|
|
PDF MIC2876 Data sheet ( Hoja de datos )
| Número de pieza | MIC2876 | |
| Descripción | Synchronous Boost Regulator | |
| Fabricantes | Micrel Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de MIC2876 (archivo pdf) en la parte inferior de esta página. Total 20 Páginas | ||
|
No Preview Available !
MIC2876
4.8A ISW, Synchronous Boost Regulator with
Bi-Directional Load Disconnect
General Description
The MIC2876 is a compact and highly-efficient 2MHz
synchronous boost regulator with a 4.8A switch. It features
a bi-directional load disconnect function which prevents
any leakage current between the input and output when
the device is disabled. The MIC2876 operates in bypass
mode automatically when the input voltage is greater than
the target output voltage. At light loads, the boost
converter goes to the PFM mode to improve the efficiency.
The MIC2876 also features an integrated anti-ringing
switch to minimize EMI.
The MIC2876 is available in a 8-pin 2mm × 2mm Thin DFN
(TDFN) package, with a junction temperature range of
−40°C to +125°C.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• Input voltage range: 2.5V to 5.5V
• Fully-integrated, high-efficiency, 2MHz synchronous
boost regulator
• Bi-directional true load disconnect
• Integrated anti-ringing switch
• Up to 95% efficiency
• <1µA shutdown current
• Bypass mode for VIN ≥ VOUT
• Overcurrent protection and thermal shutdown
• Fixed and adjustable output versions
• 8-pin 2mm × 2mm TDFN package
Applications
• Tablet and smartphones
• USB OTG and HDMI hosts
• Portable power reserve supplies
• High-current parallel Lithium cell applications
• Portable equipment
Simplified Application Schematics
MIC2876 (Adjustable Output)
MIC2876 (Fixed Output)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 20, 2014
Revision 1.0
1 page  
Micrel, Inc.
MIC2876
Electrical Characteristics(7) (Continued)
VIN = 3.6V, VOUT = 5V, CIN = 4.7µF, COUT = 22µF, L = 1µH TA = 25°C, bold values indicate −40°C ≤ TJ ≤ +125°C, unless otherwise
noted.
Symbol Parameter
Soft-Start
Condition
Min.
Typ.
Max. Unit
TSS Soft-Start Time
EN, /PG Control Pins
VEN EN Threshold Voltage
EN Pin Current
VOUT = 5.0V
Boost converter and chip logic ON
Boost converter and chip logic OFF
VIN = VEN = 3.6V
1.1 ms
1.5
V
0.4
1.5 3 µA
V/PG-THR Power-Good Thershold (Rising)
V/PG-THF Power-Good Thershold (Falling)
0.90 × VOUT
0.83 × VOUT
V
V
October 20, 2014
5
Revision 1.0
5 Page 
Micrel, Inc.
Application Information
General Description
The MIC2876 is a 2MHz, current-mode, PWM,
synchronous boost converter with an operating input
voltage range of 2.5V to 5.5V. At light load, the converter
enters pulse-skipping mode to maintain high efficiency
over a wide range of load current. The maximum peak
current in the boost switch is limited to 4.8A (typical).
Bi-Directional Output Disconnect
The power stage of the MIC2876 consists of a NMOS
transistor as the main switch and a PMOS transistor as
the synchronous rectifier. A control circuit turns off the
back gate diode of the PMOS to isolate the output from
the input supply when the chip is disabled (VEN = 0V). An
“always on” maximum supply selector switches the
cathode of the backgate diode to either the IN or the OUT
(whichever of the two has the higher voltage). As a result,
the output of the MIC2876 is bi-directionally isolated from
the input as long as the device is disabled. The maximum
supply selector and hence the output disconnect function
requires only 0.3V at the IN pin to operate.
Integrated Anti-Ringing Switch
The MIC2876 includes an anti-ringing switch that
eliminates the ringing on the SW node of a conventional
boost converter operating in the discontinuous
conduction mode (DCM). At the end of a switching cycle
during DCM operation, both the NMOS and PMOS are
turned off. The anti-ringing switch in the MIC2876 clamps
the SW pin voltage to IN to dissipate the remaining
energy stored in the inductor and the parasitic elements
of the power switches.
Automatic Bypass Mode (when VIN > VOUT)
The MIC2876 automatically operates in bypass mode
when the input voltage is higher than the target output
voltage. In bypass mode, the NMOS is turned off while
the PMOS is fully turned-on to provide a very low
impedance path from IN to OUT.
Soft-Start
The MIC2876 integrates an internal soft-start circuit to
limit the inrush current during start-up. When the device
is enabled, the PMOS is turned-on slowly to charge the
output capacitor to a voltage close to the input voltage.
Then, the device begins boost switching cycles to
gradually charge up the output voltage to the target
VOUT.
MIC2876
Output Voltage Programming
The MIC2876 has an adjustable version that allows the
output voltage to be set by an external resistor divider R2
and R3. The typical feedback voltage is 900mV, the
recommended maximum and minimum output voltage is
5.5V and 3.2V, respectively. The current through the
resistor divider should be significantly larger than the
current into the FB pin (typically 0.01µA). It is
recommended that the total resistance of R2 + R3 should
be around 1MΩ. The appropriate R2 and R3 values for
the desired output voltage are calculated as in Equation
1:
R2 = R3 × VOUT − 1
0.9V
Eq. 1
October 20, 2014
11
Revision 1.0
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet MIC2876.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| MIC2870 | 1.5A Synchronous Boost Flash LED Driver | Micrel Semiconductor |
| MIC2871 | 1.2A High-Brightness LED Flash Driver | Micrel Semiconductor |
| MIC2873 | 1.2A High-Brightness Flash LED Driver | Micrel Semiconductor |
| MIC2874 | 1.2A High-Brightness Flash LED Driver | Micrel 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 |