Si91842
Vishay Siliconix
150-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
mV
(rms)
Available
(10-Hz to 100-kHz Bandwidth)
D
Out-of-Regulation Error Flag (power good)
D
Shutdown Control
D
110-mA Ground Current at 150-mA Load
D
Fast Start-Up (50
mS)
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
ms)
D
1-mA Maximum Shutdown Current
D
Output Current Limit
D
Reverse Battery Protection
D
Built-in Short Circuit and Thermal Protection
D
Output—Auto-Discharge In Shutdown Mode
D
Fixed 1.2, 1.8, 2.5, 2.6, 2.8, 2.85, 3.0, 3.3, 5.0-V Output
Voltage Options
D
Thin 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 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 also offers ultra low dropout voltage to prolong
battery life in portable electronics. Systems requiring a quiet
voltage source will benefit from the Si91842’s low output noise.
The Si91842 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 to clamp the output
voltage when it rises beyond normal regulation. The Si91842
automatically 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 features reverse battery protection to limit
reverse current flow to approximately 1-mA in the event
reversed battery is applied at the input, thus preventing
damage to the IC.
The Si91842 is available in both standard and lead (Pb)-free
packages.
TYPICAL APPLICATION CIRCUIT
Si91842
V
IN
1
mF
2
GND
51 kW
1
V
IN
V
OUT
5
V
OUT
1
mF
SD
3
SD
ERROR
4
ERROR
Thin SOT-23, 5-Lead
Document Number: 71732
S-50956—Rev. F, 16-May-05
www.vishay.com
1
Si91842
Vishay Siliconix
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
)
b
. . . . . . . . . . . . . . . . . . . . . . . . . . . 440 mW
Package Thermal Resistance, (q
JA
)
a
. . . . . . . . . . . . . . . . . . . . . . . . . 180_C/W
Maximum Junction Temperature, T
J(max)
. . . . . . . . . . . . . . . . . . . . . . . 150_C
Storage Temperature, T
STG
. . . . . . . . . . . . . . . . . . . . . . . . . .
−65_C
to 150_C
Notes
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
SD
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to V
IN
C
IN
= C
OUT
= 1
mF
(ceramic)
Maximum ESR of C
OUT
: 0.4
W
Operating Ambient Temperature, T
A
. . . . . . . . . . . . . . . . . . . .
−40_C
to 85_C
SPECIFICATIONS
Test Conditions Unless Specified
Parameter
Input Voltage Range
Limits
−40
to 85_C
Symbol
V
IN
T
A
= 25_C, V
IN
= V
OUT(nom)
+ 1 V, I
OUT
= 1 mA,
C
IN
= 1
mF,
C
OUT
= 1.0
mF,
V
SD
= 1.5 V
Temp
a
Full
Min
b
2
−1.5
−2.5
−2.0
−3.0
−0.06
0
0
Typ
c
Max
b
6
Unit
V
V
OUT
w
1 8 V
1.8
Output Voltage Accuracy
1 mA
v
I
OUT
v
150 mA
V
OUT
= 1 2 V
1.2
Line Regulation (V
OUT
v
3 V)
Line Regulation
(3.0 V < V
OUT
v3.6
V)
Line Regulation (5-V Version)
DV
OUT
DV
IN
100
From V
IN
= V
OUT(nom)
+ 1 V to V
OUT(nom)
+ 2 V
V
OUT(nom)
From V
IN
= 5.5 V to 6 V
I
OUT
= 1 mA
d,
Dropout V lt
D
t Voltage
d g
(V
OUT(nom)
w
2.6 V)
Room
Full
Room
Full
Full
Full
Full
Room
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Full
Room
1
1
1
1
1.5
2.5
2.0
3.0
0.18
0.3
0.4
%/V
%
1
45
50
130
65
190
100
110
110
120
300
75
80
90
180
220
100
120
250
300
150
180
200
230
170
200
200
230
mA
mV(rms)
mA
mV
I
OUT
= 50 mA
I
OUT
= 150 mA
I
OUT
= 50 mA
I
OUT
= 150 mA
I
OUT
= 0 mA
I
OUT
= 150 mA
I
GND
I
OUT
= 0 mA
I
OUT
= 150 mA
I
O(peak)
e
N
V
OUT
w
0.95 x V
OUT(nom)
. t
PW
= 2 ms
V
OUT
= 2.6 V, BW = 10 Hz to 100 kHz,
0 mA
t
I
OUT
t
150 mA
V
IN
−
V
OUT
Dropout Voltage
d, g
(V
OUT(nom)
t
2.6 V, V
IN
w
2 V)
(
)
Ground Pin Current
e, g
(V
OUT(nom)
v
3 V)
(
)
Ground Pin Current
e, g
(V
OUT(nom)
u
3 V)
(
)
Peak Output current
Output Noise Voltage
www.vishay.com
2
Document Number: 71732
S-50956—Rev. F, 16-May-05
Si91842
Vishay Siliconix
SPECIFICATIONS
Test Conditions Unless Specified
Parameter
Symbol
T
A
= 25_C, V
IN
= V
OUT(nom)
+ 1 V, I
OUT
= 1 mA,
C
IN
= 1
mF,
C
OUT
= 1.0
mF,
V
SD
= 1.5 V
Limits
−40
to 85_C
Temp
a
Room
Room
Room
Room
Room
Room
Room
Min
b
Typ
c
60
40
30
20
25
150
20
1
700
Max
b
Unit
f = 1 kHz
Ripple Rejection
pp
j
DV
OUT
/DV
IN
DV
O(line)
DV
O(load)
T
J(S/D)
T
HYST
I
R
I
SC
V
IN
=
−6.0
V
V
OUT
= 0 V
I
OUT
= 150 mA
f = 10 kHz
f = 100 kHz
Dynamic Line Regulation
Dynamic Load Regulation
Thermal Shutdown Junction
Temperature
Thermal Hysteresis
Reverse current
Short Circuit Current
V
IN
: V
OUT(nom)
+ 1 V to V
OUT(nom)
+ 2 V
t
r
/t
f
= 2
ms,
I
OUT
= 150 mA
I
OUT
: 1 mA to 150 mA, t
r
/t
f
= 2
ms
dB
mV
_C
C
mA
mA
Room
Room
Shutdown
Shutdown Supply Current
SD Pin Input Voltage
Auto Discharge Resistance
SD Pin Input Current
f
SD Hysteresis
V
OUT
Turn-On Time
I
CC(off)
V
SD
R_DIS
I
IN(SD)
V
HYST(SD)
t
ON
V
SD
(See Figure 1), I
LOAD
= 100 mA
V
SD
= 0 V
High = Regulator ON (Rising)
Low = Regulator OFF (Falling)
Si91842 Only
V
SD
= 1.5 V, V
IN
= 6 V
Room
Full
Full
Room
Room
Full
Room
100
0.7
150
50
1.5
0.1
1
V
IN
0.4
mA
V
W
mA
mV
mS
ERROR Output
ERROR High Leakage
ERROR Low Voltage
ERROR Voltage Threshold
ERROR Voltage Threshold
Hysteresis
I
OFF
V
OL
V
ERROR
V
HYST(ERROR)
ERROR
v
V
IN
. V
OUT
in Regulation
I
SINK
= 0.5 mA
V
OUT
Below V
OUT(nom)g
, V
IN
w
2 V
V
OUT
Falling, I
OUT
= 1 mA, V
OUT(nom)
w
2 V
V
OUT(nom)g
t
2 V, V
IN
u
2 V
Full
Full
Full
Full
Room
−2
−4
−4
1.5
1
0.4
−6
%
mA
V
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-MW internal pull-down resistor connected to ground.
g. V
OUT(nom)
is V
OUT
when measured with a 1-V differential to V
IN
.
TIMING WAVEFORMS
V
IN
V
SD
t
r
v
1
mS
0V
t
ON
V
NOM
0.95 V
NOM
V
OUT
FIGURE 1.
Timing Diagram for Power-Up
Document Number: 71732
S-50956—Rev. F, 16-May-05
www.vishay.com
3
Si91842
Vishay Siliconix
PIN CONFIGURATION
Thin SOT-23, 5-Lead
V
IN
1
5
V
OUT
PIN DESCRIPTION
Pin No.
1
2
Name
V
IN
GND
SD
ERROR
V
OUT
Function
Input supply pin. Bypass this pin with a 1-mF ceramic or tantalum capacitor to ground
Ground pin. For better thermal capability, directly connected to large ground plane
By applying less than 0.4 V to this pin, the device will be turned off. Connect this pin to
V
IN
if unused
The open drain output is an error flag output which goes low when V
OUT
drops 4%
below its nominal voltage.
Output voltage. Connect C
OUT
between this pin and ground.
GND
SD
2
ERROR
3
4
4
5
3
ORDERING INFORMATION Si91842
Part Number
Si91842DT-12-T1
Si91842DT-18-T1
Si91842DT-25-T1
Si91842DT-26-T1
Si91842DT-28-T1
Si91842DT-285-T1
Si91842DT-29-T1
Si91842DT-30-T1
Si91842DT-33-T1
Si91842DT-50-T1
LLL = Lot Code
Lead (Pb)-Free
Part Number
Si91842DT-12-T1—E3
Si91842DT-18-T1—E3
Si91842DT-25-T1—E3
Si91842DT-26-T1—E3
Si91842DT-28-T1—E3
Si91842DT-285—E3
Si91842DT-29-T1—E3
Si91842DT-30-T1—E3
Si91842DT-33-T1—E3
Si91842DT-50-T1—E3
Marking
J8LLL
C8LLL
D1LLL
D2LLL
D4LLL
D5LLL
D6LLL
D7LLL
D8LLL
E1LLL
Voltage
1.2
1.8
2.5
2.6
2.8
2.85
2.9
3.0
3.3
5.0
Temperature
Range
Package
−40
to 85_C
ThinSOT23-5
www.vishay.com
4
Document Number: 71732
S-50956—Rev. F, 16-May-05
Si91842
Vishay Siliconix
TYPICAL CHARACTERISTICS (INTERNALLY REGULATED, 25_C UNLESS NOTED)
0.30
0.15
0.00
−0.15
−0.30
−0.45
−0.60
−0.75
0
25
50
75
100
125
150
Load Current (mA)
V
OUT
(%)
Normalized Output Voltage vs. Load Current
V
IN
= V
OUT(nom)
+ 1 V
0.4
0.2
Normalized V
OUT
vs. Temperature
V
IN
= V
OUT(nom)
+ 1 V
I
OUT
= 0 mA
Output Voltage (%)
−0.0
−0.2
−0.4
−0.6
−0.8
−1.0
−40
I
OUT
= 75 mA
I
OUT
= 150 mA
−15
10
35
60
85
Ambient Temperature (_C)
150
GND Current vs. Load Current
V
OUT
= 3.0 V
V
IN
= 4.0 V
300
250
200
I
GND
(
mA)
150
100
No Load GND Pin Current vs. Input Voltage
85_C
125
25_C
I
GND
(
mA)
100
−40_C
75
50
50
0
25
50
75
100
125
150
Load Current (mA)
0
2
3
4
5
6
7
Input Voltage (V)
85_C
25_C
−40_C
0
Power Supply Rejection
C
IN
= 1
mF
C
OUT
= 1
mF
I
LOAD
= 150 mA
V
OUT
= 3.0 V
I
SC
(mA)
750
725
700
Output Short Circuit Current vs. Temperature
V
OUT
= 2.6 V
−20
Gain (dB)
−40
675
650
−60
625
−80
10
600
−40
100
1000
10000
100000
1000000
−15
10
35
60
85
Frequency (Hz)
Document Number: 71732
S-50956—Rev. F, 16-May-05
AmbientTemperature (_C)
www.vishay.com
5
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