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MIC5253
Micrel
MIC5253
100mA Low Noise Cap TeenyTM LDO
General Description
The MIC5253 is an efficient, CMOS voltage regulator optimized for ultra-low-noise applications. It offers 1.5% initial accuracy, extremely low dropout voltage (165mV at 100mA), and low ground current (typically 95A at full load). The MIC5253 provides a very low noise output, ideal for RF applications where a clean voltage source is required. A noise bypass pin is also available for further reduction of output noise. Designed specifically for handheld and battery-powered devices, the MIC5253 provides a TTL-logic-compatible enable pin. When disabled, power consumption drops nearly to zero. The MIC5253 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. Available in the TeenyTM SC-70-5 package, the MIC5253 offers a wide range of output voltages. Key features include current limit, thermal shutdown, faster transient response, and an active clamp to speed up device turn-off.
Features
* * * * * * * Input voltage range: 2.7V to 5.5V TeenyTM SC-70-5 package Ultra-low output noise: 30V(rms) 100mA continuous output current, 150mA peak current Stability with ceramic output capacitors Ultralow dropout: 165mV @ 100mA High output accuracy: 1.5% initial accuracy 3.0% over temperature Low ground current: 95A TTL-Logic-controlled enable input "Zero" off-mode current Thermal shutdown and current limit protection
* * * *
Applications
* * * * * Cellular phones and pagers Cellular accessories Battery-powered equipment Laptop, notebook, and palmtop computers Consumer/personal electronics
Ordering Information
Part Number MIC5253-1.8BC5 MIC5253-1.85BC5 MIC5253-2.6BC5 MIC5253-2.9BC5 MIC5253-3.0BC5 MIC5253-3.3BC5 Marking LCN L71J LCP L729 LCG L733 Voltage 1.8V 1.85V 2.6V 2.9V 3.0V 3.3V Junction Temp. Range* -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package SC-70-5 SC-70-5 SC-70-5 SC-70-5 SC-70-5 SC-70-5
Other voltages available. Contact Micrel for details.
Typical Application
CIN = 1.0F Ceramic
Enable Shutdown
VIN
MIC5253-x.xBC5
1 2 3 4 5
VOUT COUT = 1.0F Ceramic CBYP = 0.01F
EN
EN (pin 3) may be connected directly to IN (pin 1).
Ultra-Low-Noise Regulator Application
Teeny is a trademark of Micrel, Inc. Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
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Pin Configuration
EN GND IN
3 2 1
LCxx
4 5
BYP
OUT
SC-70-5 (C5)
Pin Description
Pin Number 1 2 3 4 5 Pin Name IN GND EN BYP OUT Pin Function Supply Input. Ground. Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not leave open. Reference Bypass: Connect external 0.01F CBYP 1.0F capacitor to GND to reduce output noise. May be left open. Regulator Output.
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Absolute Maximum Ratings(1)
Supply Input Voltage (VIN) .................................. 0V to +7V Enable Input Voltage (VEN) ................................. 0V to +7V Power Dissipation (PD) ........................ Internally Limited(3) Junction Temperature (TJ) ....................... -40C to +125C Storage Temperature ............................... -65C to +150C Lead Temperature (soldering, 5 sec.) ....................... 260C ESD Rating(4) ................................................................................ 2kV
Operating Ratings(2)
Input Voltage (VIN) ...................................... +2.7V to +5.5V Enable Input Voltage (VEN) .................................. 0V to VIN Junction Temperature (TJ) ....................... -40C to +125C Thermal Resistance SC-70-5 (JA) .................................................... 400C/W
Electrical Characteristics(5)
VIN = VOUT + 1V, VEN = VIN; IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless otherwise noted. Symbol VO VLNR VLDR VIN - VOUT IQ IGND PSRR Parameter Output Voltage Accuracy Line Regulation Load Regulation Dropout Voltage(7) Conditions IOUT = 100A VIN = VOUT + 1V to 6V IOUT = 0.1mA to 100mA, Note 6 IOUT = 50mA IOUT = 100mA Quiescent Current Ground Pin Current(8) VEN 0.4V (shutdown) IOUT = 0mA IOUT = 100mA Ripple Rejection f = 100Hz, COUT = 1.0F, CBYP = 0.1F f = 1kHz, VIN = VOUT +1, CBYP = 0.1F f = 10kHz, VIN = VOUT +1, CBYP = 0.1F tON ILIM en Enable Input VIL VIH IEN Enable Input Logic-Low Voltage Enable Input Logic-High Voltage Enable Input Current VIN = 2.7V to 5.5V, regulator shutdown VIN = 2.7V to 5.5V, regulator enabled VIL 0.4V, regulator shutdown VIH 1.6V, regulator enabled Thermal Protection Thermal Shutdown Temperature Thermal Shutdown Hysteresis
Notes: 1. Exceeding the absolute maximum ratings may damage the device. 2. The device is not guaranteed to function outside its operating ratings. 3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max)-TA)/JA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The JA of the MIC5253-x.xBC5 (all versions) is 400C/W on a PC board (see "Thermal Considerations" section for further details). 4. Devices are ESD sensitive. Handling precautions recommended. 5. Specification for packaged product only. 6. 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. 7. 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. For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum input operating voltage is 2.7V. 8. 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.
Min -1.5 -3
Typical
Max 1.5 3
Units % % %/V % mV mV A A A dB dB dB s mA V(rms)
0.035 1.5 80 165 0.2 75 90 66 70 65 30
0.05 2.5 150 300 1 100 150
Turn-On Time Current Limit Output Voltage Noise VOUT = 0V COUT = 1.0F, CBYP = 0.01F, f = 10Hz to 100kHz 150
150 450
250 30
0.4 1.6 0.01 0.01
V V A A C C
150 10
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Typical Characteristics
Power Supply Rejection Ratio
80 70 60
PSRR (dB)
Power Supply Rejection Ratio
80
GROUND CURRENT (A)
Ground Pin Current
88 87 86 85 84 83 82 81 0 VOUT =1.8V VIN = VOUT + 1V 25 50 75 100 125 150 OUTPUT CURRENT (mA)
70 60
PSRR (dB)
50 40 30 20
100A 1mA 10mA
50 100A 1mA 30 10mA 100mA 20 V = 1.8V COUT = 1F 10 OUT CBYP = 0.01F VIN = 2.8V 0 10k 100k 1k 100 FREQUENCY (Hz) 40
100mA VOUT = 1.8V COUT = 1F 10 V = 2.8V CBYP = 0.1F IN 0 1k 10k 100k 100 FREQUENCY (Hz)
1M
1M
Ground Pin Current
90 88 86 84 82 80 78 76 74 72 I = 100mA LOAD 70 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 84
GROUND CURRENT (A)
Ground Pin Current
80
Ground Pin Current
GROUND CURRENT (A)
70 60 50 40 30 20 10 0 0 ILOAD = 100A 1 2 3 4 INPUT VOLTAGE (V) 5
GROUND CURRENT (A)
82 80 78 76 74 72 I = 100A LOAD 70 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
Ground Pin Current
90
GROUND CURRENT (A)
Dropout Characteristics
2
Dropout Voltage
250
DROPOUT VOLTAGE (mV)
OUTPUT VOLTAGE (mV)
80 70 60 50 40 30 20 10 0 0 I
LOAD
1.8 1.6
= 100mA 5
1 2 3 4 INPUT VOLTAGE (V)
ILOAD = 100mA 1.4 ILOAD = 100A 1.2 1 0.8 0.6 0.4 0.2 VOUT = 1.85V 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V)
200 150 100 50 VIN = 3.6V VOUT = 2.6V ILOAD = 100mA
0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
Dropout Voltage
SHORT CIRCUIT CURRENT (mA)
350
DROPOUT VOLTAGE (mV)
Short Circuit Current
2.7
Output Voltage vs. Temperature
OUTPUT VOLTAGE (V)
290 270 250 230 210 190 170 150 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 INPUT VOLTAGE (V)
2.65
300 250 200 150 100 50 0 0 -40C 25C 125C VIN = 3.6V VOUT = 2.6V 25 50 75 100 125 150 OUTPUT CURRENT (mA)
2.6
2.55
2.5 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
ILOAD = 100A VOUT = 2.6V VIN = 3.6V
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Functional Characteristics
Line Transient Response
Output Voltage (20mV/div)
Load Transient Response
Input Voltage (1V/div)
5V 4V
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F IOUT = 100A
100mA
Output Current (50mA/div)
Output Voltage (50mV/div)
100A
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F VIN = 4V
TIME (500s/div)
TIME (5s/div)
Enable Pin Delay
Enable Voltage (1V/div)
Shutdown Delay
Enable Voltage (1V/div)
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F IOUT = 100A
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F VIN = 4V
Output Voltage (500mV/div)
TIME (5s/div)
Output Voltage (500mV/div)
TIME (500s/div)
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Block Diagram
IN Reference Voltage Startup/ Shutdown Control Quickstart/ Noise Cancellation BYP
EN
Thermal Sensor Undervoltage Lockout
FAULT
Error Amplifier
Current Amplifier
OUT
ACTIVE SHUTDOWN
GND
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No-Load Stability The MIC5253 will remain stable and in regulation with no load unlike many other voltage regulators. This is especially important in CMOS RAM keep-alive applications. Thermal Considerations The MIC5253 is designed to provide 100mA of continuous current in a very small package. Maximum ambient operating temperature can be calculated based on the output current and the voltage drop across the part. Given that the input voltage is 5.0V, the output voltage is 2.9V, and the output current = 100mA. The actual power dissipation of the regulator circuit can be determined using the equation: PD = (VIN - VOUT) IOUT + VIN IGND Because this device is CMOS and the ground current is typically <100A over the load range, the power dissipation contributed by the ground current is < 1% and can be ignored for this calculation. PD = (5.0V - 2.9V) x 100mA PD = 0.21W To determine the maximum ambient operating temperature of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation: T (max) - TA PD (max) = J JA TJ(max) = 125C, the max. junction temperture of the die JA thermal resistance = 400C/W Table 1 shows junction-to-ambient thermal resistance for the MIC5253 in the SC-70 package.
Package SC-70-5 (C5) JA Recommended Minimum Footprint 400C/W JA 1" Sq. Copper Clad 325C JC 250C/W
Applications Information
Enable/Shutdown The MIC5253 comes with an active-high enable pin that allows the regulator to be disabled. Forcing the enable pin low disables the regulator and sends it into a "zero" off-modecurrent state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. This part is CMOS and the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor The MIC5253 is a high performance, high bandwidth device. Therefore, it requires a well-bypassed input supply for optimal performance. A 1F capacitor is required from the input to ground to provide stability. Low-ESR ceramic capacitors provide optimal performance at a minimum of space. Additional high-frequency capacitors, such as small valued NPO dielectric type capacitors, help filter out high frequency noise and are good practice in any RF based circuit. Output Capacitor The MIC5253 requires an output capacitor for stability. The design requires 1F or greater on the output to maintain stability. The design is optimized for use with low-ESR ceramic chip capacitors. High ESR capacitors may cause high frequency oscillation. The maximum recommended ESR is 300m. The output capacitor can be increased, but performance has been optimized for a 1F ceramic output capacitor and does not improve significantly with larger capacitance. X7R/X5R dielectric-type ceramic capacitors are recommended because of their temperature performance. X7Rtype capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 50% and 60%, respectively, over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. Bypass Capacitor A capacitor can be placed from the noise bypass pin to ground to reduce output voltage noise. The capacitor bypasses the internal reference. A 0.01F capacitor is recommended for applications that require low-noise outputs. The bypass capacitor can be increased, further reducing noise and improving PSRR. Turn-on time increases slightly with respect to bypass capacitance. A unique quick-start circuit allows the MIC5253 to drive a large capacitor on the bypass pin without significantly slowing turn-on time. Refer to the "Typical Characteristics" section for performance with different bypass capacitors. Active Shutdown The MIC5253 also features an active shutdown clamp, which is an N-channel MOSFET that turns on when the device is disabled. This allows the output capacitor and load to discharge, de-energizing the load. August 2004 7
Table 1. Thermal Resistance Substituting PD for PD(max) and solving for the ambient operating temperature will give the maximum operating conditions for the regulator circuit. The junction-to-ambient thermal resistance for the minimum footprint is 400C/W, from Table 1. The maximum power dissipation must not be exceeded for proper operation. For example, when operating the MIC5253-2.9BC5 at an input voltage of 5.0V and 100mA load with a minimum footprint layout, the maximum ambient operating temperature TA can be determined as follows:
0.21W = 125C - TA 400C/W
TA = 41C
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Therefore, a 2.9V application at 100mA of output current can accept an ambient operating temperature of 41C in a SC-70 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the "Regulator Thermals" section of Micrel's Designing with Low-Dropout Voltage Regulators handbook. This information can be found on Micrel's website at: http://www.micrel.com/_PDF/other/LDOBk_ds.pdf
Micrel
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Package Information
0.65 (0.0256) BSC
1.35 (0.053) 2.40 (0.094) 1.15 (0.045) 1.80 (0.071) 2.20 (0.087) 1.80 (0.071) DIMENSIONS: MM (INCH) 1.00 (0.039) 1.10 (0.043) 0.80 (0.032) 0.80 (0.032) 0.18 (0.007) 0.10 (0.004)
0.30 (0.012) 0.15 (0.006)
0.10 (0.004) 0.00 (0.000)
0.30 (0.012) 0.10 (0.004)
5-Pin SC-70-5 (C5)
MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
USA
+ 1 (408) 944-0800
FAX
+ 1 (408) 474-1000
WEB
http://www.micrel.com
The 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 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) 2004 Micrel, Incorporated.
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