MIC79050_05 MICREL [Micrel Semiconductor], MIC79050_05 Datasheet

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MIC79050_05

Manufacturer Part Number
MIC79050_05
Description
Simple Lithium-Ion Battery Charger
Manufacturer
MICREL [Micrel Semiconductor]
Datasheet
General Description
The MIC79050 is a simple single-cell lithium-ion battery char-
ger. It includes an on-chip pass transistor for high precision
charging. Featuring ultrahigh precision (+0.75% over the Li-
ion battery charging temperature range) and “zero” off mode
current, the MIC79050 provides a very simple, cost effective
solution for charging lithium-ion battery.
Other features of the MIC79050 include current limit and
thermal shutdown protection. In the event the input voltage
to the charger is disconnected, the MIC79050 also provides
minimal reverse-current and reversed-battery protection.
The MIC79050 is a fixed 4.2V device and comes in the ther-
mally-enhanced MSO-8, SO-8, and SOT-223 packages. The
8-pin versions also come equipped with enable and feedback
inputs. All versions are specified over the temperature range
of –40°C to +125°C.
Ordering Information
Typical Applications
August 2005
MIC79050
Standard
MIC79050-4.2BS
MIC79050-4.2BM
MIC79050-4.2BMM
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
Part Number
Pb-Free
MIC79050-4.2YS
MIC79050-4.2YM
MIC79050-4.2YMM
Regulated or
wall adapter
unregulated
Regulated or
wall adapter
unregulated
Simplest Battery Charging Solution
Voltage
4.2V
4.2V
4.2V
Pulse-Charging Application
MIC79050-4.2BMM
MIC79050-4.2BS
IN
EN
GND
IN
–40ºC to +125ºC
–40ºC to +125ºC
–40ºC to +125ºC
GND
BAT
Temp. Range
FB
BAT
Junction
1
Features
• High accuracy charge voltage:
• “Zero” off-mode current
• 10µA reverse leakage
• Ultralow 380mV dropout at 500mA
• Wide input voltage range
• Logic controlled enable input (8-pin devices only)
• Thermal shutdown and current limit protection
• Power MSOP-8, Power SOIC-8, and SOT-223
• Pulse charging capability
Applications
• Li-ion battery charger
• Celluar phones
• Palmtop computers
• PDAs
• Self charging battery packs
*See Applications Information
±0.75% over -5°C to + 60°C (Li-ion charging
temperature range)
4.2V 0.75% Over Temp
Simple Lithium-Ion Battery Charger
Li-Ion
Cell
SOT-223-3
4.2V 0.75%
Package
MSOP-8
SOIC-8
External PWM*
Li-Ion
Cell
MIC79050
Micrel, Inc.
MIC79050

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MIC79050_05 Summary of contents

Page 1

MIC79050 General Description The MIC79050 is a simple single-cell lithium-ion battery char- ger. It includes an on-chip pass transistor for high precision charging. Featuring ultrahigh precision (+0.75% over the Li- ion battery charging temperature range) and “zero” off mode current, ...

Page 2

MIC79050 Pin Configuration Pin Description Pin No. Pin No. Pin Name SOT-223 SOIC-8 MSOP 5–8 GND TAB 3 3 BAT MIC79050 GND TAB GND BAT MIC79050-x.xBS/YS SOT-223 EN ...

Page 3

MIC79050 Absolute Maximum Ratings Supply Input Voltage (V ) ..............................–20V to +20V IN Power Dissipation (P ) ................ Internally Limited, Note 3 D Junction Temperature (T ) ........................ –40°C to +125°C J Lead Temperature (soldering, 5 sec.) ........................ 260°C Storage ...

Page 4

MIC79050 Typical Characteristics Dropout Voltage vs. Output Current 400 300 200 100 0 0 100 200 300 400 500 OUTPUT CURRENT (mA) Dropout Characteristics 5 4 250mA 500mA INPUT VOLTAGE (V) Ground ...

Page 5

MIC79050 Typical Voltage Drift Limits vs. Time 0.75 0. Lower -0.25 -0.75 0 200 400 600 800 TIME (hrs) August 2005 Reverse Leakage Current vs. Output Voltage ...

Page 6

MIC79050 Block Diagrams Current Limit Thermal Shutdown MIC79050-x.xBS 3-Pin Version Functional Description The MIC79050 is a high-accuracy, linear battery charging circuit designed for the simplest implementation of a single lithium-ion (Li-ion) battery charger. The part can operate ...

Page 7

MIC79050 Applications Information Simple Lithium-Ion Battery Charger. Figure 1A shows a simple, complete lithium-ion battery char- ger. The charging circuit comprises of a cheap wall adapter, with a load-line characteristic. This characteristic is always present with cheap adapters due to ...

Page 8

MIC79050 End of Charge (V Unregulated Input Voltage(V 79050 Programmed Output Voltage (No LoadVoltage) Battery Voltage (V Battery Current (I The Charging Cycle (See Figure 1C.) 1. State A: Initial charge. Here the battery’s charging cur- rent is limited by ...

Page 9

MIC79050 Protected Constant-Current Charger Another form of charging is using a simple wall adapter that offers a fixed voltage at a controlled, maximum current rating. The output of a typical charger will source a fixed voltage at a maximum current ...

Page 10

MIC79050 MIC79050-4.2BMM IN BAT VIN 4.7µ GND 100k R1 R2 GND V V Figure 4. Pulse Charging For Top-off Voltage Charging Rate Lithium-ion cells are typically charged at rates that are frac- tional multiples of their rated capacity. ...

Page 11

MIC79050 Simple Charging The MIC79050 is available in a three-terminal package, allow- ing for extremely simple battery charging. When used with a current-limited, low-power input supply, the MIC79050-4.2BS completes a very simple, low-charge-rate, battery-charger circuit. It provides the accuracy required ...

Page 12

MIC79050 temperature is +40°C and the power dissipation is as above, 0.46W, the curve in Figure 10 shows that the required area 2 of copper is 50mm . The θ of this package is ideally 63°C/W, but it will vary ...

Page 13

MIC79050 Package Information August 2005 SOT-223 (S) 8-Pin SOIC (M) 13 Micrel, Inc. MIC79050 ...

Page 14

MIC79050 0.122 (3.10) 0.112 (2.84) 0.036 (0.90) 0.032 (0.81) 0.012 (0.3) 0.0256 (0.65) TYP MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA + 1 (408) 944-0800 TEL This information furnished by Micrel in this data sheet is believed ...

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