L6740L STMicroelectronics, L6740L Datasheet - Page 15

• Manufacturer Part Number: L6740L
• Description: IC HYBRID CONTROLLERS 48TQFP
• Manufacturer: STMicroelectronics

Specifications of L6740L

• Applications: Hybrid Controllers
• Voltage - Supply: 9 V ~ 15 V
• Current - Supply: 20mA
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 48-TQFP Exposed Pad, 48-eTQFP, 48-HTQFP, 48-VQFP
• Number Of Outputs: 2
• Output Current: 170 A
• Input Voltage: 13.2 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Hybrid Controller: compatible with PVI and SVI CPUs
• Dual Controller: 2 to 4 scalable phases for CPU CORE, 1 phase for NB
• Dual Over-current Protection: Average and per-phase
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

L6740L
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Device description and operation
L6740L is a hybrid CPU power supply controller compatible with both parallel (PVI) and
Serial (SVI) protocols for AMD K8 - second generation processors. The device provides
complete control logic and protections for a high-performance step-down DC-DC voltage
regulator, optimized for advanced microprocessor power supply supporting both PVI and
SVI communication. It embeds two independent controllers for CPU CORE and the
integrated NB, each one with its own set of protections.
L6740L is able to detect which kind of CPU is connected in order to configure itself to work
as a single-plane PVI controller or dual-plane SVI controller.
The controller performs a single-phase control for the NB section and a programmable 2-to-
4 phase control for the CORE section featuring dual-edge non-latched architecture: this
allows fast load-transient response optimizing the output filter consequently reducing the
total BOM cost. Further reduction can be achieved by enabling LTB Technology
phase (when enabled) will be automatically phase-shifted with respect to the CORE phases
in order to reduce the total input RMS current amount.
PSI_L Flag is sent to the VR through the SVI bus. The controller monitors this flag and
selectively modifies the phase number in order to optimize the system efficiency when the
CPU enters low-power states. This causes the over-all efficiency to be maximized at light
loads so reducing losses and system power consumption.
Both sections feature programmable over-voltage protection and adjustable constant over-
current protection. Voltage positioning (LL) is possible thanks to an accurate fully-differential
current-sense across the main inductors for the CORE section and thanks to the loss-less
current sense across low-side MOSFET R
be disabled and the generated current information may be used to implement a Load
Indicator function.
L6740L features dual remote sensing for the regulated outputs (CORE and NB) in order to
recover from PCB voltage drops also protecting the load from possible feedback network
disconnections.
LSLess start-up function allows the controller to manage pre-biased start-up avoiding
dangerous current return through the main inductors as well as negative undershoot on the
output voltage if the output filter is still charged before start-up.
L6740L also supports V_FIX mode for system debugging: in this particular configuration the
SVI bus is used as a static bus configuring 4 operative voltages for both the sections and
ignoring any serial-VID command.
When working in PVI mode, the device features on-the-fly VID management: VID code is
continuously sampled and the reference update according to the variation detected,
L6740L is available in TQFP48 package.
DS(on)
for the NB section. In both cases, LL may
Device description and operation
(TM)
. NB
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