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19-0785; Rev 0; 4/07
High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN
General Description
The MAX8804Y/MAX8804Z intelligent, dual-input, stand-alone, constant-current, constant-voltage (CCCV), thermally regulated linear chargers are designed for a single-cell lithium-ion (Li+) battery. They integrate the current-sense circuit, MOS pass element, thermal-regulation circuitry, and overvoltage protection (OVP), and eliminate the reverse-blocking Schottky diode to create a simple and small charging solution for handheld equipment. The MAX8804Z functions as a stand-alone charger to control the charging sequence from the prequalification state through fast-charge, top-off charge, and fullcharge indication. The MAX8804Y eliminates the prequalification state to allow startup into a load without a battery. Proprietary thermal-regulation circuitry limits the die temperature when fast-charging or while exposed to high ambient temperatures, allowing maximum charging current without damaging the IC. The MAX8804Y/MAX8804Z achieve high flexibility by providing an adjustable DC/USB fast-charge current through a simple single-wire interface (SET input). The chargers automatically select between either a USB or AC adapter input source. The AC adapter charge current is programmable from 400mA to 700mA in 50mA steps through a serial interface. The USB charge current is programmable to 95mA, 380mA, or 475mA through the same interface. Other features include an active-low battery charging-status indicator (CHG), an active-low power-OK indicator (POK), and an active-low USB input detection output (USBPWR). The MAX8804Y/MAX8804Z accept a 4.15V to 30V DC source voltage or a 4.15V to 16V USB input voltage, but disable charging when either input voltage exceeds 7.5V to protect against unqualified or faulty input sources. The MAX8804Y/MAX8804Z operate over the extended temperature range (-40C to +85C) and are available in a tiny 8-pin thermally enhanced 2mm x 3mm TDFN package.
Features
Complete Chargers for Single-Cell Li+ Battery Dual-Input, 30V AC Adapter/16V USB No External FET, Blocking Diode, or Sense Resistor Required Automatic USB/AC Adapter Input Selection Easy Programmable Fast-Charge Current and Top-Off Threshold Proprietary Die Temperature Regulation Control 5% Fast-Charge Current-Limit Accuracy Power-Present and Charger-Status Outputs No Prequalification Charge (MAX8804Y) Tiny 2mm x 3mm Thermally Enhanced TDFN Package USB Charging Protected by US Patent #6,507,172
MAX8804Y/MAX8804Z
Ordering Information
PART MAX8804YETA+ MAX8804ZETA+ PINPACKAGE 8 TDFN-EP* 8 TDFN-EP* PKG CODE T823+1 T823+1 TOP MARK AAD AAC
*EP = Exposed paddle. +Denotes a lead-free package. Note: All devices are specified to operate over the -40C to +85C operating temperature range.
Typical Application Circuit
+3.3V
Applications
Cell Phones/Smartphones Digital Cameras Portable Media Players MP3 Players Other Handheld Devices
AC ADAPTER 1F
DC CHG GND
USB PORT
MAX8804Y MAX8804Z
POK USBPWR BAT
USB 1F
ENABLE/DISABLE AND PROGRAMMING SET
2.2F
Li+
Pin Configuration appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
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.
High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
ABSOLUTE MAXIMUM RATINGS
DC to GND .............................................................-0.3V to +30V USB to GND ...........................................................-0.3V to +16V BAT, CHG, SET, POK, USBPWR to GND ..............-0.3V to +5.5V Continuous Power Dissipation (TA = +70C) 8-Pin TDFN 2mm x 3mm (derate 16.7mW/C above +70C) (multilayer board) .......................................................1333mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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.
ELECTRICAL CHARACTERISTICS
((VDC = 5V, VSET = 0V) or (VUSB = 5V, VSET = 5V), VBAT = unconnected, TA = -40C to +85C, unless otherwise noted.) (Note 1)
PARAMETER DC AND USB DC Input Voltage Range USB Input Voltage Range Input Operating Range Input Undervoltage Threshold Input Overvoltage Threshold DC Input Supply Current (Notes 2, 3) VIN rising, 500mV hysteresis (typ) (Note 2) VIN rising, 200mV hysteresis (typ) (Note 2) VUSB = 0V, IBAT = 0mA, charge mode VSET = 5V, standby mode VDC = VBAT = 4.3V, shutdown mode VDC = 0V, VSET = 5V, IBAT = 0mA, charge mode USB Input Supply Current DC to BAT On-Resistance USB to BAT On-Resistance Input to BAT Comparator Threshold (Note 2) BAT BAT Regulation Voltage Battery Removal Detection Threshold IBAT = 0mA VBAT rising Hysteresis Default and 1st to 3rd interface pulse VUSB = 0V, VBAT = 3.6V, rising edge detection on SET 4th to 7th interface pulse 8th to 11th interface pulse 12th to 15th interface pulse 16th to 19th interface pulse 20th to 23rd interface pulse 24th to 27th interface pulse 475 523 570 428 380 618 665 TA = +25C TA = -40C to +85C 4.179 4.158 4.40 4.200 4.200 4.67 0.1 500 550 600 450 400 650 700 525 578 630 473 420 683 735 mA 4.221 4.242 4.90 V V VSET = 0V, standby mode VUSB = VBAT = 4.3V, shutdown mode VDC = 3.7V, VBAT = 3.6V VUSB = 3.7V, VBAT = 3.6V VIN rising VIN falling 145 0 0 4.15 3.85 7.2 4.0 7.5 800 300 300 800 300 300 0.55 0.65 260 55 28 14 7.00 4.15 7.8 1200 550 550 1200 550 550 1.0 1.2 385 mV A A V V V V V CONDITIONS MIN TYP MAX UNITS
DC Charging Current
2
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN
ELECTRICAL CHARACTERISTICS (continued)
((VDC = 5V, VSET = 0V) or (VUSB = 5V, VSET = 5V), VBAT = unconnected, TA = -40C to +85C, unless otherwise noted.) (Note 1)
PARAMETER USB Charging Current Soft-Start Time BAT Prequal Threshold BAT Prequal Charge Current BAT Leakage Current SET Logic Input Thresholds Logic-High Time Logic-Low Time SET DC Mode Shutdown Delay SET USB Mode Shutdown Delay SET Internal Pulldown Resistor POK, CHG, USBPWR Logic Output-Voltage Low Logic Output-Current High CHG VDC = 0V, VUSB = 5V Default, 4th, 8th, 12th, 16th, 20th, 24th, 28th interface pulse IBAT falling, battery is charged, rising edge on SET 1st, 5th, 9th, 13th, 17th, 21st, 25th interface pulse 2nd, 6th, 10th, 14th, 18th, 22nd, 26th interface pulse 3rd, 7th, 11th, 15th, 19th, 23rd, 27th interface pulse 60 80 100 I POK = I CHG = I USBPWR = 5mA V POK = V CHG = V USBPWR = 5.5V, VDC = VUSB = 0V TA = +25C TA = +85C 60 0.001 0.01 500 1 A mV VSET rising VSET falling Pulse width required to program DC charge current Pulse width required to program USB charge current VUSB = 0V, VDC = 5V, measured from VSET low to high VDC = 0V, VUSB = 5V, measured from VSET high to low 0.4 1 1 1.5 1.5 2 2 2 1000 1000 2.5 2.5 4 1.6 V s s ms ms M CONDITIONS VDC = 0V, VBAT = 3.6V, rising edge detection on SET Default 1st interface pulse 2nd interface pulse MIN 90 360 450 2.35 TYP 95 380 475 250 2.50 95 2 2.65 MAX 100 400 500 s V mA A mA UNITS
MAX8804Y/MAX8804Z
Ramping time from 0 to 500mA MAX8804Z only, VBAT rising, 300mV hysteresis (typ) MAX8804Z only VDC = VUSB = 0V, VBAT = 4.2V
60
80
100
CHG Top-Off Threshold
VDC = 5V, VUSB = 0V
67.5
90
112.5
mA
75
100
125
52.7
70
87.5
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
ELECTRICAL CHARACTERISTICS (continued)
((VDC = 5V, VSET = 0V) or (VUSB = 5V, VSET = 5V), VBAT = unconnected, TA = -40C to +85C, unless otherwise noted.) (Note 1)
PARAMETER CHG Hysteresis CHG Detection Delay THERMAL LOOP Thermal-Regulation Set Point Thermal-Regulation Gain Junction temperature when the charge current is reduced, TJ rising Reduction of IBAT for increase of TJ DC charging USB charging +105 -40 -24 C mA/C IBAT rising after top-off is detected (Note 4) CONDITIONS DC mode USB mode 3 MIN TYP 57 51 4 5 MAX UNITS mA ms
IBAT falls below top-off threshold
Note 1: Devices are 100% production tested at TA = +25C. Limits over the operating temperature range are guaranteed by design and characterization. Note 2: VIN refers to the input for the IC. For the MAX8804Y/MAX8804Z, VIN is VDC with VUSB = 0V or VUSB with VDC = 0V. Note 3: Guaranteed by undervoltage and overvoltage threshold testing. For charge completion, the input voltage must be greater than 4.28V. Note 4: This hysteresis is for all charge current except 95mA. In the case of 95mA charge current, voltage-mode to current-mode detection gives indication of charge mode.
Typical Operating Characteristics
(VBAT = 3.6V; DC charge mode: VDC = 5V, VUSB = 0V, VSET = 0V or unconnected; USB charge mode: VUSB = 5V, VDC = 0V, VSET = 5V; TA = +25C, unless otherwise noted.)
SUPPLY CURRENT vs. INPUT VOLTAGE (DC CHARGING MODE)
MAX8804Y/Z toc01
SUPPLY CURRENT vs. INPUT VOLTAGE (USB CHARGING MODE)
MAX8804Y/Z toc02
DISABLED-MODE SUPPLY CURRENT vs. INPUT VOLTAGE (DC CHARGING MODE)
MAX8804Y/Z toc03
1.0
1.0
0.8
0.8 SUPPLY CURRENT (mA)
0.8 SUPPLY CURRENT (mA)
0.6
0.6
SUPPLY CURRENT (mA) 0 2 4 6 8 10 12 INPUT VOLTAGE (V) 14 16
0.6
0.4
0.4
0.4
0.2
0.2
0.2
0 0 3 6 9 12 15 18 21 24 27 30 INPUT VOLTAGE (V)
0
0 0 5 10 15 20 INPUT VOLTAGE (V) 25 30
4
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN
Typical Operating Characteristics (continued)
(VBAT = 3.6V; DC charge mode: VDC = 5V, VUSB = 0V, VSET = 0V or unconnected; USB charge mode: VUSB = 5V, VDC = 0V, VSET = 5V; TA = +25C, unless otherwise noted.)
STANDBY-MODE SUPPLY CURRENT vs. INPUT VOLTAGE (USB CHARGING MODE)
MAX8804Y/Z toc04
MAX8804Y/MAX8804Z
CHARGE CURRENT vs. BATTERY VOLTAGE (DC CHARGING MODE)
MAX8804Y/Z toc05
CHARGE CURRENT vs. BATTERY VOLTAGE (USB CHARGING MODE)
MAX8804Y/Z toc06
0.8
600 500 CHARGE CURRENT (mA) 400 300 200 100
200
SUPPLY CURRENT (mA)
CHARGE CURRENT (mA) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 BATTERY VOLTAGE (V)
0.6
160
120
0.4
80
0.2
40
0 0 2 4 6 8 10 12 INPUT VOLTAGE (V) 14 16
0
0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 BATTERY VOLTAGE (V)
CHARGE CURRENT vs. DC INPUT VOLTAGE
MAX8804Y/Z toc07
CHARGE CURRENT vs. USB INPUT VOLTAGE
MAX8804Y/Z toc08
CHARGE CURRENT vs. SET PULSE (USB CHARGING MODE)
MAX8804Y/Z toc09
600 500 CHARGE CURRENT (mA) 400 300 200 100 0 0 5 10 15 20 INPUT VOLTAGE (V) 25
120
CHARGE CURRENT (mA)
90
VSET 1V/div
60
475mA 380mA ICHG 95mA
475mA
380mA
475mA 200mA/div
30
95mA
95mA
0 30 0 2 4 6 8 10 12 INPUT VOLTAGE (V) 14 16 2ms/div
CHARGE CURRENT vs. SET PULSE (DC CHARGING MODE)
MAX8804Y/Z toc10
CHARGE CURRENT vs. INPUT VOLTAGE HEADROOM
INPUT VOLTAGE DECREASING 500 1V/div CHARGE CURRENT (mA)
MAX8804Y/Z toc11
600
VSET
400 DC MODE 300 200 100 0 USB MODE
700mA ICHG 550mA 500mA 600mA 450mA
650mA
700mA 200mA/div 500mA
400mA
2ms/div
0
100 200 300 400 INPUT VOLTAGE HEADROOM (mV)
500
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
Typical Operating Characteristics (continued)
(VBAT = 3.6V; DC charge mode: VDC = 5V, VUSB = 0V, VSET = 0V or unconnected; USB charge mode: VUSB = 5V, VDC = 0V, VSET = 5V; TA = +25C, unless otherwise noted.)
BATTERY REGULATION VOLTAGE vs. AMBIENT TEMPERATURE
MAX8804Y/Z toc12
CHARGE CURRENT vs. AMBIENT TEMPERATURE
MAX8804Y/Z toc13
BATTERY REGULATION VOLTAGE vs. LOAD CURRENT
MAX8804Y/Z toc14
4.210 BATTERY REGULATION VOLTAGE (V) USB MODE 4.204
700
4.30 BATTERY REGULATION VOLTAGE (V)
600 CHARGE CURRENT (mA)
4.25
4.198
500
4.20
4.192
DC MODE
400
4.15 550mA CHARGE-CURRENT SETTING 4.10
4.186
300 DC CHARGE MODE 650mA
4.180 -40 -15 10 35 60 AMBIENT TEMPERATURE (C) 85
200 -40 -15 10 35 60 AMBIENT TEMPERATURE (C) 85
0
100
200 300 400 500 LOAD CURRENT (mA)
600
700
Pin Description
PIN 1 2 3 4 5 6 NAME BAT USBPWR POK DC USB CHG FUNCTION Battery Connection. The IC delivers charging current and monitors battery voltage using BAT. Bypass BAT to GND with a 2.2F or larger ceramic capacitor. BAT is high impedance when the IC is disabled. USB Power Status Output. USBPWR is internally pulled low if a valid voltage is present at USB, otherwise it is high impedance. USBPWR circuitry is active regardless of SET and charger on/off status. Power-OK Monitor. POK is an open-drain output that is internally pulled low when a valid charging source is detected at either DC or USB. POK is high impedance when both input voltages are less than VUVLO or VBAT. DC Input Supply. Connect DC to a 4.15V to 7V charging source. Bypass DC to GND with a 1F or larger ceramic capacitor. DC takes priority over USB when both are valid. USB Input Source. Connect USB to a USB port. Bypass USB to GND with a 1F or larger ceramic capacitor. Charging-Status Output. CHG is internally pulled low when the battery is being charged. CHG is high impedance when the charger is in top-off mode or disabled. Enable/Disable, Charging Current, and Top-Off Threshold Set Input. Drive SET low to enable DC charge mode and drive high to enable USB charge mode. If both DC and USB inputs are present, SET is used for the DC charge mode only and USB charge is disabled. SET is also used for programming the charge current and top-off threshold. See the DC/USB Mode and Charging Current Setting section for details. Ground Exposed Paddle. Connect to the GND plane for optimum thermal dissipation.
7
SET
8 --
GND EP
6
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
4.15V TO 30V DC BAT Li+ 4.15V TO 16V USB
+105C DC AND USB OUTPUT CONTROL TEMP SENSOR
VOLTAGE LOOP
MAX8804Y MAX8804Z
OVERVOLTAGE PROTECTION
DC POK LOGIC CONTROL USB POK
SET CHG POK USBPWR
REF
BIAS CIRCUIT
GND
Figure 1. Functional Diagram
Detailed Description
The MAX8804Y/MAX8804Z dual-input linear battery chargers use voltage, current, and thermal-control loops to charge and protect a single Li+ battery. When a Li+ battery with a cell voltage below 2.5V is inserted, the MAX8804Z charger enters the prequalification stage where it precharges that cell with 95mA (Figure 2). The CHG indicator output is driven low to indicate entry into the prequalification state. When battery voltage exceeds 2.5V, the charger soft-starts as it enters the fast-charge stage. The MAX8804Y eliminates the prequalification state and enters fast-charge when the battery is inserted. In the MAX8804Y/MAX8804Z, the fast-charge current
level is programmed by a simple single-wire interface. As the battery voltage approaches 4.2V, the charging current is reduced. If the battery current drops below the top-off current threshold, the CHG indicator goes high impedance, signaling that the battery is fully charged. The ICs then enter a constant voltage-regulation mode to maintain the battery at full charge. The MAX8804Y/MAX8804Z automatically select between either a USB or AC adapter input source. The AC adapter charge current is programmable from 400mA to 700mA in 50mA steps through a simple single-wire interface. The USB charge current is programmable to 95mA, 380mA, or 475mA through the same interface.
7
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
ASYNCHRONOUS FROM ANYWHERE tSET = HIGH > 2ms FOR DC MODE tSET = LOW > 2ms FOR USB MODE
STANDBY MODE CHARGER = OFF POK = LOW CHG = HIGH IMPEDANCE tSET = LOW > 2ms FOR DC MODE tSET = HIGH > 2ms FOR USB MODE
VUVLO < VIN < VOVP AND VIN > VBAT
SHUTDOWN CHARGER = OFF POK = HIGH IMPEDANCE* CHG = HIGH IMPEDANCE VIN < VUVLO OR VIN > VOVP OR VBAT > VIN
MAX8804Z
ASYNCHRONOUS FROM ANYWHERE VIN < VUVLO OR VIN > VOVP OR VBAT > VIN
VBAT < 2.5V
PREQUALIFICATION DEFAULT CHARGE CURRENT POK = LOW CHG = LOW
MAX8804Y tSET = LOW > 2ms FOR DC MODE tSET = HIGH > 2ms FOR USB MODE
VBAT < 2.2V MAX8804Z
VBAT > 2.5V
FAST-CHARGE 100% CHARGE CURRENT POK = LOW CHG = LOW
ICHG > ITOP-OFF + 57mA FOR ALL FASTCHARGE OPTIONS EXCEPT 95mA CV MODE TO CC MODE FOR 95mA FAST-CHARGE OPTION
ICHG< ITOP-OFF
FULL BAT VBAT = 4.2V POK = LOW CHG = HIGH IMPEDANCE
*POK = LOW WHEN VIN > VOVP
Figure 2. Charger State Diagram
DC Charging
The MAX8804Y/MAX8804Z are designed to charge a single-cell Li+ battery from a DC source voltage between 4.15V and 7V and withstand up to 30V maximum input voltage. The charge current and top-off threshold are programmed with the SET input.
USB Charging
The MAX8804Y/MAX8804Z contain a USB input that allows operation from a USB port with voltages between 4.15V and 7V and can withstand up to 16V maximum input voltage. Pulsing SET allows programming a 95mA, 380mA, or 475mA maximum charging current when using the USB input.
8
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN
Table 1. SET Truth Table
SET 0 0 0 0 1 1 1 1 VDC Invalid Invalid Valid Valid Invalid Invalid Valid Valid VUSB Invalid Valid Invalid Valid Invalid Valid Invalid Valid Off Off DC charging mode enabled, USB charging mode disabled DC charging mode enabled, USB charging mode disabled Off DC charging mode disabled, USB charging mode enabled Off Off CHARGER STATUS
DC Charge Mode Drive SET low or leave it unconnected to enable DC charging mode. Subsequent pulses on SET program the charging current and the top-off threshold. There are seven fast-charge current options and four top-off threshold options. Default fast-charge current and top-off threshold current are 500mA and 80mA. Pulse SET high (1s to 1ms pulse width) subsequently to realize charging current and top-off threshold programming and transition. After the 28th pulse, the MAX8804Y/MAX8804Z go into the default mode and start a new cycle. See Table 2 and Figure 3 to set the desired charging current and top-off threshold. Drive SET high longer than 2ms to disable DC charging-control circuitry.
MAX8804Y/MAX8804Z
DC/USB Mode and Charging Current Setting
SET is a logic input that sets DC/USB charging mode and charging current. Drive SET low or leave it unconnected to enable DC charging mode. Drive SET high to enable USB charging mode (see Table 1). SET can also be driven by series pulses to program the charging current in both DC and USB mode.
Table 2. DC Charging Current Programming by Series Pulses
PULSE NUMBER ICHG (mA) Top-Off Current Threshold (mA) PULSE NUMBER ICHG (mA) Top-Off Current Threshold (mA) DEFAULT 500 80 -- -- -- 1st 500 90 15th 450 70 2nd 500 100 16th 400 80 3rd 500 70 17th 400 90 4th 550 80 18th 400 100 5th 550 90 19th 400 70 6th 550 100 20th 650 80 7th 550 70 21st 650 90 8th 600 80 22nd 650 100 9th 600 90 23rd 650 70 10th 600 100 24th 700 80 11th 600 70 25th 700 90 12th 450 80 26th 700 100 13th 450 90 27th 700 70 14th 450 100 28th 500 80
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
DC
POK
1
2
3
4
24
25
26
27
28 > 2ms
SET tHIGH 2ms tSOFTSTART DELAY 500mA 700mA 550mA 500mA
ICHG
0mA
0mA
TOP-OFF CURRENT THRESHOLD
90mA 80mA
100mA 80mA 70mA 80mA
90mA
100mA 70mA 80mA
Figure 3. DC Charging Current and Top-Off Threshold Programming
USB Charge Mode Drive SET high to enable USB charging mode when the USB input is valid. Subsequent low pulses with 1s to 1ms pulse width on SET program the fast charging current from 95mA, 380mA, to 475mA and then repeat new cycle as shown in Table 3. Drive SET low or leave it unconnected longer than 2ms to disable USB charging-control circuitry.
Table 3. USB Charging Current Programming by Series Pulses
PULSE NUMBER ICHG (mA) Top-Off Current Threshold (mA) DEFAULT 95 80 1st 380 80 2nd 475 80 3rd 95 80
10
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
USB
POK
USBPWR
1 SET tLOW 2ms t DELAY SOFTSTART 95mA 0mA
2
3 > 2ms
475mA 380mA 95mA 0mA 80mA
ICHG TOP-OFF CURRENT THRESHOLD
Figure 4. USB Charging Current Programming
Soft-Start
The soft-start circuitry activates when entering fastcharge mode. In the MAX8804Y, soft-start is entered directly after being enabled, and the charging current ramps up in 250s from 0 to 500mA (95mA in USB mode). This reduces the inrush current on the input supply. Note that the MAX8804Z has a prequalification state and the charging current ramps up when the prequalification state is complete (VBAT exceeds 2.5V).
Charging-Status Output (CHG)
CHG is an open-drain output that indicates charger status. CHG goes low during charge cycles where the MAX8804Y/MAX8804Z are in prequalification or fastcharge mode. CHG goes high impedance when the charge current reaches the top-off threshold for more than 4ms, indicating charging is done. The CHG status is latched after the top-off threshold is reached. The latch is reset by toggling the SET input, recycling input power, or increasing the charging current to the top-off threshold plus 57mA (typ). When the MAX8804Y/MAX8804Z are used in conjunction with a microprocessor (P), connect a pullup resistor between CHG and the logic I/O voltage to indicate charge status to the P. Alternatively, CHG can sink up to 5mA for an LED charge indicator.
Thermal Regulation Control
The thermal-regulation loop limits the MAX8804Y/ MAX8804Z die temperature to +105C by reducing the charge current as necessary. This feature not only protects the ICs from overheating, but also allows a higher charge current at room temperature without risking damage to the system.
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
Power-OK Monitor (POK)
The MAX8804Y/MAX8804Z contain an open-drain POK output that goes low when a valid input source is detected at either DC or USB. A valid input source is one whose voltage is greater than 4.15V and exceeds the battery voltage by 250mV. After a valid input has been established, charging is sustained with inputs as low as 3.5V as long as the input voltage remains above the battery voltage by at least 40mV. POK status is maintained regardless of SET status. When the MAX8804Y/MAX8804Z are used in conjunction with a P, connect a pullup resistor between POK and the logic I/O voltage to indicate power-OK to the P. Alternatively, POK can sink up to 5mA for an LED power-OK indicator.
Thermal Considerations
The MAX8804Y/MAX8804Z are available in a thermally enhanced TDFN package with an exposed paddle. Connect the exposed paddle to a large copper ground plane to provide a thermal contact between the device and the PCB for increased power dissipation. The exposed paddle transfers heat away from the device, allowing the IC to charge the battery with maximum current, while minimizing the die temperature increase.
Input Sources
The MAX8804Y/MAX8804Z operate from well-regulated input sources. The operating input voltage range is 4.15V to 7V. The device survives DC input supply voltages up to 30V and USB input source voltages up to 16V without damage to the IC. If the input voltage is greater than 7.5V (typ), the IC stops charging. An appropriate power supply must provide at least 4.2V plus the voltage drop across the internal pass transistor when sourcing the desired maximum charging current: VIN(MIN) > 4.2V + ICHARGE(MAX) x RON where R ON is the input-to-BAT resistance (typically 0.55 for DC or 0.65 for USB). Failure to meet this requirement results in an incomplete charge or increased charge time.
USB Power Status Output (USBPWR)
USBPWR is internally pulled low when VUSB > VUVLO and VUSB - VBAT > 250mV. Otherwise, it is high impedance. USBPWR indicates the USB input presence regardless of SET status and charger status. When the MAX8804Y/MAX8804Z are used in conjunction with a P, connect a pullup resistor between USBPWR and the logic I/O voltage to indicate USB power status to the P. Alternatively, USBPWR can sink up to 5mA for an LED USB power status indicator.
Application Circuits
Stand-Alone Li+ Charger The MAX8804Y/MAX8804Z provide a complete Li+ charging solution. The Typical Application Circuit shows the MAX8804Y/MAX8804Z as a stand-alone Li+ battery charger. The LED indicates when either fastcharge or prequalification has begun. When the battery is fully charged, the LED turns off. Microprocessor-Interfaced Li+ Charger Figure 5 shows the MAX8804Y/MAX8804Z as a Pinterfaced Li+ battery charger. The P drives SET to enable/disable DC/USB mode charging. CHG can be used to detect the charge status of a battery.
Applications Information
Capacitor Selection
Connect a 2.2F ceramic capacitor from BAT to GND for proper stability. Connect a 1F ceramic capacitor from DC to GND. If using the USB input, bypass USB to GND with a 1F ceramic capacitor. Use a larger input bypass capacitor for high charging currents to reduce supply noise. All capacitors should be X5R dielectric or better. Be aware that some capacitors have large voltage and temperature coefficients and should be avoided.
12
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High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
SYSTEM I/O
AC ADAPTER
DC 1F
CHG
USB PORT 1F
USB
MAX8804Y MAX8804Z
POK P USBPWR
BAT Li+ 2.2F GND
SET
Figure 5. Microprocessor-Interfaced Li+ Charger with the MAX8804Y/MAX8804Z
Layout and Bypassing
Connect the input capacitors as close as possible to the IC. Provide a large copper GND plane to allow the exposed paddle to sink heat away from the IC. Connect the battery to BAT as close as possible to the IC to provide accurate battery voltage sensing. Make all highcurrent traces short and wide to minimize voltage drops. A sample layout is available in the MAX8804Z evaluation kit to speed designs.
TOP VIEW
GND 8 SET 7
Pin Configuration
CHG 6 USB 5
Chip Information
PROCESS: BiCMOS
+ 1
MAX8804Y MAX8804Z
2
3
4 DC
BAT USBPWR POK
TDFN 2mm x 3mm
______________________________________________________________________________________
13
High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN MAX8804Y/MAX8804Z
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.)
PACKAGE OUTLINE 8L TDFN, EXPOSED PAD, 2x3x0.8mm
21-0174
B
1 2
14
______________________________________________________________________________________
8L, TDFN.EPS
High-Voltage, Dual-Input, USB/AC Adapter Chargers in 2mm x 3mm TDFN
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.)
MAX8804Y/MAX8804Z
DIMENSIONS SYMBOL A E D A1 L k A2 N e b 0.18 MIN. 0.70 2.95 1.95 0.00 0.30 NOM. 0.75 3.00 2.00 0.02 0.40 0.20 MIN. 0.20 REF. 8 0.50 BSC 0.25 MAX. 0.80 3.05 2.05 0.05 0.50 PKG. CODE T823-1 MIN. 1.60 EXPOSED PAD PACKAGE E2 NOM. 1.75 MAX. 1.90 MIN. 1.50 D2 NOM. 1.63 MAX. 1.75
0.30
PACKAGE OUTLINE 8L TDFN, EXPOSED PAD, 2x3x0.8mm
21-0174
B
2 2
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
(c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Heaney

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