E LECTRICAL CHARACTERISTICS The l denotes specifications that apply over the specified operating
junction temperature range, otherwise specifications are at TA = 25°C. (Note 2) VIN = 3.3V, VOUT = 4.8V, unless otherwise noted.
MIN TYP MAX UNITS
PROG Pin Gain
Internal Sense Resistor Value
Measured at IIN = 1A (Note 3)
Peak Inductor Current Limit
l 5.50 6.5 9.00
Linear Inductor Current Limit
l 4.00 5.0 6.85
N-Channel MOSFET Leakage
Switches B and C and E
P-Channel MOSFET Leakage
Switches A and D
N-Channel MOSFET On-Resistance
P-Channel MOSFET On-Resistance
Switch E (VOUT = 0V)
MID Leakage Current
MID Pin Regulation
Active Charge Balancer Enable Threshold
Active Charge Balancer Hysteresis
VMID = 0V, VIN = 3.3V, VSW1 = 3.3V
VOUT = 4.8V
Active Charge Balancer Peak Current
Active Charge Balancer Valley Current
RUN Input High Threshold Voltage
RUN Input Low Threshold Voltage
l 0.3 V
RUN Input Current
RUN = 5.5V
Note 1. Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2. The LTC3128 is tested under pulsed load conditions such that TJ ≈
TA. The LTC3128E is guaranteed to meet specifications from 0°C to 85°C
junction temperature. Specifications over the –40°C to 125°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3128I is guaranteed
over the full –40°C to 125°C operating junction temperature range.
The junction temperature (TJ) is calculated from the ambient temperature
(TA) and power dissipation (PD) according to the formula: TJ = TA + (PD
• θJA°C/W), where θJA is the package thermal impedance. Note that the
maximum ambient temperature consistent with these specifications is
determined by specific operating conditions in conjunction with board
layout, the rated package thermal resistance and other environmental
Note 3. Current measurements are made when the output is not switching.
Note 4. This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may result in device degradation or failure.
Note 5. Failure to solder the exposed backside of the package to the PC
board ground plane will result in a thermal resistance much higher than
43°C/W in the QFN and 38°C/W in the TSSOP.
Note 6. Guaranteed by design. Not tested.
Note 7. Accuracy of this specification is directly related to the accuracy of
the resistor used to program the parameter.
4 For more information www.linear.com/LTC3128