|
|
Teilenummer | LMZ10501 |
|
Beschreibung | 1A SIMPLE SWITCHER Nano Module | |
Hersteller | National Semiconductor | |
Logo | ||
Gesamt 20 Seiten LMZ10501
October 5, 2011
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)
SE08A 8 Pin Package
30124731
3.0 x 2.5 x 1.2 mm (0.118 x 0.098 x 0.047 in)
RoHS Compliant
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%
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
Applications
■ Point of load conversions from 3.3V and 5V rails
■ Space constrained applications
■ Low output noise applications
Performance Benefits
■ Small solution size
■ Low output voltage ripple
■ Easy component selection and simple PCB layout
■ High efficiency reduces system heat generation
© 2011 National Semiconductor Corporation 301247
Typical Efficiency at VIN = 3.6V
100
90
80
70
60
50 VOUT = 1.2V
40
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
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)
30124730
Output Voltage Ripple
VIN = 5.0V, VOUT = 1.8V, IOUT = 1A
30124733
Radiated EMI (CISPR22)
VIN = 5.0V, VOUT = 1.8V, IOUT = 1A
80 Emissions (Evaluation Board)
70
EN 55022 Class B Limit
EN 55022 Class A Limit
60
50
40
30
20
10
0
0 200 400 600 800 1000
FREQUENCY (MHz)
30124732
www.national.com
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
VIN = 2.7V
0.30 VIN = 3.3V
VIN = 3.6V
0.25 VIN = 4.0V
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
30124749
Thermal Derating VOUT = 1.8V, θJA = 120°C/W
1.2
VIN = 3.3V
1.0
VIN = 3.6V
VIN = 5.0V
VIN = 5.5V
0.8
0.6
0.4
0.2
0.0
60 70 80 90 100 110 120 130
AMBIENT TEMPERATURE (°C)
30124743
Thermal Derating VOUT = 1.2V, θJA = 120°C/W
1.2
VIN = 3.3V
1.0
VIN = 3.6V
VIN = 5.0V
VIN = 5.5V
0.8
0.6
0.4
0.2
0.0
60 70 80 90 100 110 120 130
AMBIENT TEMPERATURE (°C)
30124744
Thermal Derating VOUT = 2.5V, θJA = 120°C/W
1.2
VIN = 3.3V
1.0
VIN = 3.6V
VIN = 5.0V
VIN = 5.5V
0.8
0.6
0.4
0.2
0.0
60 70 80 90 100 110 120 130
AMBIENT TEMPERATURE (°C)
30124742
www.national.com
6
6 Page FIGURE 1. Functional Block Diagram
30124704
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 inte-
grated inductor. The LMZ10501 operates in fixed 2.0MHz
PWM (Pulse Width Modulation) mode, and is designed to de-
liver 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 volt-
age of the LMZ10501 can also be dynamically adjusted be-
tween 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 syn-
chronous 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 sig-
nal 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 en-
ergy 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 com-
pared with the slope compensated output of the error ampli-
fier. 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 in-
crease 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 in-
ductor 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 (<0.5V). In
the shutdown mode all internal circuits are turned OFF.
www.national.com
12
12 Page | ||
Seiten | Gesamt 20 Seiten | |
PDF Download | [ LMZ10501 Schematic.PDF ] |
Teilenummer | Beschreibung | Hersteller |
LMZ10500 | LMZ10500 650-mA SIMPLE SWITCHER Nano Module With 5.5-V Maximum Input Voltage (Rev. F) | Texas Instruments |
LMZ10500 | 650mA SIMPLE SWITCHER Nano Module | National Semiconductor |
LMZ10501 | LMZ10501 1-A SIMPLE SWITCHER Nano Module With 5.5-V Maximum Input Voltage (Rev. F) | Texas Instruments |
LMZ10501 | 1A SIMPLE SWITCHER Nano Module | National Semiconductor |
LMZ10503 | Power Module | Texas Instruments |
Teilenummer | Beschreibung | Hersteller |
CD40175BC | Hex D-Type Flip-Flop / Quad D-Type Flip-Flop. |
Fairchild Semiconductor |
KTD1146 | EPITAXIAL PLANAR NPN TRANSISTOR. |
KEC |
www.Datenblatt-PDF.com | 2020 | Kontakt | Suche |