Datasheet

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LT3008 Series

3008fc

TEMPERATURE (°C)

DROPOUT VOLTAGE (mV)

QUIESCENT CURRENT (µA)

400

3008 TA01b

200

100

500

300

250

150

350

450

–50 –25 0 25 50 75 100 125 150

LOAD

= 20mA

DROPOUT

VOLTAGE

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

A I

, 20mA, 45V

Low Dropout Linear Regulators

The LT

3008 series are micropower, low dropout voltage

(LDO) linear regulators. The devices supply 20mA output

current with a dropout voltage of 300mV. No-load quiescent

current is 3µA. Ground pin current remains at less than

5% of output current as load increases. In shutdown,

quiescent current is less than 1µA.

The LT3008 regulators optimize stability and transient

response with low ESR ceramic capacitors, requiring a

minimum of only 2.2µF. The regulators do not require

the addition of ESR as is common with other regulators.

Internal protection circuitry includes current limiting,

thermal limiting, reverse-battery protection and reverse-

current protection.

The LT3008 series are ideal for applications that require

moderate output drive capability coupled with ultralow

standby power consumption. The device is available in

ﬁ xed output voltages of 1.2V, 1.5V, 1.8V, 2.5V, 3.3V and

5V, and an adjustable version with an output voltage range

of 0.6V to 44.5V. The LT3008 is available in the thermally

enhanced 6-lead DFN and 8-lead TSOT-23 packages.

3.3V, 20mA Supply with Shutdown

Ultralow Quiescent Current: 3μA

Input Voltage Range: 2.0V to 45V

Output Current: 20mA

Dropout Voltage: 300mV

Adjustable Output (V

ADJ

= V

OUT(MIN)

= 600mV)

Fixed Output Voltages: 1.2V, 1.5V, 1.8V, 2.5V, 3.3V, 5V

Output Tolerance: ±2% Over Load, Line and

Temperature

Stable with Low ESR, Ceramic Output Capacitors

(2.2µF Minimum)

Shutdown Current: <1µA

Current Limit Protection

Reverse-Battery Protection

Thermal Limit Protection

TSOT-23 and 2mm × 2mm DFN Packages

Automotive

Low Current Battery-Powered Systems

Keep-Alive Power Supplies

Remote Monitoring

Utility Meters

Low Power Industrial Applications

SHDN

2.2µF

3008 TA01a

OUT

SENSE

3.8V TO

45V

GND

LT3008-3.3

OUT

3.3V

20mA

1µF

Dropout Voltage/Quiescent Current

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Summary of content (20 pages)

PAGE 1
LT3008 Series 3µA IQ, 20mA, 45V Low Dropout Linear Regulators FEATURES DESCRIPTION n The LT®3008 series are micropower, low dropout voltage (LDO) linear regulators. The devices supply 20mA output current with a dropout voltage of 300mV. No-load quiescent current is 3μA. Ground pin current remains at less than 5% of output current as load increases. In shutdown, quiescent current is less than 1μA. n n n n n n n n n n n n Ultralow Quiescent Current: 3μA Input Voltage Range: 2.
PAGE 2
LT3008 Series ABSOLUTE MAXIMUM RATINGS (Note 1) IN Pin Voltage .........................................................±50V OUT Pin Voltage ......................................................±50V Input-to-Output Differential Voltage ........................±50V ADJ Pin Voltage ......................................................±50V SENSE Pin Voltage ..................................................±50V SHDN Pin Voltage (Note 8) .....................................
PAGE 3
LT3008 Series ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3008ITS8#PBF LT3008ITS8#TRPBF LTDSX 8-Lead Plastic TSOT-23 –40°C to 125°C LT3008MPTS8#PBF LT3008MPTS8#TRPBF LTDSX 8-Lead Plastic TSOT-23 –55°C to 125°C LT3008ETS8-1.2#PBF LT3008ETS8-1.2#TRPBF LTFHD 8-Lead Plastic TSOT-23 –40°C to 125°C LT3008ITS8-1.2#PBF LT3008ITS8-1.2#TRPBF LTFHD 8-Lead Plastic TSOT-23 –40°C to 125°C LT3008MPTS8-1.2#PBF LT3008MPTS8-1.
PAGE 4
LT3008 Series ORDER INFORMATION LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3008ETS8-1.5 LT3008ETS8-1.5#TR LTFHG 8-Lead Plastic TSOT-23 –40°C to 125°C LT3008ITS8-1.5 LT3008ITS8-1.5#TR LTFHG 8-Lead Plastic TSOT-23 –40°C to 125°C LT3008MPTS8-1.5 LT3008MPTS8-1.5#TR LTFHG 8-Lead Plastic TSOT-23 –55°C to 125°C LT3008ETS8-1.8 LT3008ETS8-1.8#TR LTFHJ 8-Lead Plastic TSOT-23 –40°C to 125°C LT3008ITS8-1.8 LT3008ITS8-1.
PAGE 5
LT3008 Series ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TJ = 25°C. (Note 2) PARAMETER CONDITIONS Load Regulation (Note 3) LT3008-1.2: VIN = 2V, ILOAD = 1μA to 10mA VIN = 2V, ILOAD = 1μA to 20mA Dropout Voltage VIN = VOUT(NOMINAL) (Notes 5, 6) MIN TYP MAX l l 0.8 1 4 10 mV mV LT3008-1.5: VIN = 2.05V, ILOAD = 1μA to 10mA VIN = 2.05V, ILOAD = 1μA to 20mA l l 1 1.3 5 13 mV mV LT3008-1.
PAGE 6
LT3008 Series ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TJ = 25°C. (Note 2) PARAMETER CONDITIONS Current Limit VIN = 45V, VOUT = 0 VIN = VOUT(NOMINAL) + 1V, ΔVOUT = – 5% l Input Reverse-Leakage Current VIN = –45V, VOUT = 0 l Reverse-Output Current VOUT = 1.2V, VIN = 0 Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.
PAGE 7
LT3008 Series TYPICAL PERFORMANCE CHARACTERISTICS Dropout Voltage Dropout Voltage 350 300 DROPOUT VOLTAGE (mV) DROPOUT VOLTAGE (mV) TJ = 125°C TJ = 25°C 250 200 150 100 2 400 1.8 350 200 100μA 100 0 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA) 1mA 150 0 4 10mA 250 50 2 20mA 300 50 0 Minimum Input Voltage 450 –50 –25 1.4 1.2 1 0.8 0.6 0.4 0 25 50 75 0 100 125 150 –50 –25 1.224 IL = 100μA 1.220 1.530 ILOAD = 100μA 1.525 1.520 1.212 1.515 0.596 0.
PAGE 8
LT3008 Series TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage LT3008-5 ADJ Pin Bias Current 5.100 Adjustable Quiescent Current 10 ILOAD = 100μA 6 8 5.050 5.025 5.000 4.975 4.950 4.925 5 6 QUIESCENT CURRENT (μA) ADJ PIN BIAS CURRENT (nA) 5.075 OUTPUT VOLTAGE (V) TA = 25°C, unless otherwise noted. 4 2 0 –2 –4 –6 4 3 2 1 –8 4.
PAGE 9
LT3008 Series TYPICAL PERFORMANCE CHARACTERISTICS GND Pin Current LT3008-5 TA = 25°C, unless otherwise noted. SHDN Pin Thresholds GND Pin Current vs ILOAD 1000 500 450 VIN = 3.8V VOUT = 3.3V 300 250 200 RL = 500Ω, IL = 10mA 150 SHDN PIN THRESHOLD (V) RL = 250Ω, IL = 20mA 350 GND CURRENT (μA) GND PIN CURRENT (μA) 400 100 10 RL = 50k, IL = 100μA 100 50 RL = 5k, IL = 1mA 0 0 1 3 4 5 6 7 INPUT VOLTAGE (V) 2 8 9 1 0.001 10 0.01 0.1 1 10 100 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.
PAGE 10
LT3008 Series TYPICAL PERFORMANCE CHARACTERISTICS $IL = 1μA to 20mA VOUT = 600mV VIN = 2V 4 LOAD REGULATION (mV) OUTPUT NOISE SPECTRAL DENSITY (μV Hz) 5 4.5 3.5 3 2.5 2 1.5 1 0.5 0 –50 –25 0 RMS Output Noise vs Load Current Output Noise Spectral Density 25 50 75 100 125 150 TEMPERATURE (°C) 100 COUT = 2.2μF ILOAD = 20mA 5V 3.3V 2.5V 1.8V 1.5V 1V 0.6V 10 1 0.1 10 100 1k 10k FREQUENCY (Hz) 100k 500 450 5V 350 3.3V 300 2.5V 250 1.8V 200 1.5V 150 100 1.2V 50 0.6V 0 0.001 0.
PAGE 11
LT3008 Series PIN FUNCTIONS (TSOT-23/DFN) SHDN (Pin 1/Pin 5): Shutdown. Pulling the SHDN pin low puts the LT3008 into a low power state and turns the output off. If unused, tie the SHDN pin to VIN. The LT3008 does not function if the SHDN pin is not connected. The SHDN pin cannot be driven below GND unless tied to the IN pin. If the SHDN pin is driven below GND while IN is powered, the output will turn on. SHDN pin logic cannot be referenced to a negative rail. GND (Pins 2, 3, 4/Pin 6): Ground.
PAGE 12
LT3008 Series APPLICATIONS INFORMATION The LT3008 is a low dropout linear regulator with ultralow quiescent current and shutdown. Quiescent current is extremely low at 3μA and drops well below 1μA in shutdown. The device supplies up to 20mA of output current. Dropout voltage at 20mA is typically 300mV. The LT3008 incorporates several protection features, making it ideal for use in battery-powered systems. The device protects itself against both reverse-input and reverse-output voltages.
PAGE 13
LT3008 Series APPLICATIONS INFORMATION Because the ADJ pin is relatively high impedance (depending on the resistor divider used), stray capacitances at this pin should be minimized. Special attention should be given to any stray capacitances that can couple external signals onto the ADJ pin, producing undesirable output transients or ripple. Extra care should be taken in assembly when using high valued resistors. Small amounts of board contamination can lead to signiﬁcant shifts in output voltage.
PAGE 14
LT3008 Series APPLICATIONS INFORMATION piezoelectric response. A piezoelectric device generates voltage across its terminals due to mechanical stress, similar to the way a piezoelectric accelerometer or microphone works. For a ceramic capacitor, the stress can be induced by vibrations in the system or thermal transients. The resulting voltages produced can cause appreciable amounts of noise, especially when a ceramic capacitor is used for noise bypassing.
PAGE 15
LT3008 Series APPLICATIONS INFORMATION Table 3: Measured Thermal Resistance for TSOT-23 Package COPPER AREA TOPSIDE* BACKSIDE BOARD AREA THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 2500mm2 2500mm2 2500mm2 65°C/W 1000mm2 2500mm2 2500mm2 67°C/W 225mm2 2500mm2 2500mm2 70°C/W 100mm2 2500mm2 2500mm2 75°C/W 50mm2 2500mm2 2500mm2 85°C/W *Device is mounted on the topside.
PAGE 16
LT3008 Series APPLICATIONS INFORMATION The LT3008 incurs no damage if OUT is pulled below ground. If IN is left open circuit or grounded, OUT can be pulled below ground by 50V. No current ﬂows from the pass transistor connected to OUT. However, current ﬂows in (but is limited by) the resistor divider that sets output voltage. Current ﬂows from the bottom resistor in the divider and from the ADJ pin’s internal clamp through the top resistor in the divider to the external circuitry pulling OUT below ground.
PAGE 17
LT3008 Series TYPICAL APPLICATIONS Keep-Alive Power Supply NO PROTECTION DIODES NEEDED! VIN 12V IN 1μF 3.3V OUT 2.2μF LT3008-3.3 SHDN LOAD: SYSTEM MONITOR, VOLATILE MEMORY, ETC. SENSE GND 3009 TA02 Last-Gasp Circuit LINE POWER VLINE 12V TO 15V SENSE DCHARGE LINE INTERRUPT DETECT RLIMIT IN SUPERCAP 1μF OUT LT3008-5 5V TO MONITORING CENTER FAULT PWR GND 2.
PAGE 18
LT3008 Series PACKAGE DESCRIPTION TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637 Rev A) 0.40 MAX 2.90 BSC (NOTE 4) 0.65 REF 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.22 – 0.36 8 PLCS (NOTE 3) 0.65 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) 1.95 BSC TS8 TSOT-23 0710 REV A NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3.
PAGE 19
LT3008 Series REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION PAGE NUMBER B 02/10 Added MP grade in TS8 package Revised curve G04 in Typical Performance Characteristics 7 C 04/12 Clariﬁed E-Grade Operating Temperature 6 Updated Package Drawings 2-4, 6 17, 18 3008fc Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use.
PAGE 20
LT3008 Series TYPICAL APPLICATION Low Duty Cycle Applications IN 1μF OUT 100 3.3V 90 2.2μF LT3008-3.3 SHDN LOW DUTY CYCLE PULSED LOAD 0mA TO 10mA SENSE GND 3008 TA04a 80 POWER SAVINGS (%) VIN 12V Average Power Savings for Low Duty Cycle Applications 0mA to 10mA Pulsed Load, IN = 12V 70 60 100μA IQ 50 40 30μA IQ 30 20 10 0 0.1 10μA IQ 1 10 DUTY CYCLE (%) 3008 TA04b RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1761 100mA, Low Noise Micropower LDO VIN : 1.8V to 20V, VOUT = 1.