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Электронный компонент: NCP1580

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Semiconductor Components Industries, LLC, 2004
September, 2004- Rev. 2
1
Publication Order Number:
NCP1580/D
NCP1580
Low Voltage Synchronous
Buck Controller
The NCP1580 is a voltage mode PWM controller designed to
operate from a 5.0 V or 12 V supply and produce an output voltage as
low as 0.8 V. This 8-pin device provides an optimal level of
integration to reduce size and cost of the power supply. The NCP1580
has a fixed 350 kHz oscillator and soft-start function. The NCP1580
provides a 1.5 A floating gate driver design to drive N-Channel
MOSFETs in a synchronous configuration. Adaptive non-overlap
circuitry reduces switching losses by preventing simultaneous
conduction of both outputs. Protection features include thermal
shutdown and undervoltage lockout (UVLO). The NCP1580 is
available in an 8-pin SOIC package.
Features
Input Voltage Range from 4.5 V to 13.2 V
350 kHz Internal Oscillator
Boost Pin Operates to 26.5 V
Voltage Mode PWM Control
0.8 V
$1.5% Internal Reference Voltage
Adjustable Output Voltage
Internal Soft-Start
Internal 1.5 A Gate Drivers
Adaptive Non-Overlap Circuit
90% Max Duty Cycle
Input UVLO
Overtemperature Protection
Fully Specified over -40
C to 85
C
Applications
Graphics Cards
Desktop Computers
Servers/Networking
DSP and FPGA Power Supply
DC-DC Regulator Modules
BST
TG
GND
BG
COMP
FB
V
CC
SWN
V
IN
V
OUT
Figure 1. Typical Application Diagram
SO-8
D SUFFIX
CASE 751
1
8
MARKING
DIAGRAM
PIN CONNECTIONS
A
= Assembly Location
L
= Wafer Lot
Y
= Year
W
= Work Week
1
BST
8 PHASE
2
TG
3
GND
4
BG
7 COMP
6 FB
5 V
CC
(Top View)
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1580
ALYW
1
8
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Device
Package
Shipping
ORDERING INFORMATION
NCP1580DR2
SO-8
2500/Tape & Reel
For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
NCP1580
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2
V
IN
V
OUT
Figure 2. Application Diagram; 12 V Input, 1.0 V at 20 A Output
BST
PHASE
TG
GND
BG
COMP
FB
V
CC
3.3 nF
10 nF
15 k
1
m
F
10 nF
68.1
5.36 k
20 k
0.1
m
F
RB751V40T10
NTD60N02R
NTD1
10N02R
2.2
4.7 nF
2 x
1500
m
F
4 x
22
m
F
2 x
100
m
F
2 x
1800
m
F
MBR130LSFT1
GND
1
m
H
Figure 3. Block Diagram
FAULT
SS
OSC
+
-
+
FB
COMP
Error Amp
0.8 V (V
REF
)
V
CC
+
-
Clock
Ramp
OSC
OSC
R
S
Q
POR
FAULT
FAULT
+
-
Comparator
2 V
+
-
2 V
FAULT
TG
BST
PHASE
V
CC
BG
GND
DETAILED BLOCK DIAGRAM
TSD
(V
SS
)
6
7
5
1
2
8
4
3
NCP1580
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3
PIN FUNCTION DESCRIPTION
Pin No.
Symbol
Description
1
BST
Supply rail for the floating top gate driver. To form a boost circuit, use an external diode to bring the
desired input voltage to this pin (cathode connected to BST pin). Connect a capacitor (C
BST
) between this
pin and the PHASE pin. Typical values for C
BST
range from 0.1
m
F to 1
m
F. Ensure that C
BST
is placed
near the IC.
2
TG
Top gate MOSFET driver pin. Connect this pin to the gate of the top N-Channel MOSFET.
3
GND
IC ground reference. All control circuits are referenced to this pin.
4
BG
Bottom gate MOSFET driver pin. Connect this pin to the gate of the bottom N-Channel MOSFET.
5
V
CC
Supply rail for the internal circuitry. Operating supply range is 4.5 V to 13.2 V. Decouple with a 1
m
F
capacitor to GND. Ensure that this decoupling capacitor is placed near the IC.
6
FB
This pin is the inverting input to the error amplifier. Use this pin in conjunction with the COMP pin to
compensate the voltage-control feedback loop. Connect this pin to the output resistor divider (if used) or
directly to Vout.
7
COMP
Compensation Pin. This is the output of the error amplifier (EA) and the non-inverting input of the PWM
comparator. Use this pin in conjunction with the FB pin to compensate the voltage-control feedback loop.
This pin should not be shorted to ground to disable switching.
8
PHASE
Switch node pin. This is the reference for the floating top gate driver. Connect this pin to the source of the
top MOSFET. A Schottky diode between this pin and ground is recommended to reduce negative transient
voltages which is common in a power supply system.
ABSOLUTE MAXIMUM RATINGS
Pin Name
Symbol
V
MAX
V
MIN
Main Supply Voltage Input
V
CC
15 V
-0.3 V
Bootstrap Supply Voltage Input
BST
30 V wrt/GND
15 V wrt/PHASE
-0.3 V
Switching Node (Bootstrap Supply Return)
PHASE
30 V
-0.7 V
High-Side Driver Output (Top Gate)
TG
30 V wrt/GND
15 V wrt/PHASE
-0.3 V
wrt/PHASE
Low-Side Driver Output (Bottom Gate)
BG
15 V
-0.3 V
Feedback
FB
5.5 V
-0.3 V
COMP
COMP
5.5 V
-0.3 V
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
Thermal Resistance, Junction-to-Ambient
R
q
JA
165
C/W
Thermal Resistance, Junction-to-Case
R
q
JC
45
C/W
Operating Junction Temperature Range
T
J
-40 to 150
C
Operating Ambient Temperature Range
T
A
-40 to 85
C
Storage Temperature Range
T
stg
-55 to +150
C
ESD Susceptibility
Human Body Model
Charge Device Model
2.0
200
kV
V
Moisture Sensitivity Level
MSL
1
-
Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit
values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied,
damage may occur and reliability may be affected.
NCP1580
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4
ELECTRICAL CHARACTERISTICS
(-40
C < T
A
< 85
C, -40
C < T
J
< 125
C (Note 1), 4.5 V < V
CC
< 13.2 V, 4.5 V < BST < 26.5 V,
C
TG
= C
BG
= 1.0 nF, for min/max values unless otherwise noted.)
Characteristic
Conditions
Min
Typ
Max
Unit
Input Voltage Range
-
4.5
-
13.2
V
Boost Voltage Range
-
4.5
-
26.5
V
Supply Current
Quiescent Supply Current
V
FB
= 1.0 V, No Switching
V
CC
= 13.2 V
-
1.0
1.75
mA
Boost Quiescent Current
V
FB
= 1.0 V, No Switching
-
140
-
m
A
Undervoltage Lockout
UVLO Threshold
V
CC
Rising Edge
3.85
4.2
-
V
UVLO Hysteresis
-
-
0.5
-
V
Switching Regulator
VFB Feedback Voltage,
Control Loop in Regulation
T
A
= 0 to 70
C
T
A
= -40 to 85
C
0.788
0.784
0.800
-
0.812
0.816
V
Oscillator Frequency
-
288
350
412
kHz
Ramp-Amplitude Voltage
-
-
1.1
-
V
Minimum Duty Cycle
-
-
0
-
%
Maximum Duty Cycle
-
85
90
95
%
Minimum Pulse Width
Static Operating (Note 2)
50
100
150
nsec
Error Amplifier
DC Gain
(Note 2 )
70
80
-
dB
Gain-Bandwidth Product
(Note 2)
8.0
10
-
MHz
Slew Rate
COMP_GND = 100 pF (Note 2)
2.0
4.0
-
V/
m
S
FB Bias Current
VFB = 1 V (Note 2)
-
0.1
1.0
m
A
Gate Drivers
TG Rise Time
-
6.0
15
ns
TG Fall Time
Load = 1.0 nF
-
15
30
ns
BG Rise Time
Load = 1.0 nF
V
CC
= 8.0 V
-
6.0
15
ns
BG Fall Time
-
6.0
15
ns
TG Sink Current
-
1.0
-
A
TG Source Current
V
CC
= 12 V
V
TG
= V
BG
= 2 0 V
-
1.5
-
A
BG Sink Current
V
TG
= V
BG
= 2.0 V
(Note 2)
-
1.5
-
A
BG Source Current
(
)
-
1.5
-
A
PHASE falling to BG rising delay
V
CC
= 12 V
PHASE < 2.0 V
BG > 2.0 V
-
30
90
ns
BG falling to TG rising delay
V
CC
= 12 V
BG < 2.0 V
TG > 2.0 V
-
30
40
ns
Internal Soft-Start
Time
-
1.0
2.0
3.0
ms
Thermal Shutdown
Overtemperature Trip Point
(Note 2)
-
160
-
C
1. Specifications to -40
C are guaranteed via correlation using standard statistical quality control (SQC), not tested in production.
2. Guaranteed by design, not tested in production.
NCP1580
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5
TYPICAL CHARACTERISTIC CURVES
400
390
380
370
360
350
340
330
320
310
410
-50
-25
0
25
50
75
100
125
150
T
J
, JUNCTION TEMPERATURE (
C)
f
SW
, FREQUENCY (kHz)
816
-50
-25
0
25
50
75
100
125
150
T
J
, JUNCTION TEMPERATURE (
C)
V
REF
, REFERENCE (mV)
812
808
804
800
796
792
788
784
Figure 4. Reference Voltage (V
REF
) vs.
Temperature
Figure 5. Oscillator Frequency (f
SW
) vs.
Temperature
300
290
V
CC
= 5.0 V
V
CC
= 12 V
2.15
2.10
2.05
2.00
1.95
1.90
1.85
1.80
2.20
-50
-25
0
25
50
75
100
125
150
T
J
, JUNCTION TEMPERATURE (
C)
t
SS
, SOFT-ST
AR
T TIME (ms)
1.25
-50
-25
0
25
50
75
100
125
150
T
J
, JUNCTION TEMPERATURE (
C)
I
CC
, SUPPL
Y CURRENT (mA)
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.75
-50
-25
0
25
50
75
100
125
150
T
J
, JUNCTION TEMPERATURE (
C)
I
CC
, SUPPL
Y CURRENT (mA)
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
Figure 6. Soft-Start Time (t
SS
) vs. Temperature
Figure 7. Quiescent Current (I
CC
) vs. Temperature
(No Switching)
Figure 8. Quiescent Current (I
CC
) vs. Temperature
(Switching)
100
80
60
40
20
0
-20
-40
-60
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
Figure 9. Error Amplifier
0.80
0.85
V
CC
= 5.0 V
V
CC
= 12 V
V
CC
= 5.0 V
V
CC
= 12 V
V
CC
= 5.0 V
V
CC
= 12 V
V
CC
= 8.0 V
NCP1580
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6
DETAILED OPERATING DESCRIPTION
General
The NCP1580 is an 8-pin PWM controller intended for
DC-DC conversion from 5.0 V and 12 V buses. The
NCP1580 has a 1.5 A internal floating gate driver circuit
designed to drive N-Channel MOSFETs in a
synchronous-rectifier buck topology. The internal floating
gate driver simplifies design, improves performance, and
minimizes board area. The output voltage of the converter
can be precisely regulated down to 800 mV
$ 1.5% when
the V
FB
pin is tied to V
OUT
. The switching frequency, which
is internally set to 350 kHz, and soft-start are completely
integrated. The voltage error amplifier features a 10 MHz
unity gain bandwidth and 4 V/
msec slew rate for fast
transient response.
Duty Cycle and Maximum Pulse Width Limits
In steady state DC operation, the duty cycle will stabilize
at an operating point defined by the ratio of the input to the
output voltage. The NCP1580 can achieve a 90% duty cycle.
There is a built in off-time which ensures that the bootstrap
supply is charged every cycle. The NCP1580, which is
capable of a 100 nsec minimum pulse width (typ), can allow
a 12 V to 1.0 V conversion at 350 kHz.
Input Voltage Range (V
CC
and BST)
The input voltage range for both V
CC
and BST is 4.5 V to
13.2 V with respect to GND and PHASE, respectively.
Although BST is rated at 13.2 V with respect to PHASE, it
can also tolerate 26.5 V with respect to GND.
Normal Shutdown Behavior
Normal shutdown occurs when the IC stops switching
because the input supply reaches UVLO threshold. In this
case, switching stops, the internal SS is discharged, and all
GATE pins go low. The switch node enters a high impedance
state and the output capacitors discharge through the load
with no ringing on the output voltage.
Internal Soft-Start
The NCP1580 features an internal soft-start function,
which reduces inrush current and overshoot of the output
voltage. Figure 10 shows a typical soft-start sequence.
Soft-start is achieved by ramping up the internal soft-start
voltage (V
SS
) which is applied to the input of the error
amplifier. This ramp is generated by applying 0.5
mA to a
100 pf capacitor for 1
msec on every fourth clock pulse. This
sequence begins once V
CC
surpasses its UVLO threshold
(see Figure 11). The typical soft-start time is 2 msec. The
internal soft-start voltage is held low when the part is in
UVLO.
Figure 10. Normal Startup
4.2 V
2 ms
V
CC
TG
V
OUT
UVLO
Startup
Normal Operation
Figure 11. Achieving Internal Soft-Start
4.2 V
1
m
S
V
CC
V
SS
5 mV
SS
CLK
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7
UVLO
Undervoltage Lockout (UVLO) is provided to ensure that
unexpected behavior does not occur when V
CC
is too low to
support the internal rails and power the converter. For the
NCP1580, the UVLO is set to ensure that the IC will start up
when V
CC
reaches 4.2 V and shutdown when V
CC
drops
below 3.7 V. This permits operation when converting from
a 5.0 V input voltage.
Thermal Shutdown
The NCP1580 also provides Thermal Shutdown (TSD)
for added protection. The TSD circuit monitors the die
temperature and turns off the top and bottom gate drivers if
an over temperature condition is detected. The internal soft-
start capacitor is also discharged. This is a latched state and
requires a power cycle to reset.
Drivers
The NCP1580 includes 1.5 A gate drivers to switch
external N-Channel MOSFETs. This allows the NCP1580
to address high-power as well as low-power conversion
requirements. The gate drivers also include adaptive
non-overlap circuitry. The non-overlap circuitry increases
efficiency, which minimizes power dissipation, by
minimizing the body diode conduction time.
A detailed block diagram of the non-overlap and gate
drive circuitry used in the chip is shown in Figure 12.
Careful selection and layout of external components is
required, to realize the full benefit of the onboard drivers.
The capacitors between V
CC
and GND and between BST
and SWN must be placed as close as possible to the IC. The
current paths for the TG and BG connections must be
optimized. A ground plane should be placed on the closest
layer for return currents to GND in order to reduce loop area
and inductance in the gate drive circuit.
Figure 12. Block Diagram
UVLO
FAULT
+
-
2 V
+
-
2 V
PHASE
TG
BST
V
CC
BG
GND
UVLO
FAULT
PWM
OUT
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8
APPLICATION SECTION
Input Capacitor Selection
The input capacitor has to sustain the ripple current
produced during the on time of the upper MOSFET, so it
must have a low ESR to minimize the losses. The RMS value
of this ripple is:
IinRMS
+
IOUT D
(1
*
D) ,
where D is the duty cycle, I
inRMS
is the input RMS current,
and I
OUT
is the load current. The equation reaches its
maximum value with D = 0.5. Losses in the input capacitors
can be calculated with the following equation:
PCIN
+
ESRCIN
IinRMS2,
where P
CIN
is the power loss in the input capacitors and
ESR
CIN
is the effective series resistance of the input
capacitance. Due to large dI/dt through the input capacitors,
electrolytic or ceramics should be used. If a tantalum must
be used, it must be surge protected. Otherwise, capacitor
failure could occur.
Calculating Input Startup Current
To calculate the input startup current, the following
equation can be used.
Iinrush
+
COUT
VOUT
tSS
,
where I
inrush
is the input current during startup, C
OUT
is
the total output capacitance, V
OUT
is the desired output
voltage, and t
SS
is the internal soft-start interval.
If the inrush current is higher than the steady state input
current during max load, then the input fuse should be rated
accordingly, if one is used.
Output Capacitor Selection
The output capacitor is a basic component for the fast
response of the power supply. In fact, during load transient,
for the first few microseconds it supplies the current to the
load. The controller immediately recognizes the load
transient and sets the duty cycle to maximum, but the current
slope is limited by the inductor value.
During a load step transient the output voltage initially
drops due to the current variation inside the capacitor and the
ESR. (neglecting the effect of the effective series inductance
(ESL)):
D
VOUT-ESR
+ D
IOUT
ESRCOUT,
where V
OUT-ESR
is the voltage deviation of V
OUT
due to the
effects of ESR and the ESR
COUT
is the total effective series
resistance of the output capacitors.
A minimum capacitor value is required to sustain the
current during the load transient without discharging it. The
voltage drop due to output capacitor discharge is given by
the following equation:
D
VOUT
*
DISCHARGE
+
D
IOUT2
LOUT
2
COUT
(VIN
D
*
VOUT)
,
where V
OUT-DISCHARGE
is the voltage deviation of V
OUT
due to the effects of discharge, L
OUT
is the output inductor
value and V
IN
is the input voltage.
It should be noted that
DV
OUT-DISCHARGE
and
DV
OUT-ESR
are out of phase with each other, and the larger
of these two voltages will determine the maximum deviation
of the output voltage (neglecting the effect of the ESL).
Inductor Selection
Both mechanical and electrical considerations influence
the selection of an output inductor. From a mechanical
perspective, smaller inductor values generally correspond to
smaller physical size. Since the inductor is often one of the
largest components in the regulation system, a minimum
inductor value is particularly important in
space-constrained applications. From an electrical
perspective, the maximum current slew rate through the
output inductor for a buck regulator is given by:
SlewRateLOUT
+
VIN
*
VOUT
LOUT
This equation implies that larger inductor values limit the
regulator's ability to slew current through the output
inductor in response to output load transients. Consequently,
output capacitors must supply the load current until the
inductor current reaches the output load current level. This
results in larger values of output capacitance to maintain
tight output voltage regulation. In contrast, smaller values of
inductance increase the regulator's maximum achievable
slew rate and decrease the necessary capacitance, at the
expense of higher ripple current. The peak-to-peak ripple
current is given by the following equation:
Ipk-pkLOUT
+
VOUT(1
*
D)
LOUT
350 kHZ
,
where Ipk-pk
LOUT
is the peak to peak current of the output.
From this equation it is clear that the ripple current increases
as L
OUT
decreases, emphasizing the trade-off between
dynamic response and ripple current.
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9
Feedback and Compensation
The NCP1580 allows the output of the DC-DC converter
to be adjusted from 0.8 V to 5.0 V via an external resistor
divider network. The controller will try to maintain 0.8 V at
the feedback pin. Thus, if a resistor divider circuit was
placed across the feedback pin to V
OUT
, the controller will
regulate the output voltage proportional to the resistor
divider network in order to maintain 0.8 V at the FB pin.
VOUT
FB
R1
R2
Figure 13.
The relationship between the resistor divider network in
Figure 13 and the output voltage is shown in the following
equation:
R2
+
R1
VREF
VOUT
*
VREF
.
Resistor R1 is selected based on a design trade off between
efficiency and output voltage accuracy. For high values of
R1 there is less current consumption in the feedback
network, However the trade off is output voltage accuracy
due to the bias current in the error amplifier. The output
voltage error of this bias current can be estimated using the
following equation (neglecting resistor tolerance):
Error%
+
0.1
m
A
R1
VREF
100%
Once R1 has been determined, R2 can be calculated.
The NCP1580 utilizes voltage mode control. This is to
say, the control loop regulates V
OUT
by monitoring V
OUT
and controlling the output current. However, since the
control loop is controlling the output current to regulate the
output voltage, there are some stability concerns since the
inductor current is 90 degrees out of phase with the voltage.
It is inherent with all voltage-mode control loops to have a
compensation network.
Figure 14. Simplified Diagram of Control Loop
V
IN
V
OUT
L
OUT
-
+
-
+
V
RAMP
PWM
COMPARATOR
C1
C2
C3
R1
R4
R3
R2
V
REF
C
OUT
ESR
The compensation network consists of the internal error
amplifier and the impedance networks Z
IN
(R1, R3 and C3)
and Z
FB
(R4, C1 and C2). The compensation network has to
provide a closed loop transfer function with the highest 0 dB
crossing frequency to have fast response (but always lower
than f
SW
/8) and the highest gain in DC conditions to
minimize the load regulation. A stable control loop has a
gain crossing with -20 dB/decade slope and a phase margin
greater than 45
. Include worst-case component variations
when determining phase margin. To place the poles and
zeroes of the compensation networks, the following
equations may be used:
Modulator frequencies:
w
LC
+
1
LOUT
COUT
w
ESR
+
1
ESR
COUT
Compensation network frequency:
w
P1
+
1
R4
C1
C2
C1
)
C2
w
P2
+
1
R3
C3
w
Z1
+
1
R4
C2
w
Z2
+
1
(R1
)
R3)
C3
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10
Place
w
Z1
, and
w
Z2
around the output filter resonance
w
LC
; Place
w
P1
at the output capacitor ESR zero
w
ESR
; Place
w
P2
at one half of the switching frequency;
The modulator transfer function is the small-signal
transfer function of V
OUT
/V
COMP
. This function has a
double pole at frequency
w
LC
and a zero at
w
ESR
. The DC
Gain of the modulator is simply the input voltage V
IN
divided by the peak-to-peak oscillator voltage
DV
OSC
.
Error Amplifier
Modulator Gain
Closed Loop
Gain
Compensation
Network
w
Z1
w
Z2
w
P1
w
P2
w
LC
w
ESR
Figure 15.
Visit http://www.onsemi.com/pub/Collateral/COMPCALC
for self extracting compensation program for design
assistance.
Thermal Considerations
The power dissipation of the NCP1580 varies with the
MOSFETs used, V
CC
, and the boost voltage (V
BST
). The
average MOSFET gate current typically dominates the
control IC power dissipation. The IC power dissipation is
determined by the formula:
PIC
+
(ICC
VCC)
)
PTG
)
PBG.
Where:
P
IC
= Control IC power dissipation,
I
CC
= IC measured supply current,
V
CC
= IC supply voltage,
P
TG
= Top gate driver losses,
P
BG
= Bottom gate driver losses.
The upper (switching) MOSFET gate driver losses are:
PTG
+
QTG
fSW
VBST.
Where:
Q
TG
= Total upper MOSFET gate charge at VBST,
f
SW
= The switching frequency,
V
BST
= The BST pin voltage.
The lower (synchronous) MOSFET gate driver losses are:
PBG
+
QBG
fSW
VCC.
Where:
Q
BG
= total lower MOSFET gate charge at V
CC
.
The junction temperature of the control IC can then be
calculated as:
TJ
+
TA
)
PIC
q
JA.
Where:
T
J
= The junction temperature of the IC,
T
A
= The ambient temperature,
JA
= The junction-to-ambient thermal resistance of the
IC package.
The package thermal resistance can be obtained from the
specifications section of this data sheet and a calculation can
be made to determine the IC junction temperature. However,
it should be noted that the physical layout of the board, the
proximity of other heat sources such as MOSFETs and
inductors, and the amount of metal connected to the IC,
impact the temperature of the device. Use these calculations
as a guide, but measurements should be taken in the actual
application.
NCP1580
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11
Layout Considerations
As in any high frequency switching converter, layout is
very important. Switching current from one power device to
another can generate voltage transients across the
impedances of the interconnecting bond wires and circuit
traces. These interconnecting impedances should be
minimized by using wide, short printed circuit traces. The
critical components should be located as close together as
possible using ground plane construction or single point
grounding. Figure 16 shows the critical power components
of the converter. To minimize the voltage overshoot the
interconnecting wires indicated by heavy lines should be
part of ground or power plane in a printed circuit board. The
components shown in Figure 16 should be located as close
together as possible. Please note that the capacitors C
IN
and
C
OUT
each represent numerous physical capacitors. It is
desirable to locate the NCP1580 within 1 inch of the
MOSFETs, Q1 and Q2. The circuit traces for the MOSFETs'
gate and source connections from the NCP1580 must be
sized to handle up to 2.0 A peak current.
Figure 16.
V
IN
V
OUT
L
OUT
R1
C
OUT
Q1
Q2
D2
C
IN
TG
PHASE
BG
GND
NCP1580
RETURN
LOAD
NCP1580
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12
PACKAGE DIMENSIONS
SO-8
D SUFFIX
CASE 751-07
ISSUE AB
SEATING
PLANE
1
4
5
8
N
J
X 45
_
K
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSION A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
6. 751-01 THRU 751-06 ARE OBSOLETE. NEW
STANDARD IS 751-07.
A
B
S
D
H
C
0.10 (0.004)
DIM
A
MIN
MAX
MIN
MAX
INCHES
4.80
5.00
0.189
0.197
MILLIMETERS
B
3.80
4.00
0.150
0.157
C
1.35
1.75
0.053
0.069
D
0.33
0.51
0.013
0.020
G
1.27 BSC
0.050 BSC
H
0.10
0.25
0.004
0.010
J
0.19
0.25
0.007
0.010
K
0.40
1.27
0.016
0.050
M
0
8
0
8
N
0.25
0.50
0.010
0.020
S
5.80
6.20
0.228
0.244
-X-
-Y-
G
M
Y
M
0.25 (0.010)
-Z-
Y
M
0.25 (0.010)
Z
S
X
S
M
_
_
_
_
1.52
0.060
7.0
0.275
0.6
0.024
1.270
0.050
4.0
0.155
mm
inches
SCALE 6:1
SOLDERING FOOTPRINT
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