MCP73812T-420I/OT - MICROCHIP

MCP73811/2

Features

• Complete Linear Charge Management Controller

- Integrated Pass Transistor

- Integrated Current Sense

- Integrated Reverse Discharge Protection

• Constant Current / Constant Voltage Operation

with Thermal Regulation

• High Accuracy Preset Voltage Regulation: + 1%

• Voltage Regulation: 4.20V

• Selectable Charge Current:

- MCP73811: 85 mA / 450 mA

• Programmable Charge Current:

- MCP73812: 50 mA - 500 mA

• Minimum External Components Required:

- MCP73811: 2 Ceramic Capacitors

- MCP73812: 2 Ceramic Capacitors and

1 Resistor

• No Preconditioning

• External End-of-Charge Control

• Automatic Power-Down when Input Power

Removed

• Active High Charge Enable

• Temperature Range:

- -40°C to +85°C

• Packaging:

- 5-Lead SOT-23

Applications

• Low-Cost Lithium-Ion/Lithium-Polymer Battery

Chargers

• Rechargeable Toys

• Electronic Cigarettes

• Bluetooth Headsets

• USB Chargers

Description

The MCP73811/2 devices are linear charge manage-

ment controllers that are designed for use in space

limited and cost sensitive applications. The

MCP73811/2 provide specific charge algorithms for

single cell Li-Ion or Li-Polymer battery to achieve

optimal capacity in the shortest charging time possible.

Along with its small physical size, the low number of

external components required make the MCP73811/2

ideally suited for portable applications. For applications

charging from a USB port, the MCP73811 adheres to

all the specifications governing the USB power bus.

The MCP73811/2 employ a constant current/constant

voltage charge algorithm. The constant voltage regula-

tion is fixed at 4.20V, with a tight regulation tolerance of

1%. For the MCP73811, the constant current value is

selected as 85 mA (low power USB port) or 450 mA

(high power USB port) with a digital input signal on the

PROG input. For the MCP73812, the constant current

value is set with one external resistor. The

MCP73811/2 limit the charge current based on die

temperature during high power or high ambient

conditions. This thermal regulation optimizes the

charge cycle time while maintaining device reliability.

The MCP73811/2 are fully specified over the ambient

temperature range of -40°C to +85°C. The

MCP73811/2 are available in a 5-Lead, SOT-23

package.

Package Types

VDD

VBAT

5-Pin SOT-23

CE PROG

VSS

Simple, Miniature Single-Cell, Fully Integrate d

Li-Ion / Li-Polymer Charge Management Controllers

MCP73811/2

Typical Applications

Functional Block Diagram

VDD

VSS

PROG

VBAT +

Single

Li-Ion

Cell

MCP73812

500 mA Li-Ion Battery Charger

2kΩ

VDD

VSS

PROG

VBAT +

Single

Li-Ion

Cell

MCP73811

1µF

450 mA Li-Ion Battery Charger

VIN

1µF 1µF

VIN

1µF

Reference

Generator

VREF (1.21V)

VBAT

VDD VBAT

G=0.001

VSS

Direction

Control

Direction

Control

6µA

157.3 kΩ

388.7 kΩ

Charge

Enable

2.7 kΩ

PROG

111 kΩ

528.6 kΩ

MCP73811MCP73812

12 kΩ

MCP73811/2

1.0 ELECTRICAL

CHARACTERISTICS

Absolute Maximum Ratings†

VDDN................................................................................7.0V

All Inputs and Outputs w.r.t. VSS ............... -0.3 to (VDD+0.3)V

Maximum Junction Temperature, TJ............ Internally Limited

Storage temperature .....................................-65°C to +150°C

ESD protection on all pins

Human Body Model (1.5 kW in Series with 100 pF) ......≥ 4kV

Machine Model (200pF, No Series Resistance) ..............400V

† Notice: Stresses above those listed under “Maximum

Ratings” may cause permanent damage to the device.

This is a stress rating only and functional operation of

the device at those or any other conditions above those

indicated in the operational listings of this specification

is not implied. Exposure to maximum rating conditions

for extended periods may affect device reliability.

DC CHARACTERISTICS

Electrical Specifications: Unless otherwise indicated, all limits apply for VDD= [VREG(typ.) + 0.3V] to 6V,

TA = -40°C to +85°C. Typical values are at +25°C, VDD = [VREG (typ.) + 1.0V]

Parameters Sym Min Typ Max Units Conditions

Supply Input

Supply Voltage VDD 3.75 — 6 V

Supply Current ISS — 1000 1500 µA Charging

— 50 100 µA Standby (CE = VSS)

— 1.2 5 µA Shutdown

(VDD < VBAT - 100 mV)

Voltage Regulation (Constant Voltage Mode)

Regulated Output Voltage VREG —4.20—VV

DD=[VREG(Typ)+1V]

IOUT=10 mA

Output Voltage Tolerance VRTOL -1 — +1 % TA=-5°C to +55°C

Line Regulation |(ΔVBAT/VBAT)

/ΔVDD|

— 0.09 0.30 %/V VDD=[VREG(Typ)+1V] to 6V

IOUT=10 mA

Load Regulation |ΔVBAT/VBAT| — 0.09 0.30 % IOUT=10 mA to 50 mA

VDD=[VREG(Typ)+1V]

Supply Ripple Attenuation PSRR — 52 — dB IOUT=10 mA, 10 Hz to 1 kHz

—47—dBI

OUT=10 mA, 10 Hz to 10 kHz

—22—dBI

OUT=10 mA, 10 Hz to 1 MHz

Current Regulation (Fast Charge Constant-Current Mode)

Fast Charge Current IREG — 85 — mA MCP73811 - PROG = Low

Regulation — 450 — mA MCP73811 - PROG = High

— 50 — mA MCP73812 - PROG = 20 kΩ

— 100 — mA MCP73812 - PROG = 10 kΩ

— 500 — mA MCP73812 - PROG = 2 kΩ

Charge Current Tolerance IRTOL -10 — +10 % TA=-5°C to +55°C

Pass Transistor ON-Resistance

ON-Resistance RDSON — 400 — mΩVDD = 3.75V, TJ = 105°C

Battery Discharge Current

Output Reverse Leakage IDISCHARGE

Current — 0.5 2 µA Shutdown

(VDD < VBAT - 100 mV)

MCP73811/2

TEMPERATURE SPECIFICATIONS

Charge Enable (CE), PROG Input - MCP73811

Input High Voltage Level VIH 2——V

Input Low Voltage Level VIL ——0.8V

Input Leakage Current ILK —0.01 1µAV

CE = VDD, VPROG = VDD

PROG Input - MCP73812

Charge Impedance Range RPROG 2—20kΩMCP73812

Automatic Power Down (Direction Control)

Automatic Power Down

Entry Threshold

VPD VBAT +

10 mV

VBAT +

50 mV

— V 2.3V < VBAT < VREG

VDD Falling

Automatic Power Down

Exit Threshold

VPDEXIT —V

BAT +

150 mV

VBAT +

250 mV

V2.3V < VBAT < VREG

VDD Rising

Thermal Shutdown

Die Temperature TSD — 150 — °C

Die Temperature TSDHYS —10—°C

Hysteresis

Electrical Specifications: Unless otherwise indicated, all limits apply for VDD = [VREG (typ.) + 0.3V] to 6V.

Typical values are at +25°C, VDD = [VREG (typ.) + 1.0V]

Parameters Sym Min Typ Max Units Conditions

Temperature Ranges

Specified Temperature Range TA-40 — +85 °C

Operating Temperature Range TJ-40 — +125 °C

Storage Temperature Range TA-65 — +150 °C

Thermal Package Resistances

Thermal Resistance, 5-Lead, SOT-23 θJA — 230 — °C/W 4-Layer JC51-7 Standard Board,

Natural Convection

DC CHARACTERISTICS (Continued)

Electrical Specifications: Unless otherwise indicated, all limits apply for VDD= [VREG(typ.) + 0.3V] to 6V,

TA = -40°C to +85°C. Typical values are at +25°C, VDD = [VREG (typ.) + 1.0V]

Parameters Sym Min Typ Max Units Conditions

MCP73811/2

2.0 TYPICAL PERFORMANCE CURVES

Note: Unless otherwise indicated, VDD = [VREG(typ.) + 1V], IOUT = 10 mA and TA= +25°C, Constant-voltage mode.

FIGURE 2-1: Battery Regulation Voltage

(VBAT) vs. Supply Voltage (VDD).

FIGURE 2-2: Battery Regulation Voltage

(VBAT) vs. Ambient Temperature (TA).

FIGURE 2-3: Output Leakage Current

(IDISCHARGE) vs. Battery Regulation Voltage

(VBAT).

FIGURE 2-4: Charge Current (IOUT) vs.

Supply Voltage (VDD) - MCP73811.

FIGURE 2-5: Charge Current (IOUT) vs.

Supply Voltage (VDD) - MCP73811.

FIGURE 2-6: Charge Current (IOUT) vs.

Ambient Temperature (TA) - MCP73811.

Note: The graphs and tables provided following this note are a statistical summary based on a limited number of

samples and are provided for informational purposes only. The performance characteristics listed herein

are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified

operating range (e.g., outside specified power supply range) and therefore outside the warranted range.

4.170

4.175

4.180

4.185

4.190

4.195

4.200

4.205

4.210

4.50 4.75 5.00 5.25 5.50 5.75 6.00

Supply Voltage (V)

Battery Regulation Voltage

(V)

IOUT = 10 mA

IOUT = 100 mA

IOUT = 450 mA

4.170

4.175

4.180

4.185

4.190

4.195

4.200

4.205

4.210

-40

-30

-20

-10

Ambient Temperature (°C)

Battery Regulation Voltage (V)

IOUT = 10 mA

IOUT = 100 mA

IOUT = 450 mA

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

3.00 3.20 3.40 3.60 3.80 4.00 4.20

Battery Regulation Voltage (V)

Output Leakage Current (µA)

+85°C

-40°C

+25°C

4.5 4.75 5 5.25 5.5 5.75 6

Supply Voltage (V)

Charge Current (mA)

PROG = Low

Temp = +25°C

425

430

435

440

445

450

455

460

4.5 4.75 5 5.25 5.5 5.75 6

Supply Voltage (V)

Charge Current (mA)

PROG = High

Temp = 25°C

100

-40-30-20-100 1020304050607080

Ambient Temperature (°C)

Charge Current (mA)

PROG = Low

VDD

= 5

MCP73811/2

Typical Performance Curves (Continued)

Note: Unless otherwise indicated, VDD = [VREG(typ.) + 1V], IOUT = 10 mA and TA= +25°C, Constant-voltage mode.

FIGURE 2-7: Charge Current (IOUT) vs.

Ambient Temperature (TA) - MCP73811.

FIGURE 2-8: Charge Current (IOUT) vs.

Programming Resistor (RPROG) - MCP73812.

FIGURE 2-9: Charge Current (IOUT) vs.

Supply Voltage (VDD) - MCP73812.

FIGURE 2-10: Charge Current (IOUT) vs.

Supply Voltage (VDD) - MCP73812.

FIGURE 2-11: Charge Current (IOUT) vs.

Ambient Temperature (TA) - MCP73812.

FIGURE 2-12: Charge Current (IOUT) vs.

Ambient Temperature (TA) - MCP73812.

400

410

420

430

440

450

460

470

480

-40-30-20-100 1020304050607080

Ambient Temperature (°C)

Charge Current (mA)

PROG = High

VDD = 5V

100

150

200

250

300

350

400

450

500

550

2 4 6 8 10 12 14 16 18 20

Programming Resistor (kΩ)

Charge Current (mA)

100

101

102

103

104

4.50 4.75 5.00 5.25 5.50 5.75 6.00

Supply Voltage (V)

Charge Current (mA)

RPROG = 10 kΩ

500

502

504

506

508

510

512

514

516

4.50 4.75 5.00 5.25 5.50 5.75 6.00

Supply Voltage (V)

Charge Current (mA)

RPROG = 2 kΩ

100

101

102

103

104

-40

-30

-20

-10

Ambient Temperature (°C)

Charge Current (mA)

RPROG = 10 kΩ

500

502

504

506

508

510

512

514

516

-40

-30

-20

-10

Ambient Temperature (°C)

Charge Current (mA)

RPROG = 2 kΩ

MCP73811/2

Typical Performance Curves (Continued)

Note: Unless otherwise indicated, VDD = [VREG(typ.) + 1V], IOUT = 10 mA and TA= +25°C, Constant-voltage mode.

FIGURE 2-13: Charge Current (IOUT) vs.

Junction Temperature (TJ) - MCP73812.

FIGURE 2-14: Charge Current (IOUT) vs.

Junction Temperature (TJ) - MCP73812.

FIGURE 2-15: Power Supply Ripple

Rejection (PSRR).

FIGURE 2-16: Power Supply Ripple

Rejection (PSRR).

FIGURE 2-17: Line Transient Response.

FIGURE 2-18: Line Transient Response.

105

120

105

115

125

135

145

155

Junction Temperature (°C)

Charge Current (mA)

RPROG

= 10 kΩ

150

225

300

375

450

525

105

115

125

135

145

155

Junction Temperature (°C)

Charge Current (mA)

RPROG = 2 kΩ

-60

-50

-40

-30

-20

-10

0.01 0.1 1 10 100 1000

Frequency (kHz)

Attenuation (dB)

VAC = 100 mVp-p

IOUT = 10 mA

COUT = 4.7 μF, X7R

Ceramic

-60

-50

-40

-30

-20

-10

0.01 0.1 1 10 100 1000

Frequency (kHz)

Attenuation (dB)

VAC = 100 mVp-p

IOUT = 100 mA

COUT = 4.7 µF, X7R

Ceramic

-2

100

120

140

160

180

200

Time (µs)

Source Voltage (V)

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Output Ripple (V)

IOUT = 10 mA

COUT = 4.7 µF, X7R

Ceramic

-2

100

120

140

160

180

200

Time (µs)

Source Voltage (V)

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Output Ripple (V)

IOUT = 100 mA

COUT = 4.7 µF, X7R

Ceramic

MCP73811/2

Typical Performance Curves (Continued)

Note: Unless otherwise indicated, VDD = [VREG(typ.) + 1V], IOUT = 10 mA and TA= +25°C, Constant-voltage mode.

FIGURE 2-19: Load Transient Response.

FIGURE 2-20: Load Transient Response.

FIGURE 2-21: Typical Charge Profile

(950 mAh) Li-Ion Battery.

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

100

120

140

160

180

200

Time (µs)

Output Current (A)

-0.12

-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

Output Ripple (V)

COUT = 4.7 µF, X7R

Ceramic

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

100

120

140

160

180

200

Time (µs)

Output Current (A)

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Output Ripple (V)

COUT = 4.7 µF, X7R

Ceramic

0.0

1.0

2.0

3.0

4.0

5.0

105

120

135

150

165

180

Time (Minutes)

Battery Voltage (V)

Charge Current (mA)

100

200

300

400

500

MCP73812T-420I/OT

VDD = 5.0V

RPROG = 2 kΩ

MCP73811/2

3.0 PIN DESCRIPTION

The descriptions of the pins are listed in Table 3-1.

TABLE 3-1: PIN FUNCTION TABLES

3.1 Charge Enable Input (CE)

A logic High enables battery charging. A logic Low

disables battery charging. The charge enable input is

compatible with 1.8V logic.

3.2 Battery Management 0V Reference

(VSS)

Connect to negative terminal of battery and input

supply.

3.3 Battery Charge Control Output

(VBAT)

Connect to positive terminal of battery. Drain terminal

of internal P-channel MOSFET pass transistor. Bypass

to VSS with a minimum of 1 µF to ensure loop stability

when the battery is disconnected.

3.4 Battery Management Input Supply

(VDD)

A supply voltage of [VREG (typ.) + 0.3V] to 6V is

recommended. Bypass to VSS with a minimum of 1 µF.

3.5 Current Regulation Set (PROG)

For the MCP73811, the current regulation set input

(PROG) functions as a digital input selection. A logic

Low selects a 85 mA charge current; a logic High

selects a 450 mA charge current.

For the MCP73812, the charge current is set by placing

a resistor from PROG to VSS.

Pin Number

Symbol Function

SOT-23-5

1 CE Active High Charge Enable

SS Battery Management 0V Reference

BAT Battery Charge Control Output

DD Battery Management Input Supply

5 PROG Current Regulation Set and Charge Control Enable

MCP73811/2

4.0 DEVICE OVERVIEW

The MCP73811/2 are simple, but fully integrated linear

charge management controllers. Figure 4-1 depicts the

operational flow algorithm.

FIGURE 4-1: Flow Chart.

4.1 Undervoltage Lockout (UVLO)

The MCP73811/2 does not have an internal under

voltage lockout (UVLO) circuit.

4.2 Charge Qualification

When the input power is applied, the input supply must

rise 150 mV above the battery voltage before the

MCP73811/2 becomes operational.

The automatic power down circuit places the device in

a shutdown mode if the input supply falls to within

+50 mV of the battery voltage.

The automatic circuit is always active. Whenever the

input supply is within +50 mV of the voltage at the VBAT

pin, the MCP73811/2 is placed in a shutdown mode.

During power down condition, the battery reverse dis-

charge current is less than 2 µA.

For a charge cycle to begin, the automatic power down

conditions must be met and the charge enable input

must be above the input high threshold.

4.3 PRECONDITIONING

The MCP73811/2 does not support preconditioning of

deeply depleted cells.

4.4 Constant Current MODE - Fast

Charge

During the constant current mode, the selected

(MCP73811) or programmed (MCP73812) charge

current is supplied to the battery or load.

For the MCP73812, the charge current is established

using a single resistor from PROG to VSS. The program

resistor and the charge current are calculated using the

following equation:

EQUATION 4-1:

Constant current mode is maintained until the voltage

at the VBAT pin reaches the regulation voltage, VREG

4.5 Constant Voltage Mode

When the voltage at the VBAT pin reaches the

regulation voltage, VREG

, constant voltage regulation

begins. The regulation voltage is factory set to 4.20V

with a tolerance of ±1.0%.

4.6 Charge Termination

The charge cycle is terminated by removing the battery

from the charger, removing input power, or driving the

charge enable input (CE) to a logic Low. An automatic

charge termination method is not implemented.

4.7 Automatic Recharge

The MCP73811/2 does not support automatic recharge

cycles since automatic charge termination has not

been implemented. In essence, the MCP73811/2 is

always in a charge cycle whenever the qualification

parameters have been met.

SHUTDOWN MODE*

VDD < VPD

CONSTANT CURRENT

MODE

Charge Current = IREG

CONSTANT VOLTAGE

MODE

Charge Voltage = VREG

* Continuously

Monitored

VBAT = VREG

STANDBY MODE*

CE = Low

VBAT < VREG

IREG

1000V

RPROG

-----------------=

Where:

RPROG = kilo-ohms

IREG = milliamperes

MCP73811/2

4.8 Thermal Regulation

The MCP73811/2 limits the charge current based on

the die temperature. The thermal regulation optimizes

the charge cycle time while maintaining device

reliability. Figure 4-2 depicts the thermal regulation for

the MCP73811/2.

FIGURE 4-2: Thermal Regulation.

4.9 Thermal Shutdown

The MCP73811/2 suspends charge if the die

temperature exceeds 150°C. Charging will resume

when the die temperature has cooled by approximately

10°C. The thermal shutdown is a secondary safety

feature in the event that there is a failure within the

thermal regulation circuitry.

150

225

300

375

450

525

105

115

125

135

145

155

Junction Temperature (°C)

Charge Current (mA)

RPROG = 2 kΩ

MCP73811/2

5.0 DETAILED DESCRIPTION

5.1 Analog Circuitry

5.1.1 BATTERY MANAGEMENT INPUT

SUPPLY (VDD)

The VDD input is the input supply to the MCP73811/2.

The MCP73811/2 automatically enters a Power-down

mode if the voltage on the VDD input falls to within

+50 mV of the battery voltage. This feature prevents

draining the battery pack when the VDD supply is not

present.

5.1.2 MCP73812 CURRENT REGULATION

SET (PROG)

For the MCP73812, the charge current regulation can

be scaled by placing a programming resistor (RPROG)

from the PROG input to VSS. The program resistor and

the charge current are calculated using the following

equation:

EQUATION 5-1:

5.1.3 BATTERY CHARGE CONTROL

OUTPUT (VBAT)

The battery charge control output is the drain terminal

of an internal P-channel MOSFET. The MCP73811/2

provides constant current and voltage regulation to the

battery pack by controlling this MOSFET in the linear

region. The battery charge control output should be

connected to the positive terminal of the battery pack.

5.2 Digital Circuitry

5.2.1 CHARGE ENABLE (CE)

The charge enable input pin (CE) can be used to

terminate a charge at any time during the charge cycle,

as well as to initiate a charge cycle or initiate a recharge

cycle.

Driving the input to a logic High enables the device.

Driving the input to a logic Low disables the device and

terminates a charge cycle. When disabled, the device’s

supply current is reduced to 50 µA, typically.

5.2.2 MCP73811 CURRENT REGULATION

SELECT (PROG)

For the MCP73811, driving the PROG input to a logic

Low selects the low charge current setting (85 mA).

Driving the PROG input to a logic High selects the high

charge current setting (450 mA).

IREG

1000V

RPROG

-----------------=

Where:

RPROG = kilo-ohms

IREG = milliamperes

MCP73811/2

6.0 APPLICATIONS

The MCP73811/2 is designed to operate in conjunction

with a host microcontroller or in stand-alone

applications. The MCP73811/2 provides the preferred

charge algorithm for Lithium-Ion and Lithium-Polymer

cells Constant-current followed by Constant-voltage.

Figure 6-1 depicts a typical stand-alone application

circuit, while Figures 6-2 depict the accompanying

charge profile.

FIGURE 6-1: Typical Application Circuit.

FIGURE 6-2: Typical Charge Profile

(950 mAh Li-Ion Battery).

6.1 Application Circuit Design

Due to the low efficiency of linear charging, the most

important factors are thermal design and cost, which

are a direct function of the input voltage, output current

and thermal impedance between the battery charger

and the ambient cooling air. The worst-case situation is

when the device has transitioned from the

Preconditioning mode to the Constant-current mode. In

this situation, the battery charger has to dissipate the

maximum power. A trade-off must be made between

the charge current, cost and thermal requirements of

the charger.

6.1.1 COMPONENT SELECTION

Selection of the external components in Figure 6-1 is

crucial to the integrity and reliability of the charging

system. The following discussion is intended as a guide

for the component selection process.

6.1.1.1 Charge Current

The preferred fast charge current for Lithium-Ion cells

is at the 1C rate, with an absolute maximum current at

the 2C rate. For example, a 500 mAh battery pack has

a preferred fast charge current of 500 mA. Charging at

this rate provides the shortest charge cycle times

without degradation to the battery pack performance or

life.

VDD

VSS

PROG

VBAT +

Single

Li-Ion

Cell

MCP73812

CIN

Li-Ion Battery Charger

RPROG

COUT

REGULATED

WALL CUBE

0.0

1.0

2.0

3.0

4.0

5.0

105

120

135

150

165

180

Time (Minutes)

Battery Voltage (V)

Charge Current (mA)

100

200

300

400

500

MCP73812T-420I/OT

VDD = 5.0V

RPROG = 2 kΩ

MCP73811/2

6.1.1.2 Thermal Considerations

The worst-case power dissipation in the battery

charger occurs when the input voltage is at the

maximum and the device has transitioned from the

Preconditioning mode to the Constant-current mode. In

this case, the power dissipation is:

EQUATION 6-1:

Power dissipation with a 5V, ±10% input voltage source

is:

EQUATION 6-2:

This power dissipation with the battery charger in the

SOT-23-5 package will cause thermal regulation to be

entered as depicted in Figure 6-3.

6.1.1.3 External Capacitors

The MCP73811/2 is stable with or without a battery

load. In order to maintain good AC stability in the

Constant-voltage mode, a minimum capacitance of

1 µF is recommended to bypass the VBAT pin to VSS.

This capacitance provides compensation when there is

no battery load. In addition, the battery and intercon-

nections appear inductive at high frequencies. These

elements are in the control feedback loop during

Constant-voltage mode. Therefore, the bypass

capacitance may be necessary to compensate for the

inductive nature of the battery pack.

Virtually any good quality output filter capacitor can be

used, independent of the capacitor’s minimum

Effective Series Resistance (ESR) value. The actual

value of the capacitor (and its associated ESR)

depends on the output load current. A 1 µF ceramic,

tantalum or aluminum electrolytic capacitor at the

output is usually sufficient to ensure stability for output

currents up to a 500 mA.

6.1.1.4 Reverse-Blocking Protection

The MCP73811/2 provides protection from a faulted or

shorted input. Without the protection, a faulted or

shorted input would discharge the battery pack through

the body diode of the internal pass transistor.

6.1.1.5 Charge Inhibit

The charge enable input pin (CE) can be used to

terminate a charge at any time during the charge cycle,

as well as to initiate a charge cycle or initiate a recharge

cycle.

Driving the input to a logic High enables the device.

Driving the input to a logic Low disables the device and

terminates a charge cycle. When disabled, the device’s

supply current is reduced to 50 µA, typically.

6.2 PCB Layout Issues

For optimum voltage regulation, place the battery pack

as close as possible to the device’s VBAT and VSS pins,

recommended to minimize voltage drops along the

high current-carrying PCB traces.

If the PCB layout is used as a heatsink, adding many

vias in the heatsink pad can help conduct more heat to

the backplane of the PCB, thus reducing the maximum

junction temperature. Figures 6-3 and 6-4 depict a

typical layout with PCB heatsinking.

FIGURE 6-3: Typical Layout (Top).

FIGURE 6-4: Typical Layout (Bottom).

PowerDissipation VDDMAX VPTHMIN

–()IREGMAX

×=

Where:

VDDMAX = the maximum input voltage

IREGMAX = the maximum fast charge current

VPTHMIN = the minimum transition threshold

voltage

PowerDissipation 5.5V 2.7V–()500mA

1.4W==

COUT

RPROG

CIN

MCP73812

VBAT VDD

VSS

VBAT

VSS

VDD

MCP73811/2

7.0 PACKAGE INFORMATION

7.1 Package Marking Information

5-Pin SOT-23

XXNN

Standard *

Part Number Code

MCP73811T-420I/OT KSNN

MCP73812T-420I/OT KWNN

Example:

Legend: XX...X Customer-specific information

Y Year code (last digit of calendar year)

YY Year code (last 2 digits of calendar year)

WW Week code (week of January 1 is week ‘01’)

NNN Alphanumeric traceability code

Pb-free JEDEC designator for Matte Tin (Sn)

*This package is Pb-free. The Pb-free JEDEC designator ( )

can be found on the outer packaging for this package.

Note: In the event the full Microchip part number cannot be marked on one line, it will

be carried over to the next line, thus limiting the number of available

characters for customer-specific information.

KSNN

* Custom output voltages available upon request.

Contact your local Microchip sales office for more information.

MCP73811/2

5-Lead Plastic Small Outl ine Transistor (OT) [SOT-23]

Notes:

1. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not ex ceed 0.127 mm per side.

2. Dimensioning and tolerancing per ASME Y14.5M.

BSC: Basic Dimension. Theoretically exact value shown without tolerances.

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

Units MILLIMETERS

Dimension Limits MIN NOM MAX

Number of Pins N 5

Lead Pitch e 0.95 BSC

Outside Lead Pitch e1 1.90 BSC

Overall Height A 0.90 – 1.45

Molded Package Thickness A2 0.89 – 1.30

Standoff A1 0.00 – 0.15

Overall Width E 2.20 – 3.20

Molded Package Width E1 1.30 – 1.80

Overall Length D 2.70 – 3.10

Foot Length L 0.10 – 0.60

Footprint L1 0.35 – 0.80

Foot Angle φ0° – 30°

Lead Thickness c 0.08 – 0.26

Lead Width b 0.20 – 0.51

123

A2 c

Microchip Technology Drawing C04-091B

MCP73811/2

APPENDIX A: REVISION HISTORY

Revision B (September 2007)

The following is the list of modifications:

1. Modified “No End-of-Charge Control” bullet to

read “External End-of-Charge Control”.

2. Deleted No Undervoltage Lockout (UVLO) bullet

3. Replaced Figure 2-21 with new plot and

changed figure caption.

4. Deleted Figure 2-22.

5. Replaced Figure 6-2 with new plot and changed

figure caption.

6. Deleted Figure 6-3.

7. Updated revision history.

Revision A (March 2007)

• Original Release of this Document.

MCP73811/2

NOTES:

MCP73811/2

PRODUCT IDENTIFICATION SYSTEM

To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.

Device: MCP73811T: Li-Ion Charger w/Selectable Charge Current,

Tape and Reel

MCP73812T: Li-Ion Charger w/Selectable Charge Current,

Tape and Reel

Voltage Options *: 420 = 4.2V “Standard”

*Contact factory for other output voltage options.

Temperature: I = -40°C to +85°C

Package Type: OT = Small Outline Transistor (SOT-23), 5-lead

PART NO. XXX

Voltage

Device

Options

Temperature

/XX

Package

Examples:

a) MCP73811T-420I/OT: 4.2V Charger

SOT-23-5 pkg.

a) MCP73812T-420I/OT: 4.2V Charger

SOT-23-5 pkg.

—

MCP73811/2

NOTES:

Information contained in this publication regarding device

applications and the like is provided only for your convenience

and may be superseded by updates. It is your responsibility to

ensure that your application meets with your specifications.

MICROCHIP MAKES NO REPRESENTATIONS OR

WARRANTIES OF ANY KIND WHETHER EXPRESS OR

IMPLIED, WRITTEN OR ORAL, STATUTORY OR

OTHERWISE, RELATED TO THE INFORMATION,

INCLUDING BUT NOT LIMITED TO ITS CONDITION,

QUALITY, PERFORMANCE, MERCHANTABILITY OR

FITNESS FOR PURPOSE. Microchip disclaims all liability

arising from this information and its use. Use of Microchip

devices in life support and/or safety applications is entirely at

the buyer’s risk, and the buyer agrees to defend, indemnify and

hold harmless Microchip from any and all damages, claims,

suits, or expenses resulting from such use. No licenses are

conveyed, implicitly or otherwise, under any Microchip

intellectual property rights.

Trademarks

The Microchip name and logo, the Microchip logo, Accuron,

dsPIC, KEELOQ, KEELOQ logo, microID, MPLAB, PIC,

PICmicro, PICSTART, PRO MATE, rfPIC and SmartShunt are

registered trademarks of Microchip Technology Incorporated

in the U.S.A. and other countries.

AmpLab, FilterLab, Linear Active Thermistor, Migratable

Memory, MXDEV, MXLAB, SEEVAL, SmartSensor and The

Embedded Control Solutions Company are registered

trademarks of Microchip Technology Incorporated in the

U.S.A.

Analog-for-the-Digital Age, Application Maestro, CodeGuard,

dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,

ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,

In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi,

MPASM, MPLAB Certified logo, MPLIB, MPLINK, PICkit,

PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal,

PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB, Select

Mode, Smart Serial, SmartTel, Total Endurance, UNI/O,

WiperLock and ZENA are trademarks of Microchip

Technology Incorporated in the U.S.A. and other countries.

SQTP is a service mark of Microchip Technology Incorporated

in the U.S.A.

All other trademarks mentioned herein are property of their

respective companies.

Printed on recycled paper.

Note the following details of the code protection feature on Microchip devices:

• Microchip products meet the specification contained in their particular Microchip Data Sheet.

• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the

intended manner and under normal conditions.

• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our

knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data

Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

• Microchip is willing to work with the customer who is concerned about the integrity of their code.

• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not

mean that we are guaranteeing the product as “unbreakable.”

Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our

products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts

allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Microchip received ISO/TS-16949:2002 certification for its worldwide

headquarters, design and wafer fabrication facilities in Chandler and

Tempe, Arizona; Gresham, Oregon and design centers in California

and India. The Company’s quality system processes and procedures

are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping

devices, Serial EEPROMs, microperipherals, nonvolatile memory and

analog products. In addition, Microchip’s quality system for the design

and manufacture of development systems is ISO 9001:2000 certified.

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06/25/07