DC1540A Linear Technology, DC1540A Datasheet
DC1540A
Specifications of DC1540A
Related parts for DC1540A
DC1540A Summary of contents
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... EEPROM. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 7382203 and 7420359. ...
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LTC2978 Table oF conTenTs Features .............................................................................................................................1 Applications ........................................................................................................................1 Typical Application ................................................................................................................1 Description..........................................................................................................................1 Absolute Maximum Ratings ......................................................................................................3 Order Information ..................................................................................................................3 Pin Configuration ..................................................................................................................3 Electrical Characteristics .........................................................................................................4 Timing Diagram ....................................................................................................................8 Typical Performance Characteristics ...........................................................................................8 Pin Functions ..................................................................................................................... 12 Block Diagram .................................................................................................................... 14 ...
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MaxiMuM raTings (Notes 1, 2) Supply Voltages GND ......................................... –0.3V to 15V PWR V to GND ..................................... –0.3V to 15V IN_SNS V to GND ....................................... –0.3V to 3.6V DD33 V to GND ..................................... –0.3V to 2.75V DD25 ...
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LTC2978 elecTrical characTerisTics temperature range, otherwise specifications are at T otherwise indicated 100nF , C VDD33 VDD25 SYMBOL PARAMETER Power-Supply Characteristics V V Supply Input Operating Range PWR PWR I V Supply Current PWR PWR I V Supply ...
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T otherwise indicated 100nF , C VDD33 VDD25 SYMBOL PARAMETER I Input Leakage Current IN_ADC Differential Input Current Voltage Buffered IDAC Output Characteristics N_V Resolution DACP V Full-Scale Output Voltage ...
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LTC2978 elecTrical characTerisTics temperature range, otherwise specifications are at T otherwise indicated 100nF , C VDD33 VDD25 SYMBOL PARAMETER I Output Sourcing Current VOUT_ENn Output Sinking Current Output Leakage Current V Enable Output (V [7:4]) Characteristics OUT OUT_EN ...
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T otherwise indicated 100nF , C VDD33 VDD25 SYMBOL PARAMETER Digital Outputs SDA, ALERTB, PWRGD, SHARE_CLK, FAULTB00, FAULTB01, FAULTB10, FAULTB11 V Digital Output Low Voltage OL f Output Frequency Operating ...
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LTC2978 TiMing DiagraM SDA LOW SCL t HD(STA) t HD(DAT) START CONDITION Typical perForMance characTerisTics Reference Voltage vs Temperature 1.2355 1.2350 1.2345 1.2340 1.2335 1.2330 1.2325 1.2320 1.2315 THREE TYPICAL PARTS 1.2310 –50 –35 –20 ...
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Typical perForMance characTerisTics ADC Rejection vs Frequency –20 –40 –60 –80 –100 –120 0 12500 25000 37500 50000 62500 FREQUENCY (Hz) 2978 G07 ADC Rejection vs Frequency at V (Current Sense Mode, Zoom –20 ...
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LTC2978 Typical perForMance characTerisTics Voltage Buffered IDAC Offset Voltage vs Temperature 2.5 2.3 2.1 1.9 1.7 1.5 1.3 1.1 0.9 0.7 0.5 –50 –35 – – TEMPERATURE (°C) 2978 G16 Voltage Buffered IDAC Load ...
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Typical perForMance characTerisTics V Regulator Output Voltage DD33 vs Temperature 3.275 3.270 3.265 3.260 3.255 3.250 3.245 3.240 3.235 –50 –35 –20 – TEMPERATURE (°C) 2978 G25 Supply Current vs Supply Voltage 10.5 V ...
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LTC2978 Typical perForMance characTerisTics PWRGD and FAULTBzn V vs Current 1.2 1.0 0.8 0.6 0.4 0 (mA) SINK pin FuncTions PIN NAME PIN NUMBER PIN TYPE SENSEM6 SENSEP7 ...
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FuncTions FAULTB00 23 In/Out FAULTB01 24 In/Out FAULTB10 25 In/Out FAULTB11 26 In/Out SDA 27 In/Out SCL 28 In ALERTB 29 Out CONTROL0 30 In CONTROL1 31 In ASEL0 32 In ASEL1 33 In REFP 34 Out REFM 35 ...
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LTC2978 block DiagraM 3.3V REGULATOR PWR IN OUT DD33 2.5V REGULATOR DD33 IN V OUT V 18 DD25 3R V SENSEM0 V 14 IN_SNS V SENSEP0 R V SENSEM1 ...
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OPERATION OVERVIEW The LTC2978 is a PMBus programmable power supply controller, monitor, sequencer and voltage supervisor that can perform the following operations: Accept PMBus compatible programming commands. n Provide DC/DC converter input voltage and output volt- n age/current read ...
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LTC2978 operaTion PMBus SERIAL DIGITAL INTERFACE The LTC2978 communicates with a host (master) using the standard PMBus serial bus interface. The Timing Diagram shows the timing relationship of the signals on the bus. The two bus lines, SDA and SCL, ...
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SLAVE ADDRESS SLAVE ADDRESS SLAVE ADDRESS SLAVE ADDRESS SLAVE ADDRESS ...
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LTC2978 operaTion REGISTER COMMAND SET Summary COMMAND FUNCTION DESCRIPTION PAGE OPERATION Operating mode control. ON_OFF_CONFIG CONTROL pin and PMBus bus on/off command setting. CLEAR_FAULTS CLEAR_FAULTS is used to clear any fault bits that have been set. WRITE_PROTECT Provides protection against ...
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Summary COMMAND FUNCTION DESCRIPTION VOUT_UV_FAULT_LIMIT Undervoltage DC/DC converter fault limit setting. This limit is also used to determine if Ton_max_fault has been met and the unit is on. VOUT_UV_FAULT_RESPONSE The VOUT_UV_FAULT_RESPONSE command instructs the device on what action to ...
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LTC2978 operaTion Summary COMMAND FUNCTION DESCRIPTION TOFF_DELAY Time, in ms, from CONTROL and/or Operation off to VOUT_EN off. STATUS_BYTE Fault status reporting. STATUS_WORD The STATUS_WORD command returns two bytes of information with a summary of the unit’s fault condition. STATUS_VOUT ...
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Summary COMMAND FUNCTION DESCRIPTION MFR_VINEN_UV_FAULT_RESPONSE Determines the response of the VIN_EN pin to a VOUT_UV_FAULT MFR_RETRY_DELAY Sets retry interval during retry mode. MFR_RESTART_DELAY Sets delay from actual CONTROL active edge to virtual CONTROL active edge. MFR_VOUT_PEAK Returns the maximum ...
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LTC2978 operaTion Summary COMMAND FUNCTION DESCRIPTION MFR_COMMON Contains manufacturer status bits that are common across multiple LTC chips. MFR_SPARE_0 Scratchpad register. MFR_SPARE_2 Paged scratchpad register. MFR_VOUT_MIN Returns the minimum measured value of VOUT. MFR_VIN_MIN Returns the minimum measured value of ...
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OPERATION The OPERATION command is used to turn the unit on and off in conjunction with the CONTROLn pin and ON_OFF_ CONFIG. This command register responds to the global page command. The contents and functions of the data byte ...
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LTC2978 operaTion ON_OFF_CONFIG The ON_OFF_CONFIG command configures the combina- tion of CONTROLn pin input and PMBus bus commands needed to turn the LTC2978 on/off, including the power-on behavior, as shown in the following table. This command register responds to the ...
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CLEAR_FAULTS The CLEAR_FAULTS command is used to clear any status faults that have been set. This command clears all bits in all unpaged status registers, and the paged status registers selected by the current PAGE setting. At the same ...
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LTC2978 operaTion VOUT_MODE The data byte for the VOUT_MODE command is 8 bits that consists of a three bit format and a five bit exponent. The three bit format specifies PMBus linear mode for all output voltage related commands. The ...
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Input Voltage Related Commands VIN_ON, VIN_OFF , VIN_OV_FAULT_LIMIT, VIN_OV_ WARN_LIMIT, VIN_UV_WARN_LIMIT and VIN_UV_ FAULT_LIMIT These commands use the same format and provide voltage supervising limits for VIN. Data Contents BIT(S) SYMBOL OPERATION b[15:0] Vin_on[15:0], These commands relate to input ...
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LTC2978 operaTion Fault Response for Voltages Measured by the High Speed Supervisor VOUT_OV_FAULT_RESPONSE and VOUT_UV_FAULT_ RESPONSE The fault response documented here is for voltages that are measured by the high speed supervisor. These voltages are measured over a short period ...
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Fault Response for Values Measured by the ADC OT_FAULT_RESPONSE, UT_FAULT_RESPONSE, VIN_OV_FAULT_RESPONSE and VIN_UV_FAULT_ RESPONSE The fault response documented here is for values that are measured by the ADC. These values are measured over a longer period of time and ...
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LTC2978 operaTion Timed Fault Response TON_MAX_FAULT_RESPONSE This command defines the LTC2978 response to a TON_MAX_FAULT. At start-up, the TON_MAX_FAULT_ RESPONSE is disarmed once the output voltage reaches the VOUT_UNDER_VOLTAGE_LIMIT. The only way to protect against a short-circuited output at start-up ...
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STATUS_BYTE: The STATUS_BYTE command returns the summary of the most critical faults or warnings which have occurred, as shown in the following table: STATUS_BYTE Data Contents BIT(S) SYMBOL OPERATION b[7] Status_byte_busy Device busy when PMBus command received. b[6] Status_byte_off ...
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LTC2978 operaTion STATUS_VOUT The STATUS_VOUT command returns the summary of the voltage faults or warnings which have occurred, as shown in the following table: STATUS_VOUT Data Contents BIT(S) SYMBOL OPERATION b[7] Status_vout_ov_fault Overvoltage fault. b[6] Status_vout_ov_warn Overvoltage warning. b[5] Status_vout_uv_warn ...
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STATUS_MFR_SPECIFIC The STATUS_MFR_SPECIFIC command returns manufac- turer specific status flags. Bits marked FAULT = No are intended to support polled handshaking; these are not latched nor do they assert ALERTB. Bits marked Channel = All can be read from ...
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LTC2978 operaTion ADC Monitoring Commands READ_VIN This command returns the most recent ADC measured value of the voltage measured at the V READ_VIN Data Contents BIT(S) SYMBOL OPERATION b[15:0] Read_vin[15:0] The data uses the linear format: V(Symbol • ...
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MANUFACTURER SPECIFIC COMMANDS MFR_CONFIG: This command is used to configure various manufacturer specific operating parameters for each channel. MFR_CONFIG Data Contents BIT(S) SYMBOL b[15:12] Reserved b[11] Mfr_config_fast_servo_off b[10] Mfr_config_supervisor_resolution Selects supervisor resolution: b[9] Mfr_config_adc_hires b[8] Mfr_config_controln_sel b[7] Mfr_config_servo_continuous b[6] ...
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LTC2978 operaTion MFR_CONFIG_ALL: This command is used to configure parameters that are common to all channels on the IC. They may be set or reviewed from any PAGE setting. MFR_CONFIG_ALL Data Contents BIT(S) SYMBOL OPERATION b[7] Mfr_config_fault_log_enable Enable fault logging ...
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MFR_FAULTB00_PROPAGATE, MFR_FAULTB01_ PROPAGATE, MFR_FAULTB10_PROPAGATE and MFR_FAULTB11_PROPAGATE These manufacturer specific commands enable channels that have faulted off to propagate that state to the ap- propriate fault pin. There are two zones in the LTC2978. In zone 0, faulted off states ...
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LTC2978 operaTion MFR_PWRGD_EN This command register controls the mapping of power good status to the power good pin. Note that odd num- bered channels whose ADC is in high res mode do not contribute to power good. MFR_PWRGD_EN Data Contents ...
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MFR_FAULTB00_RESPONSE, MFR_FAULTB01_ RESPONSE, MFR_FAULTB10_RESPONSE and MFR_ FAULTB11_RESPONSE These manufacturer specific commands share the same format and specify the response to assertions of the bidi- rectional fault pins. For fault zone 0, MFR_FAULTB00_RE- SPONSE determines how channels 0-3 respond when ...
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LTC2978 operaTion MFR_VINEN_OV_FAULT_RESPONSE This command register determines whether V voltage faults from a given channel cause the forced off. MFR_VINEN_OV_FAULT_RESPONSE Data Contents BIT(S) SYMBOL b[7] Mfr_vinen_ov_fault_response_chan7 b[6] Mfr_vinen_ov_fault_response_chan6 b[5] Mfr_vinen_ov_fault_response_chan5 b[4] Mfr_vinen_ov_fault_response_chan4 b[3] Mfr_vinen_ov_fault_response_chan3 b[2] Mfr_vinen_ov_fault_response_chan2 b[1] ...
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MFR_VINEN_UV_FAULT_RESPONSE This command register determines whether V voltage faults from a given channel cause the forced off. MFR_VINEN_UV_FAULT_RESPONSE Data Contents BIT(S) SYMBOL b[7] Mfr_vinen_uv_fault_response_chan7 b[6] Mfr_vinen_uv_fault_response_chan6 b[5] Mfr_vinen_uv_fault_response_chan5 b[4] Mfr_vinen_uv_fault_response_chan4 b[3] Mfr_vinen_uv_fault_response_chan3 b[2] Mfr_vinen_uv_fault_response_chan2 b[1] Mfr_vinen_uv_fault_response_chan1 ...
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LTC2978 operaTion MFR_RETRY_DELAY This command determines the retry interval when the LTC2978 is in hiccup mode in response to a fault condition. MFR_RETRY_DELAY Data Contents BIT(S) SYMBOL OPERATION b[15:0] Mfr_retry_delay The data uses the linear format: T(Symbol • ...
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LTC2978 emerges from power-on reset or when a CLEAR_FAULTS command is executed. MFR_TEMPERATURE_PEAK Data Contents BIT(S) SYMBOL OPERATION b[15:0] Mfr_temperature_peak[15:0] The data uses the linear format: V(Symbol • ...
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LTC2978 operaTion MFR_PAGE_FF_MASK The MFR_PAGE_FF_MASK command is used to select which channels respond when the global page (FF use. Note that the only commands that support PAGE = ‘hFF are OPERATION and ON_OFF_CONFIG. MFR_PAGE_FF_MASK Data Contents BIT(S) SYMBOL ...
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MFR_VOUT_DISCHARGE_THRESHOLD This register contains the coefficient that multiplies VOUT_COMMAND in order to determine the OFF thresh- old voltage for the associated output. If the output volt- age has not decayed below MFR_VOUT_DISCHARGE_ THRESHOLD • VOUT_COMMAND prior to the channel ...
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LTC2978 operaTion MFR_FAULT_LOG Read only. This 2048-bit data block contains a copy of the RAM buffer fault log. The RAM buffer is continuously updated after each ADC conversion as long as Mfr_fault_ log_status_ram is clear. With Mfr_config_fault_log_en = 1 and ...
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Data is logged into memory in the order shown in the following table. When data is returned during a block read it is returned in reverse order based on the value of Position_last[7:0]. Data byte Read_vout0[7:0] is followed by ...
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LTC2978 operaTion MFR_VOUT_MIN This command returns the minimum ADC measured value of the channel’s output voltage. The contents of this reg- ister is reset to ‘hFFFF when the LTC2978 emerges from power-on reset or when a CLEAR_FAULTS command is executed. ...
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WATCHDOG A non-zero write to the MFR_WATCHDOG_T register will reset the watchdog timer. Low-to-high transitions on the WDI pin also reset the watchdog timer. If the timer expires, ALERTB is asserted and the PWRGD output is optionally deasserted and ...
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LTC2978 applicaTions inForMaTion LTC2978 Overview The LTC2978 is a power management IC that is capable of sequencing, margining, trimming, OV/UV supervision, providing fault management, and voltage read back for eight DC/DC converters. Input voltage and temperature read back is also ...
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ON State Operation Once a channel has reached the ON state, the OPERATION command can be used to command the DC/DC converter’s output to margin high, margin low, or return to a nominal output voltage indicated by VOUT_COMMAND. ...
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LTC2978 applicaTions inForMaTion V OV/UV Warnings OUT OV and UV warning threshold voltages are processed by the LTC2978’s ADC. These thresholds are set by the VOUT_OV_WARN_LIMIT and VOUT_UV_WARN_LIMIT commands warning occurs, the corresponding bits are set in the ...
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MFR_FAULTB00_RESPONSE, PAGE = 0 MFR_FAULTB01_RESPONSE, PAGE = 0 MFR_FAULTB00_RESPONSE, PAGE = 1 MFR_FAULTB01_RESPONSE, PAGE = 1 MFR_FAULTB00_RESPONSE, PAGE = 2 MFR_FAULTB01_RESPONSE, PAGE = 2 MFR_FAULTB00_RESPONSE, PAGE = 3 MFR_FAULTB01_RESPONSE, PAGE = 3 ZONE 0 ZONE 1 MFR_FAULTB10_RESPONSE, PAGE ...
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LTC2978 applicaTions inForMaTion Interconnect Between Multiple LTC2978s Figure 14 shows how to interconnect the pins in a typical multi-LTC2978 array. • All V lines should be tied together in a star type IN_SNS connection at the point where V This ...
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Trimming and Margining DC/DC Converters with External Feedback Resistors Figure 16 shows a typical application circuit for trim- ming/margining a power supply with an external feedback network. The V and V SENSEP0 SENSEM0 sense the load voltage directly, ...
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LTC2978 applicaTions inForMaTion 4-Step Resistor Selection Procedure for DC/DC Converters with External Feedback Resistors The following 4-step procedure should be used to calcu- late the resistor values required for the application circuit shown in Figure 16. 1. Assume values for ...
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Trimming and Margining DC/DC Converters with a TRIM Pin Figure 17 illustrates a typical application circuit for trim- ming/margining the output voltage of a DC/DC converter with a TRIM Pin. The LTC2978’s V DACPn the TRIM pin through ...
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LTC2978 applicaTions inForMaTion Measuring Current Odd numbered ADC channels may be used to measure supply current. Set the ADC to high resolution mode to configure for current measuring and improve sensitivity. Note that faults or warnings ...
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Antialiasing Filter Considerations Extremely noisy environments may require an antialiasing filter on the input to the LTC2978’s ADC. The R-C circuit shown in Figure 19 is adequate for most situations. Keep V IN 4.5V < V < 15V ...
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LTC2978 applicaTions inForMaTion Dongle Connections Figure 20 illustrates the application schematic for powering and programming one or more LTC2978’s from the LTC PMBus controller in the absence of system power. Because of the controller’s limited current sourcing capability, only SYSTEM ...
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PCB ASSEMBLY AND LAYOUT SUGGESTIONS Bypass Capacitor Placement The LTC2978 requires 0.1µF bypass capacitors between the V pins and GND, the V DD33 DD25 REFP pin and REFM pin. If the chip is being powered from the V ...
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LTC2978 Typical applicaTion OUT 37 R30 DC/DC CONVERTER R20 V LOAD FB 38 R10 39 RUN/SS SGND GND OUT 47 R32 DC/DC CONVERTER R22 V LOAD ...
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... SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 6. DRAWING NOT TO SCALE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. UP Package 64-Lead Plastic QFN (9mm × ...
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... LTM4608 8A, Low V DC/DC µModule with Tracking, Margining, IN Multiphase and Frequency Synchronization µModule is a registered trademark of Linear Technology Corporation. PowerPath, ThinSOT and Hot Swap are trademarks of Linear Technology Corporation. Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● ...