ml4875 ETC-unknow, ml4875 Datasheet

no-image

ml4875

Manufacturer Part Number
ml4875
Description
Voltage Boost Regulator With Shutdown
Manufacturer
ETC-unknow
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ml4875-3
Manufacturer:
MICROLINEAR
Quantity:
20 000
Part Number:
ml4875CS-5
Manufacturer:
MCLN
Quantity:
20 000
GENERAL DESCRIPTION
The ML4875 is a boost regulator designed for DC to DC
conversion in 1 to 3 cell battery powered systems. The
combination of BiCMOS process technology, internal
synchronous rectification, variable frequency operation,
and low supply current make the ML4875 ideal for 1 cell
applications. The ML4875 is capable of start-up with input
voltages as low as 1V and is available in 5V, 3.3V, and 3V
output versions with an output voltage accuracy of ±3%.
Unlike regulators using external Schottky diodes, the
ML4875 isolates the load from the battery when the
SHDN pin is high. This is accomplished by an integrated
synchronous rectifier which eliminates the need for an
external Schottky diode and provides a lower forward
voltage drop, resulting in higher conversion efficiency. In
addition, low quiescent battery current and variable
frequency operation result in high efficiency even at light
loads. The ML4875 requires only one inductor and two
capacitors to build a very small regulator circuit capable
of achieving conversion efficiencies in excess of 90%.
The circuit contains a RESET output which goes low when
the DETECT input drops below 200mV.
BLOCK DIAGRAM
*Optional
*C
IN
Low Voltage Boost Regulator with Shutdown
V
BAT
1
3
V
GND
IN
GND
PWR
8
REGULATION
SHUTDOWN
FROM POWER
MANAGEMENT
CONTROL
L1
&
V
2
L
SHDN
6
*Some Packages Are End Of Life Or Obsolete
FEATURES
Guaranteed start-up and operation at 1V input
Pulse Frequency Modulation and Internal Synchronous
Rectification for high efficiency
Isolates the load from the input during shutdown
Minimum external components
Low ON resistance internal switching FETs
Micropower operation
5V, 3.3V, and 3V output versions
CONTROL
DETECT
BOOST
REF
*R
A
4
*R
+
FEEDBACK
B
RESET
V
OUT
5V
5
7
C
V
OUT
OUT
ML4875*
July 2000
1

Related parts for ml4875

ml4875 Summary of contents

Page 1

... Low Voltage Boost Regulator with Shutdown GENERAL DESCRIPTION The ML4875 is a boost regulator designed for conversion cell battery powered systems. The combination of BiCMOS process technology, internal synchronous rectification, variable frequency operation, and low supply current make the ML4875 ideal for 1 cell applications ...

Page 2

... IN 2 SHDN Pulling this pin high shuts down the regulator, isolating the load from the input 3 GND Analog signal ground 4 DETECT When this pin below V the RESET pin to go low 2 ML4875-5/-3/-T 8-Pin SOIC (S08) V PWR GND SHDN RESET 2 7 GND V 3 ...

Page 3

... RESET OFF Current Note 1: Limits are guaranteed by 100% testing, sampling or correlation with worst case test conditions. Lead Temperature (Soldering 10 sec.) ..................... 260°C Thermal Resistance ( OPERATING CONDITIONS Temperature Range ML4875CS-X .............................................. 0°C to 70°C 7V ML4875ES-X ........................................... –20°C to 70°C + 0.3V OUT V Operating Range IN 1.5A ML4875CS-X ................................. 1. 300mA ML4875ES-X ...

Page 4

... ML4875 V IN START- (Sumida CD75) 100 F V PWR GND IN SHDN RESET GND V L DETECT V OUT 100 F Figure 1. Application Test Circuit – ONE SHOT – 200mV Figure 2. PFM Regulator Block Diagram V OUT I OUT SHUTDOWN ...

Page 5

... Q1 & Q2 OFF Figure 3. PFM Inductor Current Waveforms and Timing. SHUTDOWN The ML4875 output can be shut down by pulling the SHDN pin high. When SHDN is high, the regulator stops switching, the control circuitry is powered down, and the body diode of the PMOS synchronous rectifier is disconnected from the output, allowing the output voltage to drop below the input voltage ...

Page 6

... Many use a conservative current level, where inductance has dropped to 90% of its normal level. In any case good idea to try inductors of various current ratings with the ML4875 to determine which inductor is the best choice. Check efficiency and maximum output current, and if a current probe is available, look at the inductor current to see if it looks like the waveform shown in Figure 3 ...

Page 7

... Tantalum capacitors which meet these requirements can be obtained from the following suppliers: Matsuo Sprague If ESL spikes are causing output noise problems, an EMI filter can be added in series with the output. ML4875 ML4875-3.3 100 ...

Page 8

... Use adequate ground and power traces or planes • Keep components as close as possible to the ML4875 • Use short trace lengths from the inductor to the V and from the output capacitor to the V • Use a single point ground for the ML4875 ground pins, and the input and output capacitors , and to ensure IN ...

Page 9

... L = 56µH 1.0 73.9 19.5 1.5 118.5 47.2 2.0 156.8 83.4 2.5 189.0 125.7 3.0 206.6 165.5 ML4875-3.0 (mA) EFFICIENCY % V ( 15µH 75.2 1.0 77.0 1.5 76.7 2.0 75.8 2.5 75 27µH 73.9 1.0 1.5 79.6 2.0 82.8 2.5 83 56µH 83.5 1.0 83.3 1.5 83.3 2.0 83.3 2.5 83.5 84.1 87.8 88.7 89.0 89.1 89.3 89.5 89.8 (mA) EFFICIENCY % 74.1 77.5 72.4 71.7 71.8 80.8 81.5 81.1 80.9 81.2 87.1 87.6 87.8 87.8 88.1 ML4875 I (mA) I (mA) EFFICIENCY % IN OUT 242.8 59.2 73.1 362.6 131.3 72.4 461.6 219.2 71.2 523.5 308.5 70.7 144.9 38.9 80.5 218.7 88.2 80.7 286.8 153.4 80.2 325.6 217.5 80.2 74.3 21.5 86.8 119.1 52.0 87.3 154.9 90.2 87.3 183.0 133.2 87.3 9 ...

Page 10

... ORDERING INFORMATION PART NUMBER ML4875CS-T (Obsolete) ML4875CS-3 ML4875CS-5 ML4875ES-T ML4875ES-3 (End Of Life) ML4875ES-5 (End Of Life) © Micro Linear 1996 is a registered trademark of Micro Linear Corporation Products described in this document may be covered by one or more of the following patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940. Other patents are pending. ...

Related keywords