Si91845/6
Vishay Siliconix
150-mA Ultra Low-Noise LDO Regulator
With Error Flag and Discharge Option
FEATURES
D
Ultra Low Dropout—130 mV at 150-mA Load
D
Ultra Low Noise—30
mV
(rms)
(10-Hz to 100-kHz
Bandwidth)
D
Out-of-Regulation Error Flag (power good)
D
Shutdown Control
D
Only 110-mA Ground Current at 150-mA Load
D
Fast Start-Up (50
mS)
D
1.5% Guaranteed Output Voltage Accuracy
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
Si91845: Output, Auto-Discharge in Shutdown Mode
D
Si91846: Output, No-Discharge in Shutdown Mode
D
Fixed 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
Built-in Short Circuit and Thermal Protection
D
Reverse Battery Protection
D
Thin SOT23-6 Package
APPLICATIONS
D
Cellular Phones, Wireless Handsets
D
Noise-Sensitive Electronic Systems, Laptop and
Palmtop Computers
D
PDAs
D
Digital Cameras
D
Pagers
D
MP3 Players
D
Wireless Modems
DESCRIPTION
The Si91845/6 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 Si91845/6 also offers ultra low dropout voltage to prolong
battery life in portable electronics. Systems requiring a quiet
voltage source will benefit from the Si91845/6’s low output
noise. The Si91845/6 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 Si91845/6 to clamp the output
voltage when it rises beyond normal regulation. The Si91845
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 Si91845/6 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 Si91845/6 is available in both standard and lead (Pb)-free
packages.
TYPICAL APPLICATION CIRCUIT
Si91845/6
V
IN
1
mF
2
GND
ERROR
5
1
V
IN
V
OUT
6
51 kW
V
OUT
1
mF
ERROR
SD
3
SD
BP
4
10 nF
Thin SOT-23, 6-Lead
Document Number: 71733
S-40591—Rev. B, 29-Mar-04
www.vishay.com
1
Si91845/6
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings
Input Voltage, V
IN
to GND
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−6.0
to 6.5 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
Output Voltage Accuracy
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)
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
−0.06
0
0
Typ
c
Max
b
6
Unit
V
%
1 mA
v
I
OUT
v
150 mA
Room
Full
Full
Full
Full
Room
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Room
Full
Full
Room
Room
Room
Room
1
1
1.5
2.5
0.18
0.3
0.4
%/V
1
45
50
130
65
190
100
110
110
120
300
30
60
40
30
Document Number: 71733
S-40591—Rev. B, 29-Mar-04
dB
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
NOM
= 2.6 V, BW = 10 Hz to 100 kHz,
0 mA
t
I
OUT
t
150 mA
f = 1 kHz
I
OUT
= 150 mA
f = 10 kHz
f = 100 kHz
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
Ripple Rejection
pp
j
DV
OUT
/DV
IN
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Si91845/6
Vishay Siliconix
SPECIFICATIONS
Test Conditions Unless Specified
Parameter
Dynamic Line Regulation
Dynamic Load Regulation
Thermal Shutdown Junction
Temperature
Thermal Hysteresis
Reverse current
Short Circuit Current
Limits
−40
to 85_C
Symbol
DV
O(line)
DV
O(load)
T
J(S/D)
T
HYST
I
R
I
SC
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
Room
Room
Room
Room
Min
b
Typ
c
20
25
150
20
1
700
Max
b
Unit
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
mV
_C
C
mA
mA
V
IN
=
−6.0
V
V
OUT
= 0 V
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)
Si91845 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
ERROR Voltage Threshold
ERROR Voltage Threshold
Hysteresis
I
OFF
V
OL
V
ERROR
V
HYST(ERROR)
V
ERROR
V
HYST(ERROR)
ERROR
v
V
IN
. V
OUT
in Regulation
I
SINK
= 0.5 mA
V
OUT
Below V
OUT(nom)
V
OUT
Falling, I
OUT
= 1 mA, V
OUT(nom)
u
2 V
V
OUT
u
2 V
V
OUT
Below V
OUT(nom)g
V
OUT
Falling, I
OUT
= 1 mA, V
OUT(nom)
t
2 V
V
OUT
t
2 V
g
Full
Full
Full
Room
Room
Room
−2
−4
1.5
1
0.4
−6
mA
V
%
−10
4
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 differiential 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: 71733
S-40591—Rev. B, 29-Mar-04
www.vishay.com
3
Si91845/6
Vishay Siliconix
PIN CONFIGURATION
PIN DESCRIPTION
Thin SOT-23, 6-Lead
V
IN
1
6
V
OUT
Pin No.
1
2
3
4
Name
V
IN
GND
SD
BP
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
Noise bypass pin. For low noise applications, a 0.01
mF
ceramic capacitor should be
connected from this pin to ground.
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
5
4
ERROR
BP
3
5
6
ORDERING INFORMATION Si91845
Part Number
Si91845DT-18-T1
Si91845DT-20-T1
Si91845DT-22-T1
Si91845DT-25-T1
Si91845DT-26-T1
Si91845DT-27-T1
Si91845DT-28-T1
Si91845DT-285-T1
Si91845DT-29-T1
Si91845DT-30-T1
Si91845DT-33-T1
Si91845DT-35-T1
Si91845DT-36-T1
Si91845DT-50-T1
Note: LL = Lot Code
Lead (Pb)-Free
Part Number
Si91845DT-18-T1—E3
Si91845DT-20-T1—E3
Si91845DT-22-T1—E3
Si91845DT-25-T1—E3
Si91845DT-26-T1—E3
Si91845DT-27-T1—E3
Si91845DT-28-T1—E3
Si91845DT-285—E3
Si91845DT-29-T1—E3
Si91845DT-30-T1—E3
Si91845DT-33-T1—E3
Si91845DT-35-T1—E3
Si91845DT-36-T1—E3
Si91845DT-50-T1—E3
Marking
G0LL
H1LL
H2LL
H3LL
H4LL
H5LL
H6LL
H7LL
H8LL
H9LL
H0LL
I1LL
I2LL
I3LL
Voltage
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
Temperature
Range
Package
−40
to 85_C
Thin SOT23-6
ORDERING INFORMATION Si91846
Part Number
Si91846DT-18-T1
Si91846DT-20-T1
Si91846DT-22-T1
Si91846DT-25-T1
Si91846DT-26-T1
Si91846DT-27-T1
Si91846DT-28-T1
Si91846DT-285-T1
Si91846DT-29-T1
Si91846DT-30-T1
Si91846DT-33-T1
Si91846DT-35-T1
Si91846DT-36-T1
Si91846DT-50-T1
Note: LL = Lot Code
www.vishay.com
Document Number: 71733
S-40591—Rev. B, 29-Mar-04
Lead (Pb)-Free
Part Number
Si91846DT-18-T1—E3
Si91846DT-20-T1—E3
Si91846DT-22-T1—E3
Si91846DT-25-T1—E3
Si91846DT-26-T1—E3
Si91846DT-27-T1—E3
Si91846DT-28-T1—E3
Si91846DT-285-—E3
Si91846DT-29-T1—E3
Si91846DT-30-T1—E3
Si91846DT-33-T1—E3
Si91846DT-35-T1—E3
Si91846DT-36-T1—E3
Si91846DT-50-T1—E3
Marking
I4LL
I5LL
I6LL
I7LL
I8LL
I9LL
I0LL
J1LL
J2LL
J3LL
J4LL
J5LL
J6LL
J7LL
Voltage
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
Temperature
Range
Package
−40
to 85_C
Thin SOT23-6
4
Si91845/6
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: 71733
S-40591—Rev. B, 29-Mar-04
AmbientTemperature (_C)
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5
