ON NCP3163 3.4 a, step−up/down/inverting 50−300 khz switching regulator Datasheet

NCP3163, NCV3163
3.4 A, Step−Up/Down/
Inverting 50−300 kHz
Switching Regulator
The NCP3163 Series is a performance enhancement to the popular
MC33163 and MC34163 monolithic DC−DC converters. These
devices consist of an internal temperature compensated reference,
comparator, controlled duty cycle oscillator with an active current
limit circuit, driver and high current output switch. This controller was
specifically designed to be incorporated in step−down, step−up, or
voltage−inverting applications with a minimum number of external
components. The NCP3163 comes in an exposed pad package which
can greatly increase the power dissipation of the built in power switch.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Output Switch Current in Excess of 3.0 A
3.4 A Peak Switch Current
Frequency is Adjustable from 50 kHz to 300 kHz
Operation from 2.5 V to 40 V Input
Externally Adjustable Operating Frequency
Precision 2% Reference for Accurate Output Voltage Control
Driver with Bootstrap Capability for Increased Efficiency
Cycle−by−Cycle Current Limiting
Internal Thermal Shutdown Protection
Low Voltage Indicator Output for Direct Microprocessor Interface
Exposed Pad Power Package
Low Standby Current
NCV Prefix for Automotive and Other Applications Requiring Site
and Control Changes
These are Pb−Free Devices
8
−
Current
Limit
9
+
7
10
6
16
1
SOIC−16W
EXPOSED PAD
PW SUFFIX
CASE 751AG
18
NCx3163yPW
AWLYYWWG
1
1
18−LEAD DFN
MN SUFFIX
CASE 505
1
NCx3163x
A
WL
YY
WW
G or G
18
NCP3163y
AWLYYWW G
G
= Specific Device Code
x = P or V
y = blank or B
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
See detailed ordering and shipping information in the package
dimensions section on page 18 of this data sheet.
11
Oscillator
R
5
*For additional information on our Pb−Free strategy
and soldering details, please download the
ON Semiconductor Soldering and Mounting
Techniques Reference Manual, SOLDERRM/D.
12
Q
Thermal
4
16
ORDERING INFORMATION
VCC
Cin
MARKING
DIAGRAMS
(Note: Microdot may be in either location)
+
Vin
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S
13
VCC
3
14
+
+
−
2
1
LVI
15
+
+
−
16
VCC
(Bottom View)
Figure 1. Typical Buck Application Circuit
© Semiconductor Components Industries, LLC, 2007
January, 2007 − Rev. 4
CO
1
Vout
+
Publication Order Number:
NCP3163/D
NCP3163, NCV3163
IPKsense
0.25 V
8
−
Current
Limit
9
RSC
7
VCC
10
VCC
Timing Capacitor
6
Switch Collector
Q2
R
5
RDT
12
Q
Gnd
Thermal
4
11
Q1
Oscillator
CT
Shutdown
Driver Collector
+
60
S
Latch
13
VCC
Voltage Feedback 1
3
14
Voltage Feedback 2
2
LVI Output
1
Switch Emitter
2.0 mA
45 k
+
+
−
LVI
+
+
−
15
Feedback
Comparator
1.25 V 15 k
7.0 V
1.125 V
16
Bootstrap Input
VCC
+
(Bottom View)
−
= Sink Only
Positive True Logic
Figure 2. Representative Block Diagram
PIN FUNCTION DESCRIPTION
SOIC16
DFN18
PIN NAME
DESCRIPTION
1
15
LVI Output
2
16
Voltage Feedback 2
Connecting this pin to a resistor divider off of the output will regulate the application
according to the Vout design equation in Figure 22.
3
17
Voltage Feedback 1
Connecting this pin directly to the output will regulate the device to 5.05 V.
4
18
GND
6
1
Timing Capacitor
7
3
VCC
8
4
Ipk Sense
9
5
Drive Collector
10,11
6,7,8,9
Switch Collector
14,15
10,11,12,13
Switch Emitter
Internal switch transistor emitter
16
14
Bootstrap Input
Connect this pin to VCC for operation at low VCC levels. For some topologies, a
series resistor and capacitor can be utilized to improve the converter efficiency.
5,12,13
2
No Connect
Exposed
Pad
Exposed
Pad
Exposed Pad
This pin will sink current when FB1 and FB2 are less than the LVI threshold (Vth).
Ground pin for all internal circuits and power switch.
Connect a capacitor to this pin to set the frequency. The addition of a parallel resistor will decrease the maximum duty cycle and increase the frequency.
Power pin for the IC.
When (VCC−VIPKsense) > 250 mV the circuit resets the output driver on a pulse by
pulse basis.
Voltage driver collector
Internal switch transistor collector
These pins have no connection.
The exposed pad beneath the package must be connected to GND (pin 4). Additionally, using proper layout techniques, the exposed pad can greatly enhance the
power dissipation capabilities of the NCP3163.
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NCP3163, NCV3163
MAXIMUM RATINGS (Note 1)
Rating
Symbol
Value
Unit
VCC
0 to +40
V
VCSW
−1.0 to +40
V
Switch Emitter Voltage Range
VESW
−2.0 to +40
V
Switch Collector to Emitter Voltage
VCESW
+40
V
Switch Current
ISW
3.4
A
Driver Collector Voltage (Pin 8)
VCC
−1.0 to +40
V
Driver Collector Current (Pin 8)
ICC
150
mA
Bootstrap Input Current Range
IBST
−100 to +100
mA
VIPKSNS
(VCC − 7.0) to (VCC + 1.0)
V
Vin
−1.0 to +7.0
V
Low Voltage Indicator Output Voltage Range
VCLVI
−1.0 to +40
V
Low Voltage Indicator Output Sink Current
ICLVI
10
mA
RqJC
RqJA
15
56
Tstg
−65 to +150
°C
TJmax
+150
°C
Power Supply Voltage
Switch Collector Voltage Range
Current Sense Input Voltage Range
Feedback and Timing Capacitor Input Voltage Range
Power Dissipation and Thermal Characteristics
°C/W
Thermal Characteristics
Thermal Resistance, Junction−to−Case
Thermal Resistance, Junction−to−Air
Storage Temperature Range
Maximum Junction Temperature
Operating Ambient Temperature (Note 3)
NCP3163PW
NCP3163BPW
NCV3163PW
°C
TA
0 to +70
−40 to +85
−40 to +125
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. This device series contains ESD protection and exceeds the following tests:
Human Body Model 1500 V per MIL−STD−883, Method 3015.
Machine Model Method 150 V.
2. This device contains latch−up protection and exceeds 100 mA per JEDEC Standard JESD78.
3. Maximum package power dissipation limits must be observed. Maximum Junction Temperature must not be exceeded.
4. The pins which are not defined may not be loaded by external signals.
PIN CONNECTIONS
LVI Output
Voltage Feedback 2
Voltage Feedback 1
GND
N/C
Timing Capacitor
VCC
Ipk Sense
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
Bootstrap Input
Timing Capacitor
N/C
VCC
Ipk Sense
Driver Collector
Switch Collector
Switch Collector
Switch Collector
Switch Collector
Switch
Emitter
N/C
Switch Collector
Driver Collector
1
2
3
4
5
6
7
8
9
18
GND
EP Flag
17
16
15
14
13
12
11
10
GND
Voltage Feedback 1
Voltage Feedback 2
LVI Output
Bootstrap Input
Switch Emitter
Switch Emitter
Switch Emitter
Switch Emitter
(Top View)
Note: Pin 18 must be tied to EP Flag on PCB
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NCP3163, NCV3163
ELECTRICAL CHARACTERISTICS (VCC = 15 V, Pin 16 = VCC, CT = 270 pF, RT = 15 kW, for typical values TA = 25°C, for min/max
values TA is the operating ambient temperature range that applies (Note 7), unless otherwise noted.)
Symbol
Characteristic
Min
Typ
Max
225
212
250
250
275
288
Unit
OSCILLATOR
Frequency
TA = 25°C, VCC = 15 V
Total Variation over VCC = 2.5 V to 40 V and Temperature
fOSC
kHz
Ichg
−
225
−
mA
Idischg
−
25
−
mA
Ichg/Idischg
8.0
9.0
10.5
−
Sawtooth Peak Voltage
VOSC(P)
−
1.25
−
V
Sawtooth Valley Voltage
VOSC(V)
−
0.55
−
V
4.9
4.85
5.05
−
5.2
5.25
−
0.008
0.03
−
100
200
1.225
1.213
1.25
−
1.275
1.287
−
0.008
0.03
− 0.4
−
0.4
−
225
250
−
−
270
−
1.0
20
−
−
−
0.6
0.6
1.0
1.0
1.2
1.4
−
0.02
100
mA
Charge Current
Discharge Current
Charge to Discharge Current Ratio
FEEDBACK COMPARATOR 1
Threshold Voltage
TA = 25°C
Total Variation over VCC = 2.5 V to 40 V and Temperature
Vth(FB1)
Threshold Voltage
Line Regulation (VCC = 2.5 V to 40 V, TA = 25°C)
V
REGline(FB1)
Input Bias Current (VFB1 = 5.05 V)
IIB(FB1)
%/V
mA
FEEDBACK COMPARATOR 2
Threshold Voltage
TA = 25°C, VCC = 15 V
Total Variation over VCC = 2.5 V to 40 V and Temperature
Vth(FB2)
Threshold Voltage
Line Regulation (VCC = 2.5 V to 40 V, TA = 25°C)
V
REGline(FB1)
Input Bias Current (VFB2 = 1.25 V)
IIB(FB2)
%/V
mA
CURRENT LIMIT COMPARATOR
Threshold Voltage
TA = 25°C
Total Variation over VCC = 2.5 V to 40 V, and Temperature
Vth(Sense)
Input Bias Current (VIpk (Sense) = 15 V)
IIB(Sense)
mV
mA
DRIVER AND OUTPUT SWITCH (Note 6)
Saturation Voltage (ISW = 2.5 A, Pins 14, 15 grounded)
NCP3163 − Non−Darlington (RPin 9 = 110 W to VCC, ISW/IDRV ≈ 20)
NCV3163 − Non−Darlington (RPin 9 = 110 W to VCC, ISW/IDRV ≈ 20)
Darlington Connection (Pins 9, 10, 11 connected)
Collector Off−State Leakage Current (VCE = 40 V)
VCE(sat)
IC(off)
Bootstrap Input Current Source (VBS = VCC + 5.0 V)
V
Isource(DRV)
0.5
2.0
4.0
mA
VZ
VCC + 6.0
VCC + 7.0
VCC + 9.0
V
Input Threshold (VFB2 Increasing)
Vth
1.07
1.125
1.18
V
Input Hysteresis (VFB2 Decreasing)
VH
−
15
−
mV
Output Sink Saturation Voltage (Isink = 2.0 mA)
VOL(LVI)
−
0.15
0.4
V
Output Off−State Leakage Current (VOH = 15 V)
IOH
−
0.01
5.0
mA
ICC
−
6.0
10
mA
Bootstrap Input Zener Clamp Voltage (IZ = 25 mA)
LOW VOLTAGE INDICATOR
TOTAL DEVICE
Standby Supply Current (VCC = 2.5 V to 40 V, Pin 8 = VCC,
Pins 6, 14, 15 = GND, remaining pins open)
5. Maximum package power dissipation limits must be observed.
6. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
7. Tlow = 0°C for NCP3163
Thigh = + 70°C for NCP3163
= − 40°C for NCP3163B
= + 85°C for NCP3163B
= − 40°C for NCV3163
= + 125°C for NCV3163
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NCP3163, NCV3163
300
VCC = 15 V
TA = 25°C
FREQUENCY (kHz)
250
200
Rt = 15 kW
150
Rt = open
100
50
0
100
200
300
400
500
CT, TIMER CAPACITANCE (pF)
600
700
Δ f OSC, OSCILLATOR FREQUENCY CHANGE (%)
Δ f OSC, OSCILLATOR FREQUENCY CHANGE (%)
Figure 3. Oscillator Frequency vs. Timer
Capacitance (CT)
2.0
VCC = 15 V
CT = 620 pF
0
−2.0
−4.0
−6.0
−55
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
IIB , INPUT BIAS CURRENT (A)
μ
VCC = 15 V
VFB1 = 5.05 V
120
100
80
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
0
−2.0
−4.0
−6.0
−8.0
−10
−50
−25
0
25
50
TEMPERATURE (°C)
75
100
125
Figure 5. Oscillator Frequency Change vs.
Temperature when CT and RT are connected to Pin 6
140
60
−55
VCC = 15 V
CT = 230 pF
RT = 20 kW
2.0
V th(FB2), COMPARATOR 2 THRESHOLD VOLTAGE (mV)
Figure 4. Oscillator Frequency Change vs.
Temperature when only CT is connected to Pin 6
4.0
125
Figure 6. Feedback Comparator 1 Input Bias
Current vs. Temperature
1300
1260
Vth Max = 1275 mV
Vth Typ = 1250 mV
1240
Vth Min = 1225 mV
1220
1200
−55
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5
VCC = 15 V
1280
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
Figure 7. Feedback Comparator 2 Threshold
Voltage vs. Temperature
125
V Z, BOOTSTRAP INPUT ZENER CLAMP VOLTAGE (V
I source (DRV), BOOTSTRAP INPUT CURRENT SOURCE (mA
NCP3163, NCV3163
2.8
VCC = 15 V
Pin 16 = VCC + 5.0 V
2.4
2.0
1.6
1.2
−55
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
IZ = 25 mA
7.4
7.2
7.0
6.8
−55
Figure 8. Bootstrap Input Current
Source vs. Temperature
−0.8
VCE (sat), SINK SATURATION (V)
−0.4
Darlington Configuration
Emitter Sourcing Current to GND
Pins 7, 8, 10, 11 = VCC
Pins 4, 5, 12, 13 = GND
TA = 25°C, (Note 2)
100
125
Bootstrapped, Pin 16 = VCC + 5.0 V
−1.2
−1.6
Non−Bootstrapped, Pin 16 = VCC
0
0.8
2.4
1.6
IE, EMITTER CURRENT (A)
0.8
Grounded Emitter Configuration
Collector Sinking Current From VCC
Pins 7, 8 = VCC = 15 V
Pins 4, 5, 12, 13, 14, 15 = GND
TA = 25°C, (Note 2)
Saturated Switch, RPin9 = 110 W to VCC
0.6
0.4
0.2
0
3.2
Darlington, Pins 9, 10, 11 Connected
1.0
GND
0
Figure 10. Output Switch Source Saturation
vs. Emitter Current
−0.4
V OL (LVI) , OUTPUT SATURATION VOLTAGE (V)
GND
IC = 10 mA
−0.8
IC = 10 mA
−1.2
VCC = 15 V
Pins 7, 8, 9, 10, 16 = VCC
Pins 4, 6 = GND
Pin 14 Driven Negative
−1.6
−2.0
−55
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
0.8
1.6
2.4
IC, COLLECTOR CURRENT (A)
3.2
Figure 11. Output Switch Sink Saturation
vs. Collector Current
0
V E , EMITTER VOLTAGE (V)
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
1.2
VCC
−2.0
−25
Figure 9. Bootstrap Input Zener Clamp
Voltage vs. Temperature
0
VCE (sat), SOURCE SATURATION (V)
7.6
125
Figure 12. Output Switch Negative Emitter
Voltage vs. Temperature
0.5
VCC=5 V
TA=25°C
0.4
0.3
0.2
0.1
0
0
2.0
4.0
6.0
Isink, OUTPUT SINK CURRENT (mA)
Figure 13. Low Voltage Indicator Output Sink
Saturation Voltage vs. Sink Current
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6
8.0
254
VCC = 15 V
IIB (Sense), INPUT BIAS CURRENT (μ A)
V th (Ipk Sense) , THRESHOLD VOLTAGE (mV
NCP3163, NCV3163
252
250
248
246
−55
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
1.6
1.2
1.0
0.8
0.6
−55
Figure 14. Current Limit Comparator Threshold
Voltage vs. Temperature
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
I CC, SUPPLY CURRENT (mA)
7.2
6.0
4.0
Pins 7, 8, 16 = VCC
Pins 4, 6, 14 = GND
Remaining Pins Open
TA = 25°C
2.0
0
10
20
30
VCC, SUPPLY VOLTAGE (V)
VCC = 15 V
Pins 7, 8, 16 = VCC
Pins 4, 6, 14 = GND
Remaining Pins Open
6.4
5.6
4.8
4.0
−55
40
−25
Figure 16. Standby Supply Current
vs. Supply Voltage
V CC(min) , MINIMUM OPERATING SUPPLY VOLTAGE (V)
I CC, SUPPLY CURRENT (mA)
−25
Figure 15. Current Limit Comparator Input Bias
Current vs. Temperature
8.0
0
VCC = 15 V
VIpk (Sense) = 15 V
1.4
CT = 620 pF
Pins 7,8 = VCC
Pins 4, 14 = GND
Pin 9 = 1.0 kW to 15 V
Pin 10 = 100 W to 15 V
2.6
1.8
Pin 16 Open
Pin 16 = VCC
1.4
1.0
−55
−25
0
100
Figure 17. Standby Supply Current
vs. Temperature
3.0
2.2
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
25
50
75
100
TA, AMBIENT TEMPERATURE (°C)
Figure 18. Minimum Operating Supply
Voltage vs. Temperature
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125
125
NCP3163, NCV3163
INTRODUCTION
The NCP3163 is a monolithic power switching regulator
optimized for DC−to−DC converter applications. The
combination of its features enables the system designer to
directly implement step−up, step−down, and voltage−
inverting converters with a minimum number of external
components. Potential applications include cost sensitive
consumer products as well as equipment for the automotive,
computer, and industrial markets. A representative block
diagram is shown in Figure 2.
oscillator cycle, a partial cycle plus a complete cycle,
multiple cycles, or a partial cycle plus multiple cycles.
Oscillator
The oscillator frequency and on−time of the output switch
are programmed by the value selected for timing capacitor
CT. Capacitor CT is charged and discharged by a 9 to 1 ratio
internal current source and sink, generating a negative going
sawtooth waveform at Pin 6. As CT charges, an internal
pulse is generated at the oscillator output. This pulse is
connected to the NOR gate center input, preventing output
switch conduction, and to the AND gate upper input,
allowing the latch to be reset if the comparator output is low.
Thus, the output switch is always disabled during ramp−up
and can be enabled by the comparator output only at the start
of ramp−down. The oscillator peak and valley thresholds are
1.25 V and 0.55 V, respectively, with a charge current of
225 mA and a discharge current of 25 mA, yielding a
maximum on−time duty cycle of 90%. A reduction of the
maximum duty cycle may be required for specific converter
configurations. This can be accomplished with the addition
of an external deadtime resistor (RDT) placed across CT. The
resistor increases the discharge current which reduces the
on−time of the output switch. The converter output can be
inhibited by clamping CT to ground with an external NPN
small−signal transistor. To calculate the frequency when
only CT is connected to Pin 6, use the equations found in
Figure 22. When RT is also used, the frequency and
maximum duty cycle can be calculated with the NCP3163
design tool found at www.onsemi.com.
OPERATING DESCRIPTION
The NCP3163 operates as a fixed on−time, variable
off−time voltage mode ripple regulator. In general, this
mode of operation is somewhat analogous to a capacitor
charge pump and does not require dominant pole loop
compensation for converter stability. The Typical Operating
Waveforms are shown in Figure 19. The output voltage
waveform shown is for a step−down converter with the
ripple and phasing exaggerated for clarity. During initial
converter startup, the feedback comparator senses that the
output voltage level is below nominal. This causes the
output switch to turn on and off at a frequency and duty cycle
controlled by the oscillator, thus pumping up the output filter
capacitor. When the output voltage level reaches nominal,
the feedback comparator sets the latch, immediately
terminating switch conduction. The feedback comparator
will inhibit the switch until the load current causes the output
voltage to fall below nominal. Under these conditions,
output switch conduction can be inhibited for a partial
1
Comparator Output
0
1.25 V
Timing Capacitor CT
0.55 V
t
9t
1
Oscillator Output
0
On
Output Switch
Off
Nominal Output
Voltage Level
Output Voltage
Startup
Quiescent Operation
Figure 19. Typical Operating Waveforms
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NCP3163, NCV3163
Feedback and Low Voltage Indicator Comparators
output state is controlled by the highest voltage applied to
either of the two noninverting inputs.
The Low Voltage Indicator (LVI) comparator is designed
for use as a reset controller in microprocessor−based
systems. The inverting input is internally biased at 1.125 V,
which sets the noninverting input thresholds to 90% of
nominal. The LVI comparator has 15 mV of hysteresis to
prevent erratic reset operation. The Open Collector output is
capable of sinking in excess of 6.0 mA (see Figure 13). An
external resistor (RLVI) and capacitor (CDLY) can be used to
program a reset delay time (tDLY) by the formula shown
below, where Vth(MPU) is the microprocessor reset input
threshold. Refer to Figure 20.
Output voltage control is established by the Feedback
comparator. The inverting input is internally biased at 1.25 V
and is not pinned out. The converter output voltage is
typically divided down with two external resistors and
monitored by the high impedance noninverting input at Pin 2.
The maximum input bias current is ±0.4 mA, which can cause
an output voltage error that is equal to the product of the input
bias current and the upper divider resistance value. For
applications that require 5.0 V, the converter output can be
directly connected to the noninverting input at Pin 3. The high
impedance input, Pin 2, must be grounded to prevent noise
pickup. The internal resistor divider is set for a nominal
voltage of 5.05 V. The additional 50 mV compensates for a
1.0% voltage drop in the cable and connector from the
converter output to the load. The Feedback comparator’s
tDLY = RLVI ⋅ CDLY ⋅ In
3
Feedback
Comparator
+
+
−
RLVI
1
CDLY
Ǔ
14
2
Low Voltage
Indicator Output
ǒ
1
Vth(MPU)
1−
Vout
LVI
+
+
−
1.25 V
15
16
1.125 V
L
CO
(Bottom View)
Vout
Figure 20. Partial Application Schematic Showing
Implementation of LVI Delay with RLVI and CDLY
Current Limit Comparator, Latch and Thermal
Shutdown
200 ns. The parasitic inductance associated with RSC and the
circuit layout should be minimized. This will prevent
unwanted voltage spikes that may falsely trip the Current
Limit comparator.
Internal thermal shutdown circuitry is provided to protect
the IC in the event that the maximum junction temperature
is exceeded. When activated, typically at 170°C, the Latch
is forced into the “Set” state, disabling the Output Switch.
This feature is provided to prevent catastrophic failures from
accidental device overheating. It is not intended to be used
as a replacement for proper heatsinking.
With a voltage mode ripple converter operating under
normal conditions, output switch conduction is initiated by
the oscillator and terminated by the Voltage Feedback
comparator. Abnormal operating conditions occur when the
converter output is overloaded or when feedback voltage
sensing is lost. Under these conditions, the Current Limit
comparator will protect the Output Switch.
The switch current is converted to a voltage by inserting
a fractional ohm resistor, RSC, in series with VCC and output
switch transistor Q2. The voltage drop across RSC is
monitored by the Current Sense comparator. If the voltage
drop exceeds 250 mV with respect to VCC, the comparator
will set the latch and terminate output switch conduction on
a cycle−by−cycle basis. This Comparator/Latch
configuration ensures that the Output Switch has only a
single on−time during a given oscillator cycle. The
calculation for a value of RSC is:
Driver and Output Switch
To aid in system design flexibility and conversion
efficiency, the driver current source and collector, and
output switch collector and emitter are pinned out
separately. This allows the designer the option of driving the
output switch into saturation with a selected force gain or
driving it near saturation when connected as a Darlington.
The output switch has a typical current gain of 70 at 2.5 A
and is designed to switch a maximum of 40 V collector to
emitter, with up to 3.4 A peak collector current. The
minimum value for RSC is:
RSC + 0.25 V
Ipk (Switch)
Figures 14 and 15 show that the Current Sense comparator
threshold is tightly controlled over temperature and has a
typical input bias current of 1.0 mA. The propagation delay
from the comparator input to the Output Switch is typically
RSC(min) + 0.25 V + 0.0735 W
3.4 A
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9
NCP3163, NCV3163
When configured for step−down or voltage−inverting
applications (see application notes at the end of this
document) the inductor will forward bias the output rectifier
when the switch turns off. Rectifiers with a high forward
voltage drop or long turn−on delay time should not be used.
If the emitter is allowed to go sufficiently negative, collector
current will flow, causing additional device heating and
reduced conversion efficiency.
Figure 12 shows that by clamping the emitter to 0.5 V, the
collector current will be in the range 10 mA over
temperature. A 1N5822 or equivalent Schottky barrier
rectifier is recommended to fulfill these requirements.
A bootstrap input is provided to reduce the output switch
saturation voltage in step−down and voltage−inverting
converter applications. This input is connected through a
series resistor and capacitor to the switch emitter and is used
to raise the internal 2.0 mA bias current source above VCC.
An internal zener limits the bootstrap input voltage to VCC
+7.0 V. The capacitor’s equivalent series resistance must
limit the zener current to less than 100 mA. An additional
series resistor may be required when using tantalum or other
low ESR capacitors. The equation below is used to calculate
a minimum value bootstrap capacitor based on a minimum
zener voltage and an upper limit current source.
t
CB(min) + I Dt + 4.0 mA on + 0.001 ton
DV
4.0 V
Parametric operation of the NCP3163 is guaranteed over
a supply voltage range of 2.5 V to 40 V. When operating
below 3.0 V, the Bootstrap Input should be connected to
VCC. Figure 18 shows that functional operation down to
1.7 V at room temperature is possible.
Package
The NCP3163 is contained in a heatsinkable 16−lead
plastic package in which the die is mounted on a special heat
tab copper alloy pad. This pad is designed to be soldered
directly to a GND connection on the printed circuit board to
improve thermal conduction. Since this pad directly
contacts the substrate of the die, it is important that this pad
be always soldered to GND, even if surface mount heat
sinking is not being used. Figure 21 shows recommended
layout techniques for this package.
Vias to 2nd Layer Metal
for Maximum Heat Sinking
Exposed Pad
0.175
0.188
Minimum
Recommended
Exposed Copper
0.145
Flare Metal for Maximum Heat Sinking
Figure 21. Layout Guidelines to Obtain Maximum
Package Power Dissipation
APPLICATIONS
Figures 23 through 30 show the simplicity and flexibility
of the NCP3163. Three main converter topologies are
demonstrated with actual test data shown below each of the
circuit diagrams. Figure 22 gives the relevant design
equations for the key parameters. Additionally, a complete
application design aid for the NCP3163 can be found at
www.onsemi.com.
http://onsemi.com
10
NCP3163, NCV3163
Step−Down
Calculation
(See Notes 1,2,3)
ton
toff
V
V out ) V F
* V sat * V out
in
ǒ
ton
t on
t off
Voltage−Inverting
V out ) V F – V in
V – V sat
in
|V out| ) V F
V * V sat
in
Ǔ
t on
) 1
t
off
ƒ
ƒ
IL(avg)
IL(avg) )
DI L
ǒ
V
L
Vripple(pp)
DIL
in
V
Vout
ref
ǒ
ǒ
Ǔ
ǒ
V
t on
R1
) (ESR)2
[
Ǔ
) 1
V
ref
ǒ
R2
R1
ǒ
Ǔ
t on
) 1
t
off
I out
ǒ
Ǔ
t on
) 1
t
off
IL(avg) )
2
DI L
2
0.25
Ipk (Switch)
Ǔ
ǒ
V
t on
t on I out
C
t on
t off
32.143 · 10*6 * 20 @ 10 *12
f
DI L
* V sat
DI L
in
2
R2
Ǔ
t on
) 1
t
off
ƒ
0.25
Ipk (Switch)
* V sat * V out
DI L
ǒ8 ƒ1COǓ
Ǔ
t on
) 1
t
off
IL(avg) )
2
0.25
Ipk (Switch)
RSC
ǒ
I out
Iout
Ipk (Switch)
t on
t off
32.143 · 10*6 * 20 @ 10 *12
f
32.143 · 10*6 * 20 @ 10 *12
f
CT
Step−Up
in
* V sat
DI L
[
O
Ǔ
) 1
V
ref
ǒ
Ǔ
t on
t on I out
C
R2
R1
O
Ǔ
) 1
The following Converter Characteristics must be chosen:
Vin −
Vout −
Iout −
DI L −
Nominal operating input voltage.
Desired output voltage.
Desired output current.
Desired peak−to−peak inductor ripple current. For maximum output current it is suggested that DIL be chosen to be less
than 10% of the average inductor current IL(avg). This will help prevent Ipk (Switch) from reaching the current limit
threshold set by RSC. If the design goal is to use a minimum inductance value, let DIL = 2(IL(avg)). This will
proportionally reduce converter output current capability.
p − Maximum output switch frequency.
Vripple(pp) − Desired peak−to−peak output ripple voltage. For best performance the ripple voltage should be kept to a low value
since it will directly affect line and load regulation. Capacitor CO should be a low equivalent series resistance (ESR)
electrolytic designed for switching regulator applications.
NOTES:
NOTES:
NOTES:
NOTES:
1.
2.
3.
3.
Vsat − Saturation voltage of the output switch, refer to Figures 10 and 11.
VF − Output rectifier forward voltage drop. Typical value for 1N5822 Schottky barrier rectifier is 0.5 V.
The calculated ton/toff must not exceed the minimum guaranteed oscillator charge to discharge ratio of 8, at the minimum
operating input voltage.
Figure 22. Design Equations
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11
NCP3163, NCV3163
−
+
RSC
Vin
Current
Limit
0.25 V
8
9
7
Cin
10
VCC
6
Oscillator
11
Q1
CT
RT
R
Q
S
Latch
5
Thermal
4
Q2
12
60
13
VCC
3
14
45 k
R1
1
R2
Feedback
Comparator
+
+
−
2
LVI
+
+
−
D
2.0 mA
1.25 V 15 k
1.125 V
15
16
VCC
7.0 V
CB
RB
L
Vout
CO
(Bottom View)
Figure 23. Typical Buck Application Schematic
Value of Components
Name
Value
Name
L
47 mH
R1
D
Value
15 kW
2 A, 40 V Schottky Rectifier
R2
24.9 kW
Cin
47 mF, 35 V
Rsc
80 mW, 1 W
Cout
100 mF, 10 V
Cb
4.7 nF
Ct
270 pF ±10%
Rb
200 W
Rt
15 kW
Test Results for Vout = 3.3 V
Test
Condition
Results
Line Regulation
Vin = 8.0 V to 24 V, Iout = 2.5 A
13 mV
Load Regulation
Vin = 12 V, Iout = 0 to 2.5 A
25 mV
Output Ripple
Vin = 12 V, Iout = 0 to 2.5 A
100 mVpp
Efficiency
Vin = 12 V, Iout = 2.5 A
70.3%
Short Circuit Current
Vin = 12 V, RL = 0.1 W
3.1 A
Condition
Results
Test Results for Vout = 5.05 V
Test
Line Regulation
Vin = 10.2 V to 24 V, Iout = 2.5 A
54 mV
Load Regulation
Vin = 12 V, Iout = 0 to 2.5 A
28 mV
Output Ripple
Vin = 12 V, Iout = 0 to 2.5 A
150 mVpp
Efficiency
Vin = 12 V, Iout = 2.5 A
75.5%
Short Circuit Current
Vin = 12 V, RL = 0.1 W
3.1 A
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12
NCP3163, NCV3163
Figure 24. Buck Layout
APPLICATION SPECIFIC CHARACTERISTICS
85
5.0 V Eff
EFFICIENCY (%)
80
75
3.3 V Eff
70
65
60
55
50
0
0.5
1.0
1.5
2.0
2.5
Iout (A)
Figure 25. Efficiency vs. Output Current for the
Buck Demo Board at Vin = 12 V, TA = 255C
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13
NCP3163, NCV3163
8
−
+
RSC
Vin
+ 7
Cin
6
RT
Current
Limit
0.25 V
L
9
10
VCC
Oscillator
11
Q1
CT
Q2
R
Q
S
Latch
5
Thermal
4
12
60
13
VCC
D
3
14
45 k
+
+
−
2
1
LVI
15
2.0 mA
1.25 V 15 k
+
+
−
1.125 V
R1
R2
Feedback
Comparator
16
VCC
7.0 V
CO
(Bottom View)
+
Vout
Figure 26. Typical Boost Application Schematic
Value of Components for Vout = 24 V
Name
Value
Name
Value
L
33 mH
R1
42.2 kW
D
2 A, 40 V Schottky Rectifier
R2
2.32 kW
Cin
330 mF, 35 V
Cout
330 mF, 25 V
Ct
270 pF ±10%
Rsc
80 mW, 1 W
Rt
15 kW
Test Results for Vout = 24 V
Test
Condition
Results
Line Regulation
Vin = 10 V to 20 V, Iout = 700 mA
90 mV
Load Regulation
Vin = 12 V, Iout = 0 to 700 mA
80 mV
Output Ripple
Vin = 12 V, Iout = 0 to 700 mA
300 mVpp
Efficiency
Vin = 12 V, Iout = 700 mA
83%
Short Circuit Current
Vin = 12 V, RL = 0.1 W
3.1 A
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14
NCP3163, NCV3163
Figure 27. Boost Demo Board Layout
86
EFFICIENCY (%)
84
82
80
78
76
74
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Iout (A)
Figure 28. Efficiency vs. Output Current for the
Boost Demo Board at Vin = 12 V, TA = 255C
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15
NCP3163, NCV3163
−
+
RSC
Vin
Cin
Current
Limit
0.25 V
8
7
+
10
VCC
6
Oscillator
11
Q1
CT
RT
9
Q2
R
Q
S
Latch
5
Thermal
4
12
60
13
VCC
3
14
45 k
+
+
−
2
1
LVI
R2
R1
+
+
−
Feedback
Comparator
15
2.0 mA
1.25 V 15 k
1.125 V
VCC
7.0 V
16
L
RB
CB
D
Vout
+ CO
(Bottom View)
Figure 29. Typical Voltage Inverting Application Schematic
Value of Components for Vout = −15 V
Name
Value
Name
Value
L
47 mH
R1
1.07 kW
D
2 A, 40 V Schottky Rectifier
R2
11.8 kW
Cin
270 mF, 16 V
Rsc
80 mW, 1 W
Cout
2 X 270 mF, 16 V
Cb
4.7 nF
150 pF ±10%
Rb
200 mW
Ct
Test Results for Vout = −15 V
Test
Condition
Results
Line Regulation
Vin = 7.0 V to 16 V, Iout = 500 mA
35 mV
Load Regulation
Vin = 12 V, Iout = 0 to 500 mA
20 mV
Output Ripple
Vin = 12 V, Iout = 0 to 500 mA
100 mVpp
Efficiency
Vin = 12 V, Iout = 500 mA
68%
Short Circuit Current
Vin = 12 V, RL = 0.1 W
3.1 A
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16
NCP3163, NCV3163
Figure 30. Voltage Inverting Demo Board Layout
70
EFFICIENCY (%)
66
62
58
54
50
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Iout (A)
Figure 31. Efficiency vs. Output Current for the
Voltage Inverting Demo Board at Vin = 12 V, TA = 255C
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17
NCP3163, NCV3163
ORDERING INFORMATION
Package
Shipping †
NCP3163PWG
SOIC−16 W Exposed Pad
(Pb−Free)
47 Units / Rail
NCP3163PWR2G
SOIC−16 W Exposed Pad
(Pb−Free)
1000 / Tape & Reel
NCP3163BPWG
SOIC−16 W Exposed Pad
(Pb−Free)
47 Units / Rail
NCP3163BPWR2G
SOIC−16 W Exposed Pad
(Pb−Free)
1000 / Tape & Reel
NCP3163MNR2G
DFN18
(Pb−Free)
2500 / Tape & Reel
NCP3163BMNR2G
DFN18
(Pb−Free)
2500 / Tape & Reel
NCV3163PWG
SOIC−16 W Exposed Pad
(Pb−Free)
47 Units / Rail
NCV3163PWR2G
SOIC−16 W Exposed Pad
(Pb−Free)
1000 / Tape & Reel
Device
†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.
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18
NCP3163, NCV3163
PACKAGE DIMENSIONS
SOIC 16 LEAD WIDE BODY, EXPOSED PAD
PW SUFFIX
CASE 751AG−01
ISSUE O
−U−
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 PROTRUSION SHALL BE
0.13 (0.005) TOTAL IN EXCESS OF THE D DIMENSION
AT MAXIMUM MATERIAL CONDITION.
6. 751R−01 OBSOLETE, NEW STANDARD 751R−02.
A
M
16
9
P
0.25 (0.010)
M
W
M
B
1
R x 45_
8
−W−
G
PIN 1 I.D.
14 PL
DIM
A
B
C
D
F
G
H
J
K
L
M
P
R
DETAIL E
TOP SIDE
C
F
−T−
0.10 (0.004) T
K
D 16 PL
0.25 (0.010)
M
T U
SEATING
PLANE
W
S
S
J
DETAIL E
H
EXPOSED PAD
1
8
16
9
MILLIMETERS
MIN
MAX
10.15
10.45
7.40
7.60
2.35
2.65
0.35
0.49
0.50
0.90
1.27 BSC
3.31
3.51
0.25
0.32
0.00
0.10
4.58
4.78
0_
7_
10.05
10.55
0.25
0.75
INCHES
MIN
MAX
0.400
0.411
0.292
0.299
0.093
0.104
0.014
0.019
0.020
0.035
0.050 BSC
0.130
0.138
0.010
0.012
0.000
0.004
0.180
0.188
0_
7_
0.395
0.415
0.010
0.029
SOLDERING FOOTPRINT*
L
0.350
Exposed
Pad
0.175
0.050
BACK SIDE
CL
0.200
0.188
CL
0.376
0.074
0.024
0.145
DIMENSIONS: INCHES
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
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19
NCP3163, NCV3163
PACKAGE DIMENSIONS
DFN18
CASE 505−01
ISSUE D
NOTES:
1. DIMENSIONS AND TOLERANCING PER
ASME Y14.5M, 1994.
2. DIMENSIONS IN MILLIMETERS.
3. DIMENSION b APPLIES TO PLATED
TERMINAL AND IS MEASURED BETWEEN
0.25 AND 0.30 MM FROM TERMINAL
4. COPLANARITY APPLIES TO THE EXPOSED
PAD AS WELL AS THE TERMINALS.
A
B
D
PIN 1 LOCATION
E
2X
DIM
A
A1
A3
b
D
D2
E
E2
e
K
L
0.15 C
2X
0.15 C
TOP VIEW
(A3)
0.10 C
A
18X
0.08 C
A1
MILLIMETERS
MIN
MAX
0.80
1.00
0.00
0.05
0.20 REF
0.18
0.30
6.00 BSC
3.98
4.28
5.00 BSC
2.98
3.28
0.50 BSC
0.20
−−−
0.45
0.65
C
SIDE VIEW
SEATING
PLANE
SOLDERING FOOTPRINT*
D2
18X
18X
L
5.30
e
1
9
1
0.50
PITCH
E2
K
18
18X
0.75
4.19
10
18X
BOTTOM VIEW
b
0.10 C A B
18X
0.05 C
0.30
NOTE 3
3.24
DIMENSIONS: MILLIMETERS
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
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LITERATURE FULFILLMENT:
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For additional information, please contact your local
Sales Representative
NCP3163/D