1A SIMPLE SWITCHER® Nano Module with 5.5V Maximum Input Voltage
October 5, 2011
LMZ10501 1A SIMPLE SWITCHER® Nano Module with 5.5V Maximum Input Voltage
8 Pin LLP-Footprint Package
System Performance
(Quick Overview Links: VOUT = 1.2V, 1.8V, 2.5V, 3.3V) Typical Efficiency at VIN = 3.6V
100 90
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EFFICIENCY (%)
SE08A 8 Pin Package 3.0 x 2.5 x 1.2 mm (0.118 x 0.098 x 0.047 in) RoHS Compliant
80 70 60 50 40 30 20 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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Electrical Specifications
■ ■ ■ ■
Up to 1A output current Input voltage range 2.7V to 5.5V Output voltage range 0.6V to 3.6V Efficiency up to 95%
VOUT = 1.2V VOUT = 1.8V VOUT = 2.5V VOUT = 3.3V
Key Features
■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
Integrated inductor Miniature form factor (3.0 mm x 2.5 mm x 1.2 mm) 8-pin LLP footprint -40°C to 125°C junction temperature range Adjustable output voltage 2.0MHz fixed PWM switching frequency Integrated compensation Soft start function Current limit protection Thermal shutdown protection Input voltage UVLO for power-up, power-down, and brown-out conditions ■ Only 5 external components — resistor divider and 3 ceramic capacitors
Output Voltage Ripple VIN = 5.0V, VOUT = 1.8V, IOUT = 1A
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Applications
RADIATED EMISSIONS (dBμV/m)
■ Point of load conversions from 3.3V and 5V rails ■ Space constrained applications ■ Low output noise applications
Radiated EMI (CISPR22) VIN = 5.0V, VOUT = 1.8V, IOUT = 1A
80 70 60 50 40 30 20 10 0 0 200 400 600 800 FREQUENCY (MHz) 1000 Emissions (Evaluation Board) EN 55022 Class B Limit EN 55022 Class A Limit
Performance Benefits
■ ■ ■ ■
Small solution size Low output voltage ripple Easy component selection and simple PCB layout High efficiency reduces system heat generation
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© 2011 National Semiconductor Corporation
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LMZ10501
Connection Diagram
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NS Package Number SE08A
Order Information
Order Number LMZ10501SEE LMZ10501SE LMZ10501SEX Package Marking (Note) XVS SP XVS SP XVS SP Supplied As 250 units, Tape-and-Reel 1000 units, Tape-and-Reel 3000 units, Tape-and-Reel
Note: The actual physical placement of the package marking will vary from part to part. The package marking “X” designates the date code. “V” is a NSC internal code for die traceability. Both will vary in production. “S” designates device type as switcher and “SP” identifies the device (part number).
Pin Descriptions
Pin # 1 2 Name EN VCON Description Enable Input. Set this digital input higher than 1.2V for normal operation. For shutdown, set low. Pin is internally pulled up to VIN and can be left floating for always-on operation. Output voltage control pin. Connect to analog voltage from resisitve divider or DAC/controller to set the VOUT voltage. VOUT = 2.5 x VCON. Connect a small (470pF) capacitor from this pin to SGND to provide noise filtering. Feedback of the error amplifier. Connect directly to output capacitor to sense VOUT. Ground for analog and control circuitry. Connect to PGND at a single point. Output Voltage. Connected to one terminal of the integrated inductor. Connect output filter capacitor between VOUT and PGND. Power ground for the power MOSFETs and gate-drive circuitry. Voltage supply input. Connect ceramic capacitor between VIN and PGND as close as possible to these two pins. Typical capacitor values are between 4.7µF and 22µF. 2.35V voltage reference output. Typically connected to VCON pin through a resistive divider to set the output voltage. The 3 pads underneath the module are not internally connected to any node. These pads should be connected to the ground plane for improved thermal performance.
3 4 5 6 7 8
FB SGND VOUT PGND VIN VREF PAD
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LMZ10501
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VIN, VREF to SGND PGND to SGND EN, FB, VCON −0.2V to +6.0V −0.2V to +0.2V (SGND −0.2V) to (VIN +0.2V) w/6.0V max (PGND −0.2V) to (VIN +0.2V) w/6.0V max +150°C −65°C to +150°C +260°C ±2kV
Operating Ratings
(Note 1) 2.7V to 5.5V 0 mA to 1000 mA −40°C to +125°C
Input Voltage Range Recommended Load Current Junction Temperature (TJ) Range
Thermal Properties
Junction-to-Ambient Thermal Resistance (θJA), SE08A Package (Note 3) 120°C/W
VOUT
Junction Temperature (TJ-MAX) Storage Temperature Range Maximum Lead Temperature ESD Susceptibility(Note 2)
Electrical Characteristics
(Note 4) Specifications with standard typeface are for TJ = 25°C only; Limits in bold face type apply over the operating junction temperature range TJ of -40°C to 125°C. Minimum and maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Unless otherwise stated the following conditions apply: VIN = 3.6V, VEN = 1.2V. Symbol Parameter Conditions Min Typ (Note 4) (Note 5) Max (Note 4) Units
SYSTEM PARAMETERS VREF x GAIN GAIN VINUVLO VINUVLO ISHDN Iq RDROPOUT I LIM FOSC VIH,ENABLE VIL,ENABLE TSD TSD-HYST DMAX TON-MIN θJA Reference voltage x VCON to VIN = VEN = 5.5V, VCON = 1.44V FB Gain VCON to FB Gain VIN rising threshold VIN falling theshold Shutdown supply current DC bias current into VIN VIN to VOUTresistance DC Output Current Limit Internal oscillator frequency Enable logic HIGH voltage Enable logic LOW voltage Thermal shutdown Thermal shutdown hysteresis Maximum duty cycle Minimum on-time Package Thermal Resistance 20mm x 20mm board 2 layers, 2 oz copper, 0.5W, no airlow 15mm x 15mm board 2 layers, 2 oz copper, 0.5W, no airlow 10mm x 10mm board 2 layers, 2 oz copper, 0.5W, no airlow Rising Threshold 150 20 100 50 118 VIN = 3.6V, VEN = 0.5V (Note 6) VIN = 5.5V, VCON = 1.6V, IOUT = 0A IOUT = 200 mA VCON = 0.24V (Note 7) 1125 1.75 1.2 0.5 VIN = 5.5V, VCON = 1.44V 5.7575 2.4375 5.875 2.5 2.4 2.25 11 6.5 285 1350 2.0 2.25 18 8.5 425 5.9925 2.5750 V V/V V V µA mA mΩ mA MHz V V °C °C % ns
132
°C/W
157
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LMZ10501
System Characteristics
Symbol Parameter
The following specifications are guaranteed by design providing the component values in the Typical Application Circuit are used (CIN = COUT = 10 µF, 6.3V, 0603, TDK C1608X5R0J106K). These parameters are not guaranteed by production testing. Unless otherwise stated the following conditions apply: TA = 25°C. Conditions Min Typ ±1.75 Max Units % ΔVOUT/VOUT Output Voltage Regulation Over VOUT = 0.6V Line Voltage and Load Current ΔVIN =2.7V to 4.2V ΔIOUT = 0A to 1A ΔVOUT/VOUT Output Voltage Regulation Over VOUT = 1.5V Line Voltage and Load Current ΔVIN = 2.7V to 5.5V ΔIOUT = 0A to 1A ΔVOUT/VOUT Output Voltage Regulation Over VOUT = 3.6V Line Voltage and Load Current ΔVIN = 4.0V to 5.5V ΔIOUT = 0A to 1A VREF TRISE Rise time of reference voltage EN = Low to High, VIN = 4.2V VOUT = 2.7V, IOUT = 1A VIN = 5.0V, VOUT = 3.3V IOUT = 200 mA VIN = 5.0V, VOUT = 3.6V IOUT = 1000 mA VIN = 5.0V, VOUT = 1.8V IOUT = 1000 mA (Note 8) VIN = 2.7V to 5.5V, TR = TF= 10 µs, VOUT = 1.8V, IOUT = 1000mA VIN = 5.0V TR = TF = 40 µs, VOUT = 1.8V IOUT = 100mA to 1000 mA 10 95 % 91 10 mV pk-pk µs ±0.38 % ±0.92 %
Peak Efficiency η Full Load Efficiency
VOUT Ripple Output voltage ripple
Line Transient
Line transient response
30
mV pk-pk
Load Transient
Load transient response
30
mV pk-pk
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LMZ10501
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device is intended to be functional. For guaranteed specifications and test conditions, see the Electrical Characteristics. Note 2: The human body model is a 100pF capacitor discharged through a 1.5 kΩ resistor into each pin. Test method is per JESD-22-114. Note 3: Junction-to-ambient thermal resistance (θJA) is based on 4 layer board thermal measurements, performed under the conditions and guidelines set forth in the JEDEC standards JESD51-1 to JESD51-11. θJA varies with PCB copper area, power dissipation, and airflow. Note 4: Min and Max limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods. Limits are used to calculate National’s Average Outgoing Quality Level (AOQL). Note 5: Typical numbers are at 25°C and represent the most likely parametric norm. Note 6: Shutdown current includes leakage current of the high side PFET. Note 7: Current limit is built-in, fixed, and not adjustable. Note 8: Ripple voltage should be measured across COUT on a well-designed PC board using the suggested capacitors.
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LMZ10501
Typical Performance Characteristics
Unless otherwise specified the following conditions apply: VIN = 3.6V, TA = 25°C Dropout Voltage vs Load Current and Input Voltage
0.35 DROPOUT VOLTAGE (V) 0.30 0.25 0.20 0.15 0.10 0.05 0.00 0.0 0.2 0.4 0.6 0.8 LOAD CURRENT (A) 1.0
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Thermal Derating VOUT = 1.2V, θJA = 120°C/W
1.2 1.0 0.8 0.6 0.4 0.2 0.0 60 70 80 90 100 110 120 130 AMBIENT TEMPERATURE (°C)
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Thermal Derating VOUT = 1.8V, θJA = 120°C/W
1.2 1.0 0.8 0.6 0.4 0.2 0.0 60 70 80 90 100 110 120 130 AMBIENT TEMPERATURE (°C)
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Thermal Derating VOUT = 2.5V, θJA = 120°C/W
1.2 1.0 0.8 0.6 0.4 0.2 0.0 60 70 80 90 100 110 120 130 AMBIENT TEMPERATURE (°C)
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OUTPUT CURRENT (A)
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OUTPUT CURRENT (A)
VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
OUTPUT CURRENT (A)
VIN = 2.7V VIN = 3.3V VIN = 3.6V VIN = 4.0V
VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
LMZ10501
Thermal Derating VOUT = 3.3V, θJA = 120°C/W
1.2 1.0 0.8 0.6 0.4 0.2 0.0 60 70 80 90 100 110 120 130 AMBIENT TEMPERATURE (°C)
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OUTPUT CURRENT (A)
RADIATED EMISSIONS (dBμV/m)
VIN = 4.0V VIN = 4.5V VIN = 5.0V VIN = 5.5V
Radiated EMI (CISPR22) VIN = 5.0V, VOUT = 1.8V, IOUT = 1A Default evaluation board BOM
80 70 60 50 40 30 20 10 0 0 200 400 600 800 FREQUENCY (MHz) 1000
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Emissions (Evaluation Board) EN 55022 Class B Limit EN 55022 Class A Limit
Conducted EMI VIN = 5.0V, VOUT = 1.8V, IOUT = 1A Default evaluation board BOM with additional 1µH 1µF LC input filter
80 CONDUCTED EMISSIONS (dBμV) 70 60 50 40 30 20 10 0 100m 1 10 FREQUENCY (MHz) 100
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Startup
Conducted Emissions CISPR 22 Quasi Peak CISPR 22 Average
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LMZ10501
1.2V
Schematic VOUT = 1.2V
100 90 EFFICIENCY (%) 80 70 60 50 40 30 20
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Efficiency VOUT = 1.2V
VIN = 2.7V VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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Output Ripple VOUT = 1.2V
Load Transient VOUT = 1.2V
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Line and Load Regulation VOUT = 1.2V
1.24 1.5 1.4 1.3 1.2 1.1
DC Current Limit VOUT = 1.2V
OUTPUT VOLTAGE (V)
TA = 85°C
1.23
1.22 VIN = 2.7V VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
1.21
1.20
DC CURRENT LIMIT (A)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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1.0 2.5
3.0
3.5 4.0 4.5 5.0 INPUT VOLTAGE (V)
5.5
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LMZ10501
1.8V
Schematic VOUT = 1.8V
100 90 EFFICIENCY (%) 80 70 60 50 40 30 20
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Efficiency VOUT = 1.8V
VIN = 2.7V VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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Output Ripple VOUT = 1.8V
Load Transient VOUT = 1.8V
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Line and Load Regulation VOUT = 1.8V
1.81 1.5 1.4 1.3 1.2 1.1
DC Current Limit VOUT = 1.8V
OUTPUT VOLTAGE (V)
TA = 85°C
1.80
1.79 VIN = 2.7V VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
1.78
1.77
DC CURRENT LIMIT (A)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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1.0 2.5
3.0
3.5 4.0 4.5 5.0 INPUT VOLTAGE (V)
5.5
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LMZ10501
2.5V
Schematic VOUT = 2.5V
100 90 EFFICIENCY (%) 80 70 60 50 40 30 20
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Efficiency VOUT = 2.5V
VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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Output Ripple VOUT = 2.5V
Load Transient VOUT = 2.5V
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Line and Load Regulation VOUT = 2.5V
2.53 1.5 1.4 1.3 1.2 1.1
DC Current Limit VOUT = 2.5V
OUTPUT VOLTAGE (V)
TA = 85°C
2.52
2.51
2.50
2.50
VIN = 3.3V VIN = 3.6V VIN = 5.0V VIN = 5.5V
DC CURRENT LIMIT (A)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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1.0 2.5
3.0
3.5 4.0 4.5 5.0 INPUT VOLTAGE (V)
5.5
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LMZ10501
3.3V
Schematic VOUT = 3.3V
100 90 EFFICIENCY (%) 80 70 60 50 40 30 20
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Efficiency VOUT = 3.3V
VIN = 3.6V VIN = 4.0V VIN = 4.5V VIN = 5.0V VIN = 5.5V
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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Output Ripple VOUT = 3.3V
Load Transient VOUT = 3.3V
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Line and Load Regulation VOUT = 3.3V
3.30 1.5 1.4 1.3 1.2 1.1
DC Current Limit VOUT = 3.3V
TA = 85°C
3.28
3.26 VIN = 3.6V VIN = 4.0V VIN = 4.5V VIN = 5.0V VIN = 5.5V
3.24
3.22 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
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DC CURRENT LIMIT (A)
OUTPUT VOLTAGE (V)
1.0 2.5
3.0
3.5 4.0 4.5 5.0 INPUT VOLTAGE (V)
5.5
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Block Diagram
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LMZ10501
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FIGURE 1. Functional Block Diagram
Overview
The LMZ10501 SIMPLE SWITCHER® nano module is an easy-to-use step-down DC-DC solution capable of driving up to 1A load in space-constrained applications. Only an input capacitor, an output capacitor, a small VCON filter capacitor, and two resistors are required for basic operation. The nano module comes in 8-pin LLP footprint package with an integrated inductor. The LMZ10501 operates in fixed 2.0MHz PWM (Pulse Width Modulation) mode, and is designed to deliver power at maximum efficiency. The output voltage is typically set by using a resistive divider between the built-in reference voltage VREF and the control pin VCON. The VCON pin is the positive input to the error amplifier. The output voltage of the LMZ10501 can also be dynamically adjusted between 0.6V and 3.6V by driving the VCON pin externally. Internal current limit based softstart function, current overload protection, and thermal shutdown are also provided. CIRCUIT OPERATION The LMZ10501 is a synchronous Buck power module using a PFET for the high side switch and an NFET for the synchronous rectifier switch. The output voltage is regulated by modulating the PFET switch on-time. The circuit generates a duty-cycle modulated rectangular signal. The rectangular signal is averaged using a low pass filter formed by the integrated inductor and an output capacitor. The output voltage is equal to the average of the duty-cycle modulated rectangular signal. In PWM mode, the switching frequency is constant. The energy per cycle to the load is controlled by modulating the
PFET on-time, which controls the peak inductor current. In current mode control architecture, the inductor current is compared with the slope compensated output of the error amplifier. At the rising edge of the clock, the PFET is turned ON, ramping up the inductor current with a slope of (VIN - VOUT)/ L. The PFET is ON until the current signal equals the error signal. Then the PFET is turned OFF and NFET is turned ON, ramping down the inductor current with a slope of VOUT /L. At the next rising edge of the clock, the cycle repeats. An increase of load pulls the output voltage down, resulting in an increase of the error signal. As the error signal goes up, the peak inductor current is increased, elevating the average inductor current and responding to the heavier load. To ensure stability, a slope compensation ramp is subtracted from the error signal and internal loop compensation is provided. INPUT UNDER VOLTAGE DETECTION The LMZ10501 implements an under voltage lock out (UVLO) circuit to ensure proper operation during startup, shutdown and input supply brownout conditions. The circuit monitors the voltage at the VIN pin to ensure that sufficient voltage is present to bias the regulator. If the under voltage threshold is not met, all functions of the controller are disabled and the controller remains in a low power standby state. SHUTDOWN MODE To shutdown the LMZ10501, pull the EN pin low (