Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

LM5010MHX Datasheet(PDF) 10 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor.
Part # LM5010MHX
Description  High Voltage 1A Step Down Switching Regulator
Download  19 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  NSC [National Semiconductor (TI)]
Direct Link  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM5010MHX Datasheet(HTML) 10 Page - National Semiconductor (TI)

Back Button LM5010MHX Datasheet HTML 6Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 7Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 8Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 9Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 10Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 11Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 12Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 13Page - National Semiconductor (TI) LM5010MHX Datasheet HTML 14Page - National Semiconductor (TI) Next Button
Zoom Inzoom in Zoom Outzoom out
 10 / 19 page
background image
Hysteretic Control Circuit
Overview (Continued)
Typically when the load current increases suddenly, the off-
times are temporarily at the minimum of 265 ns. Once regu-
lation is established, the off-time resumes its normal value.
The output voltage is set by two external resistors (R1, R2).
The regulated output voltage is calculated as follows:
V
OUT = 2.5V x (R1 + R2) / R2
(1)
Output voltage regulation is based on ripple voltage at the
feedback input, requiring a minimum amount of ESR for the
output capacitor C2. The LM5010 requires a minimum of 25
mV of ripple voltage at the FB pin. In cases where the
capacitor’s ESR is insufficient additional series resistance
may be required (R3 in Figure 1 ).
When in regulation, the LM5010 operates in continuous
conduction mode at heavy load currents and discontinuous
conduction mode at light load currents. In continuous con-
duction mode current always flows through the inductor,
never reaching zero during the off-time. In this mode the
operating frequency remains relatively constant with load
and line variations. The minimum load current for continuous
conduction mode is one-half the inductor’s ripple current
amplitude. The approximate operating frequency is calcu-
lated as follows:
(2)
The buck switch duty cycle is approximately equal to:
(3)
At low load current, the circuit operates in discontinuous
conduction mode, during which the inductor current ramps
up from zero to a peak during the on-time, then ramps back
to zero before the end of the off-time. The next on-time
period starts when the voltage at FB falls below the refer-
ence - until then the inductor current remains zero, and the
load current is supplied by the output capacitor (C2). In this
mode the operating frequency is lower than in continuous
conduction mode, and varies with load current. Conversion
efficiency is maintained at light loads since the switching
losses reduce with the reduction in load and frequency. The
approximate discontinuous operating frequency can be cal-
culated as follows:
(4)
where R
L = the load resistance.
For applications where lower output voltage ripple is re-
quired the output can be taken directly from a low ESR
output capacitor as shown in Figure 9. However, R3 slightly
degrades the load regulation.
Start-up Regulator (V
CC)
The startup regulator is integral to the LM5010. The input pin
(V
IN) can be connected directly to line voltages up to 75V.
The V
CC output is regulated at 7.0V, ±6%, and is current
limited to 10 mA. Upon power up the regulator sources
current into the external capacitor at V
CC (C3). With a 0.1 µF
capacitor at V
CC, approximately 58 µs are required for the
V
CC voltage to reach the under-voltage lockout threshold
(UVLO) of 5.8V (t1 in Figure 8), at which time the buck switch
is enabled, and the softstart pin is released to allow the
softstart capacitor (C6) to charge up. V
OUT then increases to
its regulated value as the softstart voltage increases (t2 in
Figure 8).
The minimum input operating voltage is determined by the
regulator’s dropout voltage, the V
CC UVLO falling threshold
()5.65V), and the frequency. When V
CC falls below the
falling threshold the V
CC UVLO activates to shut off the buck
switch and ground the softstart pin. If V
CC is externally
loaded, the minimum input voltage increases since the out-
put impedance at V
CC is
)140
Ω at low V
IN. See Figures 2
and 3. In applications involving a high value for V
IN where
power dissipation in the startup regulator is a concern, an
auxiliary voltage can be diode connected to the V
CC pin
(Figure 10). Setting the auxiliary voltage to between 7.5V
and 14V shuts off the internal regulator, reducing internal
power dissipation. The current required into the V
CC pin is
shown in Figure 4. Internally a diode connects V
CC to VIN.
20119915
FIGURE 9. Low Ripple Output Configuration
www.national.com
10


Similar Part No. - LM5010MHX

ManufacturerPart #DatasheetDescription
logo
Texas Instruments
LM5010MHX TI1-LM5010MHX Datasheet
1Mb / 24P
[Old version datasheet]   High-Voltage 1-A Step-Down Switching Regulator
LM5010MHX/NOPB TI1-LM5010MHX/NOPB Datasheet
1Mb / 26P
[Old version datasheet]   High-Voltage 1-A Step-Down Switching Regulator
More results

Similar Description - LM5010MHX

ManufacturerPart #DatasheetDescription
logo
National Semiconductor ...
LM5010A NSC-LM5010A Datasheet
775Kb / 17P
   High Voltage 1A Step Down Switching Regulator
logo
List of Unclassifed Man...
GM7110 ETC-GM7110 Datasheet
295Kb / 11P
   1A STEP-DOWN VOLTAGE SWITCHING REGULATOR
logo
Gamma Microelectronics ...
GM7110 GAMMA-GM7110_05 Datasheet
213Kb / 12P
   1A STEP-DOWN VOLTAGE SWITCHING REGULATOR
logo
STMicroelectronics
L4976 STMICROELECTRONICS-L4976 Datasheet
100Kb / 11P
   1A STEP DOWN SWITCHING REGULATOR
May 2000
L4976 STMICROELECTRONICS-L4976_07 Datasheet
256Kb / 17P
   1A step down switching regulator
L5981 STMICROELECTRONICS-L5981 Datasheet
823Kb / 37P
   1A step-down switching regulator
logo
Guangdong Youtai Semico...
LM2591HV UMW-LM2591HV Datasheet
1Mb / 14P
   1A Step-Down Voltage Regulator
logo
HTC Korea TAEJIN Techno...
LM2575 HTC-LM2575 Datasheet
632Kb / 13P
   1A, 52kHz, Step-Down Switching Regulator
logo
Linear Technology
LT3682 LINER-LT3682_15 Datasheet
264Kb / 24P
   1A Micropower Step-Down Switching Regulator
LT3503 LINER-LT3503_15 Datasheet
433Kb / 20P
   1A, 2.2MHz Step-Down Switching Regulator
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
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