LTC1626

Features:

Wide Input Supply Voltage Range: 2.5V to 6V
High Efficiency: Up to 95%
Low R_DS(ON) Internal Switch: 0.32 (V_IN = 4.5V)
Current Mode Operation for Excellent Line and Load Transient Response
Short-Circuit Protected
Low Dropout Operation: 100% Duty Cycle
Built-In Low-Battery Detector
Low Quiescent Current at Light Loads: I_Q = 165A
Ultralow Shutdown Current: I_Q = 0.5A
Peak Inductor Current Independent of Inductor Value
Available in 14-Pin SO Package


Application

Single Cell Li-Ion Step-Down Converters
3- or 4-Cell NiMH Step-Down Converters
Cellular Telephones
5V to 3.3V Conversion
3.3V to 2.5V Conversion
Inverting Converters
Portable Instruments


Pinout




Specifications

(Voltages Referred to GND Pin)
Input Supply Voltage (Pins 1, 2, 13) ....................... 0.3V to 7V
Shutdown Input Voltage (Pin 10) ........................... 0.3V to 7V
Sense, Sense⁺ (Pins 7, 8)..................................... 0.3V to (V_IN + 0.3V)
LBO, LBI (Pins 3, 4) ................................................ 0.3V to 7V
C_T, I_TH, V_FB (Pins 5, 6, 9) ....................................... 0.3V to (V_IN + 0.3V)
DC Switch Current (Pin 14) .................................... 1.2A
Peak Switch Current (Pin 14) ................................. 1.6A
Switch Voltage (Pin 14) .........................................(V_IN 7.5V) to (V_IN + 0.3V)
Operating Temperature Range .............................. 0°C to 70°C
Extended Commercial Operating
    Temperature Range (Note 4) ............................ 40°C to 85°C
Junction Temperature (Note 1) ............................. 125°C
Storage Temperature Range ................................ 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C


Description

The LTC^®1626 is a monolithic, low voltage, step-down current mode DC/DC converter featuring Burst ModeTM operation at low output current.

The input supply voltage range of 2.5V to 6V makes the LTC1626 ideal for single cell Li-Ion and 3- or 4-cell NiCd/ NiMH applications. A built-in 0.32 switch (V_IN = 4.5V) allows up to 0.6A of output current.

The LTC1626 incorporates automatic power saving Burst Mode operation to reduce gate charge losses when the load current drops below the level required for continuous operation. With no load, the converter draws only 165A. In shutdown, it draws a mere 0.5A-making it ideal for current sensitive applications.

The inductor current is user-programmable via an external current sense resistor. In dropout, the internal P-channel MOSFET switch is turned on continuously, maximizing battery life.