Enpirion® Power Datasheet
EN6310QI 1A PowerSoC
Voltage Mode Synchronous
PWM Buck with Integrated Inductor
www.altera.com/enpirion
Description
The EN6310QI is a member of Altera Enpirion’s high
efficiency EN6300 family of PowerSoCs. It can support
up to 1A of con tinuous output current and has an input
voltage range of 2.7V to 5.5V.
The EN6310QI employs Altera Enpirion’s EDMOS
MOSFET technology for monolithic integration and
very low switching loss. The device switches at
2.2MHz in fixed PWM operation to eliminate the low
frequency noise that is created by pulse frequency
modulation operating modes. The MOSFET ratios are
optimized to offer high conversion efficiency for lower
VOUT settings.
Output voltage settings are programmable via a simple
resistor divider circuit. Output voltage can be
programmed from as low as 0.6V to 3.3V. The device
has a programmable soft-start ramp rate to
accommodate sequencing and to prevent un-wanted
current inrush at start up. A Power OK (POK) flag is
provided to indicate a fault condition.
The Altera Enpirion power solution significantly helps
in system design and productivity by offering greatly
simplified board design, layout and manufacturing
requirements. In addition, a reduction in the number of
vendors required for the complete power solution helps
to enable an overall system cost savings.
All Enpirion products are RoHS compliant and lead-
free manufacturing environment compatible.
Features
• Integrated inductor, MOSFET and Controller
• Small 4mm x 5mm x 1.85mm QFN
• High Efficiency up to 96%
• Solution Footprint Less than 65mm2
• 1A Continuous Output Current
• VIN Range of 2.7V to 5.5V
• VOUT Range from 0.6V to 3.3V
• Programmable Soft Start and Power OK Flag
• Fast Transient Response and Recovery Time
• Low Noise and Low Output Ripple; 4mV Typical
• 2.2MHz Switching Frequency
• Under Voltage Lock-out (UVLO), Short Circuit, Over
Current and Thermal Protection
Applications
• Altera FPGAs (MAX, ARR I A, C YCLO NE, ST RATIX )
• Low Power FPGA Ap plic ati ons
• All SERDES and IO Supplies Requiring Low Noise
• Applications Requiring High Efficiency
• Enterprise Grade Solid State Drive (SSD)
• Noise Sensitive Wireless and RF Applications
Figure 1. Simplified Applications Circuit
Figure 2. Highest Efficiency in Smallest Solution
Size
V
OUT
V
IN VOUT
ENABLE
AGND
PVIN
PGND PGND
CSS
10nF
VFB
R
A
RB
RCA
CA
COUT
47µF
0805
AVIN
EN6310QI
SS
RAVIN
20Ω
CAVIN
0.47µF
OFF
ON
CIN1
100pF
CIN2
4.7µF
60
65
70
75
80
85
90
95
100
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
EFFICIENCY (%)
OUTPUT CURRENT (A)
Efficiency vs. Output Current
VOUT = 2.5V
VOUT = 1.0V
CONDITIONS
VIN = 3.3V
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EN6310QI
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Ordering Information
Part Number
Package Markings
TA (°C)
Package Description
EN6310QI
N6310
-40 to +85
30-pin (4mm x 5mm x 1.85mm) QFN T&R
EVB-EN6310QI
N6310
QFN Evaluation Board
Packing a nd Marking Information: www.altera.com/support/reliability/packing/rel-packing-and-marking.html
Pin Assignments (Top View)
Figure 3 : Pin Out Diagram (Top View)
NOT E 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: White ‘dot’ on top left is pin 1 indicator on top of the device package.
NOTE C: The Keep Out pin is the exposed metal below the package that is not to be mechanically or electrically connected
to the PCB.
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Pin Description
PIN
NAME
FUNCTION
1, 2, 24-
30
NC(SW)
NO CONNECT. Do not connect to any signal, voltage, or ground. These pins are connected
internally to the MOSFET common switch node.
3, 4 PGND
Power ground. The output filter capacitor ground terminal should be connected to these pins.
Refer to application details for proper layout and ground routing.
5-12
VOUT
Regulated output. Connect output capacitors from these pins to PGND (pins 3, 4).
15 NC
NO CONNECT. Do not connect to any signal, voltage, or ground. These pins may be
connected internally.
13
VFB
Output feed-back node. Connect to center of VOUT resistor divider.
14
AGND
Quiet analog ground for control circuits. Connect to system ground plane.
16
CSS
Soft Start startup time programming pin. Connect CSS capacitor from this pin to AGND.
17 POK
Power OK is an open drain transistor (pulled up to AVIN or similar voltage) used for power
system state indication. POK is logic high when VOUT is above 90% of VOUT nominal. Leave
this pin floating if not used.
18 ENABLE
Output enabl e;
Enable = logic high, Disable = logic low.
19
AVIN
Quiet input supply for circuitry.
20, 21 PGND
Power ground. The input filter capacitor ground terminal should be connected to these pins.
Refer to application details for proper layout and ground routing.
22, 23 PVIN
Input supply voltage for high side MOSFET Switch. Connect input filter capacitor from this pin
to PGND.
31
PGND
Bottom
Pad
Device thermal pad to be connected to the system GND plane. See Layout Recommendations
section.
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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 6.6 V
Voltages on: ENABLE, POK -0.3 VIN+0.3 V
Voltages on: VFB, SS
-0.3 2.7 V
Storage Temperature Range TSTG -65 150 °C
Maximum Operating Junction Temperature TJ-ABS Max 150 °C
Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020A 260 °C
ESD Rating (based on Human Body Model) 2000 V
ESD Rating (based on CDM) 500 V
Recommended Operating Conditions
PARAMETER
SYMBOL
MIN
MAX
UNITS
Input Voltage Range VIN 2.7 5.5 V
Output Volta ge Range VOUT 0.60 3.3 V
Output Current IOUT 1 A
Operating Ambient Temperature
TA -40 +85 °C
Operating Junction Temperature TJ -40 +125 °C
Thermal Characteristics
PARAMETER
SYMBOL
TYP
UNITS
Thermal Shutdown TSD 140 °C
Thermal Shutdown Hysteresis TSDH 20 °C
Thermal Resistance: Junction to Ambient (0 LFM) (Note 1) θJA 60 °C/W
Thermal Resistance: Junction to Case (0 LFM)
θJC
3
°C/W
Note 1: 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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Electrical Characteristics
NOTE: VIN (PVIN and AVIN) = 5.0V, Minimum and Maximum values are over operating ambient temperature range
unless otherwise noted. Typical values are at TA = 25°C.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range
VIN
VIN = AVIN = PVIN
2.7
5.5
V
Under Voltage Lockout VIN
Rising
UVLO_R 2.3 V
Under Voltage Lockout VIN
Falling
UVLO_F 1.9 V
Output Voltage Range
VOUT
0.6
3.3
V
Maximum Duty Cycle
DMAX
85
%
Feedback Pin Voltage
Initial Accuracy
VFB
T
A
= 25°C, V
IN
= 5.0V,
ILOAD = 100mA;
0.591 0.60 0.609 V
Output Volta ge
DC Accuracy
VIN = 3.3V; 0A ≤ I
OUT
≤ 1.0A;
-40°C ≤ TA ≤ +85°C
-2.0 +2.25 %
VIN = 5.0V; 0A ≤ I
OUT
≤ 1.0A;
-20°C ≤ TA ≤ +85°C
-2.0 +2.0 %
VIN = 5.0V; 0A ≤ I
OUT
≤ 1.0A;
-40°C ≤ TA ≤ +85°C
-3.0 +2.0 %
Feedback Pin Input Current
IVFB
(Note 3)
100
nA
Continuous Output Current
IOUT
1
A
Over Current Trip Point
IOCP
1.2
1.8
A
AVIN Shut-Down Current
ISD
ENABLE = Low
175
µA
PVIN Shut-Down Current
ISD
ENABLE = Low
2.2
µA
OCP Threshold
IOCP
2.7 ≤ VIN ≤ 5.5V
1.2
A
ENABLE Pin Logic Threshold
ENLOW
Pin = Low
0.0
0.4
V
ENHIGH
Pin = High
1.8
VIN
V
ENABLE Pin Input Current
I
ENABLE
ENABLE = High
5
µA
ENABLE Lock-out ENLO
Time before enable will re-assert
internally after being pulled low
12.5 ms
Switching Frequency
fSW
2.2
MHz
Soft Start Time
TSS
CSS = 10nF (Note 2 and 3)
5.2
6.5
7.8
ms
Allowable Soft Start Capacitor
Range
CSS (Note 3) 0.47 10 nF
Note 2: Soft Start Time range does not include capacitor tolerances.
Note 3: Parameter not production tested but is guaranteed by design.
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Typical Performance Curves
50
55
60
65
70
75
80
85
90
95
100
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
EFFICIENCY (%)
OUTPUT CURRENT (A)
Efficiency vs. Output Current
VOUT = 2.5V
VOUT = 1.8V
VOUT = 1.5V
VOUT = 1.2V
VOUT = 1.0V
CONDITIONS
V
IN
= 3.3V
50
55
60
65
70
75
80
85
90
95
100
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
EFFICIENCY (%)
OUTPUT CURRENT (A)
Efficiency vs. Output Current
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.8V
VOUT = 1.5V
VOUT = 1.2V
VOUT = 1.0V
CONDITIONS
V
IN
= 5.0V
0.970
0.980
0.990
1.000
1.010
1.020
1.030
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
OUTPUT VOL TAGE (V)
OUTPUT CURRENT (A)
Output Voltage vs. Output Current
VIN = 3.3V
VIN = 5V
CONDITIONS
V
OUT
= 1.0V
1.170
1.180
1.190
1.200
1.210
1.220
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
OUTPUT VOL TAGE (V)
OUTPUT CURRENT (A)
Output Voltage vs. Output Current
VIN = 3.3V
VIN = 5.0V
CONDITIONS
VOUT = 1.2V
1.470
1.480
1.490
1.500
1.510
1.520
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
OUTPUT VOL TAGE (V)
OUTPUT CURRENT (A)
Output Voltage vs. Output Current
VIN = 3.3V
VIN = 5.0V
CONDITIONS
V
OUT
= 1.5V
1.750
1.760
1.770
1.780
1.790
1.800
1.810
1.820
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
OUTPUT VOL TAGE (V)
OUTPUT CURRENT (A)
Output Voltage vs. Output Current
VIN = 3.3V
VIN = 5.0V
CONDITIONS
V
OUT
= 1.8V
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Typical Performance Curves (Continued)
2.470
2.480
2.490
2.500
2.510
2.520
2.530
2.540
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
OUTPUT VOL TAGE (V)
OUTPUT CURRENT (A)
Output Voltage vs. Output Current
VIN = 3.3V
VIN = 5.0V
CONDITIONS
V
OUT
= 2.5V
3.270
3.280
3.290
3.300
3.310
3.320
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
OUTPUT VOL TAGE (V)
OUTPUT CURRENT (A)
Output Voltage vs. Output Current
VIN = 5.0V
CONDITIONS
V
OUT
= 3.3V
0.980
0.985
0.990
0.995
1.000
1.005
1.010
1.015
1.020
-40 -15 10 35 60 85
OUTPUT VOL TAGE (V)
AMBIENT TEMPER ATURE (°C)
Output Voltage vs. Temperature
LOAD = 0.05A
LOAD = 0.2A
LOAD = 0.4A
LOAD = 0.8A
LOAD = 1A
CONDITIONS
V
IN
= 3.3V
V
OUT_NOM
= 1.0V
0.980
0.985
0.990
0.995
1.000
1.005
1.010
1.015
1.020
-40 -15 10 35 60 85
OUTPUT VOL TAGE (V)
AMBIENT TEMPER ATURE (°C)
Output Voltage vs. Temperature
LOAD = 0.05A
LOAD = 0.2A
LOAD = 0.4A
LOAD = 0.8A
LOAD = 1A
CONDITIONS
V
IN
= 5.0V
V
OUT_NOM
= 1.0V
2.400
2.420
2.440
2.460
2.480
2.500
2.520
2.540
2.560
-40 -15 10 35 60 85
OUTPUT VOL TAGE (V)
AMBIENT TEMPER ATURE (°C)
Output Voltage vs. Temperature
LOAD = 0.05A
LOAD = 0.2A
LOAD = 0.4A
LOAD = 0.8A
LOAD = 1A
CONDITIONS
V
IN
= 3.3V
V
OUT_NOM
= 2.5V
3.220
3.240
3.260
3.280
3.300
3.320
3.340
3.360
-40 -15 10 35 60 85
OUTPUT VOL TAGE (V)
AMBIENT TEMPER ATURE (°C)
Output Voltage vs. Temperature
LOAD = 0.05A
LOAD = 0.2A
LOAD = 0.4A
LOAD = 0.8A
LOAD = 1A
CONDITIONS
V
IN
= 5.0V
V
OUT_NOM
= 3.3V
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Typical Performance Curves (Continued)
1.770
1.775
1.780
1.785
1.790
1.795
1.800
1.805
1.810
1.815
1.820
2.5 33.5 44.5 55.5
OUTPUT VOL TAGE (V)
INPUT VOL TAGE (V)
Output Voltage vs. Input Voltage
LOAD = 0A
LOAD = 0.05A
LOAD = 0.25A
LOAD = 0.5A
LOAD = 1A
CONDITIONS
V
OUT_NOM
= 1.8V
T
A
= 25°C
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Typical Performance Characteristics
VOUT
(AC Coupled)
Output Ripple at 20MHz Bandwidth
CONDITIONS
VIN = 3.3V
VOUT = 1.2V
IOUT = 0A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
VOUT
(AC Coupled)
Output Ripple at 20MHz Bandwidth
CONDITIONS
VIN = 3.3V
VOUT = 1.2V
IOUT = 1A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
VOUT
(AC Coupled)
Output Ripple at 500MHz Bandwidth
CONDITIONS
VIN = 3.3V
VOUT = 1.2V
IOUT = 0A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
VOUT
(AC Coupled)
Output Ripple at 500MHz Bandwidth
CONDITIONS
VIN = 3.3V
VOUT = 1.2V
IOUT = 1A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
VOUT
(AC Coupled)
Output Ripple at 500MHz Bandwidth
CONDITIONS
VIN = 5V
VOUT = 1.2V
IOUT = 0A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
VOUT
(AC Coupled)
Output Ripple at 500MHz Bandwidth
CONDITIONS
VIN = 5V
VOUT = 1.2V
IOUT = 1A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
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Typical Performance Characteristics (Continued)
VOUT
(AC Coupled)
Output Ripple at 500MHz Bandwidth
CONDITIONS
VIN = 5V
VOUT = 3.3V
IOUT = 0A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
VOUT
(AC Coupled)
Output Ripple at 500MHz Bandwidth
CONDITIONS
VIN = 5V
VOUT = 3.3V
IOUT = 1A
CIN = 4.7µF (0603) + 100pF
COUT = 47 µF (0805)
VOUT = 1V
(AC Coupled)
50mV / DIV
Load Transient from 0A to 1A
CONDITIONS
VIN = 3.3V, VOUT = 1V
CIN = 4.7µF (0603) + 100pF
COUT = 47µF (0805)
Using Datasheet Recommended Components
LOAD
VOUT = 1.8V
(AC Coupled)
50mV / DIV
Load Transient from 0A to 1A
CONDITIONS
VIN = 3.3V, VOUT = 1.8V
CIN = 4.7µF (0603) + 100pF
COUT = 47µF (0805)
Using Datasheet Recommended Components
LOAD
VOUT = 2.5V
(AC Coupled)
50mV / DIV
Load Transient from 0A to 1A
CONDITIONS
VIN = 3.3V, VOUT = 2.5V
CIN = 4.7µF (0603) + 100pF
COUT = 47µF (0805)
Using Datasheet Recommended Components
LOAD
VOUT = 1.0V
(AC Coupled)
50mV / DIV
Load Transient from 0A to 1A
CONDITIONS
VIN = 5.0V, VOUT = 1.0V
CIN = 4.7µF (0603) + 100pF
COUT = 47µF (0805)
Using Datasheet Recommended Components
LOAD
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Typical Performance Characteristics (Continued)
VOUT = 1.8V
(AC Coupled)
50mV / DIV
Load Transient from 0A to 1A
CONDITIONS
VIN = 5.0V, VOUT = 1.8V
CIN = 4.7µF (0603) + 100pF
COUT = 47µF (0805)
Using Datasheet Recommended Components
LOAD
VOUT = 1.8V
(AC Coupled)
50mV / DIV
Load Transient from 0A to 1A
CONDITIONS
VIN = 5.0V, VOUT = 3.3V
CIN = 4.7µF (0603) + 100pF
COUT = 47µF (0805)
Using Datasheet Recommended Components
LOAD
ENABLE
Enable Startup/Shutdown W aveform (0A)
CONDITIONS
VIN = 5V, VOUT = 1.8V, No Load, Css = 10nF
CIN = 4.7µF (0603) + 100pF, COUT = 47 µF (0805)
VOUT
POK
LOAD
ENABLE
Enable Startup/Shutdown W aveform (1A)
CONDITIONS
VIN = 5V, VOUT = 1.8V, 1A Load, Css = 10nF
CIN = 4.7µF (0603) + 100pF, COUT = 47 µF (0805)
VOUT
POK
LOAD
ENABLE
Enable Startup Waveform (0A)
CONDITIONS
VIN = 5V, VOUT = 1.8V, No Load, Css = 10nF
CIN = 4.7µF (0603) + 100pF, COUT = 47 µF (0805)
VOUT
POK
LOAD
ENABLE
Enable Shutdown Waveform (0A)
CONDITIONS
VIN = 5V, VOUT = 1.8V, No Load, Css = 10nF
CIN = 4.7µF (0603) + 100pF, COUT = 47 µF (0805)
VOUT
POK
LOAD
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Functional Block Diagram
(+)
(-)
Error
Amp
VFB
VOUT
P-Drive
N-Drive
UVLO
Thermal Limit
Current Limit
Soft Start
PLL/Sawtooth
Generator
(+)
(-)PWM
Comp
PVIN
ENABLE
PGND
Logic
Compensation
Network
NC(SW)
AVIN
AGND
Internal
Regulator
Internal
Reference
CSS
Power
OK POK
Figure 4: Functional Block Diagram
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Functional Description
Functional Overview
The EN6310QI is a synchronous buck converter with
integrated MOSFET switches and Inductor. The
device can deliver up to 1A of continuous load
current. The EN6310QI has a programmable soft
start rise time and a power OK (POK) signal. The
device operates in a fixed 2.2MHz PWM mode to
eliminate noise associated with pulse frequency
modulation schemes. The control topology is a low
complexity type IV voltage mode providing high
noise immunity and stability over the entire operating
range. Output voltage is set with a simple resistor
divider. The high switching frequency enables the
use of small M LCC input and output filter capacitors.
Figure 4 shows the EN6310QI block diagram.
Protection Features:
The EN6310QI has the following protection features.
• Over-current protection (to protect the IC from
excessive load current)
• Short-Circuit protection
• Thermal shutdown with hysteresis
• Under-voltage lockout circuit to disable the
converter output when the input voltage is below
a pre-defined level
Additional Features:
• Soft-start circuit, limiting the in-rush current when
the converter is initially powered up. The soft
start time is programmable with appropriate
choice of soft start capacitor value
High Efficiency Technology
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 inte gration of all swi tching,
control, and compensation circuitry.
The proprietary magnetics design provides high-
density/high-value magnetics in a very small
footprint. Enpirion mag netics are carefully matc hed
to the control and compe nsation ci rcuitry yiel ding an
optimal solution with assured performance over the
entire operating range.
Integration for Low-Noise Low-EMI
The EN6310QI 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. Furthermore, 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. Careful package and IC design
minimize common mode noise that can be difficult to
mitigate otherwise. The integrated inductor provides
the optimal solution to the complexity, output ripple,
and noise that plague low power DCDC converter
design.
Control Topology
The EN6310QI utilizes an internal type IV voltage
mode compensation scheme. Voltage mode control
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. T h e hi g h
switching frequency allows for a very wide control
loop bandwidth and hence excellent transient
performance. The EN6310QI is optimized for fast
transient recovery for applications with demanding
transient performance. Voltage mode control
enables a high degree of stability over the entire
operating range.
Enable
The EN6310QI ENABLE pin enables and disables
operation of the device. A logic low will disable the
converter and cause it to shut dow n. A l ogic high w ill
enable the converter and initiate a normal soft start
operation. When ENABLE is pulled low, the Power
MOSFETs stop switching and the output is
discharged in a controlled manner with a soft pull
down MOSFET. Once the enable pin is pulled low,
there is a lockout period be fore the device can be re-
enabled. The lock out period can be found in the
Electrical Characteristics Table. Do not leave
ENABLE pin floating or it will be in an unknown
random state.
The EN6310QI supports startup into a pre-biased
output of up to 1.5V. The output of the EN6310QI
can be pre-biased with a voltage up to 1.5V when it
is first enabled.
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POK Operation
The POK signal is an open drain signal (requires a
pull up resistor to AVIN or similar voltage) from the
converter indicating the output voltage is within the
specified range. Typically, a 100kΩ or lower
resistance is used as the pull-up resistor. The POK
signal will be logic high (AVIN) when the output
voltage is above 90% of the programmed voltage
level. If the output voltage is below this point, the
POK sig na l will be a logic low. The POK will also be
a logic low if the input voltage is in UVLO or if the
ENABLE is pulled low. The POK signal can be used
to sequence down-stream converters by tying to
their enable pins.
Programmable Soft Start Operation
Soft start is externally programmable by adjusting
the value of the CSS capacitor, which is placed
between the respective CSS pin and AGND pin.
When the enable pin is pulled high, the output will
ramp up monotonically at a rate determined by the
CSS capacitor.
Soft start ramp time is programmable over a range
of 0.5ms to 10ms. The longer ramp times allow
startup into very large bulk capacitors that may be
present in applications such as wireless broadband
or solid state storage, without triggering an Over
Current condition. The rise time is given as:
TRISE [ms] = CSS [nF] 0.65 ± 25%
NOTE: Rise time does not include capacitor
tolerances.
If a 10nF soft-s tart capacitor is used , then the outp ut
voltage rise time will be around 6.5ms. The rise time
is measured from when VIN ≥ VUVLOR and ENABLE
pin voltage crosses its logic high threshold to when
VOUT reaches its programmed value.
Over Current/Short Circuit Protection
The current limit and short-circuit protection is
achieved by sensing the current flowing through a
sense PFET. When the sensed current exceeds t he
current limit, both NFET and PFET switches are
turned off and the output is discharged. A fter 1.6ms
the device will be re-enabled and will then go
throug h a normal soft-start cycle. If the over current
condition persists, the device will enter a hiccup
mode.
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.
Thermal Shutdown
When excess power is dissipated in the EN6310QI
the junction temperature will rise. 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 to
a safe operating level, the part will go through the
normal startup process. The thermal shutdown
temperature and hysteresis values can be found in
the electrical characteristics table.
09644 March 9, 2017 Rev F
EN6310QI
www.altera.com/enpirion, Page 15
Application Information
Output Voltage Programming
Th e E N6310QI output voltage is programmed using
a simple resistor divider network (RA and RB). The
feedback voltage at VFB is nominally 0.6V. RA is
fixed at 200kΩ and RB can be calculated based on
Figure 5. The values recommended for COUT, CA,
and RCA make up the external compensation of the
EN6310QI. It will vary with each VIN and VOUT
combination to optimize on performance. Please see
Table 1 for a li st of re com me nd ed RA, CA, RCA, and
COUT values for each solution. Since VFB is a
sensitive node, do not touch the VFB node w hile the
device is in operation as doing so may introduce
parasitic capacitance into the control loop that
causes the device to behave abnormally and
damage may occur.
The output voltage is set by the following formula:
= 1 +
Rearranging to solve for RB:
=
Where:
RA = 200kΩ
VREF = 0.60V
Then RB is given as:
=
120
0.6
RA is chosen as 200kΩ to provide constant loop
gain. The output voltage can be programmed over
the range of 0.6V to 3.3V.
VOUT
VOUT
PGND
VFB
RA
RB
RCA
CA
COUT
RA
VFB
VFB
VOUT
x-
=
VFB = 0.6V
EN6310QI
Figure 5 . Extern al Compensation
CIN = 4.7µF/0603 + 100pF
CAVIN = 20Ω + 0.47µF
COUT = 47µF/0805 or 2x22µF/0603
RA = 200kΩ, RCA = 1kΩ, RB = 0.6RA/(VOUT – 0.6)
V
IN
(V)
V
OUT
(V)
Ca
(pF)
V
IN
(V)
V
OUT
(V)
Ca
(pF)
5.5
3.3
15
5.5
1.2
27
5
15
5
27
4.5
15
4.5
33
5.5
2.5
15
3.3
33
5 15 2.7 39
4.5
15
5.5
1
39
3.3 15 5 39
5.5
1.8
15
4.5
39
5
15
3.3
47
4.5 15 2.7 47
3.3
22
5.5
0.6
39
2.7
22
5
39
5.5
1.5
22
4.5
47
5
22
3.3
56
4.5 22 2.7 56
3.3
27
2.7 33
Table 1. Compensation values. For output voltages in
between, use the values from the higher output voltage
09644 March 9, 2017 Rev F
EN6310QI
www.altera.com/enpirion, Page 16
Input Filter Capacitor
The EN6310QI requires at least a 4.7 µF/0603 and a
100pF input capacitor near the PVIN pins. Low -cost,
low-ESR ceramic capacitors should be used as input
capacitors for this converter. The dielectric must be
X5R or X7R rated. Y5V or equivalent dielectric
formulations must not be used as these lose too
much capacitance with frequency, temperature and
bias voltage. In some applications, lower value
capacitors are needed in parallel with the larger
capacitors in order to provide high frequency
decoupling. Table 2 contains a list o f recommended
input capacitors.
Description
MFG
P/N
4.7µF, 10V,
X5R, 10%,
0603
Murata GRM185R61A475KE11#
4.7µF, 10V,
X5R, 10%,
0603
Taiyo Yuden LMK107BJ475KA-T
Table 2. Recommended Input Capacitors
Output Filter Capacitor
The EN6310QI requires at least a 47µF /0805 or two
22µF/0603 output filter capacitors. Low ESR
ceramic capacitors are required with X5R or X7R
rated dielectric formulation. Y5V or equivalent
dielectric formulations must not be used as these
lose too much capacitance with frequency,
temperature and bias voltage. Table 3 contains a list
of recommended output capacitors.
Description
MFG
P/N
47µF, 6.3V,
X5R, 20%,
0805
Murata GRM21BR60J476ME15#
47µF, 6.3V,
X5R, 20%,
0805
Taiyo Yuden JMK212BBJ476MG-T
22µF, 10V,
X5R, 20%,
0603
Murata GRM188R60J226MEA0#
22µF, 10V,
X5R, 20%,
0603
Taiyo Yuden JMK107BBJ226MA-T
Table 3. Recommended Output Capacitors
09644 March 9, 2017 Rev F
EN6310QI
www.altera.com/enpirion, Page 17
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 EN6310QI DC-DC converter is
packaged in a 4x5x1.85mm 30-pin QFN package.
The QFN package is constructed with copper lead
frames that have exposed thermal pads. The
exposed thermal pad on the package should be
soldered directly on to a copper ground pad on the
printed circuit board (PCB) to act as a hea t 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
140°C.
The following example a nd calculations il lustrate the
thermal performance of the EN6310QI.
Example:
VIN = 5V
VOUT = 3.3V
IOUT = 1A
First calculate the output power.
POUT = 3.3V x 1A = 3.3W
Next, determine the input power based on the
efficiency (η) shown in Figure 6.
Figure 6. Efficiency vs. Output Current
For VIN = 5 V, VOUT = 3.3V at 1A, η ≈ 91%
η = POUT / PIN = 91% = 0.91
PIN = POUT / η
PIN ≈ 3.3W / 0.91 ≈ 3.63W
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
≈ 3.63W – 3.3W ≈ 0.33W
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 EN6310QI has
a θJA value of 60 °C/W without airflow.
Determine the change in temperature (ΔT) based on
PD and θJA.
ΔT = PD x θJA
ΔT ≈ 0.33W x 60°C/W ≈ 19.8°C ≈ 20°C
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.
TJ = TA + ΔT
TJ ≈ 25°C + 20°C ≈ 45°C
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.
TAMAX = TJMAX – PD x θJA
≈ 125°C – 20°C ≈ 105°C
The maximum ambient temperature the device can
reach is 105°C given the input and output conditions.
Note that the efficiency will be slightly lower at higher
temperatures and this calculation is an estimate.
50
55
60
65
70
75
80
85
90
95
100
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
EFFICIENCY (%)
OUTPUT CURRENT (A)
Efficiency vs. Output Current
VOUT = 3.3V
CONDITIONS
V
IN
= 5.0V
09644 March 9, 2017 Rev F
EN6310QI
www.altera.com/enpirion, Page 19
Layout Recommendation
Figure 8. Evaluation Board Layout Recommendations
Recommendation 1: Input and output filter
capacitors should be pl aced on the same sid e of
the PCB, and as close to the EN6310QI
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 EN6310QI should be as
close to each other as possible so that the gap
between the two nodes is minimized, even
under the capacitors.
09644 March 9, 2017 Rev F
EN6310QI
www.altera.com/enpirion, Page 20
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 see the Gerber files on EN6310QI’s
product page at www.altera.com/enpirion.
Recommendation 3: The large thermal pad
underneath the component must be connected
to the system ground plane through as many
vias as possible.
The dr ill diameter of the v ias shoul d 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. See
Figure 8.
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 c apac i t or s to the sy st em gr ound pla ne . It
is preferred to put these vias under the
capacitors along the edge of the GND copper
closest to the +V copper. Please see Figure 8.
These vias connect the input/output filter
capacitors to the GND plane, and help reduce
parasitic inductances in the input and output
current l oops. I f the vi as cannot be placed under
CIN and COUT, then put them just outside the
capacitors along the GND slit separating the two
components. Do not use thermal reliefs or
spokes to connect these vias to the ground
plane.
Recommendation 5: AVIN is the power supply
for the internal small-signal control circuits. It
should be connected to the input voltage at a
quiet point. A good l oc at ion is t o place the AV I N
connection on the source side of the input
capacitor, away from the PVIN pins.
Recommendation 6: The lay er 1 metal under
the device must not be more than shown in
Figure 8. See the section regarding exposed
metal on bottom of pac kage. 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 as short as
possible in order to avoi d noise c oupling into the
control loop.
Recommendation 8: Keep RA, CA, and RB
close to the VFB pin (see Figures 6 and 7). The
VFB pin is a high-impedance, 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.
09644 March 9, 2017 Rev F
EN6310QI
www.altera.com/enpirion, Page 21
Recommended PCB Footprint
Figure 9. EN6310QI PCB F ootpri nt (Top View)
Note: Don’t use the layer underneath the device keep out area as it contains the exposed metal below the package that is
not to be mechanically or electrically connected to the PCB.
09644 March 9, 2017 Rev F
EN6310QI
www.altera.com/enpirion, Page 23
Revision History
Rev
Date
Change(s)
A
March 2014
• Introductory production datasheet
B
March 2015
• Pin 12 ch an ged to VOUT instead of NC
C
June 2015
• Updated t he pre-bias section adding the capability of pre-bias ing to vo ltag e up to 1.5V
D Feb 2016
• Changed Feedback Pin Voltage Initial Accuracy on Electrical Characteristics Table
• Corrected thermal hysteresis value in thermal shutdown section
• Added section on "Design considerations for lead-frame based modules" i.e. keepout area
• Modified PCB Footprint and package drawings
• Formatting changes
E June 2016
• Added EMI scan data
• Clarified location of Gerber files in layout recommendation section
F Feb 2017
• Updating the device package drawings with the keep-out area drawing.
• Drawing the Keep-out Pins in figure 3.
Contact Information
Altera Corporation
101 Innov ati on Dr ive
San Jose, CA 95134
Phone: 408-544-7000
www.altera.com
© 2014 Altera Corporation—Confidential. All rights reserved. ALTERA, ARRIA, CYCLONE, ENPIRION, HARDCOPY, MAX, MEGACORE, NIOS, QUARTUS and STRATIX
words and logos are trademarks of Altera Corporation and registered in the U.S. Patent and Trademark Office and in other countries. All other words and logos identified as
trademarks or service marks are the property of their respective holders as describ ed at w ww .alt er a. com /c ommon/l eg al .htm l . Alt er a warr ants perform a nce of its semi co nd uc to r
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notice. Altera assumes no responsibility or liability arising out of the application or use of any information, product, or service described herein except as expressly agreed to in
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09644 March 9, 2017 Rev F
