LTC1844ES5-SD#TRMPBF 数据手册
LTC1844 Series
150mA, Micropower,
Low Noise, VLDO
Linear Regulator
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FEATURES
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Very Low Dropout:
90mV at 150mA
30mV at 50mA (LTC1844-3.3)
Wide Input Voltage Range: 1.6V to 6.5V
Low 35µA Supply Current, Even in Dropout
Low Noise: 60µVRMS (10Hz to 100kHz)
±1.75% Voltage Accuracy Over Temperature,
Voltage and Current Ranges
Fast Transient Response
10nA Supply Current in Shutdown
Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 2.8V, 3.3V
Adjustable Output Voltage: 1.25V to 6V
Output Current Limit
Reverse-Battery and Reverse-Current Protection
No Protection Diodes Needed
Stable with 1µF Output Capacitor
Stable with Ceramic Capacitors
Short-Circuit and Thermal Overload Protection
Low Profile (1mm) SOT-23 Package
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APPLICATIO S
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Portable Instruments and Battery-Powered Systems
Bluetooth/802.11 Cards
Cellular Phones
PDAs and Notebook Computers
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TYPICAL APPLICATIO
The LTC®1844 Series are low noise VLDOTM (very low
dropout) linear regulators designed for low power/portable
applications. These regulators can operate from input
voltages as low as 1.6V. Typical output noise is only
30µVRMS and typical dropout for the LTC1844-3.3 is just
90mV at the maximum load current of 150mA, reducing to
30mV at 50mA.
The internal P-channel MOSFET pass transistor requires
no base current, allowing the device to draw only 35µA
during normal operation, independent of the dropout
voltage and load current. The quiescent current falls to a
negligible 10nA during shutdown.
Other features include high output voltage accuracy,
excellent transient response, stability with ultralow ESR
ceramic capacitors as small as 1µF, reverse-battery and
reverse-current protection, short-circuit and thermal
overload protection and output current limiting.
The LTC1844 regulators are available in a low profile
(1mm) SOT-23 (ThinSOTTM) package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
VLDO and ThinSOT are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
LTC1844-3.3 Dropout Voltage vs Load Current
120
Fixed Voltage Low Noise, VLDO Linear Regulator
100
VIN
3.3V TO 6.5V
IN
1µF
OFF ON
VOUT
3.3V
OUT
LTC1844-3.3
BYP
SHDN
GND
1µF
0.1µF
1844 TA01
DROPOUT VOLTAGE (mV)
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DESCRIPTIO
80
60
40
20
0
0
25
50
75
100
IOUT (mA)
125
150
1844 TA02
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LTC1844 Series
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ABSOLUTE
RATI GS (Note 1)
Supply Voltage (IN) ....................................... – 7V to 7V
Input Voltage
SHDN, BYP, ADJ .................................... – 0.3V to 7V
Output Voltage
OUT ........................................................ – 0.3V to 7V
OUT to IN .................................................. – 7V to 7V
Output Short-Circuit Duration ......................... Indefinite
Operating Junction Temperature Range
(Notes 2, 10) .....................................–40°C to 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
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PACKAGE/ORDER I FOR ATIO
IN 1
IN 1
5 OUT
SHDN 3
4 BYP
GND 2
BYP 3
4 ADJ
4 ADJ
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
5 OUT
IN 1
5 OUT
GND 2
GND 2
SHDN 3
TOP VIEW
TOP VIEW
TOP VIEW
TJMAX = 125°C, θJA = 250°C/ W, θJC = 90°C/ W
TJMAX = 125°C, θJA = 250°C/ W, θJC = 90°C/ W
TJMAX = 125°C, θJA = 250°C/ W, θJC = 90°C/ W
SEE THE APPLICATIONS INFORMATION SECTION
SEE THE APPLICATIONS INFORMATION SECTION
SEE THE APPLICATIONS INFORMATION SECTION
ORDER PART
NUMBER
S5 PART
MARKING
ORDER PART
NUMBER
S5 PART
MARKING
ORDER PART
NUMBER
S5 PART
MARKING
LTC1844ES5-1.5
LTC1844ES5-1.8
LTC1844ES5-2.5
LTC1844ES5-2.8
LTC1844ES5-3.3
LTF1
LTF2
LTF3
LTQK
LTF4
LTC1844ES5-SD
LTE8
LTC1844ES5-BYP
LTE9
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT + 0.5V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
VIN
Input Voltage
IIN
Quiescent Current
CONDITIONS
MIN
●
TYP
1.6
SHDN = VIN
35
●
●
IINSHDN
VIN Shutdown Supply Current
SHDN = 0V
VOUT%
Regulated Output Voltage
(Notes 3, 4, 5)
LTC1844-3.3
LTC1844-3.3
VIN = 3.8V to 6.5V, IOUT = 0mA to 150mA
VIN = 3.8V to 6.5V, IOUT = 0mA to 150mA
LTC1844-2.8
LTC1844-2.8
0.01
MAX
UNITS
6.5
V
55
80
µA
µA
1
µA
●
–1.50
–1.75
1.50
1.75
%VOUT
%VOUT
VIN = 3.3V to 6.5V, IOUT = 0mA to 150mA
VIN = 3.3V to 6.5V, IOUT = 0mA to 150mA
●
–1.50
–1.75
1.50
1.75
%VOUT
%VOUT
LTC1844-2.5
LTC1844-2.5
VIN = 3.0V to 6.5V, IOUT = 0mA to 150mA
VIN = 3.0V to 6.5V, IOUT = 0mA to 150mA
●
–1.50
–1.75
1.50
1.75
%VOUT
%VOUT
LTC1844-1.8
LTC1844-1.8
VIN = 2.3V to 6.5V, IOUT = 0mA to 150mA
VIN = 2.3V to 6.5V, IOUT = 0mA to 150mA
●
–1.50
–1.75
1.50
1.75
%VOUT
%VOUT
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LTC1844 Series
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT + 0.5V, unless otherwise noted. (Note 2)
SYMBOL
VADJ
∆VLNR
PARAMETER
ADJ Pin Voltage (Notes 3, 5)
Line Regulation (Notes 3, 5)
CONDITIONS
∆VDO
Dropout Voltage (Notes 6, 7)
MAX
UNITS
VIN = 2.0V to 6.5V, IOUT = 0mA to 150mA
VIN = 2.2V to 6.5V, IOUT = 0mA to 150mA
VIN = 2.0V to 6.5V, IOUT = 0mA to 100mA
●
●
–1.50
–2.00
–2.50
1.50
2.00
2.00
%VOUT
%VOUT
%VOUT
LTC1844-BYP
LTC1844-BYP
LTC1844-BYP
VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA
VIN = 2.2V to 6.5V, IOUT = 0mA to 150mA
VIN = 1.75V to 6.5V, IOUT = 0mA to 100mA
●
●
–1.50
–1.75
–3.50
1.50
1.75
1.75
%VOUT
%VOUT
%VOUT
LTC1844-SD
LTC1844-SD
LTC1844-SD
VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA
VIN = 2.2V to 6.5V, IOUT = 0mA to 150mA
VIN = 1.75V to 6.5V, IOUT = 0mA to 100mA
●
●
–1.50
–1.75
–3.50
1.50
1.75
1.75
%VOUT
%VOUT
%VOUT
LTC1844-BYP
LTC1844-BYP
LTC1844-BYP
VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA
VIN = 2.2V to 6.5V, IOUT = 0mA to 150mA
VIN = 1.75V to 6.5V, IOUT = 0mA to 100mA
1.233
1.230
1.208
1.25
●
●
1.271
1.274
1.274
V
V
V
LTC1844-SD
LTC1844-SD
LTC1844-SD
VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA
VIN = 2.2V to 6.5V, IOUT = 0mA to 150mA
VIN = 1.75V to 6.5V, IOUT = 0mA to 100mA
1.233
1.230
1.208
1.25
●
●
1.271
1.274
1.274
V
V
V
LTC1844-3.3
VIN = 3.4V to 6.5V, IL = 1mA
●
4
20
mV
LTC1844-2.8
VIN = 2.9V to 6.5V, IL = 1mA
●
4
20
mV
LTC1844-2.5
VIN = 2.6V to 6.5V, IL = 1mA
●
4
20
mV
LTC1844-1.8
VIN = 2.2V to 6.5V, IL = 1mA
VIN = 1.9V to 6.5V, IL = 1mA
VIN = 1.9V to 6.5V, IL = 1mA
●
4
4
4
20
20
30
mV
mV
mV
LTC1844-1.5
VIN = 2.2V to 6.5V, IL = 1mA
VIN = 1.6V to 6.5V, IL = 1mA
VIN = 1.6V to 6.5V, IL = 1mA
●
4
4
4
20
20
80
mV
mV
mV
VIN = 2.2V to 6.5V, IL = 1mA
VIN = 1.6V to 6.5V, IL = 1mA
VIN = 1.6V to 6.5V, IL = 1mA
●
4
4
4
20
20
80
mV
mV
mV
VIN = 2.2V to 6.5V, IL = 1mA
VIN = 1.6V to 6.5V, IL = 1mA
VIN = 1.6V to 6.5V, IL = 1mA
●
●
4
4
4
20
20
80
mV
mV
mV
LTC1844-3.3
VIN = 3.8V, IOUT = 0mA to 150mA
●
9
20
mV
LTC1844-2.8
VIN = 3.3V, IOUT = 0mA to 150mA
●
9
20
mV
LTC1844-2.5
VIN = 3.0V, IOUT = 0mA to 150mA
●
9
20
mV
LTC1844-1.8
VIN = 2.3V, IOUT = 0mA to 150mA
●
9
20
mV
LTC1844-1.5
VIN = 2.2V, IOUT = 0mA to 150mA
VIN = 2.0V, IOUT = 0mA to 100mA
●
●
9
9
20
40
mV
mV
LTC1844-BYP
VIN = 2.2V, IOUT = 0mA to 150mA
VIN = 1.75V, IOUT = 0mA to 100mA
●
●
9
9
20
50
mV
mV
LTC1844-SD
VIN = 2.2V, IOUT = 0mA to 150mA
VIN = 1.75V, IOUT = 0mA to 100mA
●
●
9
9
20
50
mV
mV
LTC1844-3.3
IOUT = 50mA
IOUT = 150mA
●
●
30
90
55
150
mV
mV
LTC1844-2.8
IOUT = 50mA
IOUT = 150mA
●
●
35
105
60
165
mV
mV
LTC1844-2.5
IOUT = 50mA
IOUT = 150mA
●
●
45
135
75
200
mV
mV
LTC1844-1.8
IOUT = 50mA
IOUT = 150mA
●
●
85
230
120
300
mV
mV
LTC1844-SD
Load Regulation (Notes 3, 5)
TYP
LTC1844-1.5
LTC1844-1.5
LTC1844-1.5
LTC1844-BYP
∆VLDR
MIN
●
●
●
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LTC1844 Series
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT + 0.5V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
ILIM
Output Current Limit
en
Output Voltage Noise
VSHDN
SHDN Input Threshold
tDELAY
Shutdown Exit Delay
CONDITIONS
MIN
TYP
MAX
UNITS
LTC1844-1.5
IOUT = 50mA
IOUT = 150mA
●
●
115
350
160
450
mV
mV
LTC1844-BYP
IOUT = 50mA
IOUT = 150mA
●
●
45
135
75
200
mV
mV
LTC1844-SD
IOUT = 50mA
IOUT = 150mA
●
●
45
135
75
200
mV
mV
●
160
f = 10Hz to 100kHz, CBP = 0.1µF, COUT = 10µF, IL = 150mA
f = 10Hz to 100kHz, CBP = 0.1µF, COUT = 1µF, IL = 150mA
●
CBP = 0.01µF, COUT = 1µF, No load
CBP = 0.01µF, COUT = 1µF, No load
0.35
350
mA
60
65
µVRMS
µVRMS
0.65
0.9
V
70
100
200
µs
µs
●
°C
TSHDN
Thermal Shutdown Limit
∆TSHDN
Thermal Shutdown Hysteresis
IADJ
ADJ Pin Bias Current
(Notes 3, 8)
●
30
100
nA
IIRL
Input Reverse Leakage Current
LTC1844-3.3, LTC1844-2.8, LTC1844-2.5, LTC1844-1.8,
LTC1844-1.5, VIN = –5V, VOUT = 0V
●
200
500
µA
LTC1844-BYP, LTC1844-SD, VIN = –5V, VOUT = 0V
●
1000
1500
µA
Output Reverse Leakage Current
(Note 9)
VIN = 0V, VOUT = VOUT(NOMINAL)
VIN = 0V, VOUT = VOUT(NOMINAL)
0.01
●
0.1
1.2
µA
µA
VOSH
Start-Up Overshoot
RL = 1k, SHDN Rise Time ≤ 1µs
2
%VOUT
VRP
Output Ripple Rejection
(VIN – VOUT) = 1V (Avg), VRIPPLE = 0.5VP-P,
fRIPPLE = 120Hz, ILOAD = 100mA
50
dB
IORL
155
°C
10
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTC1844 is tested and specified under pulse load conditions
such that TJ ≈ TA. The LTC1844E is guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the – 40°C to 125°C
operating junction temperature range are assured by design,
characterization and correlation with statistical process controls.
Note 3: The LTC1844 adjustable versions are tested and specified for
these conditions with the ADJ pin connected to the OUT pin for a
VOUT(NOMINAL) of 1.25V.
Note 4: Operating conditions are limited by maximum junction
temperature. The regulated output voltage specification will not apply for
all possible combinations of input voltage and output current. When
operating at maximum input voltage, the output current range must be
limited. When operating at maximum output current, the input voltage
range must be limited.
Note 5: The LTC1844’s high precision degrades slightly at high
temperatures (TJ > 70°C) with input voltages below 2.2V. The lower output
voltage versions have been split into higher and lower accuracy input
voltage ranges to reflect this.
Note 6: To ensure adequate input supply voltage, the LTC1844 adjustable
versions are tested and specified for these conditions with an external
resistor divider (two 100k resistors) for an output voltage of 2.50V. The
external resistor divider will add a 5µA load on the output.
Note 7: Dropout voltage is (VIN – VOUT) when VOUT falls to 100mV below
its nominal value measured at VIN = VOUT + 0.5V. For example, the
LTC1844-3.3 is tested by measuring the VOUT at VIN = 3.8V, then VIN is
lowered until VOUT falls 100mV below the measured value. The difference
(VIN – VOUT) is then measured and defined as ∆VDO.
Note 8: ADJ pin bias current flows into the ADJ pin.
Note 9: Output reverse leakage current is tested with the IN pin grounded
and the OUT pin forced to the rated output voltage.
Note 10: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
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LTC1844 Series
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TYPICAL PERFOR A CE CHARACTERISTICS
VOUT vs Temperature
VOUT vs Temperature
1.820
VOUT = 1.5V
VOUT vs Temperature
2.520
VOUT = 1.8V
1.815
2.515
1.510
1.810
2.510
1.505
1.805
2.505
1.500
VOUT (V)
1.515
VOUT (V)
VOUT (V)
1.520
1.800
1.795
2.495
1.490
1.790
2.490
1.485
1.785
2.485
0
50
75
25
TEMPERATURE (°C)
100
1.780
– 50 – 25
125
0
50
75
25
TEMPERATURE (°C)
100
1844 G01
2.480
– 50 – 25
125
VOUT = 2.8V
VOUT = 3.3V
2.810
3.310
1.260
2.805
3.305
1.255
VOUT (V)
1.265
VOUT (V)
3.315
3.300
3.295
1.245
2.790
3.290
1.240
2.785
3.285
1.235
50
75
25
TEMPERATURE (°C)
100
125
3.280
– 50 – 25
0
50
75
25
TEMPERATURE (°C)
100
1844 G04
Quiescent Current vs Temperature
30
20
VOUT = 2.8V
50
25
75
0
TEMPERATURE (°C)
100
125
400
350
300
1844 G07
200
–50 –25
100
125
ILOAD = 1mA
750
250
10
50
75
25
TEMPERATURE (°C)
SHDN Threshold vs Temperature
800
SHDN THRESHOLD (mV)
CURRENT LIMIT (mA)
40
0
1844 G05
450
50
IQ (µA)
1.230
– 50 – 25
Current Limit vs Temperature
500
60
0
–50 –25
125
VOUT = ADJ
1844 G05
70
125
1.250
2.795
0
100
VOUT vs Temperature
1.270
2.815
2.780
– 50 – 25
50
75
25
TEMPERATURE (°C)
1844 G03
VOUT vs Temperature
3.320
2.800
0
1844 G02
VOUT vs Temperature
2.820
VOUT (V)
2.500
1.495
1.480
– 50 – 25
VOUT = 2.5V
700
650
600
550
500
450
50
25
75
0
TEMPERATURE (°C)
100
125
1844 G08
400
– 50 – 25
0
50
75
25
TEMPERATURE (°C)
100
125
1844 G09
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LTC1844 Series
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TYPICAL PERFOR A CE CHARACTERISTICS
RMS Output Noise vs Load
Current (10Hz to 100kHz)
Input Ripple Rejection
vs Frequency
300
100
60
COUT = 10µF
90 CBYP = 1000pF
IL = 100µA
80
RIPPLE REJECTION (dB)
CBYP = 0µF
200
150
100
CBYP = 0.1µF
50
RIPPLE REJECTION (dB)
250
OUTPUT NOISE (µVRMS)
Input Ripple Rejection
vs Temperature
70
60
50
40
30
20
50
40
30
20
10
10
0
0.01
0.1
1
10
100
LOAD CURRENT (mA)
1000
0
10
100
1k
10k
FREQUENCY (Hz)
1844 G10
100k
1M
1844 G11
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
1844 G12
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PI FU CTIO S
IN (Pin 1): Power for LTC1844 and Load. Power is supplied
to the device through the IN pin. The IN pin should be
locally bypassed to ground if the LTC1844 is more than a
few inches away from another source of bulk capacitance.
In general, the output impedance of a battery rises with
frequency, so it is usually advisable to include an input
bypass capacitor in battery-powered circuits. A capacitor
in the range of 0.1µF to 1µF is usually sufficient. The
LTC1844 is designed to withstand reverse voltages on the
IN pin with respect to both ground and the output pin. In
the case of a reversed input, which can happen if a battery
is plugged in backwards, the LTC1844 will act as if there
is a large resistor in series with its input and only a small
amount of current will flow.
GND (Pin 2): Ground and Heat Sink. Solder to a ground
plane or large pad to maximize heat dissipation.
SHDN (Pin 3, Fixed and SD Devices): Shutdown, Active
Low. This pin is used to put the LTC1844 into shutdown.
The SHDN pin current is typically less than 10nA. The
SHDN pin cannot be left floating and must be tied to the
input pin if not used. If reverse-battery protection is
desired, the SHDN pin must be tied to the input pin through
a large value resistor (10k to 1M).
ADJ (Pin 4, Adjustable Devices): Output Adjust. For the
adjustable versions of the LTC1844, this is the input to the
error amplifier. It has a typical bias current of 30nA flowing
into the pin. The ADJ pin reference voltage is 1.25V
referenced to ground. The output voltage range is 1.25V to
6V and is typically set by connecting ADJ to a resistor
divider from OUT to GND. See Figure 2.
BYP (Pin 4, Fixed/Pin 3, BYP Devices): Noise Bypass.
The BYP pin is used to augment the internal noise filter to
improve low noise performance. A small low leakage
bypass capacitor from this pin to ground will filter the input
of the error amplifier to lower the output voltage noise.
Any value may be used; larger values will result in lower
output noise, but will increase initial power-up time.
Shutdown exit delay time after a brief shutdown (