup
process.
COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 100uF
©Enpirion 2009 all rights reserved, E&OE
01543
13
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
Application Information
100 ohm
VIN
4.7μF
PVIN
VOUT
AVIN
VSENSE
ENABLE
LLM
VOUT
10μF
VS0
NOTE: The VID pins must not be left floating.
VS1
VS2
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.
PGND AGND
EP53A7L Low VID Range Programming
Figure 9: Application Circuit, EP53A7HQI. Note that
all control signals should be connected to an
external control signal, AVIN or AGND.
100 ohm
VIN
4.7μF
PVIN
VOUT
AVIN
VSENSE
ENABLE
LLM
VS0
VFB
VOUT
10μF
The EP53A7LQI 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.
VS1
VS2
Table 2: EP53A7LQI VID Voltage Select Settings
PGND AGND
VS2
0
0
0
0
1
1
1
1
Figure 10: Application Circuit, EP53A7LQI showing
the VFB function.
Output Voltage Programming
The EP53A7xQI 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 an
external control signal, AVIN or to AGND to
avoid noise coupling into the device. The VID
pins must not be left floating.
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
EP53A7LQI.
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 EP53A7HQI.
Internally, the output of the VID multiplexer
sets the value for the voltage reference DAC,
©Enpirion 2009 all rights reserved, E&OE
01543
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 EP53A7LQI 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.
EP53A7LQI External Voltage Divider
The external divider option is chosen by
connecting VID pins VS2-VS0 to AVIN or a
logic “1” or “high”. The EP53A7LQI uses a
separate feedback pin, VFB, when using the
external divider. VSENSE must be connected to
VOUT as indicated in Figure 11.
14
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
100 Ohm
PVIN
VIN
AVIN
ENABLE
VS0
VS1
VS2
EP53A7L
4.7uF
VSense
VOUT
VOUT
Ra
10μF
VFB
LLM
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.
Table 3: EP53A7HQI VID Voltage Select Settings
Rb
VS2
0
0
0
0
1
1
1
1
PGND AGND
Figure 11: EP53A7LQI using external divider
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:
R
=
b
142.2 x10 3
Ω
VOUT − 0.6
VOUT can be programmed over the range of
0.6V to (VIN – 0.5V).
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 when using this option.
EP53A7HQI High VID Range
Programming
The EP53A7HQI 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 EP53A7HQI does not have an
external divider option.
As with the
EP53A7LQI, the VID pin settings can be
changed while the device is enabled.
Table 3 shows the VS0-VS2 pin logic states for
the EP53A7HQI 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
©Enpirion 2009 all rights reserved, E&OE
01543
VS1
0
0
1
1
0
0
1
1
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
Input Filter Capacitor
The input filter capacitor requirement is a
4.7µF 0402 or 0603 low ESR MLCC capacitor.
Output Filter Capacitor
The output filter capacitor requirement is a
minimum of 10µF 0805 MLCC.
Ripple
performance can be improved by using 2x10µF
0603 or 2x10µF 0805 MLCC capacitors.
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
EP53A7xQI.
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. The
separation provides an inductance that isolates
the control loop from the bulk capacitance.
NOTE: Excess total capacitance on the output
(Output Filter + Bulk) can cause an overcurrent condition at startup. Refer to the
section on Soft-Start for the maximum total
capacitance on the output.
NOTE: The Input and Output capacitors 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 filter applications.
15
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
Recommended PCB Footprint
Figure 12: EP53A7xQI Package PCB Footprint
©Enpirion 2009 all rights reserved, E&OE
01543
16
11/11/2009
www.enpirion.com
Rev:B
EP53A7LQI/EP53A7HQI
Package and Mechanical
Figure 13: EP53A7xQI Package Dimensions
Contact Information
Enpirion, Inc.
Perryville III
53 Frontage Road Suite 210
Hampton, NJ 08827
Tel..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 2009 all rights reserved, E&OE
01543
17
11/11/2009
www.enpirion.com
Rev:B
Similar pages