|
|
Número de pieza | NCV8843 | |
Descripción | Buck Regulator | |
Fabricantes | ON Semiconductor | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de NCV8843 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
No Preview Available ! www.DataSheet4U.com
NCV8843
1.5 A, 340 kHz, Buck
Regulator with
Synchronization Capability
The NCV8843 is a 1.5 A buck regulator IC operating at a
fixed−frequency of 340 kHz. The device uses the V2t control
architecture to provide unmatched transient response, the best overall
regulation and the simplest loop compensation for today’s high−speed
logic. The NCV8843 accommodates input voltages from 4.5 V to 40 V
and contains synchronization circuitry.
The on−chip NPN transistor is capable of providing a minimum of
1.5 A of output current, and is biased by an external “boost” capacitor
to ensure saturation, thus minimizing on−chip power dissipation.
Protection circuitry includes thermal shutdown, cycle−by−cycle
current limiting and frequency foldback.
Features
• V2 Architecture Provides Ultra−Fast Transient Response, Improved
Regulation and Simplified Design
• 2.0% Error Amp Reference Voltage Tolerance
• Switch Frequency Decrease of 4:1 in Short Circuit Conditions
Reduces Short Circuit Power Dissipation
• BOOST Lead Allows “Bootstrapped” Operation to Maximize
Efficiency
• Sync Function for Parallel Supply Operation or Noise Minimization
• Shutdown Lead Provides Power−Down Option
• 1.0 mA Quiescent Current During Power−Down
• Thermal Shutdown
• Soft−Start
• Internally Fused Leads in SO−16L Package
• NCV Prefix for Automotive and Other Applications Requiring Site
and Control Changes
• Pb−Free Packages are Available
http://onsemi.com
MARKING
DIAGRAMS
16
16
1
SO−16 WB
PW SUFFIX
CASE 751AG
NCV8843
AWLYYWWG
1
1
18
18
18−LEAD DFN NCV8843
1 MN SUFFIX AWLYYWW G
CASE 505
G
A
WL
YY
WW
E
G or G
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Automotive Grade
= Pb−Free Package
(Note: Microdot may be in either location)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 13 of this data sheet.
© Semiconductor Components Industries, LLC, 2006
October, 2006 − Rev. 1
1
Publication Order Number:
NCV8843/D
1 page NCV8843
ELECTRICAL CHARACTERISTICS (continued) (−40°C < TJ < 125°C, 4.5 V< VIN < 40 V; unless otherwise specified.)
Characteristic
Test Conditions
Min Typ Max
General
Quiescent Current
Shutdown Quiescent Current
Boost Operating Current
Minimum Boost Voltage
ISW = 0 A
VSHDNB = 0 V
VBOOST − VSW = 2.5 V
(Note 4)
− 4.0 7.5
− 1.0 5.0
6.0 15 40
− − 2.5
Startup Voltage
− 2.2 3.3 4.4
Minimum Output Current
4. Guaranteed by design, not 100% tested in production.
−
− 7.0 12
Unit
mA
mA
mA/A
V
V
mA
SHDNB
SYNC
VIN
2.9 V LDO
Voltage
Regulator
Shutdown
Comparator
+
−
1.3 V
+
−
5.0 mA
Artificial
Ramp
SHDNB
1.46 V
∑
+
−
PWM
Comparator
Oscillator
Thermal
Shutdown
SQ
R
Output
Driver
Current
Limit
Comparator
IREF
−
VFB − +
+
0.32 V
+
−
Frequency IFOLDBACK
and Current
1.27 V
+
−
Error
Amplifier
Limit Foldback
VC
Figure 2. Block Diagram
BOOST
VSW
GND
http://onsemi.com
5
5 Page NCV8843
Figure 12. The Output Voltage Ripple Using Two 10 mF
Ceramic Capacitors in Parallel
Figure 13. The Output Voltage Ripple Using One
100 mF POSCAP Capacitor
Figure 14. The Output Voltage Ripple Using
One 100 mF OS−CON
Figure 12 to Figure 15 show the output ripple of a 5.0 V
to 3.3 V/500 mA regulator using 22 mH inductor and various
capacitor types. At the switching frequency, the low ESR
and ESL make the ceramic capacitors behave capacitively
as shown in Figure 12. Additional paralleled ceramic
capacitors will further reduce the ripple voltage, but
inevitably increase the cost. “POSCAP”, manufactured by
SANYO, is a solid electrolytic capacitor. The anode is
sintered tantalum and the cathode is a highly conductive
polymerized organic semiconductor. TPC series, featuring
low ESR and low profile, is used in the measurement of
Figure 13. It is shown that POSCAP presents a good balance
of capacitance and ESR, compared with a ceramic capacitor.
In this application, the low ESR generates less than 5.0 mV
of ripple and the ESL is almost unnoticeable. The ESL of the
through−hole OS−CON capacitor give rise to the inductive
impedance. It is evident from Figure 14 which shows the
step rise of the output ripple on the switch turn−on and large
spike on the switch turn−off. The ESL prevents the output
capacitor from quickly charging up the parasitic capacitor of
Figure 15. The Output Voltage Ripple Using
One 100 mF Tantalum Capacitor
the inductor when the switch node is pulled below ground
through the catch diode conduction. This results in the spike
associated with the falling edge of the switch node. The D
package tantalum capacitor used in Figure 15 has the same
footprint as the POSCAP, but doubles the height. The ESR
of the tantalum capacitor is apparently higher than the
POSCAP. The electrolytic and tantalum capacitors provide
a low−cost solution with compromised performance. The
reliability of the tantalum capacitor is not a serious concern
for output filtering because the output capacitor is usually
free of surge current and voltage.
Diode Selection
The diode in the buck converter provides the inductor
current path when the power switch turns off. The peak
reverse voltage is equal to the maximum input voltage. The
peak conducting current is clamped by the current limit of
the IC. The average current can be calculated from:
ID(AVG)
+
IO(VIN *
VIN
VO)
http://onsemi.com
11
11 Page |
Páginas | Total 15 Páginas | |
PDF Descargar | [ Datasheet NCV8843.PDF ] |
Número de pieza | Descripción | Fabricantes |
NCV8842 | Buck Regulator | ON Semiconductor |
NCV8843 | Buck Regulator | ON Semiconductor |
Número de pieza | Descripción | Fabricantes |
SLA6805M | High Voltage 3 phase Motor Driver IC. |
Sanken |
SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
Analog Devices |
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |