4

FN6727.0

December 22, 2009

6

ISHARE

Analog Current Output - Cascaded system level over current shutdown pin. This pin is used where you

have multiple modules configured for current sharing and is used with a common current share bus.

The bus sums each of the modules' average current contribution to the load to protect for a over current

condition at the load. The pin sources 15µA plus average module's output current. The shared bus

voltage (VISHARE) is developed across an external resistor (RISHARE). VISHARE represents the

average current of all active channel(s) that connected together.

The ISHARE bus voltage is compared with each module's internal reference voltage set by each

module's RISET resistor. This will generate and individual current share error signal in each cascaded

controller. The share bus impedance RISHARE should be set as RISET/NCTRL, RISET divided by number

of active current sharing controllers. The output current from this pin generates a voltage across the

external resistor. This voltage, VISHARE, is compared to and internal 1.2V threshold for average

overcurrent protection. For full-scale current, RISHARE should be ~10kΩ . Typically 10kΩ is used for

RSHARE and RSET. Output Current Range: 15µA to 108µA typ.

7

FSYNC IN

Analog input Control Pin - An optional external resistor (RFS-ext) connected to this pin and ground will

increase the oscillator switching frequency. It has an internal 59kΩ resistor for a default frequency of

700kHz. The internal oscillator will lock to an external frequency source when connected to a square

wave form. The external source is typically the CLKOUT signal from another ISL8200M or an external

clock. The internal oscillator synchronizes with the leading positive edge of the input signal. Input

Voltage Range for external source: 0V to 5V Square Wave.

8

CLKOUT

Digital Voltage Output - This pin provides a clock signal to synchronize with other ISL8200M(s). When

there is more than one ISL8200M in the system, the two independent regulators can be programmed

via PH_CNTRL for different degrees of phase delay.

9

PH_CNTRL Analog Input - The voltage level on this pin is used to program the phase shift of CLKOUT clock signal

to synchronize with other module(s).

10

ISHARE_BUS Open pin until first PWM pulse is generated. Then, via an internal FET, this pin connects the module’s

ISHARE to the system’s ISHARE bus after pre-bias is complete and soft-start is initiated.

11

FF

Analog Voltage Input - The voltages on this pin is fed into the controller, adjusting the sawtooth

12

EN

This is a double function pin: Analog Input Voltage - The input voltage to this pin is compared with a

through a pull up resistor maintaining a typical current of 5mA.

Analog Voltage Output - This pin can be used as a voltage monitor for input bus undervoltage lockout.

The hysteresis levels of the lockout can be programmed via this pin using a resistor divider network.

Furthermore, during fault conditions (such as overvoltage, overcurrent, and over-temperature), this

pin is used to communicate the information to other cascaded modules by pulling low the wired OR as

13

VIN

Analog Voltage Input - This pin should be tied directly to the input rail when using the internal linear

regulator. It provides power to the internal linear drive circuitry. When used with an external 5V supply,

this pin should be tied directly to VCC. The internal linear device is protected against the reversed bias

generated by the remained charge of the decoupling capacitor at VCC when losing the input rail. Input

Voltage Range 0V to 20V.

14

PVCC

Analog Output - This pin is the output of the internal series linear regulator. It provides the bias for

both low-side and high-side drives. Its operational voltage range is 3V to 5.6V. The decoupling ceramic

capacitor in the PVCC pin is 10µF.

16

PHASE

Analog Output = This pin is the phase node of the regulator. Output Voltage Range 0V to 30V.

17

PVIN

Analog Input - This input voltage is applied to the power FETS with the FET’s ground being the PGND

pin. It is recommended to place input decoupling capacitance, 22µF, directly between PVIN pin and

PGND pin as close as possible to the module. Input Voltage Range: 0V to 20V.

18

PGND

All voltage levels are referenced to this pad. This is the low side MOSFET ground. PGND and PGND1

should be connected together with a ground plane.

19

VOUT

Output voltage from the module. Output Voltage Range: 0.6V to 6V.

20

OCSET

Analog Input - This pin is used with PHASE pin to set the current limit of the module. Input Voltage

Range 0V to 30V.

PIN

NUMBER

PIN NAME

PIN DESCRIPTION

ISL8200M