LTC2977 datasheet(14/138 Pages) AD

14 / 138 page

LTM4664A

Rev. 0

For more information www.analog.com

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. All voltages are referred to GND pin unless

otherwise specified.

Note 2: The LTM4664A is tested under pulsed load conditions such that

TJ ≈ TA. 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 factors.

Note 3: All Currents into the device pins are positive, all currents out of

the device are negative. Each channel of PSM is tested independently in

production. A shorthand notation is used in this document that allows

these parameters to be referred to by “VINS3_Cn" and “VOUTCn”, where n

is permitted to take on a value of 0 or 1. This italicized “n” notation and

convention is extended to encompass all such pin names, as well as

COMMANDn refers to the VOUT_COMMAND command code data located

in Pages 0 and 1, which in turn relate to channel 0 (VOUTC0) and channel 1

(VOUTC1). Registers containing non-page-specific data, i.e., whose data is

“global” to the module or applies to both of the module’s channels lack the

italicized, “n”, e.g., FREQUENCY_SWITCH.

Note 4: See output current derating curves for different VIN, VOUT, Load

Current and TA, located in the Dual 25A/30A PSM Applications Information

section. For output voltage up to 1.2V, Dual 30A loads are rated.

Note 5: The data format in PMBus is 5 bits exponent (signed) and 11 bits

mantissa (signed). This limits the output resolution to 10 bits though the

internal ADC is 16 bits and the calculations use 32-bit words.

Note 6: VOUTCn (DC) and line and load regulation tests are performed

in production with digital servo disengaged (MFR_PWM_MODEn[6] =

0b) and low VOUTCn range selected MFR_PWM_MODEn[1] = 1b. The

digital servo control loop is exercised in production (setting MFR_PWM_

MODEn[6] = 1b), but convergence of the output voltage to its final settling

value is not necessarily observed in final test—due to potentially long

time constants involved—and is instead guaranteed by the output voltage

readback accuracy specification. Evaluation in application demonstrates

capability; see the Typical Performance Characteristics section.

Note 7: These typical parameters are based on bench measurements and

are not production tested.

Note 8: Even though VOUTC0 and VOUTC1 are specified for 3.6V absolute

maximum, the maximum recommended command voltage to regulate

output channels 0 and 1 is 1.5V with VOUT range-setting bit set using

MFR_PWM_MODEn[1].

Note 9: Channel n OV/UV comparator threshold accuracy for MFR_PWM_

MODEn[1] = 1b tested in ATE at VVOSNS+_Cn – VVOSNS–Cn = 0.5V and

2.7V. MFR_PWM_MODEn[1] = 1b is the Low Range.

Note 10: Tested at IC-level ATE

Note 11: The absolute maximum rating for the VINS3 pin is 18V. Input

voltage telemetry (READ_VIN) is obtained by digitizing a voltage scaled

down from the VINS3 pin.

Note 12: The data conversion is done by default in round robin fashion.

All inputs signals are continuously converted for a typical latency of 90ms.

Setting MFR_ADC_CONTRL value to be 0 to 12, LTM4664A can do fast

data conversion with only 8ms to 10ms. See section PMBus Command

for details.

Note 13: Part tested with PWM disabled. Evaluation in application

demonstrates capability. TUE(%) = ADC Gain Error (%) +100 • (Zero code

Offset + ADC Linearity Error)/Actual Value.

Note 14: EEPROM endurance and retention are guaranteed by wafer-level

testing for data retention. The minimum retention specification applies

for devices whose EEPROM has been cycled less than the minimum

endurance specification, and whose EEPROM data was written to at 0°C

≤ TJ ≤ 85°C. The RESTORE_USER_ALL or MFR_RESET is valid over

the entire operating temperature range and does not influence EEPROM

characteristics.

Note 15: Write operations above TJ = 85°C or below 0°C are possible

although the Electrical Characteristics are not guaranteed and the EEPROM

will be degraded. Read operations performed at temperatures below 125°C

will not degrade the EEPROM Writing to the EEPROM above 85°C will

result in a degradation of retention characteristics.

Note 16: M1-M8 power MOSFET are final tested separately before

assembly in to the µModule.

Note 17: MFR_PWM_MODE[2] = 1 or 0 sets device in low DCR mode or

regular DCR mode respectively. MFR_PWM_MODE[7]=1 or 0 sets device in

high output current range or low current range. See “Output Current Sensing

and sub milliohm DCR Current Sensing” in Operation Section for details.

Only VILIMIT codes 2–8 are supported for DCR sensing.

ELECTRICAL CHARACTERISTICS

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