ML4861CS-3 MICRO-LINEAR [Micro Linear Corporation], ML4861CS-3 Datasheet

no-image

ML4861CS-3

Manufacturer Part Number
ML4861CS-3
Description
Low Voltage Boost Regulator
Manufacturer
MICRO-LINEAR [Micro Linear Corporation]
Datasheet
GENERAL DESCRIPTION
The ML4861 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 ML4861 ideal for 1 cell
applications. The ML4861 is capable of start-up with input
voltages as low as 1V and is available in 6V, 5V, and 3.3V
output versions with output voltage accuracy of ±3%.
An integrated synchronous rectifier 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 ML4861 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 also contains a RESET output which goes low
when the IC can no longer function due to low input
voltage, or when the DETECT input drops below 200mV.
BLOCK DIAGRAM
+
*OPTIONAL
*R
*R
A
B
C
IN
*
4
2
3
GND
DETECT
V
REF
+
7
RESET
UVLO
TO MICROPROCESSOR
Low Voltage Boost Regulator
CONTROL
FEATURES
* Some Packages Are Obsolete
BOOST
1
Guaranteed full load start-up and operation at 1V input
Pulse Frequency Modulation and Internal Synchronous
Rectification for high efficiency
Minimum external components
Low ON resistance internal switching FETs
Micropower operation
6V, 5V, and 3.3V output versions
V
I N
L1
6
V
L
FEEDBACK
V
GND
PWR
OUT
5
8
ML4861*
C
OUT
October 1996
+
1

Related parts for ML4861CS-3

ML4861CS-3 Summary of contents

Page 1

GENERAL DESCRIPTION The ML4861 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 ...

Page 2

ML4861 PIN CONNECTION PIN DESCRIPTION PIN NO. NAME FUNCTION 1 V Battery input voltage 200mV reference output REF 3 GND Analog signal ground 4 DETECT When this pin below V the RESET pin to go low 2 ...

Page 3

... V (MAX), 9µ OUT OPERATING CONDITIONS Temperature Range ML4861CS-X .............................................. 0°C to 70°C ML4861ES-X ........................................... –20°C to 70°C ML4861IS-X ............................................ –40°C to 85°C V Operating Range IN ML4861CS-X ................................ 1. ML4861ES-X, ML4861IS-X ............ 1. 500mA = Operating Temperature Range (Note 1). A CONDITIONS – 0.2V IN OUT 0 < ...

Page 4

ML4861 (Sumida CD75) 100 F ML4861 V PWR GND IN 0 RESET REF GND V L DETECT V OUT 100 F Figure 1. Application Test Circuit ...

Page 5

FUNCTIONAL DESCRIPTION The ML4861 combines Pulse Frequency Modulation (PFM) and synchronous rectification to create a boost converter that is both highly efficient and simple to use. A PFM regulator charges a single inductor for a fixed period of time and ...

Page 6

ML4861 ML4861-3.3 500 L = 10µH 400 300 200 100 0 1.0 2.0 V (V) IN 500 400 300 200 100 0 Figure 5 shows efficiency under the conditions used to create Figure 4. It can be seen that efficiency ...

Page 7

ML4861-3.3 95% 90% 85% 80% 75 10µH 70% 65 95% 90% 85% 80% 75% 70% 0 OUTPUT CAPACITOR The choice of output capacitor is also important controls the output ripple and ...

Page 8

ML4861 INPUT CAPACITOR Unless the input source is a very low impedance battery, it will be necessary to decouple the input with a capacitor with a value of between 47µF and 100µF. This provides the benefits of preventing input ripple ...

Page 9

TABLE 1. MAXIMUM OUTPUT CURRENT AND EFFICIENCY. ML4861-3 (mA) EFFICIENCY PERCENTAGE IN OUT L = 10µH 1.0 77.5 1.5 191.7 2.0 310.2 2.5 409 15µH 1.0 58.5 1.5 137.1 2.0 232.1 2.5 335.3 3.0 405.0 L ...

Page 10

ML4861 TABLE 1. MAXIMUM OUTPUT CURRENT AND EFFICIENCY ML4861-6.0 V (V) I (mA 10µH 1.0 325.8 1.5 524.6 2.0 730.0 2.5 910 15µH 1.0 220.5 1.5 365.7 2.0 516.7 2.5 639.3 3.0 755.1 3.5 ...

Page 11

... PHYSICAL DIMENSIONS 0.017 - 0.027 (0.43 - 0.69) (4 PLACES) 0.055 - 0.061 (1.40 - 1.55) ORDERING INFORMATION PART NUMBER ML4861CS-3 ML4861CS-5 ML4861CS-6 ML4861ES-3 ML4861ES-5 ML4861ES-6 (Obsolete) ML4861IS-3 (Obsolete) ML4861IS-5 (Obsolete) ML4861IS-6 (Obsolete) © 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; ...

Related keywords