4

FN6488.1

November 2, 2007

Pin Descriptions

SYMBOL

DESCRIPTION

VC7/VCC Battery Cell 7 Voltage Input/VCC Supply. This pin is used to monitor the voltage of this battery cell externally at pin AO. This pin also

provides the operating voltage for the IC circuitry.

VCELLN

Battery Cell N Voltage Input. This pin is used to monitor the voltage of this battery cell externally at pin AO. VCELLN connects to the

positive terminal of CELLN and the negative terminal of CELLN+1.

CBN

Cell Balancing FET Control Output N. This internal FET diverts a fraction of the current around a cell while the cell is being charged

or adds to the current pulled from a cell during discharge in order to perform a cell voltage balancing operation. This function is generally

used to reduce the voltage on an individual cell relative to other cells in the pack. The cell balancing FETs are turned on or off by an

external controller.

VSS

Ground. This pin connects to the most negative terminal in the battery string.

DSREF

Discharge Current Sense Reference (ISL9216 only). This input provides a separate reference point for the charge and discharge

current monitoring circuits. with a separate reference connection, it is possible to minimize errors that result from voltage drops on the

ground lead when the load is drawing large currents. If a separate reference is not necessary, connect this pin to VSS.

DSENSE

Discharge Current Sense Monitor (ISL9216 only). This input monitors the discharge current by monitoring a voltage. It can monitor

the voltage across a sense resistor, or the voltage across the DFET, or by using a FET with a current sense pin. The voltage on this

pin is measured with reference to DSREF.

CSENSE

Charge Current Sense Monitor (ISL9216 only). This input monitors the charge current by monitoring a voltage. It can monitor the

voltage across a sense resistor, or the voltage across the CFET, or by using a FET with a current sense pin. The voltage on this pin is

measured with reference to VSS.

DFET

Discharge FET Control (ISL9216 only). The ISL9216 controls the gate of a discharge FET through this pin. The power FET is a N-

Channel device. The FET is turned on only by the microcontroller. The FET can be turned off by the microcontroller, but the ISL9216

can also turn off the FET in the event of an overcurrent or short circuit condition. If the microcontroller detects an undervoltage condition

on any of the battery cells, it will turn off the FET off by controlling this output with a control bit.

CFET

Charge FET Control (ISL9216 only). The ISL9216 controls the gate of a charge FET through this pin. The power FET is a N-Channel

device. The FET is turned on only by the microcontroller. The FET can be turned off by the microcontroller, but the ISL9216 can also

turn off the FET in the event of an overcurrent condition. If the microcontroller detects an overvoltage condition on any of the battery

cells, it will turn off the FET off by controlling this output with a control bit.

VMON

Discharge Load Monitoring (ISL9216 only). In the event of an overcurrent or short circuit condition, the microcontroller can enable

a series diode and resistor that connects between the VMON pin and VSS. When FETs open because of an overcurrent or short circuit

condition, and the load remains, the voltage at VMON will be near the VCC voltage. When the load is released, the voltage at VMON

drops below a threshold indicating that the overcurrent or short circuit condition is resolved. At this point, the LDFAIL flag is cleared

and operation can resume.

AO

Analog Multiplexer Output. The analog output pin is used by an external microcontroller to monitor the cell voltages and temperature

sensor voltages. The microcontroller selects the specific voltage being applied to the output by writing to a control register.

TEMP3V

Temperature Monitor Output Control (ISL9216 only). This pin outputs a voltage to be used in a divider that consists of a fixed resistor

and a thermistor. The thermistor is located in close proximity to the cells. The TEMP3V output is connected internally to the RGO

voltage through a PMOS switch only during a measurement of the temperature, otherwise the output is off. The TEMP3V output can

be turned on continuously with a special control bit.

Microcontroller Wake-up Control. This pin is also turned on when any of the DSC, DOC, or COC bits are set. This can be used to

wake-up a sleeping microcontroller to respond to overcurrent conditions with its own control mechanism.

TEMPI

Temperature Monitor Input (ISL9216 only). This pin inputs the voltage across a thermistor to determine the temperature of the cells.

When this input voltage drops below TEMP3V/13, an external over-temperature condition exists. The TEMPI voltage is also fed to the

AO output pin through an analog multiplexer so the temperature of the cells can be monitored by the microcontroller.

RGO

Regulated Output Voltage. This pin connects to the emitter of an external NPN transistor and works in conjunction with the RGC pin

to provide a regulated 3.3V. The voltage at this pin provides feedback for the regulator and power for many of the ISL9216 and ISL9217

internal circuits. For the ISL9216, this output also provides the 3.3V output voltage for the microcontroller and other external circuits.

RGC

Regulated Output Control. This pin connects to the base of an external NPN transistor and works in conjunction with the RGO pin to

provide a regulated 3.3V. The RGC output provides the control signal to provide the 3.3V regulated voltage on the RGO pin.

WKUP

Wake-up Voltage. This input wakes up the part when the voltage crosses a turn-on threshold (wake-up is edge triggered) and the

condition of the pin is reflected in the WKUP bit (The WKUP bit is level sensitive).

• WKPOL bit = ”1”: the device wakes up on the rising edge of the WKUP pin. Also, the WKUP bit is HIGH only when the WKUP pin

voltage > threshold.

• WKPOL bit = ”0”, the device wakes up on the falling edge of the WKUP pin. Also, the WKUP bit is HIGH only when the WKUP pin

voltage < threshold.

ISL9216, ISL9217