Document Number: 71732150-mA Low-Noise LDO Regulator With Error Flag and Discharge Option
FEATURES
D Ultra Low Dropout—130 mV at 150-mA Load
D Low Noise—75 m V (rms) (10-Hz to 100-kHz Bandwidth)D Out-of-Regulation Error Flag (power good)D Shutdown Control
D 110-m A Ground Current at 150-mA Load D Fast Start-Up (50 m S)
D 1.5% Guaranteed Output Voltage Accuracy (1.2 V, 2%)D 300-mA Peak Output Current Capability D Uses Low ESR Ceramic Capacitors
D Fast Line and Load Transient Response (v 30 m s)D 1-m A Maximum Shutdown Current D Output Current Limit
D Reverse Battery Protection
D
Built-in Short Circuit and Thermal Protection
D Si91842: Output—Auto-Discharge In Shutdown Mode D Si91844: Output—No-Discharge In Shutdown Mode D Fixed 1.2, 1.8, 2.0, 2.2, 2.5, 2.6, 2.7, 2.8, 2.85, 2.9, 3.0,3.3, 3.5, 3.6, 5.0-V Output Voltage Options D SOT23-5 Package
APPLICATIONS
D Cellular Phones, Wireless Handsets
D Noise-Sensitive Electronic Systems, Laptop and Palmtop Computers D PDAs D Pagers
D Digital Cameras D MP3 Player
D Wireless Modem
DESCRIPTION
The Si91842/4 is a 150-mA CMOS LDO (low dropout) voltage regulator. It is the perfect choice for low voltage, low power applications. An ultra low ground current and ultra fast turn-on make this part
attractive for battery operated power systems.The Si91842/4 also offers ultra low dropout voltage to prolong battery life in portable electronics. Systems requiring a quiet voltage source will benefit from the Si91842/4’s low output noise. The Si91842/4 is designed to maintain regulation while delivering 300-mA peak current, making it ideal for systems that have a high surge current upon turn-on.
For better transient response and regulation, an active
pull-down circuit is built into the Si91842/4 to clamp the output voltage when it rises beyond normal regulation. The Si91842automatically discharges the output voltage by connecting the output to ground through a 100-W n-channel MOSFET when the device is put in shutdown mode.
The Si91842/4 features reverse battery protection to limit reverse current flow to approximately 1-m A in the event reversed battery is applied at the input, thus preventing damage to the IC.
Si91842/4
V IN
SD V OUT F
ERROR
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings
Input Voltage, V IN to GND–6.0 to 6.5 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V ERROR, V SD (See Detailed Description)–0.3 V to V IN
. . . . . . . . . . . . . . . . . . . . . . .
Output Current, I OUT Short Circuit Protected
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Voltage, V OUT–0.3 V to V IN + 0.3 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Package Power Dissipation, (P d)b440 mW
. . . . . . . . . . . . . . . . . . . . . . . . . . . Package Thermal Resistance, (q JA)a180_C/W
. . . . . . . . . . . . . . . . . . . . . . . . . Maximum Junction Temperature, T J(max)150_C
. . . . . . . . . . . . . . . . . . . . . . . Storage Temperature, T STG–65_C to 150_C
. . . . . . . . . . . . . . . . . . . . . . . . . .
Notes
等不到你
a.Device mounted with all leads soldered or welded to PC board.
b.Derate 5.5 mW/_C above T A = 70_C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED OPERATING RANGE
Input Voltage, V IN 2 V to 6 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Voltage, V SD0 V to V IN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operating Ambient Temperature, T A–40_C to 85_C
. . . . . . . . . . . . . . . . . . . .
C IN = C OUT = 1 m F (ceramic) Maximum ESR of C OUT: 0.4 W
Document Number: 71732
Notes
a.Room = 25_C, Full = –40 to 85_C.
b.The algebraic convention whereby the most negative value is a minimum and the most positive a maximum.
c.Typical values are for DESIGN AID ONLY , not guaranteed nor subject to production testing.
d.Dropout voltage is defined as the input to output differential voltage at which the output voltage drops 2% below the output voltage measured with a 1-V
differential, provided that V IN does not not drop below 2.0 V.
e.Ground current is specified for normal operation as well as “drop-out ” operation.
f.The device ’s shutdown pin includes a typical 2-M W internal pull-down resistor connected to ground.
g.V OUT(nom) is V OUT when measured with a 1-V differential to V IN .
FIGURE 1.Timing Diagram for Power-Up
V V NOM
0 V
V IN
SD
32
SOT-23, 5-Lead
1
4
5
V IN
GND V OUT
ERROR
Notes:
a.LLL = Lot Code
b.Advanced Information, available March 2002.
Document Number: 71732
–1.0
–0.8–0.6–0.4–0.2–0.0
0.2
0.4
–40
–1510356085
Normalized V OUT vs. Temperature
Ambient Temperature (_C)
(%)
V O U T 050
100
150
200
250
300
2
3
4
5
6
7
(I G N D m A )
Input Voltage (V)
5075
100
125
150
25
50
75
100
125
150
GND Current vs. Load Current
(I G N D m A )
Load Current (mA)
600625
650
675
杨丞琳男友700
725
750
–40
金莎资料–1510356085
Output Short Circuit Current vs. Temperature
(m A )
I S C AmbientT emperature (_C)
–80
–60
–40–20
10
100
1000
10000
高晓松老婆照片100000
1000000
Power Supply Rejection
Frequency (Hz)
G a i n (d B )
–0.75
–0.60–0.45–0.30–0.150.000.150.30
25
50
75
100
125
150
Normalized Output Voltage vs. Load Current
O u t p u t V o l t a g e (%)
Load Current (mA)
050100150200250
300350
60
120
180
240
300
Dropout Voltage vs. Load Current
I LOAD (mA)
(m V )
V D R O P 050100150200250
300350
–50
–25
25
50
75
100
125
150
Dropout Voltage vs. Temperature
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1
2
34
5
6
V IN – V OUT Transfer Characteristic
V IN (V)
(V )
V O U T Junction Temperature (_C)
050100150200250300350
400
1.0
1.5
2.0
2.5
3.0 3.5
4.0
4.5
5.0
刘瑞琦明明就Dropout Voltage vs. V OUT
D r o p o u t V o l t a g e (m V )
V OUT
(m V )
V D R O P
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