MIC5204BM - Micrel, Inc. - Product.Network

MIC5204 Micrel

February 1999 1 MIC5204

MIC5204

SCSI-II Active Terminator

Final Information

Ordering Information

Part Number Junction Temp. Range Package

MIC5204BM –40°C to +125°C SO-8

MIC5204BS –40°C to +125°C SOT-223

Pin Configuration

General Description

The MIC5204 is an active terminator designed to comply with

SCSI-II specifications. The MIC5204 is enabled by a CMOS

or TTL compatible logic signal. When disabled, power

consumption drops nearly to zero and the output goes into a

high impedance state. Key MIC5204 features include protec-

tion against reversed battery, current limiting, and over-

temperature shutdown.

Features

•± 1% output voltage accuracy

• Guaranteed 500mA output

• Low quiescent current

• Low dropout voltage

• Extremely tight load and line regulation

• Very low temperature coefficient

• Current and thermal limiting

• Zero off-mode current

• Logic-controlled electronic shutdown

• Available in SO-8 and SOT-223 packages

Applications

• SCSI-II active terminator

• Desktop, laptop, notebook, and palmtop computers

• Intelligent instrumentation

• Printers

• Disk drives

• Voltage reference

GROUND

VOUT VIN

ENABLE

MIC5204BM

VOUT

NC VIN

T ypical Application

110Ω

+5V MIC5204

22µF10µF

SCSI Bus

18 to 27

Lines

110Ω

Both VIN and both VOUT pins must be tied

together. ENABLE must be pulled high for

operation.

1 2 3

IN GND OUT

TAB IS GROUND

MIC5204-xxBS

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

MIC5204 Micrel

February 1999 2 MIC5204

Electrical Characteristics

VIN = VOUT + 1V; IL = 1mA; CL = 3.3µF; VEN ≥ 2.0V; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted.

Symbol Parameter Conditions Min Typical Max Units

VOOutput Voltage Accuracy 2.821 2.85 2.87 V

2.793 2.907

∆VO/∆T Output Voltage Note 4 20 100 ppm/°C

Temperature Coef.

∆VO/VIN Line Regulation VIN = VOUT + 1V to 6V 0.004 0.10 %

0.40

∆VO/ILLoad Regulation IL = 0.1mA to 100mA, Note 5 0.04 0.16 %

0.30

VIN–VODropout Voltage, Note 6 IL = 100µA30mV

IL = 50mA 190

240

IL = 100mA 210

350

IL = 500mA 450

750

IQQuiescent Current VENABLE ≤ 0.7V (Shutdown) 0.01 µA

IGND Ground Pin Current VENABLE ≥ 2.0V, IL = 100µA130µA

IL = 20mA 240

IL = 30mA 300

IL = 50mA 450

IL = 100mA 900

PSRR Ripple Rejection 70 dB

IGNDDO Ground Pin VIN = 0.5V less than designed VOUT 270 330 µA

Current at Dropout IL = 100µA, Note 7

ILIMIT Current Limit VOUT = 0V 750 mA

∆VO/∆PDThermal Regulation Note 8 0.05 %/W

enOutput Noise 30 µV

Enable Input

Input Voltage Level

VIL Logic Low off 0.7 V

Logic High on 2.0

IIL Enable Input Current VIL ≤ 0.7V 0.01 µA

IIH VIH ≥ 2.0V 15 50

Absolute Maxim um Ratings (Note 1)

Input Voltage (VIN) ........................................ –20V to +20V

Enable Input Voltage (VEN) .......................... –0.3V to +20V

Power Dissipation (PD)................Internally Limited, Note 3

Lead Temperature (soldering, 5 sec.) ....................... 260°C

ESD Rating .............................................................>2000V

Operating Ratings (Note 2)

Input Voltage (VIN) ............................................ +3V to +6V

Enable Input Voltage (VEN) ............................. –0.3V to VIN

Junction Temperature Range (TJ) ........... –40°C to +125°C

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Note 1. Exceeding the absolute maximum rating may damage the device.

Note 2. The device is not guaranteed to function outside its operating rating.

Note 3. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max), the junction-to-ambient thermal

resistance, θJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using:

P(max) = (TJ(max) –TA) θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will

go into thermal shutdown. The θJC of the MIC5204BS is 15°C/W and θJA for the MIC5204BM is 160°C/W mounted on a PC board (see

“Thermal Considerations” for details).

Note 4. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.

Note 5. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load

range from 0.1mA to 100mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.

Note 6. Dropout Voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V

differential.

Note 7. Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of

the load current plus the ground pin current.

Note 8. Thermal regulation is defined as the change in output voltage at a time “t” after a change in power dissipation is applied, excluding load or line

regulation effects. Specifications are for a 500mA load pulse at VIN = 6V for t = 10ms.

Typical Characteristics

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

-50 -25 0 25 50 75 100 125

OUTPUT VOLTAGE VARIATION (%)

JUNCTION TEMPERATURE (˚C)

Output Voltage Variation

vs. Junction Temperature

3.0

3.5

4.0

4.5

5.0

5.5

6.0

-50 -25 0 25 50 75 100 125

GROUND CURRENT (mA)

JUNCTION TEMPERATURE (˚C)

Ground Current

vs. Junction Temperature

RL = 20Ω

VIN = 6V

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Thermal ConsiderationsApplications Information

External Capacitors

A 2.2µF capacitor is recommended between the MIC5204

output and ground to prevent oscillations due to instability.

Larger values serve to improve the regulator's transient re-

sponse. Most types of tantalum or aluminum electrolytics will

be adequate; film types will work. Many aluminum electrolytics

have electrolytes that freeze at about –30°C, so solid tantalums

are recommended for operation below –25°C. The important

parameters of the capacitor are an effective series resistance

of about 5Ω or less and a resonant frequency above 500kHz.

The value of this capacitor may be increased without limit.

A 1µF capacitor should be placed from the MIC5204 input to

ground if there is more than 10 inches of wire between the

input and the AC filter capacitor or if a battery is used as the

input.

The MIC5204 will remain stable and in regulation with no load

in addition to the internal voltage divider.

PC Board θJA

Dielectric

FR4 160°C/W

Ceramic 120°C/W

Multi-layer boards having a ground plane, wide traces near

the pads, and large supply bus lines provide better thermal

conductivity. The "worst case" value of 160°C/W assumes no

ground plane, minimum trace widths, and a FR4 material

board.

Part II. Nominal Power Dissipation and Die Temperature

The MIC5204BM at a 25°C ambient temperature will operate

reliably at up to 625mW power dissipation when mounted in

the "worst case" manner described above. At an ambient

temperature of 55°C, the device may safely dissipate 440mW.

These power levels are equivalent to a die temperature of

125°C, the recommended maximum temperature for non-

military grade silicon integrated circuits. In normal SCSI

terminator applications, the average power dissipation is very

small and this minimum geometry heat sink is suitable. The

total dissipation does not approact the 400mW to 625mW

range described above.

For MIC5204BS (SOT-223 package) heat sink characteris-

tics, please refer to Micrel Application Hint 17, “P.C. Board

Heat Sinking”. As with the SO-8, average power dissipation

in SCSI terminator applications is low and a minimum pad size

is generally adequate.

Part I. Layout

The MIC5204BM (8-pin surface mount package) has the

following thermal characteristics when mounted on a single

layer copper-clad printed circuit board.

245 mil

30 mil 50 mil

50 mil

150 mil

Minimum recommended board pad size, SO-8.

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February 1999 5 MIC5204

Package Information

45°

0°–8°

0.244 (6.20)

0.228 (5.79)

0.197 (5.0)

0.189 (4.8) SEATING

PLANE

0.026 (0.65)

MAX)

0.010 (0.25)

0.007 (0.18)

0.064 (1.63)

0.045 (1.14)

0.0098 (0.249)

0.0040 (0.102)

0.020 (0.51)

0.013 (0.33)

0.157 (3.99)

0.150 (3.81)

0.050 (1.27)

TYP

PIN 1

DIMENSIONS:

INCHES (MM)

0.050 (1.27)

0.016 (0.40)

8-Pin SOP (M)

16°

10°

0.84 (0.033)

0.64 (0.025)

1.04 (0.041)

0.85 (0.033)

2.41 (0.095)

2.21 (0.087)

4.7 (0.185)

4.5 (0.177)

6.70 (0.264)

6.30 (0.248)

7.49 (0.295)

6.71 (0.264)

3.71 (0.146)

3.30 (0.130)

3.15 (0.124)

2.90 (0.114)

10°

MAX

0.10 (0.004)

0.02 (0.0008) 0.038 (0.015)

0.25 (0.010)

DIMENSIONS:

MM (INCH)

1.70 (0.067)

1.52 (0.060)

0.91 (0.036) MIN

SOT-223 (S)

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MIC5204 Micrel

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MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com

This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or

other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.