ENPIRION EN63A0QI

EN63A0QI
12A Synchronous Highly Integrated DC-DC
PowerSoC
Description
Features
The EN63A0QI is a Power System on a Chip
(PowerSoC) DC to DC converter with an integrated
inductor,
PWM
controller,
MOSFETs
and
compensation to provide the smallest solution size in
an 10x11x3mm 76-pin QFN module. It offers high
efficiency, excellent line and load regulation over
temperature and up to the full 12A load range. The
EN63A0QI is specifically designed to meet the
precise voltage and fast transient requirements of
high-performance, low-power processor, DSP, FPGA,
memory boards and system level applications in
distributed power architecture. The EN63A0QI
features switching frequency synchronization with an
external clock or other EN63A0QIs for parallel
operation. Other features include precision enable
threshold, pre-bias monotonic start-up, and
programmable soft-start. The device’s advanced
circuit techniques, ultra high switching frequency, and
proprietary integrated inductor technology deliver
high-quality, ultra compact, non-isolated DC-DC
conversion.
The Enpirion integrated inductor solution significantly
helps to reduce noise. The complete power converter
solution enhances productivity by offering greatly
simplified board design, layout and manufacturing
requirements. All Enpirion products are RoHS
compliant and lead-free manufacturing environment
compatible.
•
•
•
•
•
•
•
•
•
•
•
High Efficiency (Up to 96%)
Excellent Ripple and EMI Performance
Up to 12A Continuous Operating Current
Input Voltage Range (2.5V to 6.6V)
Frequency Synchronization (Clock or Primary)
2% VOUT Accuracy (Over Line/Load/Temperature)
Optimized Total Solution Size (225mm2)
Precision Enable Threshold for Sequencing
Programmable Soft-Start
Master/Slave Configuration for Parallel Operation
Thermal Shutdown, Over-Current, Short Circuit,
and Under-Voltage Protection
• RoHS Compliant, MSL Level 3, 260°C Reflow
Applications
• Point of Load Regulation for Low-Power, ASICs
Multi-Core and Communication Processors, DSPs,
FPGAs and Distributed Power Architectures
• Blade Servers, RAID Storage and LAN/SAN
Adapter Cards, Wireless Base Stations, Industrial
Automation, Test and Measurement, Embedded
Computing, and Printers
• High Efficiency 12V Intermediate Bus Architectures
• Beat Frequency/Noise Sensitive Applications
Efficiency vs. Output Current
100
90
EFFICIENCY (%)
80
70
Actual Solution Size
225mm2
60
50
CONDITIONS
VIN = 3.3V
40
30
20
VOUT = 2.5V
10
VOUT = 1.2V
0
0
Figure 1. Simplified Applications Circuit
1
2
3
4 5 6 7 8 9
OUTPUT CURRENT (A)
10 11 12
Figure 2. Highest Efficiency in Smallest Solution Size
www.enpirion.com
07077
May 9, 2012
Rev: C
EN63A0QI
Ordering Information
Part Number
EN63A0QI
EN63A0QI-E
Package Markings
EN63A0QI
EN63A0QI
Temp Rating (°C)
-40 to +85
Package Description
76-pin (10mm x 11mm x 3mm) QFN T&R
QFN Evaluation Board
Packing and Marking Information: http://www.enpirion.com/resource-center-packing-and-marking-information.htm
M/S
AGND
AVIN
ENABLE
POK
61
60
59
58
33
34
35
36
37
38
PGND
PGND
PGND
PGND
PGND
PGND
VOUT
KEEP OUT
57
S_OUT
VFB
63
62
32
PGND
SS
EAOUT
65
64
30
NC(SW)
31
VSENSE
NC
NC(SW)
NC
66
29
VOUT
FQADJ
EN_PB
69
26
27
VOUT
67
NC(SW)
70
25
28
NC(SW)
71
24
VOUT
VOUT
VOUT
NC
72
23
VOUT
NC
NC
73
22
NC
74
21
VOUT
NC
75
20
VOUT
76
19
NC
68
Pin Assignments (Top View)
Figure 3: Pin Out Diagram (Top View)
NOTE 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: Shaded area highlights exposed metal below the package that is not to be mechanically or electrically
connected to the PCB. Refer to Figure 11 for details.
NOTE C: White ‘dot’ on top left is pin 1 indicator on top of the device package.
Pin Description
PIN
NAME
1-19, 29,
52-53,
67, 72-76
NC
20-28
VOUT
FUNCTION
NO CONNECT: These pins must be soldered to PCB but not electrically connected to each
other or to any external signal, voltage, or ground. These pins may be connected internally.
Failure to follow this guideline may result in device damage.
Regulated converter output. Connect to the load and place output filter capacitor(s) between
these pins and PGND pins 32 to 35.
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 2
Rev: C
EN63A0QI
PIN
NAME
30-31,7071
NC(SW)
32-38
PGND
39-51
PVIN
54
VDDB
55
BGND
56
S_IN
57
S_OUT
58
POK
59
ENABLE
60
AVIN
61
AGND
62
M/S
63
VFB
64
EAOUT
65
SS
66
VSENSE
68
FQADJ
69
EN_PB
77
PGND
FUNCTION
NO CONNECT: These pins are internally connected to the common switching node of the
internal MOSFETs. They must be soldered to PCB but not be electrically connected to any
external signal, ground, or voltage. Failure to follow this guideline may result in device damage.
Input and output power ground. Connect these pins to the ground electrode of the input and
output filter capacitors. Refer to VOUT, PVIN descriptions and Layout Recommendation for
more details.
Input power supply. Connect to input power supply and place input filter capacitor(s) between
these pins and PGND pins 36 to 38.
Internal regulated voltage used for the internal control circuitry. Decouple with an optional
0.1µF capacitor to BGND for improved efficiency. This pin may be left floating if board space is
limited.
Ground for VDDB. Refer to pin 46 description.
Digital input. A high level on the M/S pin will make this EN63A0QI a Slave and the S_IN will
accept the S_OUT signal from another EN63A0QI for parallel operation. A low level on the M/S
pin will make this device a Master and the switching frequency will be phase locked to an
external clock. Leave this pin floating if it is not used.
Digital output. A low level on the M/S pin will make this EN63A0QI a Master and the internal
switching PWM signal is output on this pin. This output signal is connected to the S_IN pin of
another EN63A0QI device for parallel operation. Leave this pin floating if it is not used.
POK is a logic level high when VOUT is within -10% to +20% of the programmed output
voltage (0.9VOUT_NOM ≤ VOUT ≤ 1.2VOUT_NOM). This pin has an internal pull-up resistor to AVIN
with a nominal value of 120kΩ.
Device enable pin. A high level or floating this pin enables the device while a low level disables
the device. A voltage ramp from another power converter may be applied for precision enable.
Refer to Power Up Sequencing.
Analog input voltage for the control circuits. Connect this pin to the input power supply (PVIN)
at a quiet point. Can also be connected to an auxiliary supply within a voltage range that is
sequencing.
The quiet ground for the control circuits. Connect to the ground plane with a via right next to the
pin.
Ternary (three states) input pin. Floating this pin disables parallel operation. A low level
configures the device as Master and a high level configures the device as a Slave. A REXT
resistor is recommended to pulling M/S high. Refer to Ternary Pin description in the Functional
Description section for REXT values. Also see S_IN and S_OUT pin descriptions.
This is the external feedback input pin. A resistor divider connects from the output to AGND.
The mid-point of the resistor divider is connected to VFB. A feed-forward capacitor (CA) and
resistor (R1) are required parallel to the upper feedback resistor (RA). The output voltage
regulation is based on the VFB node voltage equal to 0.600V. For Slave devices, leave VFB
floating.
Error amplifier output. Allows for customization of the control loop. May be left floating.
A soft-start capacitor is connected between this pin and AGND. The value of the capacitor
controls the soft-start interval. Refer to Soft-Start in the Functional Description for more details.
This pin senses output voltage when the device is in pre-bias (or back-feed) mode. Connect
VSENSE to VOUT when EN_PB is high or floating. Leave floating when EN_PB is low.
Frequency adjust pin. This pin must have a resistor to AGND which sets the free running
frequency of the internal oscillator.
Enable pre-bias input. When this pin is pulled high, the device will support monotonic start-up
under a pre-biased load. VSENSE must be tied to VOUT for EN_PB to function. This pin is
pulled high internally. Enable pre-bias feature is not available for parallel operations.
Not a perimeter pin. Device thermal pad to be connected to the system GND plane for heatsinking purposes. Refer to Layout Recommendation section.
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 3
Rev: C
EN63A0QI
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
7.0
V
Voltages on: EN, POK, M/S
-0.3
VIN+0.3
V
Voltages on: VFB, EXTREF, EAOUT, SS, S_IN, S_OUT, FQADJ
-0.3
2.5
V
-65
150
°C
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
Storage Temperature Range
TSTG
Maximum Operating Junction Temperature
TJ-ABS Max
Recommended Operating Conditions
PARAMETER
SYMBOL
MIN
MAX
UNITS
VIN
2.5
6.6
V
Output Voltage Range (Note 1)
VOUT
0.60
VIN – VDO
V
Output Current
IOUT
12
A
Input Voltage Range
Operating Ambient Temperature
TA
-40
+85
°C
Operating Junction Temperature
TJ
-40
+125
°C
Thermal Characteristics
SYMBOL
TYP
UNITS
Thermal Resistance: Junction to Ambient (0 LFM) (Note 2)
PARAMETER
θJA
14
°C/W
Thermal Resistance: Junction to Case (0 LFM)
θJC
1.0
°C/W
Thermal Shutdown
TSD
150
°C
Thermal Shutdown Hysteresis
TSDH
20
°C
Note 1: VDO (dropout voltage) is defined as (ILOAD x Dropout Resistance). Please refer to Electrical Characteristics Table.
Note 2: Based on 2oz. external copper layers and proper thermal design in line with EIJ/JEDEC JESD51-7 standard for
high thermal conductivity boards.
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 4
Rev: C
EN63A0QI
Electrical Characteristics
NOTE: VIN=6.6V, Minimum and Maximum values are over operating ambient temperature range unless otherwise noted.
Typical values are at TA = 25°C.
PARAMETER
SYMBOL
Operating Input
Voltage
VIN
VFB Pin Voltage
VVFB
Internal Voltage Reference at:
VIN = 5V, ILOAD = 0, TA = 25°C
0.594
VFB Pin Voltage
(Line, Load and
Temperature)
VVFB
2.5V ≤ VIN ≤ 6.6V
0A ≤ ILOAD ≤ 12A
0.588
VFB Pin Input Leakage
Current
IVFB
VFB Pin Input Leakage Current
Shut-Down Supply
Current
IS
Power Supply Current with
ENABLE=0
1.5
mA
Under Voltage Lockout – VIN Rising
VUVLOR
Voltage Above Which UVLO is Not
Asserted
2.2
V
Under Voltage Lockout – VIN Falling
VUVLOF
Voltage Below Which UVLO is
Asserted
2.1
V
VINMIN – VOUT at Full Load
600
1200
mV
50
100
mΩ
12
A
Dropout Voltage
VDO
TEST CONDITIONS
MIN
TYP
MAX
UNITS
6.6
V
0.600
0.606
V
0.600
0.612
V
0.2
µA
2.5
Dropout Resistance
(Note 4)
RDO
Input to Output Resistance
Continuous Output
Current
IOUT_SRC
Refer to Table 2 for conditions.
Over Current Trip
Level
IOCP
Sourcing Current
Switching Frequency
FSW
RFADJ = 4.42 kΩ, VIN = 5V
External SYNC Clock
Frequency Lock
Range
FPLL_LOCK
SYNC Clock Input Frequency
Range
S_IN Clock Amplitude
– Low
VS_IN_LO
SYNC Clock Logic Low
S_IN Clock Amplitude
– High
VS_IN_HI
S_IN Clock Duty Cycle
(PLL)
S_IN Clock Duty Cycle
(PWM)
-0.2
0
18.5
A
0.9
1.2
1.5
MHz
0.9*Fsw
Fsw
1.1*Fsw
MHz
0
0.8
V
SYNC Clock Logic High
1.8
2.5
V
DCS_INPLL
M/S Pin Float or Low
20
80
%
DCS_INPWM
M/S Pin High
10
90
%
Pre-Bias Level
VPB
Allowable Pre-bias as a Fraction of
Programmed Output Voltage for
Monotonic start up. Minimum Prebias Voltage = 300mV.
20
75
%
Non-Monotonicity
VPB_NM
Allowable Non-monotonicity Under
Pre-bias Startup
VOUT Range for POK =
High
Range of Output Voltage as a
Fraction of Programmed Value
When POK is Asserted. (Note 3)
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
100
90
mV
120
%
www.enpirion.com, Page 5
Rev: C
EN63A0QI
PARAMETER
SYMBOL
TEST CONDITIONS
POK Deglitch Delay
Falling Edge Deglitch Delay After
Output Crossing 90% level.
FSW =1.2 MHz
VPOK Logic Low level
With 4mA Current Sink into POK Pin
MIN
TYP
MAX
213
UNITS
µs
0.4
V
VPOK Logic high level
VIN
V
POK Internal pull-up
resistor
94
kΩ
+/-10
%
Current Balance
VOUT Rise Time
Accuracy
∆IOUT
∆TRISE
(Note 4)
With 2 to 4 Converters in Parallel,
the Difference Between Nominal
and Actual Current Levels.
∆VIN<50mV; RTRACE< 10 mΩ,
Iload= # Converter * IMAX
tRISE [ms] = CSS [nF] x 0.065;
10nF ≤ CSS ≤ 30nF;
(Note 5 and Note 6)
-25
+25
%
2.5V ≤ VIN ≤ 6.6V;
1.2
VIN
V
0
0.8
V
ENABLE Logic High
VENABLE_HIGH
ENABLE Logic Low
VENABLE_LOW
ENABLE Pin Current
IEN
VIN = 6.6V
M/S Ternary Pin Logic
Low
VT-LOW
Tie M/S Pin to GND
M/S Ternary Pin Logic
Float
VT-FLOAT
M/S Ternary Pin Logic
Hi (Note 7)
50
µA
0
0.7
V
M/S Pin is Open
1.1
1.4
V
VT-HIGH
Pull Up to VIN through an external
resistor REXT . Refer to Figure 7.
1.8
Ternary Pin Input
Current
ITERN
2.5V ≤ VIN ≤ 4V, REXT = 15k
4V < VIN ≤ 6.6V, REXT = 51k
117
88
µA
Binary Pin Logic Low
Threshold
VB-LOW
ENABLE, S_IN
0.8
V
Binary Pin Logic High
Threshold
VB-HIGH
ENABLE, S_IN
S_OUT Low Level
VS_OUT_LOW
S_OUT High Level
VS_OUT_HIGH
Ω
Ω
V
1.8
V
0.4
2.0
V
V
Note 3: POK threshold when VOUT is rising is nominally 92%. This threshold is 90% when VOUT is falling. After crossing
the 90% level, there is a 256 clock cycle (~213µs at 1.2 MHz) delay before POK is de-asserted. The 90% and 92% levels
are nominal values. Expect these thresholds to vary by ±3%.
Note 4: Parameter not production tested but is guaranteed by design.
Note 5: Rise time calculation begins when AVIN > VUVLO and ENABLE = HIGH.
Note 6: VOUT Rise Time Accuracy does not include soft-start capacitor tolerance..
Note 7: M/S pin is ternary. Ternary pins have three logic levels: high, float, and low. This pin is meant to be strapped to
VIN through an external resistor, strapped to GND, or left floating. The state cannot be changed while the device is on.
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 6
Rev: C
EN63A0QI
Typical Performance Curves
Efficiency vs. Output Current
Efficiency vs. Output Current
90
90
80
80
EFFICIENCY (%)
100
EFFICIENCY (%)
100
70
60
50
40
VOUT = 2.5V
30
VOUT = 1.8V
20
VOUT = 1.2V
10
VOUT = 1.0V
CONDITIONS
VIN = 3.3V
0
70
60
VOUT = 3.3V
50
VOUT = 2.5V
40
30
VOUT = 1.8V
20
VOUT = 1.2V
10
VOUT = 1.0V
0
0
1
2
3
4 5 6 7 8 9
OUTPUT CURRENT (A)
0
10 11 12
Output Voltage vs. Output Current
1.815
1.015
VOUT = 1.8V
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
2
3 4 5 6 7 8
OUTPUT CURRENT (A)
9
10 11 12
1.020
1.810
1.805
1.800
1.795
1.790
CONDITIONS
V IN = 3.3V
1.785
VOUT = 1.0V
1.010
1.005
1.000
0.995
0.990
CONDITIONS
VIN = 3.3V
0.985
1.780
0.980
0
1
2
3 4 5 6 7 8 9
OUTPUT CURRENT (A)
10 11 12
0
Output Voltage vs. Output Current
1
2
3 4 5 6 7 8 9
OUTPUT CURRENT (A)
10 11 12
Output Voltage vs. Output Current
1.820
3.315
OUTPUT VOLTAGE (V)
3.320
OUTPUT VOLTAGE (V)
1
Output Voltage vs. Output Current
1.820
VOUT = 3.3V
3.310
3.305
3.300
3.295
3.290
CONDITIONS
V IN = 5.0V
3.285
1.815
VOUT = 1.8V
1.810
1.805
1.800
1.795
1.790
CONDITIONS
VIN = 5.0V
1.785
3.280
1.780
0
1
2
3 4 5 6 7 8 9
OUTPUT CURRENT (A)
Enpirion 2012 all rights reserved, E&OE
07077
CONDITIONS
VIN = 5.0V
10 11 12
0
Enpirion Confidential
May 9, 2012
1
2
3 4 5 6 7 8 9
OUTPUT CURRENT (A)
10 11 12
www.enpirion.com, Page 7
Rev: C
EN63A0QI
Typical Performance Curves (Continued)
Output Voltage vs. Input Voltage
Output Voltage vs. Output Current
1.220
1.015
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.020
VOUT = 1.0V
1.010
1.005
1.000
0.995
0.990
CONDITIONS
VIN = 5.0V
0.985
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
0.980
0
1
2
3 4 5 6 7 8 9
OUTPUT CURRENT (A)
2.4
10 11 12
Output Voltage vs. Input Voltage
1.220
1.215
1.215
1.210
1.205
1.200
1.195
1.190
CONDITIONS
Load = 4A
1.185
6
6.6
1.210
1.205
1.200
1.195
1.190
CONDITIONS
Load = 8A
1.180
2.4
3
3.6
4.2
4.8
5.4
INPUT VOLTAGE (V)
6
6.6
2.4
3
3.6
4.2
4.8
5.4
INPUT VOLTAGE (V)
6
6.6
Output Voltage vs. Temperature
Output Voltage vs. Input Voltage
1.204
1.220
1.215
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
3.6
4.2
4.8
5.4
INPUT VOLTAGE (V)
1.185
1.180
1.210
1.205
1.200
1.195
1.190
CONDITIONS
Load = 12A
1.185
CONDITIONS
VIN = 6.6V
VOUT_NOM = 1.2V
1.202
1.200
LOAD = 0A
LOAD = 2A
LOAD = 4A
LOAD = 6A
LOAD = 8A
1.198
LOAD = 10A
1.196
LOAD = 12A
1.194
1.192
1.190
1.180
2.4
3
3.6
4.2
4.8
5.4
INPUT VOLTAGE (V)
Enpirion 2012 all rights reserved, E&OE
07077
3
Output Voltage vs. Input Voltage
1.220
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
CONDITIONS
Load = 0A
6
-40
6.6
Enpirion Confidential
May 9, 2012
-15
10
35
60
AMBIENT TEMPERATURE ( C)
85
www.enpirion.com, Page 8
Rev: C
EN63A0QI
Typical Performance Curves (Continued)
Output Voltage vs. Temperature
Output Voltage vs. Temperature
1.204
LOAD = 0A
CONDITIONS
VIN = 5V
VOUT_NOM = 1.2V
1.202
1.200
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.204
LOAD = 2A
LOAD = 4A
LOAD = 6A
LOAD = 8A
1.198
LOAD = 10A
1.196
LOAD = 12A
1.194
1.192
1.200
LOAD = 6A
LOAD = 8A
1.198
LOAD = 10A
1.196
LOAD = 12A
1.194
-15
10
35
60
AMBIENT TEMPERATURE ( C)
85
-40
MAXIMUM OUTPUT CURRENT (A)
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
VOUT = 1.8V
3.0
VOUT = 2.5V
-15
10
35
60
AMBIENT TEMPERATURE ( C)
85
Output Current De-rating
Output Current De-rating
MAXIMUM OUTPUT CURRENT (A)
LOAD = 4A
1.190
-40
CONDITIONS
VIN = 3.3V
TJMAX = 125 C
θJA = 14 C/W
10x11x3mm QFN
No Air Flow
12.0
11.0
Maximum current allowed f or this condition
10.0
9.0
8.0
7.0
CONDITIONS
VIN = 5.0V
TJMAX = 125 C
θJA = 14 C/W
10x11x3mm QFN
No Air Flow
6.0
5.0
VOUT = 1.8V
4.0
VOUT = 3.3V
3.0
2.0
2.0
55
60
65
70
75
80
AMBIENT TEMPERATURE ( C)
55
85
EMI Performance (Horizontal Scan)
60
65
70
75
80
AMBIENT TEMPERATURE ( C)
85
EMI Performance (Vertical Scan)
100.0
100.0
80.0
70.0
60.0
50.0
CISPR 22 Class B 3m
40.0
CONDITIONS
VIN = 5.0V
VOUT_NOM = 1.5V
LOAD = 0.14Ω
90.0
80.0
LEVEL (dBµV/m)
CONDITIONS
VIN = 5.0V
VOUT_NOM = 1.5V
LOAD = 0.14Ω
90.0
LEVEL (dBµV/m)
LOAD = 2A
1.192
1.190
70.0
60.0
50.0
CISPR 22 Class B 3m
40.0
30.0
30.0
20.0
20.0
10.0
10.0
30
300
FREQUENCY (MHz)
Enpirion 2012 all rights reserved, E&OE
07077
LOAD = 0A
CONDITIONS
V IN = 3.6V
V OUT_NOM = 1.2V
1.202
30
Enpirion Confidential
May 9, 2012
300
FREQUENCY (MHz)
www.enpirion.com, Page 9
Rev: C
EN63A0QI
Typical Parallel Performance Curves (Continued)
Parallel Current Share Breakdown
CURRENT MIS-MATCH (%)
4
Mis-match (%) = (I_Master - I_Slave ) / I_Average x 100
3
2
1
0
-1
-2
CONDITIONS
EN63A0QI
VIN = 5V
VOUT = 3.3V
-3
-4
-5
2
4
6
8 10 12 14 16 18
OUTPUT CURRENT (A)
Enpirion 2012 all rights reserved, E&OE
07077
20
22
24
INDIVIDUAL OUTPUT CURRENT (A)
Parallel Current Share Mis-Match
5
14
12
Master Device
10
Slave Device
8
6
CONDITIONS
EN63A0QI
VIN = 5V
VOUT = 3.3V
4
2
0
2
4
Enpirion Confidential
May 9, 2012
6
8 10 12 14 16 18 20
TOTAL OUTPUT CURRENT (A)
22
24
www.enpirion.com, Page 10
Rev: C
EN63A0QI
Typical Performance Characteristics
Output Ripple at 500MHz Bandwidth
Output Ripple at 20MHz Bandwidth
VOUT
(AC Coupled)
CONDITIONS
VIN = 5V
VOUT = 1V
IOUT = 12A
CIN = 2 X 47µF (1206)
COUT = 3 x 47 µF (1206)
VOUT
(AC Coupled)
Output Ripple at 500MHz Bandwidth
Output Ripple at 20MHz Bandwidth
VOUT
(AC Coupled)
CONDITIONS
VIN = 5V
VOUT = 2.4V
IOUT = 12A
CIN = 2 X 47µF (1206)
COUT = 3 x 47 µF (1206)
VOUT
(AC Coupled)
Enable Power Up/Down
ENABLE
CONDITIONS
VIN = 5V
VOUT = 1.0V
IOUT = 12A
Css = 15nF
CIN = 2 X 47µF (1206)
COUT = 3 x 47 µF (1206)
Enpirion 2012 all rights reserved, E&OE
07077
CONDITIONS
VIN = 5V
VOUT = 2.4V
IOUT = 12A
CIN = 2 X 47µF (1206)
COUT = 3 x 47 µF (1206)
Enable Power Up/Down
ENABLE
VOUT
CONDITIONS
VIN = 5V
VOUT = 1V
IOUT = 12A
CIN = 2 X 47µF (1206)
COUT = 3 x 47 µF (1206)
VOUT
Enpirion Confidential
May 9, 2012
CONDITIONS
VIN = 5V
VOUT = 2.4V
IOUT = 12A
Css = 15nF
CIN = 2 X 47µF (1206)
COUT = 3 x 47 µF (1206)
www.enpirion.com, Page 11
Rev: C
EN63A0QI
Typical Performance Characteristics (Continued)
Enable/Disable with POK
Load Transient from 0 to 12A
ENABLE
VOUT
(AC Coupled)
VOUT
POK
LOAD
CONDITIONS
VIN = 5V, VOUT = 1.0V
LOAD = 5A, Css = 15nF
LOAD
CONDITIONS
VIN = 6.2V
VOUT = 1.5V
CIN = 2 X 47µF (1206)
COUT = 3 x 47µF (1206)
Parallel Operation Current Sharing
Parallel Operation SW Waveforms
MASTER VSW
TOTAL LOAD = 18A
SLAVE 2 VSW
MASTER LOAD = 6A
SLAVE 1 VSW
SLAVE 2 LOAD = 6A
COMBINED LOAD(18A)
CONDITIONS
VIN = 5V
VOUT = 1.8V
LOAD = 18A
Enpirion 2012 all rights reserved, E&OE
07077
SLAVE 1 LOAD = 6A
Enpirion Confidential
May 9, 2012
CONDITIONS
VIN = 5V
VOUT = 1.8V
LOAD = 18A
www.enpirion.com, Page 12
Rev: C
EN63A0QI
Functional Block Diagram
Figure 4: Functional Block Diagram
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 13
Rev: C
EN63A0QI
Functional Description
The EN63A0QI is a synchronous, programmable
buck power supply with integrated power MOSFET
switches and integrated inductor. The switching
supply uses voltage mode control and a low noise
PWM topology. This provides superior impedance
matching to ICs processed in sub 90nm process
technologies. The nominal input voltage range is
2.5 - 6.6 volts. The output voltage is programmed
using an external resistor divider network. The
feedback control loop incorporates a type IV
voltage mode control design. Type IV voltage mode
control maximizes control loop bandwidth and
maintains excellent phase margin to improve
transient performance. The EN63A0QI is designed
to support up to 12A continuous output current
operation. The operating switching frequency is
between 0.9MHz and 1.5MHz and enables the use
of small-size input and output capacitors.
The power supply has the following features:
soft-start function to limit in-rush current during
device power-up. When the part is initially powered
up, the output voltage is gradually ramped to its
final value. The gradual output ramp is achieved by
increasing the reference voltage to the error
amplifier. A constant current flowing into the softstart capacitor provides the reference voltage ramp.
When the voltage on the soft-start capacitor
reaches 0.60V, the output has reached its
programmed voltage. Once the output voltage has
reached nominal voltage the soft-start capacitor will
continue to charge to 1.5V (Typical). The output
rise time can be controlled by the choice of softstart capacitor value.
The rise time is defined as the time from when the
ENABLE signal crosses the threshold and the input
voltage crosses the upper UVLO threshold to the
time when the output voltage reaches 95% of the
programmed value. The rise time (tRISE) is given by
the following equation:
•
Precision Enable Threshold
•
Soft-Start
•
Pre-bias Start-Up
•
Resistor Programmable Switching Frequency
The rise time (tRISE) is in milliseconds and the softstart capacitor (CSS) is in nano-Farads. The softstart capacitor should be between 10nF and 100nF.
•
Phase-Lock Frequency Synchronization
Pre-Bias Start-up
•
Parallel Operation
•
Power OK
•
Over-Current/Short Circuit Protection
•
Thermal Shutdown with Hysteresis
•
Under-Voltage Lockout
The EN63A0QI supports startup into a pre-biased
load. A proprietary circuit ensures the output
voltage rises up from the pre-bias value to the
programmed output voltage. Start-up is guaranteed
to be monotonic for pre-bias voltages in the range
of 20% to 75% of the programmed output voltage
with a minimum pre-bias voltage of 300mV. Outside
of the 20% to 75% range, the output voltage rise
will not be monotonic. The Pre-Bias feature is
automatically engaged with an internal pull-up
resistor. For this feature to work properly, VIN must
be ramped up prior to ENABLE turning on the
device. Tie VSENSE to VOUT if Pre-Bias is used.
Tie EN_PB to ground and leave VSENSE floating
to disable the Pre-Bias feature. Pre-Bias is
supported for external clock synchronization, but
not supported for parallel operations.
tRISE [ms] = Css [nF] x 0.065
Precision Enable
The ENABLE threshold is a precision analog
voltage rather than a digital logic threshold. A
precision voltage reference and a comparator
circuit are kept powered up even when ENABLE is
de-asserted. The narrow voltage gap between
ENABLE Logic Low and ENABLE Logic High
allows the device to turn on at a precise enable
voltage level. With the enable threshold pinpointed,
a proper choice of soft-start capacitor helps to
accurately sequence multiple power supplies in a
system as desired. There is an ENABLE lockout
time of 2ms that prevents the device from reenabling immediately after it is disabled.
Soft-Start
The SS pin in conjunction with a small external
capacitor between this pin and AGND provides a
Enpirion 2012 all rights reserved, E&OE
07077
Resistor Programmable Frequency
The operation of the EN63A0QI can be optimized
by a proper choice of the RFQADJ resistor. The
frequency can be tuned to optimize dynamic
performance and efficiency. Refer to Table 1 and
Table 2 for recommended RFQADJ values based on
maximum output current operations.
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 14
Rev: C
EN63A0QI
of the Master to the S_IN of all other Slave devices.
Refer to Figure 5 for details.
Table 1: Recommended RFQADJ (kΩ) at 10A
VOUT
VIN
3.3V ±10%
5.0V ±10%
6.0V ±10%
0.8V
1.2V
1.5V
1.8V
2.5V
3.3V
3.57
3.57
3.57
3.57
3.57
3.57
4.42
3.57
3.57
4.42
4.42
4.42
3.57
4.42
4.42
-3.57
3.57
Table 2: Recommended RFQADJ (kΩ) at 12A
VOUT
VIN
3.3V ±10%
5.0V ±10%
6.0V ±10%
0.8V
1.2V
1.5V
1.8V
2.5V
3.3V
3.57
3.57
20.0
3.57
12.1
20.0
4.42
12.1
20.0
4.42
4.42
NR
3.57
NR
NR
-NR
NR
Careful attention is needed in the layout for parallel
operation. The VIN, VOUT and GND of the
paralleled devices should have low impedance
connections between each other. Maximize the
amount of copper used to connect these pins and
use as many vias as possible when using multiple
layers. Place the Master device between all other
Slaves and closest to the point of load.
Note: NR = Device not rated for this operation condition
Phase-Lock Operation:
The EN63A0QI can be phase-locked to an external
clock signal to synchronize its switching frequency.
The M/S pin can be left floating or pulled to ground
to allow the device to synchronize with an external
clock signal using the S_IN pin. When a clock
signal is present at S_IN, an activity detector
recognizes the presence of the clock signal and the
internal oscillator phase locks to the external clock.
The external clock could be the system clock or the
output of another EN63A0QI. The phase locked
clock is then output at S_OUT.
Master / Slave (Parallel) Operation and
Frequency Synchronization
Multiple EN63A0QI devices may be connected in a
Master/Slave configuration to handle larger load
currents. The device is placed in Master mode by
pulling the M/S pin low or in Slave mode by pulling
M/S pin high. When the M/S pin is in float state,
parallel operation is not possible. In Master
mode, a version of the internal switching PWM
signal is output on the S_OUT pin. This PWM
signal from the Master is fed to the Slave device at
its S_IN pin. The Slave device acts like an
extension of the power FETs in the Master and
inherits the PWM frequency and duty cycle. The
inductor in the Slave prevents crow-bar currents
from Master to Slave due to timing delays. The
Master device’s switching clock may be phaselocked to an external clock source or another
EN63A0QI to move the entire parallel operation
frequency away from sensitive frequencies. The
feedback network for the Slave device may be left
open. Additional Slave devices may be paralleled
together with the Master by connecting the S_OUT
Enpirion 2012 all rights reserved, E&OE
07077
Figure 5: Master/Slave Parallel Operation Diagram
POK Operation
The POK signals that the output voltage is within
the specified range. The POK signal is asserted
high when the rising output voltage crosses 92%
(nominal) of the programmed output voltage. If the
output voltage falls outside the range of 90% to
120%, POK remains asserted for the de-glitch time
(213µs at 1.2MHz). After the de-glitch time, POK is
de-asserted. POK is also de-asserted if the output
voltage exceeds 120% of the programmed output
voltage.
Over Current Protection
The current limit function is achieved by sensing
the current flowing through a sense P-FET. When
the sensed current exceeds the current limit, both
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 15
Rev: C
EN63A0QI
power FETs are turned off for the rest of the
switching cycle. If the over-current condition is
removed, the over-current protection circuit will reenable PWM operation. If the over-current condition
persists, the circuit will continue to protect the load.
The OCP trip point is nominally set as specified in
the Electrical Characteristics table. In the event the
OCP circuit trips consistently in normal operation,
the device enters a hiccup mode. The device is
disabled for 27µs and restarted with a normal softstart. This cycle can continue indefinitely as long as
the over current condition persists.
exceeds approximately 150ºC. Once the junction
temperature drops by approx 20ºC, the converter
will re-start with a normal soft-start.
Input Under-Voltage Lock-Out
When the input voltage is below a required voltage
level (VUVHI) for normal operation, the converter
switching is inhibited. The lock-out threshold has
hysteresis to prevent chatter. Thus when the device
is operating normally, the input voltage has to fall
below the lower threshold (VUVLO) for the device to
stop switching.
Thermal Overload Protection
Temperature sensing circuits in the controller will
disable operation when the junction temperature
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 16
Rev: C
EN63A0QI
Application Information
depend on the input voltage and output voltage.
Calculate the external feedback and compensation
network values with the equations below.
Output Voltage Programming and loop
Compensation
The EN63A0QI output voltage is programmed
using a simple resistor divider network. A phase
lead capacitor plus a resistor are required for
stabilizing the loop. Figure 6 shows the required
components and the equations to calculate their
values.
The EN63A0QI output voltage is determined by the
voltage presented at the VFB pin. This voltage is
set by way of a resistor divider between VOUT and
AGND with the midpoint going to VFB.
The EN63A0QI uses a type IV compensation
network. Most of this network is integrated.
However, a phase lead capacitor and a resistor are
required in parallel with upper resistor of the
external feedback network (Refer to Figure 6). Total
compensation is optimized for use with three 47µF
output capacitance and will result in a wide loop
bandwidth and excellent load transient performance
for most applications. Additional capacitance may
be placed beyond the voltage sensing point outside
the control loop. Voltage mode operation provides
high noise immunity at light load. Furthermore,
voltage mode control provides superior impedance
matching to ICs processed in sub 90nm
technologies.
In some cases modifications to the compensation
or output capacitance may be required to optimize
device performance such as transient response,
ripple, or hold-up time. The EN63A0QI provides the
capability to modify the control loop response to
allow for customization for such applications. For
more information, contact Enpirion Applications
Engineering support.
RA [Ω] = 48,400 x VIN [V]
*Round RA up to closest standard value
RB[Ω] = (VFB x RA) / (VOUT – VFB) [V]
VFB = 0.6V nominal
*Round RB up to closest standard value
CA [F] = 4.6 x 10-6 / RA [Ω]
*Round CA down to closest standard value
R1 = 12kΩ
The feedback resistor network should be sensed at
the last output capacitor close to the device. Keep
the trace to VFB pin as short as possible.
Whenever possible, connect RB directly to the
AGND pin instead of going through the GND plane.
Input Capacitor Selection
The EN63A0QI has been optimized for use with
two 1206 47µF input capacitors. Low ESR ceramic
capacitors are required with X5R or X7R dielectric
formulation.
Y5V
or
equivalent
dielectric
formulations must not be used as these lose
capacitance with frequency, temperature and bias
voltage.
In some applications, lower value ceramic
capacitors may be needed in parallel with the larger
capacitors in order to provide high frequency
decoupling. The capacitors shown in the table
below are typical input capacitors. Other capacitors
with similar characteristics may also be used.
Table 3: Recommended Input Capacitors
Description
MFG
P/N
47µF, 10V, 20%
X5R, 1206
(2 capacitors needed)
Murata
GRM31CR61A476ME19L
Taiyo Yuden
LMK316BJ476ML-T
Output Capacitor Selection
Figure 6: External Feedback/Compensation Network
The feedback and compensation network values
Enpirion 2012 all rights reserved, E&OE
07077
The EN63A0QI has been optimized for use with
three 1206 47µF output capacitors. Low ESR, X5R
or X7R ceramic capacitors are recommended as
the primary choice. Y5V or equivalent dielectric
formulations must not be used as these lose
capacitance with frequency, temperature and bias
voltage.
The
capacitors
shown
in
the
Recommended Output Capacitors table are typical
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 17
Rev: C
EN63A0QI
Table 6: Recommended REXT Resistor
output capacitors. Other capacitors with similar
characteristics may also be used. Additional bulk
capacitance from 100µF to 1000µF may be placed
beyond the voltage sensing point outside the
control loop. This additional capacitance should
have a minimum ESR of 6mΩ to ensure stable
operation. Most tantalum capacitors will have more
than 6mΩ of ESR and may be used without special
care. Adding distance in layout may help increase
the ESR between the feedback sense point and the
bulk capacitors.
VIN (V)
IMAX (µA)
REXT (kΩ)
2.5 – 4.0
117
15
4.0 – 6.6
88
51
Table 4: Recommended Output Capacitors
Description
47µF, 10V, 20%
X5R, 1206
(3 capacitors needed)
47µF, 6.3V, 20%
X5R, 1206
(3 capacitors needed)
10µF, 6.3V, 10%
X7R, 0805
(Optional 1 capacitor in
parallel with 3x47µF)
MFG
P/N
Taiyo Yuden
LMK316BJ476ML-T
Murata
GRM31CR60J476ME19L
Taiyo Yuden
JMK316BJ476ML-T
Murata
GRM21BR70J106KE76L
Taiyo Yuden
JMK212B7106KG-T
Output ripple voltage is primarily determined by the
aggregate output capacitor impedance. Placing
multiple capacitors in parallel reduces the
impedance and hence will result in lower ripple
voltage.
1
Z Total
=
1
1
1
+
+ ... +
Z1 Z 2
Zn
Figure 7: Selection of REXT to Connect M/S pin to VIN
Table 7: M/S (Master/Slave) Pin States
M/S Pin
Function
Low
(0V to 0.7V)
M/S pin is pulled to ground directly. This is
the Master mode. Switching PWM phase
will lock onto S_IN external clock if a signal
is available. S_OUT outputs a version of
the internal switching PWM signal.
Float
(1.1V to 1.4V)
M/S pin is left floating. Parallel operation is
not feasible. Switching PWM phase will
lock onto S_IN external clock if a signal is
available. S_OUT outputs a version of the
internal switching PWM signal.
High
(>1.8V)
M/S pin is pulled to VIN with REXT. This is
the Slave mode. The S_IN signal of the
Slave should connect to the S_OUT of the
Master device. This signal synchronizes
the switching frequency and duty cycle of
the Master to the Slave device.
Table 5: Typical Ripple Voltages
Output Capacitor
Configuration
†
Typical Output Ripple (mVp-p)
3 x 47 µF
<5mV
20 MHz bandwidth limit measured on Evaluation Board
M/S - Ternary Pin
M/S is a ternary pin. This pin can assume 3 states
– A low state (0V to 0.7V), a high state (1.8V to
VIN) and a float state (1.1V to 1.4V). Device
operation is controlled by the state of the pin. The
pins may be pulled to ground or left floating without
any special care. When pulling high to VIN, a series
resistor is recommended. The resistor value may
be optimized to reduce the current drawn by the
pin. The resistance should not be too high as in that
case the pin may not recognize the high state. The
recommend resistance (REXT) value is given in the
following table.
Enpirion 2012 all rights reserved, E&OE
07077
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.
Technical Suport
Contact Enpirion Applications for additional support
regarding
the
use
of
this
product
([email protected]).
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 18
Rev: C
EN63A0QI
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 EN63A0QI DC-DC converter is
packaged in an 10x11x3mm 76-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 heat 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
150°C.
The following example and calculations illustrate
the thermal performance of the EN63A0QI.
Example:
PIN = POUT / η
PIN ≈ 21.6W / 0.85 ≈ 25.41W
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
≈ 25.41W – 21.6 ≈ 3.81W
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 EN63A0QI has
a θJA value of 14 ºC/W without airflow.
Determine the change in temperature (∆T) based
on PD and θJA.
∆T = PD x θJA
∆T ≈ 3.81W x 14°C/W = 53.36°C ≈ 53°C
VIN = 5V
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.
VOUT = 1.8V
TJ = TA + ∆T
IOUT = 12A
TJ ≈ 25°C + 53°C ≈ 78°C
First calculate the output power.
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.
POUT = 1.8V x 12A = 21.6W
Next, determine the input power based on the
efficiency (η) shown in Figure 8.
Efficiency vs. Output Current
TAMAX = TJMAX – PD x θJA
≈ 125°C – 53°C ≈ 72°C
100
90
EFFICIENCY (%)
80
70
~85%
60
50
40
30
20
VOUT = 1.8V
10
The maximum ambient temperature the device can
reach is 72°C given the input and output conditions.
Note that the efficiency used in this example is at
85°C ambient temperature and is a worst case
condition. Refer to the de-rating curves in the
Typical Performance Curves section.
CONDITIONS
VIN = 5.0V
TA = 85 C
0
0
1
2
3 4 5 6 7 8
OUTPUT CURRENT (A)
9
10 11 12
Figure 8: Efficiency vs. Output Current
For VIN = 5V, VOUT = 1.8V at 12A, η ≈ 85%
η = POUT / PIN = 87% = 0.85
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 19
Rev: C
EN63A0QI
Engineering Schematic
Figure 9: Engineering Schematic with Engineering Notes
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 20
Rev: C
EN63A0QI
Layout Recommendations
Figure 10: Top Layout with Critical Components Only
(Top View). See Figure 9 for corresponding schematic
This layout only shows the critical components and
top layer traces for minimum footprint in singlesupply mode with ENABLE tied to AVIN. Alternate
circuit configurations & other low-power pins need
to be connected and routed according to customer
application. Please see the Gerber files at
www.enpirion.com for details on all layers.
Recommendation 1: Input and output filter
capacitors should be placed on the same side of
the PCB, and as close to the EN63A0QI 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
EN63A0QI 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 PGND connections for
the input and output capacitors on layer 1 need to
have a slit between them in order to provide some
separation between input and output current loops.
Recommendation 3: 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.
Enpirion 2012 all rights reserved, E&OE
07077
Recommendation 4: The thermal pad underneath
the component must be connected to the system
ground plane through as many vias as possible.
The drill diameter of the vias should 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.
Recommendation 5: Multiple small vias (the same
size as the thermal vias discussed in
recommendation 4) 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.
Recommendation 6: 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 10 this connection is made at the input
capacitor.
Recommendation 7: The layer 1 metal under the
device must not be more than shown in Figure 10.
Refer to the section regarding Exposed Metal on
Bottom of Package. 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.
Recommendation 9: Keep RA, CA, RB, and R1
close to the VFB pin (Refer to Figure 10). 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.
Recommendation 10: Follow all the layout
recommendations as close as possible to optimize
performance. Enpirion provides schematic and
layout reviews for all customer designs. Please
contact local Applications Engineering for detailed
support ([email protected]).
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 21
Rev: C
EN63A0QI
Design Considerations for Lead-Frame Based Modules
Exposed Metal on Bottom of Package
Lead-frames offer many advantages in thermal performance, in reduced electrical lead resistance, and in
overall foot print. However, they do require some special considerations.
In the assembly process lead frame construction requires that, for mechanical support, some of the lead-frame
cantilevers be exposed at the point where wire-bond or internal passives are attached. This results in several
small pads being exposed on the bottom of the package, as shown in Figure 11.
Only the thermal pad and the perimeter pads are to be mechanically or electrically connected to the PC board.
The PCB top layer under the EN63A0QI should be clear of any metal (copper pours, traces, or vias) except for
the thermal pad. The “shaded-out” area in Figure 11 represents the area that should be clear of any metal on
the top layer of the PCB. Any layer 1 metal under the shaded-out area runs the risk of undesirable shorted
connections even if it is covered by soldermask.
The solder stencil aperture should be smaller than the PCB ground pad. This will prevent excess solder from
causing bridging between adjacent pins or other exposed metal under the package. Please consult the
Enpirion Manufacturing Application Note for more details and recommendations.
Figure 11: Lead-Frame exposed metal (Bottom View)
Shaded area highlights exposed metal that is not to be mechanically or electrically connected to the PCB.
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 22
Rev: C
EN63A0QI
Recommended PCB Footprint
Figure 12: EN63A0QI PCB Footprint (Top View)
Enpirion 2012 all rights reserved, E&OE
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 23
Rev: C
EN63A0QI
Package and Mechanical
Figure 13: EN63A0QI Package Dimensions (Bottom View)
Packing and Marking Information: http://www.enpirion.com/resource-center-packing-and-marking-information.htm
Contact Information
Enpirion, Inc.
Perryville III Corporate Park
53 Frontage Road - Suite 210
Hampton, NJ 08827 USA
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
07077
Enpirion Confidential
May 9, 2012
www.enpirion.com, Page 24
Rev: C