Data Sheet

LTM8060F

analog.com

Rev. 0

25 of 43

fSW

(MHz)

RT

(kΩ)

0.2

200

0.3

137

0.4

100

0.5

76.8

0.6

64.9

0.7

54.9

0.8

46.4

0.9

41.2

1.0

35.7

1.2

27.4

1.4

23.2

1.6

19.6

1.8

16.9

2.0

14.7

2.2

12.7

2.4

11.3

2.6

10.2

2.8

9.09

3.0

8.06

BIASn Pin Considerations

The BIASn pin provides drive power for the internal power switching stage and operates other internal circuitry. For

proper operation, it must be powered by at least 3.2V. If the output voltage is programmed to 3.2V or higher, BIASn

may be simply connected to VOUTn. If VOUTn is less than 3.2V, BIASn can be connected to VINn or some other voltage

source. If the BIASn pin voltage is too high, the efficiency of the LTM8060F may suffer. The optimum BIASn voltage

is dependent upon many factors, such as load current, input voltage, output voltage, and switching frequency. In

all cases, ensure that the maximum voltage at the BIASn pin is less than 10V. If BIASn power is applied from a

remote or noisy voltage source, it may be necessary to apply a decoupling capacitor locally to the pin. A 1µF

ceramic capacitor works well. The BIASn pin may also be connected to GND at the cost of a small degradation in

efficiency.

Maximum Load

The maximum practical continuous load that the LTM8060F can drive per channel, while rated at 3A (4A peak),

depends upon both the internal current limit and the internal temperature. The internal current limit is designed to

prevent damage to the LTM8060F in the case of overload or short-circuit. The internal temperature of the LTM8060F

depends upon operating conditions such as the ambient temperature, the power delivered, and the heat-sinking

capability of the system. For example, if VOUT1of LTM8060F is configured to regulate at 1.5V, and the other three

channels are turned off, VOUT1 may continuously deliver 4A from 24VIN if the ambient temperature is controlled to

less than 60°C. This is much higher than the 3A (4A peak) rating. See the Typical Performance Characteristics

section. Similarly, if all four channels of the LTM8060F are delivering 3.3VOUT and the ambient temperature is 100°C,

each channel will deliver at most 1.5A from 24VIN, which is less than the 3A (4A peak) rating.