Rainbow Electronics MAX1555 User Manual

General Description
The MAX1551/MAX1555 charge a single-cell lithium-ion (Li+) battery from both USB* and AC adapter sources. They operate with no external FETs or diodes, and accept operating input voltages up to 7V.
On-chip thermal limiting simplifies PC board layout and allows optimum charging rate without the thermal limits imposed by worst-case battery and input voltage. When the MAX1551/MAX1555 thermal limits are reached, the chargers do not shut down, but progressively reduce charging current.
The MAX1551 includes a POK output to indicate when input power is present. If either charging source is active, POK goes low. The MAX1555 instead features a CHG output to indicate charging status.
With USB connected, but without DC power, charge cur­rent is set to 100mA (max). This allows charging from both powered and unpowered USB hubs with no port communication required. When DC power is connected, charging current is set at 280mA (typ). No input-blocking diodes are required to prevent battery drain.
The MAX1551/MAX1555 are available in 5-pin thin SOT23 packages and operate over a -40°C to +85°C range.
Applications
PDAs
Wireless Appliances
Cell Phones
Digital Cameras
Features
Charge from USB or AC Adapter
Automatic Switchover when AC Adapter is
Plugged In
On-Chip Thermal Limiting Simplifies Board
Design
Charge Status Indicator
5-Pin Thin SOT23 Package
Protected by U.S. Patent #6,507,172
MAX1551/MAX1555
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+
Battery Chargers
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-2902; Rev 0; 7/03
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Pin Configuration
MAX1551
(MAX1555)
DC
USB
BAT
AC ADAPTER
3.7V TO 7V
USB
3.7V TO 6V
TO SYSTEM LOAD
Li+
GND
TO LOGIC RAIL
CHARGE
CONTROL
POK
(CHG)
LOGIC
CONTROL
Typical Operating Circuit
*Protected by U.S. Patent #6,507,172.
Selector Guide
PART TEMP RANGE PIN-PACKAGE
MAX1551EZK-T -40°C to +85°C 5 Thin SOT23-5
MAX1555EZK-T -40°C to +85°C 5 Thin SOT23-5
PART TOP MARK FEATURES
MAX1551EZK ADRT POK Output MAX1555EZK ADRU CHG Output
TOP VIEW
15BATUSB
MAX1551
2
GND
POK
(CHG)
(MAX1555)
34
THIN SOT23
DC
MAX1551/MAX1555
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+ Battery Chargers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDC= 5V, V
USB
= 0, I
BAT
= 0, C
BAT
= 1µF, TA = 0°C to +85°C, unless otherwise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC to GND......................................................................0 to +8V
DC to BAT .......................................................................0 to +7V
BAT, CHG, POK, USB to GND .................................-0.3V to +7V
Continuous Power Dissipation (T
A
= +70°C)
5-Pin Thin SOT23 (derate 9.1mW/°C above +70°C)....727mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature Range ............................-40°C to +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
DC
DC Voltage Range (Note 1) 3.7 7.0 V
DC to BAT Voltage Range 0.1 6.0 V
DC Undervoltage Lockout Threshold
DC Supply Current 1.75 3 mA
DC to BAT On-Resistance VDC = 3.7V, V
DC to BAT Dropout Voltage
USB
USB Voltage Range (Note 1) 3.7 6.0 V
USB Undervoltage Threshold
USB Supply Current V USB to BAT On-Resistance V
USB to BAT Dropout Voltage
BAT
BAT Regulation Voltage VDC or V
DC Charging Current V
USB Charging Current V
BAT Prequal Threshold V
Prequalification Charging Current V
BAT Leakage Current VDC = V
POK, CHG, AND THERMAL LIMIT
CHG Threshold
CHG, POK Logic-Low Output I CHG, POK Leakage Current V
Thermal-Limit Temperature
PARAMETER CONDITIONS MIN TYP MAX UNITS
Input rising, 430mV hysteresis, V
= 3.6V 1 2
BAT
When charging stops, V DC falling, 200mV hysteresis
Input rising, 430mV hysteresis, V V
= 3V (Note 1)
BAT
= 5V, VDC = 0 1.65 3 mA
USB
= 3.7V, V
USB
When charging stops, V USB falling, 200mV hysteresis, V
= 3.3V, V
BAT
= 3.3V, VDC = 0, V
BAT
rising, 100mV hysteresis 2.9 3 3.1 V
BAT
= 2.8V 20 40 80 mA
BAT
Charge current where CHG goes high, I
falling, 50mA hysteresis
BAT
, I
CHG
POK
, V
CHG
Charge current reduced by 17mA/°C above this temperature
BAT
= 5V 4.158 4.2 4.242 V
USB
USB
= 0, V
USB
= 10mA 150 300 mV
= 6V, TA = +25°C 0.001 1 µA
POK
BAT
= 3.6V, VDC = 0 2 4
BAT
= 0, VDC = 5V 220 280 340 mA
USB
= 4.2V 5 µA
BAT
= 3V (Note 1) 3.75 3.95 4.15 V
BAT
= 4V,
= 0,
DC
= 4V,
= 0
DC
= 5V 80 90 100 mA
30 60 90 mV
3.75 3.95 4.15 V
30 60 90 mV
25 50 100 mA
+110 °C
MAX1551/MAX1555
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+
Battery Chargers
_______________________________________________________________________________________ 3
Note 1: The input undervoltage lockout has 430mV of hysteresis. The charger turns on when an input rises to 3.95V (typ), and turns
off when it falls below 3.52V.
Note 2: Specifications to -40°C are guaranteed by design, not production tested.
ELECTRICAL CHARACTERISTICS
(VDC= 5V, V
USB
= 0, I
BAT
= 0, C
BAT
= 1µF, TA = -40°C to +85°C, unless otherwise noted.) (Note 2)
DC
DC Voltage Range (Note 1) 3.7 7.0 V
DC to BAT Voltage Range 0.1 6.0 V
DC Undervoltage Lockout Threshold
DC Supply Current 3mA
DC to BAT On-Resistance VDC = 3.7V, V
DC to BAT Dropout Voltage
USB
USB Voltage Range (Note 1) 3.7 6.0 V
USB Undervoltage Lockout Threshold
USB Supply Current V
USB to BAT On-Resistance V
USB to BAT Dropout Voltage
BAT
BAT Regulation Voltage VDC or V
DC Charging Current V
USB Charging Current V
BAT Prequal Threshold V
Prequalification Charging Current V
BAT Leakage Current VDC = V
POK, CHG
CHG Threshold
CHG, POK Logic-Low Output I CHG, POK Leakage Current V
PARAMETER CONDITIONS MIN MAX UNITS
Input rising, 430mV hysteresis, V
= 3.6V 2
BAT
When charging stops, V hysteresis
Input rising, 430mV hysteresis, VDC = 0, V (Note 1)
= 5V, VDC = 0 3 mA
USB
= 3.7V, V
USB
When charging stops, V hysteresis, V
USB
= 3.3V, V
BAT
= 3.3V, VDC = 0, V
BAT
rising, 100mV hysteresis 2.9 3.1 V
BAT
= 2.8V 20 80 mA
BAT
USB
Charge current where CHG goes high,
falling, 50mA hysteresis
I
BAT
, I
CHG
POK
, V
CHG
POK
= 3.6V, VDC = 0 4
BAT
= 0
DC
= 5V 4.141 4.259 V
= 0, VDC = 5V 220 340 mA
USB
= 0, V
BAT
= 10mA 300 mV
= 6V, T
= 4V, DC falling, 200mV
BAT
= 4V, USB falling, 200mV
BAT
= 5V 80 100 mA
USB
= 4.2V 5 µA
= +25°C1µA
A
= 3V (Note 1) 3.75 4.15 V
BAT
= 3V
BAT
30 95 mV
3.75 4.15 V
30 95 mV
25 100 mA
MAX1551/MAX1555
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+ Battery Chargers
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VDC= 5V, V
USB
= 0, I
BAT
= 0, C
BAT
= 1µF, TA = +25°C, unless otherwise noted.)
CHARGE CURRENT
vs. DC VOLTAGE HEADROOM
MAX1551/55 toc01
DC VOLTAGE HEADROOM (VDC - V
BAT
) (V)
CHARGE CURRENT (mA)
0.30.20.1
0
50
100
150
200
250
300
-50
00.50.4
V
BAT
= 3.8V, VDC FALLING
CHARGE CURRENT
vs. USB VOLTAGE HEADROOM
MAX1551/55 toc02
USB VOLTAGE HEADROOM (V
USB
- V
BAT
) (V)
CHARGE CURRENT (mA)
0.40.30.20.1
0
20
40
60
80
100
-20
00.5
VDC = 0, V
BAT
= 3.8V, V
USB
FALLING
DC CHARGE CURRENT
vs. BATTERY VOLTAGE
MAX1551/55 toc03
BATTERY VOLTAGE (V)
DC CHARGE CURRENT (mA)
4.03.53.02.52.01.51.00.5
0
50
100
150
200
250
300
-50
04.5
USB CHARGE CURRENT vs. BATTERY VOLTAGE
MAX1551/55 toc04
BATTERY VOLTAGE (V)
USB CHARGE CURRENT (mA)
4.03.53.02.52.01.51.00.5
0
20
40
60
80
100
-20
04.5
DC CHARGE CURRENT
vs. AMBIENT TEMPERATURE
MAX1551/55 toc05
TEMPERATURE (°C)
DC CHARGE CURRENT (mA)
7565554535
0
50
100
150
200
250
300
-50 25 85
V
BAT
= 3.8V, VDC = 5V
THERMAL LIMIT ACTIVATED
BATTERY TERMINATION VOLTAGE
vs. TEMPERATURE
MAx1551/55 toc06
TEMPERATURE (°C)
BATTERY TERMINATION VOLTAGE (V)
35 6010-15
4.19
4.20
4.21
4.22
4.18
-40 85
BAT OPEN
OFF-BATTERY LEAKAGE CURRENT
vs. DC INPUT VOLTAGE
MAX1551/55 toc07
DC OR USB INPUT VOLTAGE (V)
OFF-BATTERY LEAKAGE CURRENT (µA)
4321
0.5
1.0
1.5
2.0
2.5
0
05
VDC = 0, SWEEPING USB 0 TO 5V OR V
USB
= 0,
SWEEPING DC 0 TO 5V
V
BAT
= 4.2V
USB-TO-DC TRANSITION WAVEFORM
MAX1551/55 toc08
400ms/div
V
USB
5V/div
V
DC
5V/div
0A
0V
0V
0V
BATTERY CURRENT 200mA/div
V
POK
2V/div
Detailed Description
The MAX1551/MAX1555 charge a single-cell Li+ bat­tery from both USB and AC adapter sources, enabling portable users to forgo carrying a wall cube. These devices operate with no external FETs or diodes, and accept operating input voltages up to 7V.
An internal thermal control loop simplifies PC board lay­out and allows optimum charging rate without the ther­mal limits imposed by worst-case battery and input voltage. When the MAX1551/MAX1555 thermal limits are reached, the chargers do not shut down, but simply reduce charging current by 17mA/°C above a die tem­perature of +110°C.
With USB connected, but without DC power, the charge current is set to 100mA (max). This allows charging from both powered and unpowered USB hubs with no port communication required. When DC power is con­nected, charging current is set at 280mA (typ). The MAX1551/MAX1555 do not feature an enable input. Once power is connected to USB and/or DC, the charger is on.
When input power is removed, battery leakage current is less than 5µA. No input-blocking diodes are required to prevent battery drain. Insert a diode at DC (the adapter input) if protection from negative voltage inputs (reversed-polarity adapter plugs) is required.
USB to Adapter Power Handoff
The MAX1551/MAX1555 can charge from either the USB input or the DC input. The battery does not charge from both sources at the same time. The MAX1551/ MAX1555 automatically detect the active input and charge from that. If both power sources are active, the DC input takes precedence. The switchover between DC and USB is detailed in Table 1.
MAX1551 Power-OK (
POK
)
The MAX1551s POK is an active-low, open-drain out­put that goes low when VDCor V
USB
is above 3.95V.
POK can be used as a logic output or can drive an LED. POK indicates the charger is connected to input power and is charging.
MAX1555 Charge Status (
CHG
)
The MAX1555s CHG is an active-low, open-drain charge status indicator. CHG pulls low when the battery is charging (whenever USB or DC are powered) and charge current is greater than 50mA. CHG indicates when the battery is fully charged by going high imped­ance when the charger is in voltage mode and charge current falls below 50mA. Charging does not stop when CHG goes high. CHG is low in precharge mode.
MAX1551/MAX1555
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+
Battery Chargers
_______________________________________________________________________________________ 5
Pin Description
Table 1. USB and DC Input Selection
(VDCtakes precedence when both inputs are present.)
PIN NAME FUNCTION
1 USB
2 GND Ground
POK
3
CHG
4DC
5 BAT Battery Connection. Decouple BAT with a 1µF ceramic capacitor to GND.
USB Port Charger Supply Input. USB draws up to 100mA to charge the battery. Decouple USB with a 1µF ceramic capacitor to GND.
Power-OK Active-Low Open-Drain Charger Status Indicator. POK pulls low when either charger source is present (MAX1551 only).
Active-Low Open-Drain Charge Status Indicator. CHG pulls low when the battery is charging. CHG goes to a high-impedance state, indicating the battery is fully charged, when the charger is in voltage mode and charge current falls below 50mA. CHG is high impedance when both input sources are low (MAX1555 only).
DC Charger Supply Input for an AC Adapter. DC draws 280mA to charge the battery. Decouple DC with a 1µF ceramic capacitor to GND.
VDC > 7V OR V
Exceeds operating input range. Not allowed. See the Absolute Maximum Ratings section.
USB
> 6V
V
> 3.95V AND
DC
DONT CARE
V
USB
280mA (typ) charging from DC
V
< 3.52V AND
DC
3.95V < V
100mA (max) charging from USB
USB
< 6V
V
AND V
DC
Undervoltage lockout
USB
< 3.52V
MAX1551/MAX1555
Precharge Current
The MAX1551/MAX1555 feature a precharge current to protect deeply discharged cells. If V
BAT
is less than 3V, the device enters precharge mode where charging cur­rent is limited to 40mA.
Package Thermal Limiting
On-chip thermal limiting in the MAX1551/MAX1555 sim­plifies PC board layout and allows charging rates to be optimized without the limits imposed by worst-case bat­tery and input voltages. The device reduces the power dissipation at BAT to prevent overheating. This allows the board design to be optimized for compact size and typical thermal conditions. When the MAX1551/ MAX1555 thermal limits are reached, the chargers do
not shut down, but progressively reduce charging cur­rent by 17mA/°C above a die temperature of +110°C. Solder the MAX1551/MAX1555s GND to a large ground plane to help dissipate power and keep the die temperature below the thermal limit. The USB charge current of 100mA is unlikely to induce thermal limiting.
Bypass Capacitors
Use ceramic bypass capacitors at DC, USB, and BAT. Mount these capacitors within 1cm of their respective pins. X7R and X5R dielectrics are recommended.
Chip Information
TRANSISTOR COUNT: 541
PROCESS: BiCMOS
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+ Battery Chargers
6 _______________________________________________________________________________________
Typical Application Circuit
AC ADAPTER
3.7V TO 7V
1µF
USB
3.7V TO 6V
1µF
DC
C1
USB
C2
MAX1551
(MAX1555)
CHARGE
CONTROL
CONTROL
LOGIC
BAT
C3 1µF
POK
(CHG)
GND
TO SYSTEM LOAD
Li+
TO LOGIC RAIL
R1 100k
INDICATES THAT POWER IS PRESENT (EITHER DC OR USB)
MAX1551/MAX1555
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+
Battery Chargers
_______________________________________________________________________________________ 7
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages
.)
MAX1551/MAX1555
SOT23 Dual-Input USB/AC Adapter 1-Cell Li+ Battery Chargers
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages
.)
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