View MIIC5271_339013.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

MIC5271
Micrel
MIC5271
Cap Negative Low-Dropout Regulator
General Description
The MIC5271 is a Cap 100mA negative regulator in a SOT-23-5 package. With better than 2% initial accuracy, this regulator provides a very accurate supply voltage for applications that require a negative rail. The MIC5271 sinks 100mA of output current at very low dropout voltage (600mV maximum at 100mA of output current). The Cap regulator design is optimized to work with lowvalue, low-cost ceramic capacitors. The output typically requires only a 1F capacitance for stability. Designed for applications where small packaging and efficiency are critical, the MIC5271 combines LDO design expertise with IttyBitty packaging to improve performance and reduce power dissipation. Ground current is optimized to help improve battery life in portable applications. The MIC5271 also includes a TTL-compatible enable pin, allowing the user to put the part into a zero-current off-mode. The MIC5271 is available in the SOT-23-5 package for space saving applications and it is available with an adjustable output. Data sheets and support documentation can be found on Micrel's web site at www.micrel.com.
Features
* * * * * * * * * * Stable with ceramic or tantalum capacitor Positive and negative enable thresholds Low dropout voltage: 500mV @ 100mA Low ground current: 35A @ load = 100A Tight initial accuracy: 2% Tight load and line regulation Thermal shutdown Current limiting IttyBitty SOT-23-5 packaging Zero-current off-mode
Applications
* * * * * GaAsFET bias Portable cameras and video recorders PDAs Battery-powered equipment Post-regulation of DC-DC converters
Ordering Information
Part Number MIC5271BM5 MIC5271-3.0BM5 MIC5271-5.0BM5 Marking L9AA L930 L950 Voltage* Adj. -3.0V -5.0V Junction Temp. Range -40C to +125C -40C to +125C -40C to +125C Package SOT-23-5 SOT-23-5 SOT-23-5
* For other voltage options, please contact Micrel Marketing.
Typical Application
Enable Input
5 4
ENABLE VOLTAGE (V)
MIC5271BM5
2 1
R1 R2
3 2 1 0 -1 -2 -3 -4 -5 -3
Regulator On
GND ADJ EN -IN -OUT
3
Regulator Off
VIN -6.0V
5
4
VOUT -5.0V
Regulator On
1F
10F
-5 -7 -9 -11 -13 -15 SUPPLY VOLTAGE (V)
Regulator With Adjustable Output
IttyBitty is a registered trademark of Micrel, Inc. Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
October 2003
1
MIC5271
MIC5271
Micrel
Pin Configuration
ADJ GND EN
3 2 1
L9AA
4 5
-OUT
-IN
MIC5271BM5 Adjustable Output Voltage
Pin Description
Pin Number (Adj.) 1 2 3 4 5 Pin Name EN GND ADJ -OUT -IN Pin Function Enable Input. TTL logic compatible enable input. Logic High = ON, Logic Low or open = OFF. Ground. Adjustable (Input): Adjustable feedback output connects to resistor voltage divider. Negative Regulator Output. Negative Supply Input.
MIC5271
2
October 2003
MIC5271
Micrel
Absolute Maximum Ratings (Note 1)
Input Voltage (V-IN) ...................................... -20V to +0.3V Enable Voltage (VEN) .................................... -20V to +20V Power Dissipation (PD) ............................ Internally Limited Junction Temperature (TJ) ....................... -40C to +125C Lead Temperature (soldering, 5 sec.) ....................... 260C Storage Temperature (TS) ....................... -65C to +150C ESD Rating, Note 3
Operating Ratings (Note 2)
Input Voltage (VIN) ....................................... -16V to -3.3V Enable Voltage (VEN) .................................... -16V to +16V Junction Temperature (TJ) ....................... -40C to +125C Thermal Resistance (JA) Note 4 ......................... 235C/W
Electrical Characteristics (Note 5)
VIN = VOUT - 1.0V; COUT = 4.7F, IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Symbol VOUT VOUT/T VOUT/VOUT VOUT/VOUT VIN - VOUT Parameter Output Voltage Accuracy Output Voltage Temperature Coefficient Line Regulation Load Regulation Dropout Voltage, Note 8 Condition Variation from nominal VOUT Note 6 VIN = VOUT - 1V to -16V IOUT = 100A to 100mA, Note 7 IOUT = 100A IOUT = 50mA IOUT = 100mA IGND Ground Current, Note 9 IOUT = 100A IOUT = 50mA IOUT = 100mA IGND_SD PSRR ILIMIT Enable Input TON VEN IEN
Note 1. Note 2. Note 3. Note 4.
Min -2 -3
Typ
Max 2 3
Units % % ppm/C
100 0.04 0.4 55 360 500 25 0.9 2.0 -1.0 0.1 50 235 350 3.0 +1.0 500 700 900 100 0.15 0.2 1.8 2.0
%/V % % mV mV mV A mA mA A dB mA
Ground current in shutdown Ripple Rejection Current Limit
VEN = 0.6V f = 120Hz VOUT = 0V Time to VOUT = 90% nom. Regulator OFF Regulator ON VEN = 0.6V and -2.0V VEN = +2.0V
Turn-on Time Input Low voltage Input High Voltage Enable Input Current
60 0.6 2.0 5.6 0.1 10.0
s V V A
Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max), the junction-to-ambient thermal resistance, JA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD(max) = (TJ(max) - TA) / JA, where JA is 235C/W. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. See the "Thermal Considerations" section for details. Specification for packaged product only. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 100A to 100mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. 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. 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 5. Note 6. Note 7. Note 8. Note 9.
October 2003
3
MIC5271
MIC5271
Micrel
Typical Characteristics
Dropout Characteristics
OUTPUT VOLTAGE (V)
-3.5
OUTPUT VOLTAGE (V)
-3.305 -3.3 -3.295 -3.29 -3.285 -3.28 -3.275 -3.27 -3.265 -5 -3.26 0
Output Voltage vs. Output Current
OUTPUT VOLTAGE (V)
-3.4 -3.38 -3.36 -3.34 -3.32 -3.3 -3.28 -3.26 -3.24
Output Voltage vs. Temperature
-3 -2.5 -2 -1.5 -1 -0.5 0 0
0 Load
-100mA Load -1 -2 -3 -4 SUPPLY VOLTAGE (V)
-20 -40 -60 -80 -100 OUTPUT CURRENT (mA)
-3.22 -3.2 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
-2.5
Ground Current vs. Output Current
GROUND CURRENT (A)
-90 -80 -70 -60
Ground Current Characteristics
GROUND CURRENT (mA)
-1mA Load
-2.5
Ground Current Characteristics
GROUND CURRENT (mA)
-2 -1.5 -1 -0.5 5VIN 0 0 -20 -40 -60 -80 -100 OUTPUT CURRENT (mA)
-2 -100mA Load -1.5 -50mA Load -1 -0.5 0 0 -10mA Load
-50 -100A Load -40 -30 -20 -10 0 0 0A Load -1 -2 -3 -4 SUPPLY VOLTAGE (V) -5
-1 -2 -3 -4 SUPPLY VOLTAGE (V)
-5
-30
GROUND CURRENT (A)
Ground Current vs. Temperature
GROUND CURRENT (A)
-3.5 -3 -2.5 -2 -1.5 -1 -0.5
Ground Current vs. Temperature
ENABLE THRESHOLD (V)
1.6 1.4 1.2 1 0.8 0.6 0.4 0.2
Positive Enable Threshold vs. Supply Voltage
Enable On
-1mA Load -25 -20 -15 -10 -5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 0A Load
-100mA Load
Enable Off
-50A Load
0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
0 -4
-7 -10 -13 SUPPLY VOLTAGE (V)
-16
-1.6
Negative Enable Threshold vs. Supply Voltage
DROPOUT VOLTAGE (mV)
-600 -500 -400 -300 -200 -100 0 0
Dropout vs. Output Current
DROPOUT VOLTAGE (mV)
-400 -350 -300 -250 -200 -150 -100 -50
Dropout vs. Temperature
-10mA Load
ENABLE THRESHOLD (V)
-1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 -4
Enable On
Enable Off
0A Load
-7 -10 -13 SUPPLY VOLTAGE (V)
-16
-20 -40 -60 -80 -100 OUTPUT CURRENT (mA)
0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
MIC5271
4
October 2003
MIC5271
Micrel
Typical Characteristics (continued)
Dropout vs. Temperature
-100mA Load
-700
DROPOUT VOLTAGE (mV)
-600 -500 -400 -300 -200 -100
-50mA Load
0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
October 2003
5
MIC5271
MIC5271
Micrel
Functional Characteristics
Load Transient
Load Transient
VOUT (10mV/div.)
Output Current (50mA/div.)
-100mA
Output Current (50mA/div.)
-10mA
VOUT (10mV/div.)
COUT = 1F Ceramic VIN = 5V VOUT = 3V -10mA COUT = 1F Ceramic VIN = 5V VOUT = 3V
-100mA
TIME (2ms/div.)
TIME (2ms/div.)
Negative Enable Transient
0V
Positive Enable Transient
0V
VOUT (1V/div.)
Enable (1V/div.)
0V
Enable (1V/div.)
VOUT (1V/div.)
0V TIME (20ms/div.)
TIME (20ms/div.)
MIC5271
6
October 2003
MIC5271
Micrel
Functional Diagram
GND
ADJ
VEN VIN MIC5271-x.x
VOUT
October 2003
7
MIC5271
MIC5271
Micrel
Thermal Considerations
Applications Information
The MIC5271 is a general-purpose negative regulator that can be used in any system that requires a clean negative voltage from a negative output. This includes post regulating of DC-DC converters (transformer based or charge pump based voltage converters). These negative voltages typically require a negative low dropout voltage regulator to provide a clean output from typically noisy lines. Input Capacitor A 1F input capacitor should be placed from IN to GND if there is more than 2 inches of wire or trace between the input and the AC filter capacitor, or if a battery is used as the input. Output Capacitor The MIC5271 requires an output capacitor for stable operation. A minimum of 1F of output capacitance is required. The output capacitor can be increased without limitation to improve transient response. The output does not require ESR to maintain stability, therefore a ceramic capacitor can be used. High-ESR capacitors may cause instability. Capacitors with an ESR of 3 or greater at 100kHz may cause a high frequency oscillation. Low-ESR tantalums are recommended due to the tight capacitance tolerance over temperature. Ceramic chip capacitors have a much greater dependence on temperature, depending upon the dielectric. The X7R is recommended for ceramic capacitors because the dielectric will change capacitance value by approximately 15% over temperature. The Z5U dielectric can change capacitance value by as much 50% over temperature, and the Y5V dielectric can change capacitance value by as much as 60% over temperature. To use a ceramic chip capacitor with the Y5V dielectric, the value must be much higher than a tantalum to ensure the same minimum capacitor value over temperature. No-Load Stability The MIC5271 does not require a load for stability. Enable Input The MIC5271 comes with an enable pin that allows the regulator to be disabled. Forcing the enable pin higher than the negative threshold and lower than the positive threshold disables the regulator and sends it into a "zero" off-mode current state. In this state, current consumed by the regulator goes nearly to zero. The MIC5271 will be in the on mode when the voltage applied to the enable pin is either greater than the positive threshold or less than the negative threshold.
Enable Input
5 4
Absolute values will be used for thermal calculations to clarify the meaning of power dissipation and voltage drops across the part.
Proper thermal design for the MIC5271-5.0BM5 can be accomplished with some basic design criteria and some simple equations. The following information must be known to implement your regulator design: VIN = input voltage VOUT = output voltage IOUT = output current TA = ambient operating temperature IGND = ground current Maximum power dissipation can be determined by knowing the ambient temperature, TA, the maximum junction temperature, 125C, and the thermal resistance, junction to ambient. The thermal resistance for this part, assuming a minimum footprint board layout, is 235C/W. The maximum power dissipation at an ambient temperature of 25C can be determined with the following equation:
PD(max) = TJ(max) - TA JA
PD(max) =
125C - 25C 235C/W
PD(max) = 425mW The actual power dissipation of the regulator circuit can be determined using one simple equation. PD = (VIN - VOUT)IOUT + VIN x IGND Substituting PD(max), determined above, for PD and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. The maximum power dissipation number cannot be exceeded for proper operation of the device. The maximum input voltage can be determined using the output voltage of 5.0V and an output current of 100mA. Ground current, of 1mA for 100mA of output current, can be taken from the "Electrical Characteristics " section of the data sheet.
( ) 425mW = (100mA x VIN + 1mA x VIN ) - 500mW
425mW = VIN - 5.0V 100mA + VIN x 1mA
925mW = 101mA x VIN
VIN = 9.16Vmax
Regulator On
ENABLE VOLTAGE (V)
3 2 1 0 -1 -2 -3 -4 -5 -3
Regulator Off
Regulator On
Therefore, a -5.0V application at 100mA of output current can accept a maximum input voltage of -9.16V in a SOT-23-5 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to Regulator Thermals section of Micrel's "Designing with Low Dropout Voltage Regulators" handbook.
-5 -7 -9 -11 -13 -15 SUPPLY VOLTAGE (V)
MIC5271
8
October 2003
MIC5271
Adjustable Regulator Application
MIC5271BM5 -VIN
5
Micrel
-IN -EN
-OUT
4
R2
2
-VOUT
GND ADJ
3
R1
Figure 1. Adjustable Voltage Application The MIC5271BM5 can be adjusted from 1.20V to 14V by using two external resistors (Figure 1). The resistors set the output voltage based on the following equation: R2 ) R1 Where VREF = 1.20V VOUT = VREF (1 +
October 2003
9
MIC5271
MIC5271
Micrel
Package Information
1.90 (0.075) REF 0.95 (0.037) REF
1.75 (0.069) 1.50 (0.059)
3.00 (0.118) 2.60 (0.102)
DIMENSIONS: MM (INCH) 3.02 (0.119) 2.80 (0.110) 1.30 (0.051) 0.90 (0.035) 10 0 0.15 (0.006) 0.00 (0.000) 0.20 (0.008) 0.09 (0.004)
0.50 (0.020) 0.35 (0.014)
0.60 (0.024) 0.10 (0.004)
SOT-23-5 (M5)
MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
USA
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
http://www.micrel.com
The information furnished by Micrel in this datasheet 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 specifications at any time without notification 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 significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2003 Micrel, Incorporated.
MIC5271
10
October 2003

▲Up To Search▲

Price & Availability of MIIC5271

	To Download MIIC5271 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .