|
|
|
부품번호 | CS8271YDR8 기능 |
|
|
기능 | Adjustable Micropower Low Dropout Linear Regulator with ENABLE | ||
제조업체 | Cherry Semiconductor Corporation | ||
로고 | |||
CS8271
Adjustable Micropower Low Dropout
Linear Regulator with ENABLE
Description
Features
The CS8271 is an adjustable microp-
ower voltage regulator with very
low quiescent current (60µA typical
at 100µA load). The output supplies
100mA of load current with a maxi-
mum dropout voltage of only
600mV. Control logic includes
ENABLE. The combination of low
quiescent current, outstanding reg-
ulator performance and control
logic makes the CS8271 ideal for
any battery operated equipment.
The logic level compatible ENABLE
pin allows the user to put the regu-
lator into a shutdown mode where it
draws only 50µA of quiescent cur-
rent.
The regulator is protected against
reverse battery, short circuit, over
voltage, and over temperature con-
ditions. The device can withstand
60V load dump transients making it
suitable for use in automotive envi-
ronments.
The CS8271 is pin compatible with
the National Semiconductor
LM2931.
s Low Quiescent Current
s Adjustable Output:
5V to 12V
s ENABLE for Sleep Mode
Control
s 100mA Output Current
Capability
s Fault Protection
+60V Load Dump
-15V Reverse Voltage
Short Circuit
Thermal Shutdown
s Low Reverse Current
(Output to Input)
Block Diagram
VIN
ENABLE
Input
Rev. 3/26/97
Current Source
(Circuit Bias)
Over
Voltage
Shutdown
Current Limit
Sense
Thermal
Shutdown
Bandgap
Reference
+ - Error
Amplifier
VOUT
Adj
Gnd
Package Options
8L SOIC & PDIP
VOUT 1
Gnd
NC
Adj
VIN
NC
NC
ENABLE
Other Packages: Consult factory for
16L SO Batwing, 5L TO-220 and D2PAK.
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: [email protected]
Web Site: www.cherry-semi.com
1 A ¨ Company
Circuit Description: continued
Output Stage Protection
The output stage is protected against overvoltage, short
circuit and thermal runaway conditions (Figure 2).
If the input voltage rises above 30V (e.g. load dump), the
output shuts down. This response protects the internal cir-
cuitry and enables the IC to survive unexpected voltage
transients up to 60V in magnitude.
Short circuit protection limits the amount of current the
output transistor can supply. In the case of a CS8271 under
a short circuit condition, the output transistor current is
limited to 100mA.
Should the junction temperature of the power device exceed
180ûC (typ) the power transistor is turned off. Thermal shut-
down is an effective means to prevent die overheating since
the power transistor is the principle heat source in the IC.
ENABLE
The ENABLE switches the output transistor. When the
voltage on the ENABLE pin exceeds 2.0V typ, the output
pass transistor turns off, leaving a high impedance facing
the load. The IC will remain in Sleep mode, drawing only
20µA (typ), until the voltage on the ENABLE pin drops
below the ENABLE threshold.
> 30V
VIN
VOUT
IOUT
Load
Dump
Short
Circuit
Thermal
Shutdown
Figure 2: Typical Circuit Waveforms for Output Stage Protection.
Application Notes
Selecting the Right Capacitor Value
The output compensation capacitor COUT, determines
three main characteristics of a linear regulator: start-up
delay, load transient response and loop stability.
The selection of a capacitor value and type should be
based on cost, availability, size and temperature con-
straints. A tantalum or aluminum electrolytic capacitor is
best, since a film or ceramic capacitor with almost zero
ESR, can cause instability. The aluminum electrolytic
capacitor is the least expensive solution, but, if the circuit
operates at low temperatures (-25¡C to -40¡C), both the
value and ESR of the capacitor will vary considerably. The
capacitor manufacturers data sheet usually provide this
information.
The value for the output compensation capacitor COUT
shown in Figure 3 should work for most applications, but it
is not necessarily the least expensive or the optimal solution.
VIN
CIN
0.1mF
VOUT
CS8271
ENABLE
Adj
RRST
COUT
10mF
RL CAdj
(optional)
To determine an acceptable value for COUT for a particular
application, start with a tantalum capacitor of the recom-
mended value and work towards a less expensive alterna-
tive part.
Step 1: Place the completed circuit with a tantalum capac-
itor of the recommended value in an environmental cham-
ber at the lowest specified operating temperature. Monitor
the outputs on the oscilloscope. A decade box connected in
series with the capacitor will simulate the higher ESR of an
aluminum capacitor. (Leave the decade box outside the
chamber, the small resistance added by the longer leads is
negligible)
Step 2: With the input voltage at its maximum value,
increase the load current slowly from zero to full load
while observing the output for any oscillations. If no oscil-
lations are observed, the capacitor is large enough to
ensure a stable design under steady state conditions.
Step 3: Increase the ESR of the capacitor from zero using
the decade box and vary the load current until oscillations
appear. Record the values of load current and ESR that
cause the greatest oscillation. This represents the worst
case load conditions for the regulator at low temperature.
Step 4: Maintain the worst case load conditions set in step
3 and vary the input voltage until the oscillations increase.
This point represents the worst case input voltage condi-
tions.
Figure 3: Test and application circuit showing an output compensation
capacitor.
Step 5: If the capacitor is adequate, repeat steps 3 and 4
with the next smaller valued capacitor. (A smaller capaci-
tor will usually cost less and occupy less board space.) If
the capacitor oscillates within the range of expected oper-
ating conditions, repeat steps 3 and 4 with the next larger
standard capacitor value.
4
4페이지 | |||
구 성 | 총 6 페이지수 | ||
다운로드 | [ CS8271YDR8.PDF 데이터시트 ] |
당사 플랫폼은 키워드, 제품 이름 또는 부품 번호를 사용하여 검색할 수 있는 |
구매 문의 | 일반 IC 문의 : 샘플 및 소량 구매 ----------------------------------------------------------------------- IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한 광범위한 전력 반도체를 판매합니다. 전력 반도체 전문업체 상호 : 아이지 인터내셔날 사이트 방문 : [ 홈페이지 ] [ 블로그 1 ] [ 블로그 2 ] |
부품번호 | 상세설명 및 기능 | 제조사 |
CS8271YDR8 | Adjustable Micropower Low Dropout Linear Regulator with ENABLE | Cherry Semiconductor Corporation |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |