Datasheet LTC4126-10 (Analog Devices) - 8
| Manufacturer | Analog Devices |
| Description | 10mA Wireless Li-Ion Charger with 1.2V Step-Down DC/DC Converter |
| Pages / Page | 22 / 8 — PIN FUNCTIONS NTC (Pin 1):. ACIN (Pin 7):. EN (Pin 2):. BAT (Pin 8):. … |
| File Format / Size | PDF / 2.5 Mb |
| Document Language | English |
PIN FUNCTIONS NTC (Pin 1):. ACIN (Pin 7):. EN (Pin 2):. BAT (Pin 8):. STAT2 (Pin 9), STAT1 (Pin 10):. PBEN (Pin 3):. VCC (Pin 11):
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PIN FUNCTIONS NTC (Pin 1):
Thermistor Input. Connect a thermistor from indicate the status of the battery charger. This pin has four NTC to GND, and a bias resistor from VCC to NTC. The possible states: slow blink to indicate charging, fast blink voltage level on this pin determines if the battery tempera- to indicate a fault, pulled down to indicate charging done, ture is safe for charging. The charge current and charge and high impedance to indicate no input power. To con- timer are suspended if the thermistor indicates a tem- serve power, the pull-down current is limited to 300µA. perature that is unsafe for charging. Once the temperature
ACIN (Pin 7):
AC Input Voltage Pin. Connect the exter- returns to the safe region, charging resumes. Ground the nal LC tank, which includes the receive coil, to this pin. NTC pin if temperature qualified charging is not needed. Connect this pin to ground when not used.
EN (Pin 2):
Digital Logic Input Pin to Disable the DC/DC
BAT (Pin 8):
Battery Connection Pin. Connect a single-cell Converter. A low voltage (0.4V max) enables the regulator Li-Ion battery to this pin. Whenever enough input power provided that the LTC4126-10 is not in Battery Disconnect (AC or DC) is available, the battery will be charged via this Mode (see Battery Disconnect/Ship Mode under Operation pin. Additionally, the DC/DC Converter is powered from section). A minimum voltage of 1.1V disables the regu- the battery via this pin. To minimize the effect of switching lator and allows the pushbutton to control it. A 1MΩ noise from the DC/DC converter on charger performance, internal pull-up resistor to BAT forces this pin high when this pin should be decoupled with a 1μF capacitor to GND unconnected. If only pushbutton control is desired, leave if the DC/DC converter is enabled while charging. this pin unconnected or tie it to the BAT pin.
STAT2 (Pin 9), STAT1 (Pin 10):
Digital CMOS Logic
PBEN (Pin 3):
Pushbutton Toggle Input Pin to Enable/ Status Output Pins. The low level of these pins is refer- Disable the DC/DC Converter. Enabling of the regula- enced to GND and the high level is referenced to V tor can only occur if the LTC4126-10 is not in Battery OUT. Consequently, these indicators are not available if the Disconnect Mode (see Battery Disconnect/Ship Mode DC/DC is disabled. These two pins together with ACPR under Operation section). A weak internal pull-up forces indicate the various charging states and fault conditions. PBEN high when not driven. A normally open pushbutton However, when no input power is available and the DC/DC is connected from PBEN to ground to force a low state on converter is enabled, these pins instead indicate the volt- this pin when the button is pushed. However, the push- age level of the battery. button is ignored if the EN input is low. If the pushbutton function is not needed, leave this pin unconnected.
VCC (Pin 11):
DC Input Voltage Pin. An internal diode is connected from the ACIN pin (anode) to this pin (cath-
VSEL (Pin 4):
Digital Logic Input Pin to Select the Battery ode). When an AC voltage is present at the ACIN pin, the Charge Voltage. A logic low on this pin selects 4.1V and voltage on this pin is the rectified AC voltage. When the a logic high on this pin selects 4.2V. Do not leave this pin ACIN pin is not used (or shorted to ground), connect unconnected. this pin to a DC voltage source to provide power to the
ACPR (Pin 5):
Digital CMOS Logic Output Pin to indicate LTC4126-10 and charge the battery. if there is enough input power available to charge the bat-
OUT (Pin 12):
DC/DC Converter Output Pin. This pin pro- tery. This pin goes high when the VCC-to-BAT differential vides 1.2V to power hearing aid ASICs. A low ESR ceramic voltage rises above 80mV (typical) and goes low when the capacitor of at least 2.2μF should be placed close to this differential voltage drops below 27mV (typical). The low pin to stabilize the converter. level of this pin is referenced to GND and the high level is referenced to the OUT pin voltage. Consequently, this
GND (Exposed Pad Pin 13):
Ground Pin. The exposed pad indicator is not available if the DC/DC is disabled. on the backside of the package must be soldered to the PCB ground for a low-resistance electrical connection as
CHRG (Pin 6):
Open-Drain Charge Status Output Pin. This well as for optimum thermal performance. pin can be pulled up through a resistor and/or an LED to Rev. 0 8 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts
PIN FUNCTIONS NTC (Pin 1):
Thermistor Input. Connect a thermistor from indicate the status of the battery charger. This pin has four NTC to GND, and a bias resistor from VCC to NTC. The possible states: slow blink to indicate charging, fast blink voltage level on this pin determines if the battery tempera- to indicate a fault, pulled down to indicate charging done, ture is safe for charging. The charge current and charge and high impedance to indicate no input power. To con- timer are suspended if the thermistor indicates a tem- serve power, the pull-down current is limited to 300µA. perature that is unsafe for charging. Once the temperature
ACIN (Pin 7):
AC Input Voltage Pin. Connect the exter- returns to the safe region, charging resumes. Ground the nal LC tank, which includes the receive coil, to this pin. NTC pin if temperature qualified charging is not needed. Connect this pin to ground when not used.
EN (Pin 2):
Digital Logic Input Pin to Disable the DC/DC
BAT (Pin 8):
Battery Connection Pin. Connect a single-cell Converter. A low voltage (0.4V max) enables the regulator Li-Ion battery to this pin. Whenever enough input power provided that the LTC4126-10 is not in Battery Disconnect (AC or DC) is available, the battery will be charged via this Mode (see Battery Disconnect/Ship Mode under Operation pin. Additionally, the DC/DC Converter is powered from section). A minimum voltage of 1.1V disables the regu- the battery via this pin. To minimize the effect of switching lator and allows the pushbutton to control it. A 1MΩ noise from the DC/DC converter on charger performance, internal pull-up resistor to BAT forces this pin high when this pin should be decoupled with a 1μF capacitor to GND unconnected. If only pushbutton control is desired, leave if the DC/DC converter is enabled while charging. this pin unconnected or tie it to the BAT pin.
STAT2 (Pin 9), STAT1 (Pin 10):
Digital CMOS Logic
PBEN (Pin 3):
Pushbutton Toggle Input Pin to Enable/ Status Output Pins. The low level of these pins is refer- Disable the DC/DC Converter. Enabling of the regula- enced to GND and the high level is referenced to V tor can only occur if the LTC4126-10 is not in Battery OUT. Consequently, these indicators are not available if the Disconnect Mode (see Battery Disconnect/Ship Mode DC/DC is disabled. These two pins together with ACPR under Operation section). A weak internal pull-up forces indicate the various charging states and fault conditions. PBEN high when not driven. A normally open pushbutton However, when no input power is available and the DC/DC is connected from PBEN to ground to force a low state on converter is enabled, these pins instead indicate the volt- this pin when the button is pushed. However, the push- age level of the battery. button is ignored if the EN input is low. If the pushbutton function is not needed, leave this pin unconnected.
VCC (Pin 11):
DC Input Voltage Pin. An internal diode is connected from the ACIN pin (anode) to this pin (cath-
VSEL (Pin 4):
Digital Logic Input Pin to Select the Battery ode). When an AC voltage is present at the ACIN pin, the Charge Voltage. A logic low on this pin selects 4.1V and voltage on this pin is the rectified AC voltage. When the a logic high on this pin selects 4.2V. Do not leave this pin ACIN pin is not used (or shorted to ground), connect unconnected. this pin to a DC voltage source to provide power to the
ACPR (Pin 5):
Digital CMOS Logic Output Pin to indicate LTC4126-10 and charge the battery. if there is enough input power available to charge the bat-
OUT (Pin 12):
DC/DC Converter Output Pin. This pin pro- tery. This pin goes high when the VCC-to-BAT differential vides 1.2V to power hearing aid ASICs. A low ESR ceramic voltage rises above 80mV (typical) and goes low when the capacitor of at least 2.2μF should be placed close to this differential voltage drops below 27mV (typical). The low pin to stabilize the converter. level of this pin is referenced to GND and the high level is referenced to the OUT pin voltage. Consequently, this
GND (Exposed Pad Pin 13):
Ground Pin. The exposed pad indicator is not available if the DC/DC is disabled. on the backside of the package must be soldered to the PCB ground for a low-resistance electrical connection as
CHRG (Pin 6):
Open-Drain Charge Status Output Pin. This well as for optimum thermal performance. pin can be pulled up through a resistor and/or an LED to Rev. 0 8 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts
