Datasheet

ManualsBrandsLinear Technology ManualsIntegrated Circuits (ICs)LDO Voltage Regulator, -32 ... 0V, MSOP-12

LT3090

3090fa

For more information www.linear.com/LT3090

Output Noise: 10Hz to 100kHz

Typical applicaTion

FeaTures DescripTion

–36V, 600mA Negative

Linear Regulator with

Programmable Current

Limit

The LT

3090 is a 600mA, low dropout negative linear

regulator that is easily parallelable to increase output

current or spread heat on surface mounted boards.

Designed with

a precision current reference followed by a

high performance rail-to-rail voltage buffer, this regulator

finds use in applications requiring precision output, high

current with no heat sink, output adjustability to zero and

low dropout voltage. The device can also be configured

as a 3-terminal floating regulator.

The LT3090 features fast transient response, high PSRR

and output noise as low as 18µV

RMS

. The LT3090 generates

a wide output voltage range (0V to –32V) while maintain-

ing unity gain operation. This yields virtually constant

bandwidth, load regulation, PSRR and noise, regardless

of the programmed output voltage.

The LT3090 supplies 600mA at a typical dropout voltage

of 300mV. Operating quiescent current is nominally 1mA

and drops to << 1µA in shutdown. A single resistor ad-

justs the LT3090’s precision programmable current limit.

The LT3090’s positive or negative current monitor either

sources a current (0.5mA/A) or sinks a current (1mA/A)

proportional to output current. Built-in protection includes

reverse output protection, internal current limit with fold-

back and thermal shutdown with hysteresis.

applicaTions

L, LT, LT C , LT M, Linear Technology and the Linear logo are registered trademarks and

ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property

of their respective owners. Patent Pending.

Output Current: 600mA

Single Resistor Sets Output Voltage

50µA SET Pin Current: ±1% Initial Accuracy

Programmable Current Limit

Positive or Negative Output Current Monitor

Parallelable for Higher Current and Heat Spreading

Low Dropout Voltage: 300mV

Low Output Noise: 18µV

RMS

(10Hz to 100kHz)

Configurable as 3-Terminal Floating Regulator

Wide Input Voltage Range: –1.5V to –36V

Rail-to-Rail Output Voltage Range: 0V to –32V

Positive/Negative Shutdown Logic or UVLO

Programmable Cable Drop Compensation

Load Regulation: 1.2mV (1mA to 600mA)

Stable with 4.7µF Minimum Output Capacitor

Stable with Ceramic or Tantalum Capacitors

Thermally Enhanced 12-Lead MSOP and 10-Lead

0.75mm × 3mm × 3mm DFN Packages

Post Regulator for Switching Supplies

Low Noise Instrumentation and RF Supplies

Rugged Industrial Supplies

Precision Power Supplies

: –3.5V

OUT

: –2V

OUT

: 4.7µF, C

SET

: 0.1µF

: 600mA

OUT

100µV/DIV

1ms/DIV

3090 TA01b

LT3090

OUT

–2.5V

MAX I

OUT

600mA

SET GND

ILIM

SHDN

3090 TA01a

–

50µA

IMONP

OUT

IMONN

0.1µF

4.7µF

49.9k

3.32k

TO ADC (IMON)

–3V TO –10V

10k

3.3V

4.7µF

0.1µF

Downloaded from Arrow.com.

Summary of content (36 pages)

PAGE 1
LT3090 –36V, 600mA Negative Linear Regulator with Programmable Current Limit Description Features n n n n n n n n n n n n n n n n n Output Current: 600mA Single Resistor Sets Output Voltage 50µA SET Pin Current: ±1% Initial Accuracy Programmable Current Limit Positive or Negative Output Current Monitor Parallelable for Higher Current and Heat Spreading Low Dropout Voltage: 300mV Low Output Noise: 18µVRMS (10Hz to 100kHz) Configurable as 3-Terminal Floating Regulator Wide Input Voltage Range: –1.
PAGE 2
LT3090 Absolute Maximum Ratings (Note 1) IN Pin Voltage (Note 3) with Respect to GND Pin............................0.3V, –40V ILIM Pin Voltage with Respect to IN Pin (Note 3).................–0.3V, 0.7V IMONP Pin Voltage with Respect to IN Pin (Note 3)..................–0.3V, 40V with Respect to GND Pin.............................–40V, 20V with Respect to IMONN Pin.........................–40V, 20V IMONN Pin Voltage with Respect to IN Pin (Note 3)..................–0.3V, 40V with Respect to GND Pin......
PAGE 3
LT3090 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS Minimum IN Voltage (Note 11) ILOAD = 100mA ILOAD = 600mA SET Pin Current (ISET) Output Offset Voltage VOS (VOUT – VSET) MIN TYP l –1.9 –1.5 –1.5 VIN = –1.9V, ILOAD = 1mA, –36V < VIN < –1.9V, 1mA < ILOAD < 600mA (Note 5) l 49.5 49 50 50 VIN = –1.9V, ILOAD = 1mA, –36V < VIN < –1.
PAGE 4
LT3090 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS MIN TYP MAX UNITS Positive Current Monitor (Note 15) Positive Current Monitoring (IMONP) Scale Factor IOUT = 600mA, VIN = –2.5V, VIMONN = 2V, VIMONP = 0V IOUT = 100mA, VIN = –2.5V, VIMONN = 2V, VIMONP = 0V l l 280 42.5 0.5 300 50 320 57.
PAGE 5
LT3090 Typical Performance Characteristics SET Pin Current 50.5 2.0 N = 3122 50.2 50.1 50.0 49.9 49.8 49.7 49.5 –75 –50 –25 49 0 25 50 75 100 125 150 TEMPERATURE (°C) 49.5 50 50.5 DISTRIBUTION (µA) 1.0 0.5 0 –0.5 –1.0 –2.0 –75 –50 –25 51 3090 G02 3090 G01 Offset Voltage N = 3122 2.0 IL = 1mA VOUT = –1.25V 50.4 50.1 50.0 49.9 49.8 –55°C 25°C 125°C 150°C 49.6 –1 0 1 VOS DISTRIBUTION (mV) 49.5 2 49.9 49.
PAGE 6
LT3090 Typical Performance Characteristics Quiescent Current 450 VSHDN = VIN DROPOUT VOLTAGE (mV) 0.8 0.4 0.2 0 –75 –50 –25 400 450 350 400 300 250 200 150 –55°C 25°C 125°C 150°C 100 50 VSHDN = 0V 0 0 25 50 75 100 125 150 TEMPERATURE (°C) 0 100 400 500 200 300 OUTPUT CURRENT (mA) Dropout Voltage 300 IL = 300mA IL = 1mA 150 IL = 100mA 100 50 8 6 4 –55°C 25°C 125°C 150°C 0 100 POSITIVE SHDN TURN-ON THERSHOLD (V) MINIMUM INPUT VOLTAGE (V) –1.2 –1.0 –0.8 –0.6 –0.
PAGE 7
LT3090 Typical Performance Characteristics SHDN Pin Current VIN = –36V IMONN Pin Current 700 VIN = –15V 10 5 0 –55°C 25°C 125°C 150°C –10 –15 –36 –28 –20 –12 –4 4 SHDN PIN VOLTAGE (V) 12 15 10 5 0 –5 –75 –50 –25 20 510 500 490 480 VOUT = –1.2V VIMONN = –0.5V VIMONP = VIN ILOAD = 500mA 470 460 –75 –50 –25 110 105 100 95 90 VOUT = –1.2V VIMONN = –0.
PAGE 8
LT3090 Typical Performance Characteristics Programmable Brick-Wall Current Limit RILIM = 20k RILIM = 40k RILIM = 100k –0.75 –0.50 0 100 500 400 300 200 100 RSET = 25K VIN = –3V 0 50 600 CURRENT LIMIT (mA) –1.00 –0.25 Internal Current Limit 60 700 CURRENT LIMIT (mA) OUTPUT VOLTAGE (V) –1.25 Internal Current Limit 800 200 300 400 500 OUTPUT CURRENT (mA) 0 –75 –50 –25 600 400 300 200 60 50 40 30 20 VOUT = –2.5V ILOAD = 600mA CSET = 0.
PAGE 9
LT3090 Typical Performance Characteristics Output Noise: 10Hz to 100kHz TJ = 25°C, unless otherwise noted. Load Transient Response, –3VOUT Output Noise: 10Hz to 100kHz ILOAD 300mA/DIV VOUT 1mV/DIV VOUT 100µV/DIV ∆VOUT 100mV/DIV 1ms/DIV VIN: –3.5V COUT: 4.7µF, CSET: 20pF VOUT: –2V IL: 600mA 1ms/DIV VIN: –3.5V COUT: 4.7µF, CSET: 0.1µF VOUT: –2V IL: 600mA 3090 G37 3090 G38 20µs/DIV ILOAD: 20mA TO 600mA COUT: 4.7µF, CSET: 0.
PAGE 10
LT3090 Pin Functions (DFN/MSOP) IN (Pins 1, 2, Exposed Pad 11/1, 2, 3, Exposed Pad 13): Input. These pins supply power to the regulator. The exposed backside pad of the DFN and MSOP packages is an electrical connection to IN and the device’s substrate. For proper electrical and thermal performance, tie all IN pins together and tie IN to the exposed backside of the package on the PCB. See the Applications Information section for thermal considerations and calculating junction temperature.
PAGE 11
LT3090 Pin Functions (DFN/MSOP) GND (Pin 8/9): Ground. This pin supplies the LT3090's quiescent current and the drive current to the NPN pass transistor. The LT3090's GND pin is highly versatile. Depending on application’s requirements, it can be tied to the system ground, a positive voltage, or the OUT pin. A parasitic substrate diode exists between the LT3090’s GND and IN pins. Therefore, do not drive GND more than 0.3V below IN during normal operation or during a fault condition.
PAGE 12
LT3090 Applications Information The LT3090 is a 600mA, rail-to-rail output, negative low dropout linear regulator featuring very low output noise, high bandwidth, precision programmable current limit, precision positive or negative current monitor, and bidirectional shutdown. The LT3090 supplies 600mA at a typical dropout voltage of 300mV. Unlike other devices, the LT3090 does not require a separate supply to achieve low dropout performance. The 1mA quiescent current drops to well below 1µA in shutdown.
PAGE 13
LT3090 Applications Information reduction depends on the guard ring width. Leakages as small as 50nA into or out of the SET pin creates a 0.1% error in the reference voltage. Leakages of this magnitude, coupled with other sources of leakage, can cause significant errors in the output voltage, especially over wide operating temperature range. Figure 2 illustrates a typical guard ring layout technique. If guard ring techniques are used, then SET pin stray capacitance is practically eliminated.
PAGE 14
LT3090 Applications Information decrease peak output deviations during a load transient. The LT3090 requires a minimum 10µA load current to maintain stability under all operating conditions. Give extra consideration to the use of ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior across temperature and applied voltage. The most common dielectrics used are specified with EIA temperature characteristic codes of Z5U, Y5V, X5R and X7R.
PAGE 15
LT3090 Applications Information One problem that conventional linear regulators face is that the resistor divider setting VOUT gains up the reference noise. In contrast, the LT3090’s unity gain follower architecture presents no gain from the SET pin to the output. Therefore, output noise is virtually independent of the output voltage setting if a capacitor bypasses the SET pin. Resultant output noise is then set by the error amplifier’s noise, typically 57nV/√Hz (18µVRMS in a 10Hz to 100kHz bandwidth).
PAGE 16
LT3090 Applications Information resistor to GND – this generates a negative voltage (proportional to output current) on IMONN. Furthermore, as illustrated in Figure 6, the negative current monitor pin can also be used for cable drop compensation. Cable drop compensation corrects for load dependent voltage drop caused by a resistive connection between the LT3090’s OUT pin and its load. RCBL2 4.7µF RCDC = RCBL • 1K LOAD 0.1µF 100k IMONN GND SET OUT RCBL = RCBL1 + RCBL2 + – 4.
PAGE 17
LT3090 Applications Information PARASITIC RESISTANCE RP SET RP IMONN GND LOAD RP RSET 49.9k OUT + COUT 4.7µF – CIN 4.7µF VOUT –2.5V MAX IOUT 600mA LT3090 50µA IN VIN –3V TO –10V ILIM IMONP SHDN RILIM 3090 F08 10k Figure 8. Connections for Best Load Regulation Floating 3-Terminal Regulator The LT3090’s rail-to-rail error amp allows the LDO to be configured as a floating three-terminal regulator. With proper protection, the LT3090 can be used in arbitrarily high voltage applications.
PAGE 18
LT3090 Applications Information set below the LT3090’s –1.9V minimum input voltage. As long as there is 1.9V between IN and GND pins of LT3090, the minimum operating voltage is satisfied. Now it can operate with much lower dropout voltage, with the device dropout set by the pass device as illustrated in Figure 14. VOUT 1V/DIV VIN 2V/DIV 50ms/DIV VIN: –5V TO 0V COUT: 15µF, CSET: 0.1µF VOUT: –3V TO 0V IL: 600mA, VSHDN = 1.5V 3090 F12 0.1µF Figure 12.
PAGE 19
LT3090 Applications Information In summary, the GND pin of LT3090 is highly versatile and can be tied to different places depending on the application’s requirements: a) It can be tied to the system GND for low dropout operation for output voltages greater than –1.
PAGE 20
LT3090 Applications Information junction temperature. The dual-in-line pin arrangement allows metal to extend beyond the ends of the package on the topside (component side) of the PCB. Connect this metal to IN on the PCB. The multiple IN and OUT pins of the LT3090 further assist in spreading heat to the PCB. For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PCB and its copper traces.
PAGE 21
LT3090 Applications Information applied and input voltage rises, the output follows the input and keeps the output-to-input differential low to allow the regulator to supply large output current and startup into high current loads. Due to current limit fold back, however, at high input voltages, a problem can occur if the output voltage is low and the load current is high.
PAGE 22
LT3090 Typical Applications Parallel Devices 0.1µF LT3090 24.9k 1% 10µF GND SET IMONN OUT 20m + – 10µF VIN –3V TO –10V 50µA IN IMONP SHDN VOUT –2.5V MAX IOUT 1.2A ILIM 10k GND LT3090 SET IMONN OUT 20m + – 50µA IN SHDN IMONP ILIM 10k 3090 TA02 22 Downloaded from Arrow.com. 3090fa For more information www.linear.
PAGE 23
LT3090 Typical Applications Paralleling Devices Using IMONN to Cancel Ballast Resistor Drop CSET 0.1µF RCOMP 10 RCOMP = 1K • RBLST/N 24.9k 1% LT3090 GND SET 20m IMONN OUT 10µF + – 10µF 50µA VOUT = N • 50µA(RSET + RCOMP) IN VIN –3V TO –10V IMONP SHDN VOUT –2.5V MAX IOUT 1.2A ILIM 10k GND LT3090 SET IMONN OUT 20m + – 50µA IN SHDN IMONP ILIM 10k 3090 TA03 Load Sharing without Ballasting (Using IMONP) Master Regulator 0.1µF LT3090 Slave Regulator 24.9k 1% 24.
PAGE 24
LT3090 Typical Applications Paralleling Devices without Ballasting (50mA Minimum Load) Master Regulator 24.9k 1% 0.1µF LT3090 SET GND VOUT –2.5V IOUT 1.2A IMONN OUT 20 Slave Regulator + 10µF 20m OUT – 10µF VIN –3V TO –10V 50µA IMONN GND SET + LT3090 IN SHDN – ILIM IMONP 10k 50µA IN ILIM IMONP SHDN 10k 3090 TA05 Using Lower Value RSET for Higher Output Voltages COUT 4.7µF RSET 0.1µF 523Ω 1% 10k 1% LT3090 SET GND IMONN OUT VOUT = –0.
PAGE 25
LT3090 Typical Applications Constant-Current Constant-Voltage Lab Power Supply 0.1µF RSET LT3090 4.7µF SET GND IMONN OUT VOUT + – 4.7µF 50µA IN VIN IMONP SHDN ILIM RILIM 3090 TA07 Low Dropout Operation for Very Low Output Voltages 0.1µF LT3090 CGND 0.47µF 4.02k 1% +1.2V OR HIGHER SET GND COUT 4.7µF IMONN OUT VOUT: –0.2V MAX IOUT: 600mA + – CIN 4.7µF VIN –0.7V TO –7V 50µA IN SHDN IMONP ILIM 10k 3090 TA08 3090fa For more information www.linear.com/LT3090 Downloaded from Arrow.
PAGE 26
LT3090 Typical Applications Input Supply Tracking VIN 0.1µF LT3090 100k 1% 4.7µF SET GND VOUT = VIN – 5V MAX IOUT 600mA IMONN OUT + – 50µA 4.7µF IN IMONP SHDN ILIM 10k 3090 TA09 Floating 3-Terminal Regulator (for Arbitrarily High Voltage Applications) 0.1µF LT3090 1M 1% 4.7µF SET 36V GND IMONN OUT + – 4.7µF VIN –52V TO –57V VOUT –50V MAX IOUT 600mA 36V 50µA IN SHDN IMONP ILIM 10k 3090 TA10 26 Downloaded from Arrow.com. 3090fa For more information www.linear.
PAGE 27
LT3090 Typical Applications 500mA LED Driver with Grounded LED Tab (Heatsink) SET GND VIN 500mA 4.02k LT3090 500mA LED Driver with Positive Supply 400m IMONN OUT SET LT3090 + IMONN OUT 400m 4.7µF – 4.7µF 50µA 50µA IN IN VIN GND + 4.7µF – 4.7µF 500mA 4.02k IMONP SHDN ILIM IMONP SHDN ILIM 10k 10k 3090 TA12 3090 TA11 Low Noise Single Inductor Positive-to-Negative Converter 0.1µF 49.9k 1% VIN 12V LT3090 47µF BD VIN RUN/SS RT BOOST SW LT3480 PG D FB SYNC GND 68.
PAGE 28
LT3090 Typical Applications High Efficiency Low Noise Single Inductor Positive-to-Negative Converter with LDO Input-to-Output Control VIN 12V 47µF BD VIN RUN/SS RT BOOST SW LT3480 PG QP D GND QP 5.36k FB SYNC (500kHz) 68.1k 1% L 10µH 1µF VC 1nF M 47µF 1k 2.2nF LDOOUT – 2V MAX: –5V MIN: –0.8V Z 0.1µF 49.9k 1% LT3090 4.7µF SET GND VOUT –2.5V MAX IOUT 600mA IMONN OUT + – 4.7µF 50µA IN VIN –5V SHDN IMONP ILIM 3090 TA14 10k L: COILCRAFT XAL5050 D: DIODES INC.
PAGE 29
LT3090 Typical Applications 5V to ±2.5V Low Noise Power Supply VIN 5V VIN BD BOOST RUN/SS RT 0.47µF SW LT3480 PG D FB SYNC GND 68.1k 1% fOSC = 500kHz CTRL LT3085 L 10µH 10µA 47µF + 539k – VC 18.2k IN 100k OUT 47µF SET 330pF 249k 1% D: DIODES INC, DFLS240L L: NEC/TOKIN PLC-0755-100 VOUT2 2.5V MAX IOUT 4.7µF 500mA 0.1µF 0.1µF 49.9k 1% LT3090 4.7µF SET GND IMONN OUT + VOUT2 –2.5V MAX IOUT 600mA – 4.
PAGE 30
LT3090 Typical Applications Reference Buffer COUT 4.7µF LT1004-2.5 LT3090 SET GND VOUT –2.5V MAX IOUT 600mA IMONN OUT + – CIN 4.7µF 50µA IN VIN –3V TO –10V SHDN IMONP ILIM 10k 3090 TA16 Coincident Tracking Supplies R1 49.9k 1% LT3090 COUT 4.7µF SET GND IMONN OUT VOUT1, –2.5V 600mA + R2 16.2k 1% – CIN 4.7µF LT3090 50µA VIN –5.5V TO –10V COUT 4.7µF SET IN GND IMONN OUT VOUT2, –3.3V 600mA R3 34k 1% + SHDN IMONP ILIM – 10k LT3090 50µA COUT 4.
PAGE 31
LT3090 Typical Applications Simple Cable Drop Compensation RCBL2 RCDC = RCBL • 1k 4.7µF LOAD 0.1µF 100k 1% LT3090 SET IMONN GND RCBL1 OUT + RCBL = RCBL1 + RCBL2 – 4.7µF VOUT –5V MAX IOUT 600mA 50µA IN VIN ≤ –6V SHDN ILIM IMONP 10k 3090 TA18 Low Noise 4-Quadrant Power Supply VCC IN CTRL LT3085 4.7µF 10µA + – OUT SET 40m VSET 40m 10µF VOUT (SOURCE/SINK 500mA) VEE + VDROPOUT (LT3090) ≤ VOUT ≤ VCC – VDROPOUT (LT3085) LT3090 SET GND IMONN OUT + – 4.
PAGE 32
LT3090 Typical Applications Two-Terminal Current Source 4.02k, 1% IOUT = 200mV/R1 R1 LT3090 SET GND IMONN OUT + – 50µA IN VIN IMONP SHDN ILIM 10k 10µF 3090 TA20 Positive Output Current Monitor 0.1µF LT3090 TO ADC 49.9k 1% 3.32k 4.7µF SET GND IMONP OUT + VOUT –2.5V MAX IOUT 600mA – 4.7µF 50µA IN VIN –3V TO –10V IMONN 3V ILIM SHDN 0.1µF 10k 3090 TA21 Negative Output Current Monitor 0.1µF LT3090 49.9k 1% 1.67k TO ADC SET GND IMONN OUT + 4.7µF VOUT –2.
PAGE 33
LT3090 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699 Rev C) 0.70 ±0.05 3.55 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 3.00 ±0.10 (4 SIDES) R = 0.125 TYP 6 0.40 ±0.10 10 1.65 ±0.10 (2 SIDES) PIN 1 NOTCH R = 0.20 OR 0.
PAGE 34
LT3090 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MSE Package 12-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1666 Rev G) BOTTOM VIEW OF EXPOSED PAD OPTION 2.845 ±0.102 (.112 ±.004) 5.10 (.201) MIN 2.845 ±0.102 (.112 ±.004) 0.889 ±0.127 (.035 ±.005) 6 1 1.651 ±0.102 (.065 ±.004) 1.651 ±0.102 3.20 – 3.45 (.065 ±.004) (.126 – .136) 12 0.65 0.42 ±0.038 (.0256) (.0165 ±.
PAGE 35
LT3090 Revision History REV DATE DESCRIPTION A 01/14 Modified Ripple Rejection test condition PAGE NUMBER 3 Added units to internal Current Limit spec 3 Modified ISET Thermal Regulation test condition 4 Modified Load Sharing without Ballasting application circuit 23 Modified Coincident Tracking Supplies application circuit 30 Modified Parallel Devices application circuit 36 3090fa Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
PAGE 36
LT3090 Typical Application Parallel Devices 0.1µF LT3090 24.9k 1% 10µF SET GND IMONN OUT 20m + VOUT –2.5V MAX IOUT 1.