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MIC29201-3.3WU中文资料

400mA Low-Dropout Voltage Regulator

Features

? High output voltage accuracy ? Guaranteed 400mA output ? Low quiescent current ? Low dropout voltage

? Extremely tight load and line regulation ? Very low temperature coef?cient ? Current and thermal limiting

? Input withstands –20V reverse battery and 60V positive transients ? Error ?ag warns of output dropout ? Logic-controlled electronic shutdown

? Output programmable from 1.24V to 26V (MIC29202/MIC29204)

Available in TO-220-3, TO-220-5, and surface-mount TO-263-5, SOT-223, and SO-8 packages.Applications

? Battery-powered equipment ? Cellular telephones

? Laptop, notebook, and palmtop computers ? PCMCIA V CC and V PP regulation/switching ? Bar code scanners ? Automotive electronics ? SMPS post-regulators ? Voltage reference

High-ef?ciency linear power supplies

General Description

The MIC2920A family are “bulletproof,” ef?cient voltage regu-lators with very low dropout voltage (typically 40mV at light loads and 370mV at 250mA), and very low quiescent current (140μA typical). The quiescent current of the MIC2920A in-creases only slightly in dropout, prolonging battery life. Key MIC2920A features include protection against reversed bat-tery, fold-back current limiting, and automotive “load dump” protection (60V positive transient).

The MIC2920 is available in several con?gurations. The MIC2920A-x.x devices are three pin ?xed voltage regulators available in 3.3V, 4.85V, 5V, and 12V outputs. The MIC29201 is a ?xed regulator offering a logic compatible ON/OFF (shut-down) input and an error ?ag output. This ?ag may also be used as a power-on reset signal. A logic-compatible shutdown input is provided on the adjustable MIC29202 which allows the regulator to be switched on and off. The MIC29204 8-pin SOIC adjustable regulator includes both shutdown and error ?ag pins and may be pin-strapped for 5V output or programmed from 1.24V to 26V using two external resistors.

MIC2920A-xxBT

(TO-220)

MIC29201/29202BT

(TO-220-5)

MIC29201/29202BU

(TO-263-5)

5-Lead Package Pinouts MIC29201 MIC292021) Error Adjust 2) Input Shutdown 3) Ground Ground 4) Output Input 5) Shutdown Output

Tab is Ground on SOT-223, TO-220, and TO-263 packages. INPUT

OUTPUT

GROUND

MIC2920A-x.xBS

(SOT-223)

Pin Con?guration

INPUT NC NC E R R O R

OUTPUT S E N S E SHUTDOWN GROUND MIC29201-3.3BM (SOIC-8)

INPUT ADJUST 5V TAP E R R O R

OUTPUT S E N S E SHUTDOWN GROUND MIC29204BM (SOIC-8)

Micrel, Inc. ? 2180 Fortune Drive ? San Jose, CA 95131 ? USA ? tel + 1 (408) 944-0800 ? fax + 1 (408) 474-1000 ? https://www.wendangku.net/doc/b315681291.html,

43213OUT 2

GND 1IN

4321

Ordering Information

Part Number Voltage Junction Temp. Range Package Standard Pb-Free

MIC2920A-3.3BS MIC2920A-3.3WS* 3.3V-40°C to +125°C SOT-223 MIC2920A-3.3BT MIC2920A-3.3WT* 3.3V-40°C to +125°C TO-220-3 MIC2920A-4.8BS MIC2920A-4.8WS* 4.85V-40°C to +125°C SOT-223 MIC2920A-4.8BT MIC2920A-4.8WT* 4.85V-40°C to +125°C TO-220-3 MIC2920A-5.0BS MIC2920A-5.0WS* 5.0V-40°C to +125°C SOT-223 MIC2920A-5.0BT MIC2920A-5.0WT* 5.0V-40°C to +125°C TO-220-3 MIC2920A-12BS MIC2920A-12WS*12V-40°C to +125°C SOT-223 MIC2920A-12BT MIC2920A-12WT*12V-40°C to +125°C TO-220-3 MIC29201-3.3BM MIC29201-3.3YM 3.3V-40°C to +125°C SO-8 MIC29201-3.3BT MIC29201-3.3WT* 3.3V-40°C to +125°C TO-220-5 MIC29201-3.3BU MIC29201-3.3WU* 3.3V-40°C to +125°C TO-263-5 MIC29201-4.8BT MIC29201-4.8WT* 4.85V-40°C to +125°C TO-220-5 MIC29201-4.8BU MIC29201-4.8WU* 4.85V-40°C to +125°C TO-263-5 MIC29201-5.0BT MIC29201-5.0WT* 5.0V-40°C to +125°C TO-220-5 MIC29201-5.0BU MIC29201-5.0WU* 5.0V-40°C to +125°C TO-263-5 MIC29201-12BT MIC29201-12WT*12V-40°C to +125°C TO-220-5 MIC29201-12BU MIC29201-12WU*12V-40°C to +125°C TO-263-5 MIC29202BT MIC29202WT*Adj-40°C to +125°C TO-220-5 MIC29202BU MIC29202WU*Adj-40°C to +125°C TO-263-5 MIC29204BM MIC29204YM5V and Adj-40°C to +125°C SO-8 MIC29204BN MIC29204YN5V and Adj-40°C to +125°C8-pin PDIP * Pb-Free RoHS compliant with high-melting solder exemption.

Absolute Maximum Ratings

Input Supply Voltage .................................................–20V to +60V Adjust Input Voltage (Notes 9 and 10) ......................–1.5V to +26V Power Dissipation ...................................Internally Limited, Note 1Operating Junction Temperature Range .............–40°C to +125°C Lead Temperature (Soldering, 5 seconds) ............................260°C Storage Temperature Range ...............................–65°C to +150°C

If Military/Aerospace speci?ed devices are required, contact your local Micrel representative/distributor for availability and speci?cations.

Operating Ratings

Operating Input Supply Voltage ......................................2V ? to 26V Adjust Input Voltage (Notes 9 and 10) ......................–1.5V to +26V Shutdown Input Voltage ..........................................–0.3V to +30V Error Comparator Output Voltage .............–0.3V to +30VOperating Junction Temperature Range .............................–40°C to +125°C Thermal Characteristics:

SOT?223 θJC ..............................................................15°C/W TO-220 θJC ...................................................................3°C/W TO-263 θJC ...................................................................3°C/W 8-Pin SOIC θJA .............................................................Note 1

Across the full operating temperature, the minimum input voltage range for full output current is 4.3V to 26V. Output will remain in-regulation at lower output voltages and low current loads down to an input of 2V at 25°C.

Electrical Characteristics

Limits in standard typeface are for T J = 25°C and limits in boldface apply over the full operating temperature range. Unless otherwise speci?ed, V IN = V OUT + 1V, I L = 1mA, C L = 10μF. Adjustable versions are set for an ouptu of 5V. The MIC29202 V SHUTDOWN ≤ 0.7V. The eight pin MIC29204 is con?gured with the Adjust pin tied to the 5V Tap, the Output is tied to Output Sense (V OUT = 5V), and V SHUTDOWN ≤ 0.7V.Symbol Parameter Conditions

Min Typ

Max Units V O

Output Voltage Accuracy

Variation from factory trimmed V OUT -1 -2 1 2%

1mA ≤ I L ≤ 400mA, across temp. range -2.5 2.5MIC2920A-12 and 29201-12 only -1.5 -3 1.5 31mA ≤ I L ≤ 400mA, across temp. range

-4

4?V O ?T Output Voltage Temperature Coef.(Note 2)20100ppm/°C V OUT > 10V only 80350?V O V O Line Regulation V IN = V OUT + 1V to 26V 0.030.10 0.40%?V O V O Load Regulation IL = 1 to 250mA (Note 3)0.040.16 0.30%V IN - V O

Dropout Voltage (Note 4)

I L = 1mA

I L = 100mA

V OUT > 10V only I L = 250mA

V OUT > 10V only I L = 400mA 100 250 350 370 500 400150 180 600 750mV I GND

Ground Pin Current (Note 5)

I L = 1mA

I L = 100mA

I L = 250mA

I L = 400mA

140 1.3 5 13200 300 2 2.5 9 12 15μA mA

I GNDDO

Ground Pin Current at Dropout (Note 5)V IN = 0.5V less than designed V OUT (V OUT = 3.3V) I O = 1mA 180400

μA

I LIMIT Current Limit V OUT = 0V (Note 6)425100 1200mA ?V O ?P D Thermal Regulation (Note 7)0.050.2

%/W e n

Output Noise Voltage (10Hz to 100kHz) IL = 100mA

CL = 10μF CL = 100μF

400 260

μV RMS

Parameter Conditions Min Typ Max Units MIC29202, MIC29204

Reference Voltage MIC29202 1.223

1.2101.235 1.247

1.260

Reference Voltage MIC29202 (Note 8) 1.204 1.266V

Reference Voltage MIC29204 1.210

1.2001.235 1.260

1.270

Reference Voltage MIC29204 (Note 8) 1.185 1.285V

Adjust Pin Bia Current 2040

Reference Voltage

Temperature

Coef?cient

(Note 7)20ppm/°C

Adjust Pin Bias

Current Temperature

Coef?cient

0.1nA/°C Error Comparator MIC29201, MIC29204

Output Leakage Current V

= 26V0.01 1.00

2.00

μA

Output Low Voltage V

= 4.5V

= 250μA

150250

400

Upper Threshold Voltage (Note 9)40

60mV

Lower Threshold Voltage (Note 9)7595

140

Hysteresis(Note 9)15mV Shutdown Input MIC29201, MIC29202, MIC29204

Input Logic Voltage

Low (ON)

High (OFF) 2.01.3

0.7

Shutdown Pin Input Current V

SHUTDOWN

= 2.4V3050

100

μA

SHUTDOWN

= 26V450600

750

μA

Regulator Output Current in Shutdown (Note 10)310

μA

Notes: General: Devices are ESD protected; however, handling precautions are recommended.

Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical speci?cations do not apply when operating the device outside of its rated operating conditions. The maximum allowable power dissipation is a function of the maximum junction temperature, T J (MAX), the junction-to-ambient thermal resistance, θJA , and the ambient temperature, T A . The maximum allowable power dissipation at any ambient temperature is calculated using: P (MAX) = (T J(MAX) – T A ) / θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The junction to ambient thermal

resistance of the MIC29204BM is 160°C/W mounted on a PC board.

Note 2: Output voltage temperature coef?cient is de?ned as the worst case voltage change divided by the total temperature range.

Note 3: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Changes in output voltage due to heating effects

are covered by the thermal regulation speci?cation.

Note 4: Dropout Voltage is de?ned as the input to output differential at which the output voltage drops 100mV below its nominal value measured at 1V differential. At low values of programmed output voltage, the minimum input supply voltage of 4.3V over temperature must be taken into

account. The MIC2920A operates down to 2V of input at reduced output current at 25°C.

Note 5: Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground

pin current.

Note 6: The MIC2920A features fold-back current limiting. The short circuit (V OUT = 0V) current limit is less than the maximum current with normal

output voltage.

Note 7: Thermal regulation is de?ned as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or

line regulation effects. Speci?cations are for a 200mA load pulse at V IN = 20V (a 4W pulse) for T = 10ms.Note 8: V REF ≤ V OUT ≤ (V IN – 1 V), 4.3V ≤ V IN ≤ 26V, 1 mA < I L ≤400 mA, T J ≤ T J MAX.

Note 9: Comparator thresholds are expressed in terms of a voltage differential at the Adjust terminal below the nominal reference voltage measured at 6V input. To express these thresholds in terms of output voltage change, multiply by the error ampli?er gain = V OUT /V REF = (R1 + R2)/R2. For example, at a programmed output voltage of 5V, the Error output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 V = 384 mV. Thresholds remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at typically 5% below

nominal, 7.7% guaranteed.

Note 10: V SHUTDOWN ≥ 2V, V IN ≤ 26V,V OUT = 0, with Adjust pin tied to 5V Tap or to the R1, R2 junction (see Figure 3) with R1 ≥ 150kΩ.

Note 11: When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode clamped to

ground.

Note 12: Maximum positive supply voltage of 60V must be of limited duration (< 100ms) and duty cycle ( ≤ 1%). The maximum continuous supply

voltage is 26V.

Schematic Diagram

Typical Characteristics

or some other supply voltage. In determining a value for this resistor, note that while the output is rated to sink 250μA, this sink current adds to battery drain in a low battery condition. Suggested values range from 100k to 1MΩ. The resistor is not required if this output is unused.

Programming the Output Voltage (MIC29202/29204)

The MIC29202/29204 may be programmed for any output voltage between its 1.235V reference and its 26V maxi-mum rating, using an external pair of resistors, as shown in Figure 3.

The complete equation for the output voltage is V OUT = V REF × { 1 + R 1/R 2 } – |I FB | R 1

where V REF is the nominal 1.235 reference voltage and I FB is the A djust pin bias current, nominally 20nA. The minimum rec-ommended load current of 1μA forces an upper limit of 1.2MΩ on the value of R 2, if the regulator must work with no load (a condition often found in CMOS in standby), I FB will produce a –2% typical error in V OUT which may be eliminated at room temperature by trimming R 1. For better accuracy, choosing R 2 = 100k reduces this error to 0.17% while increasing the resistor program current to 12μA. Since the MIC29202/29204 typically draws 110μA at no load with SHUTDOWN open-circuited, this is a negligible addition. The MIC29204 may be pin-strapped for 5V using the internal voltage divider by tying Pin 1 (output) to Pin 2 (sense) and Pin 7 (Adjust) to Pin 6 (V Tap).

Con?guring the MIC29201-3.3BM

For the MIC29201-3.3BM, the output (Pin 1) and sense pin (pin 2), must be connected to ensure proper operation. They are not connected internally.

Reducing Output Noise

In reference applications it may be advantageous to reduce the AC noise present at the output. One method is to reduce the regulator bandwidth by increasing the size of the output capacitor. This is relatively inef?cient, as increasing the capaci- Figure 1. ERROR Output Timing

* SEE APPLICATIONS INFORMATION

Applications Information

External Capacitors

A 10μF (or greater) capacitor is required between the MIC2920A output and ground to prevent oscillations due to instability. Most types of tantalum or aluminum electrolytics will be adequate; ?lm types will work, but are costly and therefore not recom-mended. 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.

At lower values of output current, less output capacitance is required for output stability. The capacitor can be reduced to 2.2μF for current below 10mA or 1μF for currents below 1mA. Adjusting the MIC29202/29204 to voltages below 5V runs the error ampli?er at lower gains so that more output ca-pacitance is needed. For the worst-case situation of a 500mA load at 1.23V output (Output shorted to Adjust) a 47μF (or greater) capacitor should be used.

The MIC2920A/29201 will remain in regulation with a mini-mum load of 1mA. When setting the output voltage of the MIC29202/29204 versions with external resistors, the current through these resistors may be included as a portion of the minimum load.

A 0.1μF capacitor should be placed from the MIC2920A input to ground if there is more than 10 inches of wire between the input and the AC ?lter capacitor or if a battery is used as the input.

Error Detection Comparator Output (MIC29201/MIC29204)

A logic low output will be produced by the comparator when-ever the MIC29201/29204 output falls out of regulation by more than approximately 5%. This ?gure is the comparator’s built-in offset of about 75mV divided by the 1.235V reference voltage. (Refer to the block diagram on Page 1). This trip level remains “5% below normal” regardless of the programmed output voltage of the MIC29201/29204. For example, the error ?ag trip level is typically 4.75V for a 5V output or 11.4V for a 12V output. The out of regulation condition may be due either to low input voltage, extremely high input voltage, cur-rent limiting, or thermal limiting.

Figure 1 is a timing diagram depicting the ERROR signal and the regulated output voltage as the MIC29201/29204 input is ramped up and down. The ERROR signal becomes valid (low) at about 1.3V input. It goes high at about 5V input (the input voltage at which V OUT = 4.75). Since the MIC29201/29204’s dropout voltage is load-dependent (see curve in Typical Per-formance Characteristics), the input voltage trip point (about 5V) will vary with the load current. The output voltage trip point (approximately 4.75V) does not vary with load.

The error comparator has an NPN open-collector output which requires an external pull-up resistor. Depending on system requirements, this resistor may be returned to the 5V output

4.75V

E R R O R

OUTPUT VOLTAGE

INPUT 5V 1.3V

VOLTAGE

NOT *VALID NOT *VALID

OUT

Automotive Applications

The MIC2920A is ideally suited for automotive applications for a variety of reasons. It will operate over a wide range of input voltages with very low dropout voltages (40mV at light loads), and very low quiescent currents (100μA typical). These features are necessary for use in battery powered systems, such as automobiles. It is a “bulletproof” device with the abil-ity to survive both reverse battery (negative transients up to 20V below ground), and load dump (positive transients up to 60V) conditions. A wide operating temperature range with low temperature coef?cients is yet another reason to use these versatile regulators in automotive designs.

tor from 1μF to 220μF only decreases the noise from 430μV to 160μV RMS for a 100kHz bandwidth at 5V output. Noise can be reduced fourfold by a bypass capacitor across R 1, since it reduces the high frequency gain from 4 to unity. Pick

or about 0.01μF. When doing this, the output capacitor must be increased to 10μF to maintain stability. These changes re-duce the output noise from 430μV to 100μV rms for a 100kHz bandwidth at 5V output. With the bypass capacitor added, noise no longer scales with output voltage so that improve-ments are more dramatic at higher output voltages.

NOTE: PINS 2 AND 6 ARE LEFT OPEN

OUT

1.226V

Figure 2. MIC2920A-5.0 Fixed +5V Regulator

Figure 3. MIC29202/29204 Adjustable Regulator. Pinout is for

MIC29204.

Typical Applications

Figure 5. MIC29202/29204 5.0V or 3.3V Selectable Regulator with Shutdown. Pinout is for MIC29204.

Figure 4. MIC29204 Wide Input Voltage Range Current Limiter

PIN 3 LOW= ENABLE OUTPUT. Q1 ON = 3.3V, Q1 OFF = 5.0V.

C BYPASS

2πR1 ? 200 Hz

=* Minimum Input-Output Voltage ranges from 40mV to 400mV, depending on load current

Package Information

8-Pin SOIC (M)

0.91 (0.036) MI N

SOT-223 (S)

3-Lead TO-220 (T)

5-Lead TO-220 (T)

5-Lead TO-263 (U)

MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB https://www.wendangku.net/doc/b315681291.html,

This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use.

Micrel reserves the right to change circuitry and speci?cations at any time without noti?cation to the customer.

Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a signi?cant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify

Micrel for any damages resulting from such use or sale.

? 1998 Micrel Incorporated