LTC4261 datasheet(8/32 Pages) LINER

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LTC2945

2945f

PIN FUNCTIONS

ADIN: ADC Input. The onboard ADC measures voltages

between 0V and 2.048V. Tie to ground if unused.

ADR1, ADR0: I2C Device Address Inputs. Connecting these

pins to INTVCC, GND or leaving the pins open configures

one of nine possible addresses. See Table 1 in Applications

Information section for details.

ALERT: Fault Alert Output. Open drain logic output that

is pulled to ground after an ADC conversion resulted in

a fault to alert the host controller. A fault alert is enabled

by setting the corresponding bit in the ALERT register

as shown in Table 4. This device is compatible with the

SMBus alert protocol. See Applications Information. Tie

to ground if unused.

EXPOSED PAD (Pin 13, DD Package Only): Exposed pad

may be left open or connected to device ground. For best

thermal performance, connect to a large PCB area.

GND: Device Ground.

INTVCC: Internal Low Voltage Supply Input/Output. This

pin is used to power internal circuitry. It can be config-

ured as a direct input for a low voltage supply, as linear

regulator from higher voltage supply connected to VDD,

or as a shunt regulator. Connect this pin directly to a 2.7V

to 5.9V supply if available. When INTVCC is powered from

an external supply, short the VDD pin to INTVCC. If VDD

is connected to a 4V to 80V supply, INTVCC becomes the

5V output of an internal series regulator that can supply

up to 10mA to external circuitry. For even higher supply

voltages or if a floating topology is desired, INTVCC can

be used as a 6.3V shunt regulator. Connect the supply to

INTVCC through a shunt resistor that limits the current to

less than 35mA. An undervoltage lockout circuit disables

the ADC when the voltage at this pin drops below 2.5V.

Connect a bypass capacitor between 0.1μF and 1μF from

this pin to ground.

SCL: I2C Bus Clock Input. Data at the SDAI pin is shifted

in or out on rising edges of SCL. This pin is driven by an

open-collector output from a master controller. An external

pull-up resistor or current source is required and can be

placed between SCL and VDD or INTVCC. The voltage at

SCL is internally clamped to 6.4V (5.9V minimum)

SDAI: I2C Bus Data Input. Used for shifting in address,

command or data bits. This pin is driven by an open-

collector output from a master controller. An external

pull-up resistor or current source is required and can be

placed between SDAI and VDD or INTVCC. The voltage at

SDAI is internally clamped to 6.4V (5.9V minimum)

SDAO: I2C Bus Data Output. Open-drain output used for

sendingdatabacktothemastercontrolleroracknowledging

a write operation. An external pull-up resistor or current

source is required.

SDAO: Inverted I2C Bus Data Output. Open-drain output

used for sending data back to the master controller or

acknowledging a write operation. Data is inverted for

convenience of opto-isolation. An external pull-up resistor

or current source is required.

SENSE+:

Supply Voltage and Current Sense Input. Used as

a supply and current sense input for the internal current

sense amplifier. The voltage at this pin is monitored by the

onboard ADC with a full-scale input range of 102.4V. See

Figure 16 for recommended Kelvin connection.

SENSE–:

Current Sense Input. Connect an external sense

resistor between SENSE+ and SENSE–. The differential

voltage between SENSE+ and SENSE– is monitored by the

onboard ADC with a full-scale sense voltage of 102.4mV.

VDD:HighVoltageSupplyInput.Thispinpowersaninternal

series regulator with input voltages ranging from 4V to

80V and produces 5V at INTVCC when the input voltage

is above 7V. Connect a bypass capacitor between 0.1μF

and 1μF from this pin to ground if external load is pres-

ent on the INTVCC pin. The onboard 12-bit ADC can be

configured to monitor the voltage at VDD with a full-scale

input range of 102.4V.

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