データシートサーチシステム
  Japanese  ▼
ALLDATASHEET.JP

X  

ILC7080AIM5 データシート(PDF) 7 Page - Fairchild Semiconductor

部品番号 ILC7080AIM5
部品情報  50/100mA SOT-23 CMOS RF LDO Regulators
Download  16 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
メーカー  FAIRCHILD [Fairchild Semiconductor]
ホームページ  http://www.fairchildsemi.com
Logo FAIRCHILD - Fairchild Semiconductor

ILC7080AIM5 データシート(HTML) 7 Page - Fairchild Semiconductor

Back Button ILC7080AIM5 Datasheet HTML 3Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 4Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 5Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 6Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 7Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 8Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 9Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 10Page - Fairchild Semiconductor ILC7080AIM5 Datasheet HTML 11Page - Fairchild Semiconductor Next Button
Zoom Inzoom in Zoom Outzoom out
 7 / 16 page
background image
ILC7080/81
REV. 1.0.7 4/3/03
7
The Effects of ESR (Equivalent
Series Resistance)
The ESR of a capacitor is a measure of the resistance due to the
leads and the internal connections of the component. Typically
measured in m
Ω (milli-ohms) it can increase to ohms in some
cases.
Wherever there is a combination of resistance and current, volt-
ages will be present. The control functions of LDOs use two
voltages in order to maintain the output precisely; VOUT and
VREF.
With reference to the block diagram in figure 2, VOUT is fed
back to the error amplifier and is used as the supply voltage for
the internal components of the 7080/81. So any change in VOUT
will cause the error amplifier to try to compensate to maintain
VOUT at the set level and noise on VOUT will be reflected into
the supply of each internal circuit. The reference voltage, VREF,
is influenced by the CNOISE pin. Noise into this pin will add to
the reference voltage and be fed through the circuit. These fac-
tors will not cause a problem if some simple steps are taken.
Figure 5 shows where these added ESR resistances are present
in the typical LDO circuit.
Figure 5. ESR in COUT and CNOISE
With this in mind low ESR components will offer better perfor-
mance as LDOs may be exposed to large transients of output
voltage, and current flows through the capacitors in order to fil-
ter these transient swings. ESR is less of a problem with CIN as
the voltage fluctuations at the input will be filtered by the LDO.
However, being aware of these current flows, there is also
another potential source of induced voltage noise from the resis-
tance inherent in the PCB trace. Figure 6 shows where the addi-
tive resistance of the PCB can manifest itself. Again these
resistances may be very small, but a summation of several cur-
rents can develop detectable voltage ripple and will be amplified
by the LDO. Particularly the accumulation of current flows in
the ground plane can develop significant voltages unless care is
taken.
With a degree of care, the ILC7080/81 will yield outstanding
performance.
Printed Circuit Board Layout
Guidelines
As was mentioned in the previous section, to take full advan-
tage of any high performance LDO regulator requires paying
careful attention to grounding and printed circuit board
(PCB) layout.
Figure 6. Inherent PCB resistance
Figure 7 shows the effects of poor grounding and PCB
layout caused by the ESR and PCB resistances and the
accumulation of current flows.
Note particularly that during high output load current, the
LDO regulator’s ground pin and the ground return for COUT
and CNOISE are not at the same potential as the system
ground. This is due to high frequency impedance caused by
PCB’s trace inductance and DC resistance. The current loop
between COUT, CNOISE and the LDO regulator’s ground pin
will degrade performance of the LDO.
Figure 7. Effects of poor circuit layout
Figure 8 shows an optimum schematic. In this schematic,
high output surge current has little effect on the ground cur-
rent and noise bypass current return of the LDO regulator.
Note that the key difference here is that COUT and CNOISE are
directly connected to the LDO regulator’s ground pin. The
LDO is then separately connected to the main ground plane
and returned to a single point system ground.
ILC7080
ILC7081
V
IN
SOT-23-5
C
IN
ON
OFF
12
3
4
5
C
NOISE
RF LDOTM
Regulator
R*
R*
R
C
V
OUT
C
OUT
I
C
I
OUT
ILC7080
ILC7081
SOT-23-5
ON
OFF
12
3
4
5
C
NOISE
R
PCB
ESR
R
PCB
V
IN
V
IN
I
OUT
C
OUT
I
1
I
2
V
OUT
R
PCB
R
PCB
R
PCB
C
OUT
C
IN
ON/OFF
V
OUT
V
IN
True GND
(0V)
GND1
GND2
GND3
ILC7080/81
5
23
1
4
SOT23-5
ILOAD
ILOAD
+IC
OUT
+IC
NOISE
+IGND


同様の部品番号 - ILC7080AIM5

メーカー部品番号データシート部品情報
logo
Impala Linear Corporati...
ILC7080AIM5-285 IMPALA-ILC7080AIM5-285 Datasheet
424Kb / 16P
   50/100M SOT-23 CMOS RF LDO REGULATORS
ILC7080AIM5-30 IMPALA-ILC7080AIM5-30 Datasheet
424Kb / 16P
   50/100M SOT-23 CMOS RF LDO REGULATORS
ILC7080AIM5-33 IMPALA-ILC7080AIM5-33 Datasheet
424Kb / 16P
   50/100M SOT-23 CMOS RF LDO REGULATORS
ILC7080AIM5-36 IMPALA-ILC7080AIM5-36 Datasheet
424Kb / 16P
   50/100M SOT-23 CMOS RF LDO REGULATORS
ILC7080AIM5-50 IMPALA-ILC7080AIM5-50 Datasheet
424Kb / 16P
   50/100M SOT-23 CMOS RF LDO REGULATORS
More results

同様の説明 - ILC7080AIM5

メーカー部品番号データシート部品情報
logo
Impala Linear Corporati...
ILC7080 IMPALA-ILC7080 Datasheet
424Kb / 16P
   50/100M SOT-23 CMOS RF LDO REGULATORS
logo
Fairchild Semiconductor
ILC7071 FAIRCHILD-ILC7071 Datasheet
110Kb / 11P
   100mA SOT-23-5 Low Noise CMOS RF-LDO Regulator
logo
Impala Linear Corporati...
ILC7071 IMPALA-ILC7071 Datasheet
40Kb / 4P
   100MA SOT-23-5 ULTRA LOW NOISE CMOS RF-LDO REGULATOR
logo
Linear Technology
LT1761 LINER-LT1761 Datasheet
246Kb / 16P
   100mA, Low Noise, LDO Micropower Regulators in SOT-23
LT1761 LINER-LT1761_1 Datasheet
260Kb / 20P
   100mA, Low Noise,LDO Micropower Regulators in SOT-23
logo
Impala Linear Corporati...
ILC7062 IMPALA-ILC7062 Datasheet
379Kb / 6P
   SOT-23 CMOS LDO
ILC7362 IMPALA-ILC7362 Datasheet
157Kb / 5P
   SOT-23 CMOS NEGATIVE LDO
logo
Exar Corporation
SP6201EM5-L-5-0 EXAR-SP6201EM5-L-5-0 Datasheet
967Kb / 17P
   100mA/200mA Micropower CMOS LDO Regulators
SP6201ER-L EXAR-SP6201ER-L Datasheet
967Kb / 17P
   100mA/200mA Micropower CMOS LDO Regulators
SP6201EM5 EXAR-SP6201EM5 Datasheet
967Kb / 17P
   100mA/200mA Micropower CMOS LDO Regulators
More results


Html Pages

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


データシート ダウンロード

Go To PDF Page


リンク URL




プライバシーポリシー
ALLDATASHEET.JP
ALLDATASHEETはお客様のビジネスに役立ちますか?  [ DONATE ] 

Alldatasheetは   |   広告   |   お問い合わせ   |   プライバシーポリシー   |   リンク交換   |   メーカーリスト
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