Data Sheet

LT3097

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

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Rev. 0 | 10 of 45

Figure 3. Pin Configuration

Table 3. Pin Function Descriptions

Pin No.

Mnemonic

Description

1, 2

INP

Positive Input. The INP pins supply power to the positive regulator. The LT3097 requires a bypass capacitor at the INP pin. In general, the

output impedance of a battery rises with frequency; therefore, it is best practice to include a bypass capacitor in battery-powered applications.

While a 4.7 µF input bypass capacitor generally suffices, applications with large load transients can require higher input capacitance to prevent

input-supply droop. See Stability and Input Capacitance and PSRR and Input Capacitance sections on the proper use of a positive input

capacitor and its effect on circuit performance, particularly positive regulator PSRR. The LT3097 withstands reverse voltages on INP for GND,

OUTSP, and OUTP. In the case of a reversed input, which occurs if a battery is plugged in backward, the LT3097 positive regulator acts as if a

diode is in series with its input. Therefore, no reverse current flows into the LT3097, and no negative voltage appears at the positive load. The

positive regulator protects itself and the load.

3

ENP/UVP

Positive Enable and UVLO. Pulling the ENP/UVP pin low moves the LT3097 positive regulator to shutdown mode. The positive quiescent

current in shutdown mode drops to less than 1 µA, and the positive output voltage turns off. Alternatively, the ENP/UVP pin can set a positive

input-supply UVLO threshold using a resistor-divider between INP, ENP/UVP, and GND. The LT3097 positive regulator typically turns on when

the ENP/UVP voltage exceeds 1.24 V on its rising edge, with a 130 mV hysteresis on its falling edge. The ENP/UVP pin can be driven above

the positive input voltage and maintain proper functionality. If unused, connect ENP/UVP to INP. Do not float the ENP/UVP pin.

4

PGP

Positive Power Good. PGP is an open-collector flag that indicates positive output-voltage regulation. PGP pulls low if PGFBP is less than 300

mV. If the power-good functionality is not needed, float the PGP pin. The positive power-good functionality is disabled in shutdown. See the

Positive Regulator Programmable Power Good section if power-good functionality is needed in shutdown. A parasitic substrate diode exists

between the PGP and GND pin of the LT3097; therefore, do not drive PGP more than 0.3 V below GND during normal operation or a fault

condition.

5

ILIMP

Positive Regulator Current-Limit Programming Pin. Connecting a resistor between ILIMP and GND programs the current limit. For best

accuracy, Kelvin connects this resistor directly to the GND pin of the LT3097. The programming-scale factor is nominally 150 mA × kΩ. The

ILIMP pin sources current proportional (1:500) to the positive output current. Therefore, ILIMP also serves as a current-monitoring pin with a 0

V to 300 mV range. If the programmable current-limit functionality is not needed, connect ILIMP to GND. Do not float the ILIMP pin. A parasitic

substrate diode exists between the ILIMP and GND pin of the LT3097; therefore, do not drive ILIMP more than 0.3 V below GND during normal

operation or a fault condition.