Motor de Búsqueda de Datasheet de Componentes Electrónicos
  Spanish  ▼
ALLDATASHEET.ES

X  

TC105333ECT Datasheet(PDF) 4 Page - Microchip Technology

No. de pieza TC105333ECT
Descripción Electrónicos  PFM/PWM Step-Down DC/DC Controller
Download  14 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricante Electrónico  MICROCHIP [Microchip Technology]
Página de inicio  http://www.microchip.com
Logo MICROCHIP - Microchip Technology

TC105333ECT Datasheet(HTML) 4 Page - Microchip Technology

  TC105333ECT Datasheet HTML 1Page - Microchip Technology TC105333ECT Datasheet HTML 2Page - Microchip Technology TC105333ECT Datasheet HTML 3Page - Microchip Technology TC105333ECT Datasheet HTML 4Page - Microchip Technology TC105333ECT Datasheet HTML 5Page - Microchip Technology TC105333ECT Datasheet HTML 6Page - Microchip Technology TC105333ECT Datasheet HTML 7Page - Microchip Technology TC105333ECT Datasheet HTML 8Page - Microchip Technology TC105333ECT Datasheet HTML 9Page - Microchip Technology Next Button
Zoom Inzoom in Zoom Outzoom out
 4 / 14 page
background image
TC105
DS21349C-page 4
 2001-2012 Microchip Technology Inc.
3.0
DETAILED DESCRIPTION
The TC105 is a PFM/PWM step-down DC/DC
controller for use in systems operating from two or
more cells, or in line-powered applications. It uses
PWM as the primary modulation scheme, but automat-
ically converts to PFM at output duty cycles less than
approximately 10%. The conversion to PFM provides
reduced supply current, and therefore higher operating
efficiency at low loads. The TC105 uses an external
switching transistor, allowing construction of switching
regulators with output currents of up to 1A.
The TC105 consumes only 102
A, max, of supply
current when VIN = 5V and VOUT = 3.3V, and can be
placed in a 0.5
A shutdown mode by bringing the
shutdown input (SHDN) low. The regulator remains
disabled while in shutdown mode, and output voltage
discharges to zero through the load. Normal operation
resumes when SHDN is brought high. Other features
include a built-in undervoltage lockout (UVLO) and
externally programmable soft start time.
3.1
Low Power Shutdown Mode
The TC105 enters a low power shutdown mode when
SHDN is brought low. While in shutdown, the oscillator
is disabled and the output switch is shut off. Normal
regulator operation resumes when SHDN is again
brought high. SHDN may be tied to the input supply if
not used.
3.2
Soft Start
Soft start allows the output voltage to gradually ramp
from 0 to rated output value during start-up. This action
minimizes (or eliminates) overshoot, and in general,
reduces stress on circuit components. Figure 4-1
shows the circuit required to implement soft start
(values of 470K and 0.033
F for R
SS and CSS
respectively, are adequate for most applications).
3.3
Undervoltage Lockout (UVLO)
The TC105 is disabled when VIN is below the under-
voltage lockout threshold. This threshold is equal to the
guaranteed minimum operating voltage for the TC105
(i.e., 2.2V). When UVLO is active, the TC105 is
completely disabled.
3.4
Input Bypass Capacitors
Using an input bypass capacitor reduces peak current
transients drawn from the input supply and reduces the
switching noise generated by the regulator. The source
impedance of the input supply determines the size of
the capacitor that should be used.
3.5
Output Capacitor
The effective series resistance of the output capacitor
directly affects the amplitude of the output voltage
ripple. (The product of the peak inductor current and
the ESR determines output ripple amplitude.) There-
fore, a capacitor with the lowest possible ESR should
be selected. Smaller capacitors are acceptable for light
loads or in applications where ripple is not a concern.
The Sprague 595D series of tantalum capacitors are
among the smallest of all low ESR surface mount
capacitors
available.
Table 4-1
lists
suggested
components and suppliers.
3.6
Inductor Selection
Selecting the proper inductor value is a trade-off
between physical size and power conversion require-
ments. Lower value inductors cost less, but result in
higher ripple current and core losses. They are also
more prone to saturate since the coil current ramps
faster and could overshoot the desired peak value. This
not only reduces efficiency, but could also cause the
current rating of the external components to be
exceeded. Larger inductor values reduce both ripple
current and core losses, but are larger in physical size
and tend to increase the start-up time slightly.
A 22
H inductor is recommended as the best overall
compromise. For highest efficiency, use inductors with
a low DC resistance (less than 20 m
). To minimize
radiated noise, consider using a toroid, pot core or
shielded-bobbin inductor.
3.7
Output Diode
The high operating frequency of the TC105 requires a
high-speed diode. Schottky diodes such as the MA737
or 1N5817 through 1N5823 (and the equivalent surface
mount versions) are recommended. Select a diode
whose average current rating is greater than the peak
inductor current and whose voltage rating is higher
than VDDMAX.


Número de pieza similar - TC105333ECT

Fabricante ElectrónicoNo. de piezaDatasheetDescripción Electrónicos
logo
Microchip Technology
TC105333ECT MICROCHIP-TC105333ECT Datasheet
433Kb / 14P
   PFM/PWM Step-Down DC/DC Controller
2002
More results

Descripción similar - TC105333ECT

Fabricante ElectrónicoNo. de piezaDatasheetDescripción Electrónicos
logo
SHANGHAI BELLING CO., L...
BL8523 BELLING-BL8523 Datasheet
525Kb / 5P
   PWM/PFM Step-down DC-DC Controller
logo
Microchip Technology
TC105 MICROCHIP-TC105 Datasheet
433Kb / 14P
   PFM/PWM Step-Down DC/DC Controller
2002
logo
Unisonic Technologies
UC3750 UTC-UC3750 Datasheet
211Kb / 9P
   600kHZ PWM/PFM STEP-DOWN DC-DC CONTROLLER
UC3750 UTC-UC3750_11 Datasheet
203Kb / 8P
   600kHZ PWM/PFM STEP-DOWN DC-DC CONTROLLER
logo
Anachip Corp
AP1625 ANACHIP-AP1625 Datasheet
159Kb / 5P
   PWM/PFM Dual Mode Step-down DC/DC Controller
logo
ON Semiconductor
NCP1550SN18T1 ONSEMI-NCP1550SN18T1 Datasheet
191Kb / 18P
   600 kHz PWM/PFM Step-Down DC-DC Controller
September, 2004 ??Rev. 6
logo
Unisonic Technologies
M7085 UTC-M7085 Datasheet
130Kb / 8P
   PFM STEP-DOWN DC-DC CONTROLLER
M7085 UTC-M7085_12 Datasheet
231Kb / 7P
   PFM STEP-DOWN DC-DC CONTROLLER
logo
Microchip Technology
TC110 MICROCHIP-TC110 Datasheet
464Kb / 16P
   PFM/PWM Step-Up DC/DC Controller
2002
TC110 MICROCHIP-TC110 Datasheet
465Kb / 16P
   PFM/PWM Step-Up DC/DC Controller
2002
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14


Datasheet Descarga

Go To PDF Page


Enlace URL




Política de Privacidad
ALLDATASHEET.ES
¿ALLDATASHEET es útil para Ud.?  [ DONATE ] 

Todo acerca de Alldatasheet   |   Publicidad   |   Contáctenos   |   Política de Privacidad   |   Intercambio de Enlaces   |   Lista de Fabricantes
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com