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MC33761
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Ultra Low-Noise Low Dropout Voltage Regulator with 1V ON/OFF Control
The MC33761 is an Low DropOut (LDO) regulator featuring excellent noise performances. Thanks to its innovative concept, the circuit reaches an incredible 40VRMS noise level without an external bypass capacitor. Housed in a small SOT-23 5 leads-like package, it represents the ideal designer's choice when space and noise are at premium. The absence of external bandgap capacitor unleashes the response time to a wake-up signal and makes it stay within 40s (in repetitive mode), pushing the MC33761 as a natural candidate in portable applications. The MC33761 also hosts a novel architecture which prevents excessive undershoots when the regulator is the seat of fast transient bursts, as in any bursting systems. Finally, with a static line regulation better than -75dB, it naturally shields the downstream electronics against choppy lines.
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5 1 TSOP-5 SN SUFFIX CASE 483
PIN CONNECTIONS AND MARKING DIAGRAM
Vin GND ON/OFF 1 LxxYW 2 3 5 Vout
* Ultra low-noise: 150nV/Hz @ 100Hz, 40VRMS 100Hz - 100kHz * * * * * * * *
typical, Iout = 60mA, Co=1F Fast response time from OFF to ON: 40s typical at a 200Hz repetition rate Ready for 1V platforms: ON with a 900mVhigh level Nominal output current of 80mA with a 100mA peak capability Typical dropout of 90mV @ 30mA, 160mV @ 80mA Ripple rejection: 70dB @ 1kHz 1.5% output precision @ 25C Thermal shutdown Vout available from 2.5V to 5.0V
4
NC
xx = Version YW = Date Code (Top View)
Applications
* Noise sensitive circuits: VCOs RF stages etc. * Bursting systems (TDMA phones) * All battery operated devices
ON/ OFF NC 3 4 On/Off Band Gap Reference Vout 1 Thermal Shutdown Vin
5 *Current Limit *Antisaturation Protection *Load Transient Improvement
GND
2
Simplified Block Diagram
This document contains information on a product under development. ON Semiconductor reserves the right to change or discontinue this product without notice.
(c) Semiconductor Components Industries, LLC, 1999
ORDERING INFORMATION
See detailed ordering and shipping information in the package dimensions section on page 11 of this data sheet.
1
November, 1999 - Rev. 0
Publication Order Number: MC33761/D
MC33761
PIN FUNCTION DESCRIPTIONS
Pin # 1 2 3 4 5 Pin Name Vin GND ON/OFF NC Vout Function Powers the IC The IC's ground Shuts or wakes-up the IC None Delivers the output voltage A 900mV level on this pin is sufficient to start the IC. A 150mV shuts it down. It makes no arm to connect the pin to a known potential, like in a pin-to-pin replacement case. This pin requires a 1F output capacitor to be stable. Description A positive voltage up to 12V can be applied upon this pin.
MAXIMUM RATINGS
Value Rating Power Supply Voltage ESD Capability, HBM Model ESD Capability, Machine Model Maximum Power Dissipation NW Suffix, Plastic Package Thermal Resistance Junction-to-Air Operating Ambient Temperature Maximum Junction Temperature (1) Maximum Operating Junction Temperature (2) Storage Temperature Range (1) Internally Limited by Shutdown. (2) Specifications are guaranteed below this value. Pin # 1 All Pins All Pins PD RqJ-A TA TJmax TJ Tstg Symbol Vin Min -- Max 12 1 200 Internally Limited 210 -40 to +85 150 125 -60 to +150 Unit V kV V W C/W C C C C
ELECTRICAL CHARACTERISTICS
(For Typical Values TA = 25C, for Min/Max values TA = -40C to +85C, Max TJ = 125C unless otherwise noted) Characteristics Pin # Symbol Min Typ Max Unit
Logic Control Specifications
Input Voltage Range ON/OFF Input Resistance (all versions) ON/OFF Control Voltages (3) Logic Zero, OFF State, IO = 50 mA Logic One, ON State, IO = 50 mA 3 3 3 VON/OFF RON/OFF VON/OFF 150 900 0 250 Vin V kW mV
Currents Parameters
Current Consumption in OFF State (all versions) OFF Mode Current: Vin = Vout + 1 V, IO = 0, VOFF = 150 mV Current Consumption in ON State (all versions) ON Mode Current: Vin = Vout + 1 V, IO = 0, VON = 3.5 V Current Consumption in ON State (all versions), ON Mode Saturation Current: Vin = Vout - 0.5 V, No Output Load Current Limit Vin = Voutnom + 1 V, Output is brought to Voutnom - 0.3 V (all versions) (3) Voltage Slope should be Greater than 2 mV/ms IQOFF IQON IQSAT IMAX 100 0.1 180 800 180 2
mA mA mA
mA
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MC33761
ELECTRICAL CHARACTERISTICS
(For Typical Values TA = 25C, for Min/Max values TA = -40C to +85C, Max TJ = 125C unless otherwise noted) Characteristics Pin # Symbol Min Typ Max Unit
Output Voltages
Vout + 1 V < Vin < 6 V, TA = 25C, 1 mA < Iout < 80 mA 2.5 V 2.8 V 3.0 V 3.3 V 3.6 V Other Voltages up to 5V Available in 50mV Increments Steps Vout + 1V < Vin < 6V, TA = -40C to +85C, 1mA < Iout < 80mA 2.5 V 2.8 V 3.0 V 3.3 V 3.6 V Other Voltages up to 5V Available in 50mV Increments Steps 5 5 5 5 5 5 5 5 5 5 5 5 Vout Vout Vout Vout Vout Vout Vout Vout Vout Vout Vout Vout 2.462 2.758 2.955 3.250 3.546 -1.5 2.425 2.716 2.91 3.201 3.492 -3 2.5 2.8 3.0 3.3 3.6 X 2.5 2.8 3.0 3.3 3.6 X 2.537 2.842 3.045 3.349 3.654 +1.5 2.575 2.884 3.090 3.399 3.708 +3 V V V V V % V V V V V %
Line and Load Regulation, Dropout Voltages
Line Regulation (all versions) Vout + 1 V < Vin < 12 V, Iout = 80 mA Load Regulation (all versions) Vin = Vout + 1 V, Cout = 1 mF, Iout = 1 to 80 mA Dropout Voltage (all versions) (3) Iout = 30 mA Iout = 60 mA Iout = 80 mA 5/1 5 Regline Regload 20 40 mV mV mV 5 5 5 Vin-Vout Vin-Vout Vin-Vout 90 140 160 150 200 250
Dynamic Parameters
Ripple Rejection (all versions) Vin = Vout + 1 V + 1 kHz 100 mVpp Sinusoidal Signal Output Noise Density @ 1 kHz RMS Output Noise Voltage (all versions) Cout = 1 mF, Iout = 50 mA, F = 100 Hz to 1 MHz Output Rise Time (all versions) Cout = 1 mF, Iout = 50 mA, 10% of Rising ON Signal to 90% of Nominal Vout 5/1 5 5 5 Noise trise Ripple -70 150 35 40 dB nV/ Hz
mV ms
Thermal Shutdown
Thermal Shutdown (all versions) (3) Vout is brought to Vout - 100 mV 125 C
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MC33761
DEFINITIONS
Load Regulation Line Regulation
The change in output voltage for a change in output current at a constant chip temperature.
Dropout Voltage
The input/output differential at which the regulator output no longer maintains regulation against further reductions in input voltage. Measured when the output drops 100mV below its nominal value (which is measured at 1V differential value). The dropout level is affected by the chip temperature, load current and minimum input supply requirements.
Output Noise Voltage
The change in output voltage for a change in input voltage. The measurement is made under conditions of low dissipation or by using pulse technique such that the average chip temperature is not significantly affected. One usually distinguishes static line regulation or DC line regulation (a DC step in the input voltage generates a corresponding step in the output voltage) from ripple rejection or audio susceptibility where the input is combined with a frequency generator to sweep from a few hertz up to a defined boundary while the output amplitude is monitored.
Thermal Protection
This is the integrated value of the output noise over a specified frequency range. Input voltage and output current are kept constant during the measurement. Results are expressed in VRMS.
Maximum Power Dissipation
Internal thermal shutdown circuitry is provided to protect the integrated circuit in the event that the maximum junction temperature is exceeded. When activated at typically 125C, the regulator turns off. This feature is provided to prevent catastrophic failures from accidental overheating.
Maximum Package Power Dissipation
The maximum total dissipation for which the regulator will operate within its specs.
Quiescent Current
The quiescent current is the current which flows through the ground when the LDO operates without a load on its output: internal IC operation, bias etc. When the LDO becomes loaded, this term is called the Ground current. It is actually the difference between the input current (measured through the LDO input pin) and the output current.
The maximum power package power dissipation is the power dissipation level at which the junction temperature reaches its maximum operating value, i.e. 125C. Depending on the ambient temperature, it is possible to calculate the maximum power dissipation and thus the maximum available output current.
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MC33761
Characterization Curves
All curves taken with Vin = Vout + 1 V, Vout = 2.8 V, Cout = 1 mF
4.5 QUIESCENT CURRENT (m A) 100 4.0 GROUND CURRENT (mA) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 0 20 40 60 OUTPUT CURRENT (mA) 80 165 -60 -40 -20 0 20 40 60 AMBIENT TEMPERATURE (C) 80 100 -40C 25C 85C 185
180
175
170
Figure 1. Ground Current versus Output Current
200 85C OUTPUT VOLTAGE (V) DROPOUT (mV) 150 25C -40C 100 2.805 2.800 2.795 2.790 2.785 2.780 0 0 20 40 60 OUTPUT CURRENT (mA) 80 100 2.775 0
Figure 2. Quiescent Current versus Temperature
85C 40C
25C 0C -20C -40C 20 40 60 OUTPUT CURRENT (mA) 80 100
50
Figure 3. Dropout versus Output Current
Figure 4. Output Voltage versus Output Current
180 160 DROPOUT VOLTAGE (mV) 140 120 100 80 60 40 20 0 -60 -40 -20 20 40 0 TEMPERATURE (C) 1 mA 60 80 100 30 mA 80 mA 60 mA
Figure 5. Dropout versus Temperature
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MC33761
APPLICATION HINTS
Input Decoupling
As with any regulator, it is necessary to reduce the dynamic impedance of the supply rail that feeds the component. A 1F capacitor either ceramic or tantalum is recommended and should be connected close to the MC33761 package. Higher values will correspondingly improve the overall line transient response.
Output Decoupling
component. The output current is internally limited to a maximum value of 180 mA typical while temperature shutdown occurs if the die heats up beyond 125C. These values let you assess the maximum differential voltage the device can sustain at a given output current before its protections come into play. The maximum dissipation the package can handle is given by:
P max
Thanks to a novel concept, the MC33761 is a stable component and does not require any specific Equivalent Series Resistance (ESR) neither a minimum output current. Capacitors exhibiting ESRs ranging from a few mW up to 3W can thus safely be used. The minimum decoupling value is 1F and can be augmented to fulfill stringent load transient requirements. The regulator accepts ceramic chip capacitors as well as tantalum devices.
Noise Decoupling
+ TJmax * TA R
qJA
If TJmax is limited to 125C, then the MC33761 can dissipate up to 470mW @ 25C. The power dissipated by the MC33761 can be calculated from the following formula:
Ptot
+
V
in
I
(I ) gnd out
)
V
in
* Vout
I out
I out
or
Vin max
Unlike other LDOs, the MC33761 is a true low--noise regulator. Without the need of an external bypass capacitor, it typically reaches the incredible level of 40VRMS overall noise between 100 Hz and 100 kHz. To give maximum insight on noise specifications, ON Semiconductor includes spectral density graphics. The classical bypass capacitor impacts the start--up phase of standard LDOs. However, thanks to its low--noise architecture, the MC33761 operates without a bypass element and thus offers a typical 40s start--up phase.
Protections
out + PtotI) V) I gnd
out
If a 80mA output current is needed, the ground current is extracted from the data-sheet curves: 4mA @ 80mA. For a MC33761SNT1-28 (2.8 V) delivering 80mA and operating at 25C, the maximum input voltage will then be 8.3V.
Typical Applications
The following picture portrays the typical application of the MC33761.
The MC33761 hosts several protections, giving natural ruggedness and reliability to the products implementing the
Figure 6.
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MC33761
Dropout Charge
Input Permanently Enables the IC When Closed + C3 1 mF On/Off
1 2 3 MC33761 R1 100 k
5
Output
4 + C2 1 mF
Figure 7. A Typical Application Schematic
As for any low noise designs, particular care has to be taken when tackling Printed Circuit Board (PCB) layout. The figure below gives an example of a layout where stray inductances/capacitances are minimized. This layout is the
basis for the MC33761 performance evaluation board. The BNC connectors give the user an easy and quick evaluation mean.
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MC33761
Understanding the Load Transient Improvement The MC33761 features a novel architecture which allows the user to easily implement the regulator in burst systems where the time between two current shots is kept very small. The quality of the transient response time is related to many parameters, among which the closed-loop bandwidth with the corresponding phase margin plays an important role. However, other characteristics also come into play like the series pass transistor saturation. When a current perturbation suddenly appears on the output, e.g. a load increase, the error amplifier reacts and actively biases the PNP transistor. During this reaction time, the LDO is in open-loop and the output impedance is rather high. As a result, the voltage brutally drops until the error amplifier effectively closes the loop and corrects the output error. When the load disappears, the opposite phenomenon takes place with a positive overshoot. The problem appears when this overshoot decays down to the LDO steady-state value. During this decreasing phase, the LDO stops the PNP bias and one can consider the LDO asleep (figure 8). If by misfortune a current shot appears, the reaction time is incredibly lengthened and a strong undershoot takes place. This reaction is clearly not acceptable for line sensitive devices, such as VCOs or other Radio-Frequency parts. This problem is dramatically exacerbated when the output current drops to zero rather than a few mA. In this later case, the internal feedback network is the only discharge path, accordingly lengthening the output voltage decay period (figure 9). The MC33761 cures this problem by implementing a clever design where the LDO detects the presence of the overshoot and forces the system to go back to steady-state as soon as possible, ready for the next shot. Figure 10 and 11 show how it positively improves the response time and decreases the negative peak voltage.
Figure 8. A standard LDO behavior when the load current disappears
Figure 9. A standard LDO behavior when the load current appears in the decay zone
Figure 10. Without load transient improvement
Figure 11. MC33761 with load transient improvement
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MC33761
MC33761 has a fast start-up phase Thanks to the lack of bypass capacitor the MC33761 is able to supply its downstream circuitry as soon as the OFF to ON signal appears. In a standard LDO, the charging time of the external bypass capacitor hampers the response time. A simple solution consists in suppressing this bypass element but, unfortunately, the noise rises to an unacceptable level. MC33761 offers the best of both worlds since it no longer includes a bypass capacitor and starts in less than 40s typically (Repetitive at 200Hz). It also ensures a low-noise level of 40VRMS 100Hz-100kHz. The following picture details the typical 33761 startup phase.
Figure 12. Repetitive start-up waveforms
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MC33761
TYPICAL TRANSIENT RESPONSES
Figure 13. Output is pulsed from 2mA to 80mA
Figure 14. Discharge effects from 0 to 40mA
Figure 15. Load transient improvement effect
Figure 16. Load transient improvement effect
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MC33761
TYPICAL TRANSIENT RESPONSES
250 Vin = Vout + 1 V TA = 25C Cout = 1 mF IO = 50 mA 10 mA 100 RMS Noise, IO = 10 mA: 20 Hz - 100 kHz: 29 mV 20 Hz - 1 MHz: 31 mV 1,000 10,000 100,000 f, FREQUENCY (Hz) 1,000,000 RMS Noise, IO = 50 mA: 20 Hz - 100 kHz: 27 mV 20 Hz - 1 MHz: 30 mV
200 nV/sqrt Hz
150
50
0 100
Figure 17. MC33761 Typical Noise Density Performance
0 -10 -20 -30 Z O (OHMS) -40 (dB) -50 -60 -70 -80 -90 -100 100 1,000 10,000 100,000 f, FREQUENCY (Hz) 1,000,000 10 mA Vin = VO + 1 V TA = 25C Cout = 1 mF IO = 50 mA
3.5 3.0 2.5 2.0 1.5 1.0 0.5 20 mA 0 100 1,000 100,000 10,000 f, FREQUENCY (Hz) 1,000,000 80 mA 10 mA IO = 1 mA
Figure 18. MC33761 Typical Ripple Rejection Performance
Figure 19. Typical Output Impedance plot Cout = 1F, Vin = Vout + 1
ORDERING INFORMATION
Device MC33761SNT1-25 MC33761SNT1-28 MC33761SNT1-30 Voltage Output 2.5V 2.8V 3.0V Package TSOP-5 TSOP-5 TSOP-5 Shipping 3000 Units / Tape & Reel 3000 Units / Tape & Reel 3000 Units / Tape & Reel
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MC33761
PACKAGE DIMENSIONS
TSOP-5 SN SUFFIX PLASTIC PACKAGE CASE 483-01 ISSUE A
D
5 1 2 4 3
S
B
NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. MAXIMUM LEAD THICKNESS INCLUDES LEAD FINISH THICKNESS. MINIMUM LEAD THICKNESS IS THE MINIMUM THICKNESS OF BASE MATERIAL. DIM A B C D G H J K L M S MILLIMETERS MIN MAX 2.90 3.10 1.30 1.70 0.90 1.10 0.25 0.50 0.85 1.00 0.013 0.100 0.10 0.26 0.20 0.60 1.25 1.55 0_ 10 _ 2.50 3.00 INCHES MIN MAX 0.1142 0.1220 0.0512 0.0669 0.0354 0.0433 0.0098 0.0197 0.0335 0.0413 0.0005 0.0040 0.0040 0.0102 0.0079 0.0236 0.0493 0.0610 0_ 10 _ 0.0985 0.1181
L G A J C 0.05 (0.002) H K M
ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. "Typical" parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including "Typicals" must be validated for each customer application by customer's technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer.
PUBLICATION ORDERING INFORMATION
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MC33761/D

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