Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsVoltage RegulatorsLT1118CST2,5

LT1118/LT1118-2.5

LT1118-2.85/LT1118-5

1118fc

Low I

, Low Dropout,

800mA, Source and Sink

Regulators Adjustable and

Fixed 2.5V, 2.85V, 5V Output

The LT

1118 family of low dropout regulators has the

unique capability of maintaining output regulation while

sourcing or sinking load current. The 2.85V output voltage

regulator is ideal for use as a Boulay termination of up to

27 SCSI data lines. The regulator maintains regulation

while both sourcing and sinking current, enabling the use

of active negation drivers for improved noise immunity on

the data lines. Regulation of output voltage is maintained

for TERMPWR voltages as low as 4.0V. When unloaded,

quiescent supply current is a low 600µA, allowing continu-

ous connection to the TERMPWR lines. An ultralow power

shutdown mode is also available on the SO-8 version. In

Shutdown the output is high impedance and supply cur-

rent drops to less than 10µA.

Current limits in both sourcing and sinking modes, plus

on-chip thermal shutdown make the circuit tolerant of

output fault conditions.

The LT1118 is available in 3-lead SOT-223 and 8-lead SO

packages.

■

Active Negation SCSI Terminations

■

Computers

■

Disk Drives

■

CD-ROM

■

Supply Splitter

■

Regulates While Sourcing or Sinking Current

■

Provides Termination for up to 27 SCSI Lines

■

600µA Quiescent Current

■

Ultralow Power Shutdown Mode

■

Current Limit and Thermal Shutdown Protection

■

Stable for Any C

LOAD

≥ 0.22µF

■

Fast Settling Time

■

1V Dropout Voltage

Load Transient Response

1118 TA02.tif

0.2V

–0.2V

LT1118-2.85

GND

1118 TA01

2.2µF

1µF

CERAMIC

LOAD

OUT

LOAD

–400mA

800mA

0mA

∆V

OUT

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Summary of content (8 pages)

PAGE 1
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 Low IQ, Low Dropout, 800mA, Source and Sink Regulators Adjustable and Fixed 2.5V, 2.85V, 5V Output U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Regulates While Sourcing or Sinking Current Provides Termination for up to 27 SCSI Lines 600µA Quiescent Current Ultralow Power Shutdown Mode Current Limit and Thermal Shutdown Protection Stable for Any CLOAD ≥ 0.
PAGE 2
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 W W U W ABSOLUTE AXI U RATI GS (Note 1) Supply Voltage (VCC) ............................................... 15V Input Voltage (Enable) ................................– 0.2V to 7V Output Voltage ................................ – 0.2V to VCC + 0.5V Short-Circuit Duration ..................................... Indefinite Operating Temperature Range ..................... 0°C to 70°C Storage Temperature Range .................
PAGE 3
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS Line Regulation (Note 4) LT1118 LT1118-2.5 LT1118-2.85 LT1118-5 IL = 0mA, 4.2V ≤ VIN ≤ 15V IL = 0mA, 4.2V ≤ VIN ≤ 15V IL = 0mA, 4.75V ≤ VIN ≤ 15V IL = 0mA, 6.
PAGE 4
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 U W TYPICAL PERFORMANCE CHARACTERISTICS Ripple Rejection vs Frequency Dropout Voltage vs Output Current Ripple Rejection vs Frequency 80 1.4 80 800mA TJ = 25°C RIPPLE REJECTION (dB) TJ = 75°C DROPOUT VOLTAGE 1 0.8 TJ = 125°C 0.6 0.4 400mA 10mA 60 RIPPLE REJECTION (dB) 1.2 40 NO LOAD 20 10mA 60 40 NO LOAD 20 0.
PAGE 5
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 U U U PIN FUNCTIONS IN: Input Supply Pin. This pin should be decoupled with a 1µF or larger low ESR capacitor. The two IN pins on the SO-8 package must be directly connected on the printed circuit board to prevent voltage drops between the two inputs. When used as a SCSI active termination, IN connects to term power. When used as a supply splitter, IN is also the positive supply output. OUT: Regulated Output Voltage. Output can source or sink current.
PAGE 6
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 U OPERATIO thermally connected to the die substrate. Table 1 shows measured thermal resistance from junction to ambient for the LT1118 connected to various sized PC board ground planes. The power dissipated in the LT1118 varies with input voltage and loading. When the regulator is sourcing current the power which must be dissipated by the package is: PD = (VIN – VOUT) • ILOAD.
PAGE 7
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 U PACKAGE DESCRIPTIO ST Package 3-Lead Plastic SOT-223 (LTC DWG # 05-08-1630) .248 – .264 (6.30 – 6.71) .129 MAX .114 – .124 (2.90 – 3.15) .059 MAX .264 – .287 (6.70 – 7.30) .248 BSC .130 – .146 (3.30 – 3.71) .039 MAX .059 MAX .090 BSC .181 MAX .033 – .041 (0.84 – 1.04) .0905 (2.30) BSC RECOMMENDED SOLDER PAD LAYOUT 10° – 16° .010 – .014 (0.25 – 0.36) 10° MAX .071 (1.80) MAX 10° – 16° .024 – .033 (0.60 – 0.84) .0008 – .0040 (0.0203 – 0.1016) .012 (0.
PAGE 8
LT1118/LT1118-2.5 LT1118-2.85/LT1118-5 U TYPICAL APPLICATIO Variable 2.1V to 6.5V Regulator with Digital Control 12V 0.1µF IN 1µF R1 13.3k R2 6.19k LT1118 EN VOUT OUT GND 0.22µF VCC VDAC FB VOUT R3 6.19k DIN LTC1257 GND VREF CLK µP LOAD 1118 TA05 VOUT = 1.225 1 + R1 ( R2 || R3 ) – VDAC R1 R2 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1005 Logic Controlled Regulator 5V, 1A Main Output Plus 35mA Auxilliary Output LT1117 800mA Low Dropout Regulator Fixed 2.85V, 3.