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General Description

The MAX1519/MAX1545 are dual-phase, Quick-PWM™,

step-down controllers for desktop and mobile Pentium

(P4) CPU core supplies. Dual-phase operation reduces

input ripple current requirements and output voltage rip-

ple while easing component selection and layout difficul-

ties. The Quick-PWM control scheme provides

instantaneous response to fast load-current steps. The

MAX1519/MAX1545 include active voltage positioning

with adjustable gain and offset, reducing power dissipa-

tion and bulk output capacitance requirements.

The MAX1519/MAX1545 are intended for two different

notebook CPU core applications: stepping down the bat-

tery directly or stepping down the 5V system supply to

create the core voltage. The single-stage conversion

method allows these devices to directly step down high-

voltage batteries for the highest possible efficiency.

Alternatively, two-stage conversion (stepping down the

5V system supply instead of the battery) at a higher

switching frequency provides the minimum possible

physical size.

The MAX1519/MAX1545 comply with Intel’s P4 specifi-

cations. The switching regulator features soft-start,

power-up sequencing, and soft-shutdown. The

MAX1519/MAX1545 also feature independent four-level

logic inputs for setting the suspend voltage (S0–S1).

The MAX1519/MAX1545 include output undervoltage

protection (UVP), thermal protection, and voltage regula-

tor power-OK (VROK) output. When any of these protec-

tion features detect a fault, the controller shuts down.

Additionally, the MAX1519/MAX1545 include overvoltage

protection.

The MAX1519/MAX1545 are available in low-profile, 40-

pin, 6mm x 6mm thin QFN packages. For other CPU

platforms, refer to the pin-to-pin compatible MAX1544

and MAX1532/MAX1546/MAX1547 data sheets.

Applications

Desktop and Mobile P4 Computers

Multiphase CPU Core Supply

Voltage-Positioned Step-Down Converters

Servers/Desktop Computers

Low-Voltage, Digitally Programmable Power

Supplies

Features

♦ Dual-Phase, Quick-PWM Controllers

♦ ±0.75% V

OUT

Accuracy Over Line, Load, and

Temperature (1.3V)

♦ Active Voltage Positioning with Adjustable Gain

and Offset

♦ 5-Bit On-Board DAC

Mobile: 0.60V to 1.75V Output Range

Desktop: 1.10V to 1.85V Output Range

♦ Selectable 100kHz/200kHz/300kHz/550kHz

Switching Frequency

♦ 4V to 28V Battery Input Voltage Range

♦ Adjustable Slew-Rate Control

♦ Drive Large Synchronous Rectifier MOSFETs

♦ Output Overvoltage Protection (MAX1545 Only)

♦ Undervoltage and Thermal-Fault Protection

♦ Power Sequencing and Timing

♦ Selectable Suspend Voltage (0.675V to 1.45V)

♦ Soft-Shutdown

♦ Selectable Single- or Dual-Phase Pulse Skipping

MAX1519/MAX1545

Dual-Phase, Quick-PWM Controllers for

Programmable CPU Core Power Supplies

________________________________________________________________ Maxim Integrated Products 1

DLM

LXM

BSTM

VROK

DHM

SUS

OFS

REF

ILIM

TON

TIME

OAIN-

OAIN+

CODE

CCI

GNDS

CCV

GND

CSN

CMN

CMP

V+

BSTS

LXS

DHS

DLS

PGND

CSP

THIN QFN

MAX1519

MAX1545

TOP VIEW

SHDN

SKIP

Pin Configuration

Ordering Information

19-2734; Rev 1; 9/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

PART TEMP RANGE PIN-PACKAGE

MAX1519ETL -40°C to +100°C 40 Thin QFN 6mm

✕ 6mm

MAX1545ETL -40°C to +100°C 40 Thin QFN 6mm ✕ 6mm

Quick-PWM is a trademark of Maxim Integrated Products, Inc.

Pentium is a registered trademark of Intel Corp.

Summary of content (43 pages)

PAGE 1
9-2734; Rev 1; 9/03 KIT ATION EVALU E L B A IL AVA Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies ♦ ±0.75% VOUT Accuracy Over Line, Load, and Temperature (1.3V) ♦ Active Voltage Positioning with Adjustable Gain and Offset ♦ 5-Bit On-Board DAC Mobile: 0.60V to 1.75V Output Range Desktop: 1.10V to 1.
PAGE 2
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies ABSOLUTE MAXIMUM RATINGS V+ to GND ..............................................................-0.3V to +30V VCC to GND ..............................................................-0.3V to +6V VDD to PGND............................................................-0.3V to +6V SKIP, SUS, D0–D4 to GND.......................................-0.3V to +6V ILIM, FB, OFS, CCV, CCI, REF, OAIN+, OAIN- to GND...............
PAGE 3
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies (Circuit of Figure 1, V+ = 15V, VCC = VDD = V SHDN = VTON = V SKIP = VS0 = VS1 = VCODE = 5V, VFB = VCMP = VCMN = VCSP = VCSN = 1.3V, OFS = SUS = GNDS = D0–D4 = GND; TA = 0°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) PARAMETER On-Time (Note 3) SYMBOL tON Minimum Off-Time (Note 3) tOFF(MIN) CONDITIONS V+ = 12V, VFB = VCCI = 1.
PAGE 4
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 1, V+ = 15V, VCC = VDD = V SHDN = VTON = V SKIP = VS0 = VS1 = VCODE = 5V, VFB = VCMP = VCMN = VCSP = VCSN = 1.3V, OFS = SUS = GNDS = D0–D4 = GND; TA = 0°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.
PAGE 5
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies (Circuit of Figure 1, V+ = 15V, VCC = VDD = V SHDN = VTON = V SKIP = VS0 = VS1 = VCODE = 5V, VFB = VCMP = VCMN = VCSP = VCSN = 1.3V, OFS = SUS = GNDS = D0–D4 = GND; TA = 0°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.
PAGE 6
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 1, V+ = 15V, VCC = VDD = V SHDN = VTON = V SKIP = VS0 = VS1 = VCODE = 5V, VFB = VCMP = VCMN = VCSP = VCSN = 1.3V, OFS = SUS = GNDS = D0–D4 = GND; TA = 0°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) PARAMETER SYMBOL D0–D4 Input Current CONDITIONS D0–D4 MIN TYP -2 CODE Input High Voltage MAX UNITS +2 µA 2.
PAGE 7
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies (Circuit of Figure 1, V+ = 15V, VCC = VDD = V SHDN = VTON = V SKIP = VS0 = VS1 = VCODE = 5V, VFB = VCMP = VCMN = VCSP = VCSN = 1.3V, OFS = SUS = GNDS = D0–D4 = GND; TA = -40°C to +100°C, unless otherwise specified.) (Note 5) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS BIAS AND REFERENCE Quiescent Supply Current (VCC) ICC Measured at VCC, FB forced above the regulation point, OAIN- = FB, VOAIN+ = 1.3V 3.
PAGE 8
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 1, V+ = 15V, VCC = VDD = V SHDN = VTON = V SKIP = VS0 = VS1 = VCODE = 5V, VFB = VCMP = VCMN = VCSP = VCSN = 1.3V, OFS = SUS = GNDS = D0–D4 = GND; TA = -40°C to +100°C, unless otherwise specified.) (Note 5) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS BST_ - LX_ forced to 5V 4.5 Ω High state (pullup) 4.
PAGE 9
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies VIN = 8V EFFICIENCY (%) 1.44 80 VIN = 12V 70 VIN = 20V 1.42 1.00 OUTPUT VOLTAGE (V) 90 1.48 1.46 1.02 MAX1519 toc02 1.50 60 1.40 10 20 30 40 50 1 10 0.90 100 20 30 40 50 60 LOAD CURRENT (A) EFFICIENCY vs. LOAD CURRENT (VOUT = 1.00V) OUTPUT VOLTAGE vs. LOAD CURRENT (VOUT = 0.80V) DUAL-PHASE EFFICIENCY vs. LOAD CURRENT (VOUT = 0.80V) VIN = 12V VIN = 20V 60 0.78 0.
PAGE 10
Typical Operating Characteristics (continued) (Circuit of Figure 1, VIN = 12V, VCC = VDD = 5V, SHDN = SKIP = VCC, D0–D4 set for 1.5V (SUS = GND), S0–S1 set for 1V (SUS = VCC), OFS = GND, TA = +25°C, unless otherwise specified.) OUTPUT OFFSET VOLTAGE vs. OFS VOLTAGE 1.0 SAMPLE SIZE = 100 40 50 0 -50 30 20 10 -100 0.5 IIN -150 0 0 0.5 1.0 0 1.990 2.0 1.5 INPUT VOLTAGE (V) OFS VOLTAGE (V) 2.005 2.
PAGE 11
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies SOFT-START POWER-UP SEQUENCE MAX1519 toc19 MAX1519 toc18 5V 5V A A 0V 0V 1.5V 2V B 0V B 1V C 10A 0V 5V C 0A D 0V 0A 100µs/div 1ms/div A. SHDN, 5V/div B. 1.5V OUTPUT, 1V/div C. IL1, 10A/div D. IL2, 10A/div RLOAD = 75mΩ, RTIME = 64.9kΩ A. SHDN, 5V/div B. 1.5V OUTPUT, 1V/div C. VROK, 5V/div RTIME = 64.9kΩ 1.50V LOAD TRANSIENT (10A TO 50A LOAD) SOFT-SHUTDOWN MAX1519 toc21 MAX1519 toc20 5V A 50A A 10A 0V 1.
PAGE 12
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies Typical Operating Characteristics (continued) (Circuit of Figure 1, VIN = 12V, VCC = VDD = 5V, SHDN = SKIP = VCC, D0–D4 set for 1.5V (SUS = GND), S0–S1 set for 1V (SUS = VCC), OFS = GND, TA = +25°C, unless otherwise specified.) 1.00V LOAD TRANSIENT (10A TO 30A LOAD) OFFSET TRANSITION MAX1519 toc22 30A MAX1519 toc23 A 10A 0.2V A 0V B 1.5V B 0A 10A C 5A C 0A D 5A D 1.0V 10A 20µs/div 20µs/div A.
PAGE 13
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies SINGLE-PHASE SKIP TO DUAL-PHASE PWM TRANSITION DUAL-PHASE SKIP TO DUAL-PHASE PWM TRANSITION MAX1519 toc26 MAX1519 toc27 A 5V 2V A 1.5V B 1.5V B 0A C 0A C 0A D 0A D 5V 20µs/div 20µs/div A. SKIP = VCC TO REF, 5V/div B. 1.5V OUTPUT, 50mV/div C. IL1, 10A/div D. IL2, 10A/div 2A LOAD A. SKIP = VCC TO GND, 5V/div B. 1.5V OUTPUT, 50mV/div C. IL1, 10A/div D.
PAGE 14
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 Pin Description PIN NAME 1 TIME Slew-Rate Adjustment Pin. Connect a resistor from TIME to GND to set the internal slew-rate clock. A 150kΩ to 15kΩ resistor sets the clock from 100kHz to 1MHz, fSLEW = 500kHz × 30kΩ/RTIME. 2 TON On-Time Selection Control Input.
PAGE 15
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies PIN NAME 13 GNDS Ground Remote-Sense Input. Connect GNDS directly to the CPU ground-sense pin. GNDS internally connects to an amplifier that adjusts the output voltage, compensating for voltage drops from the regulator ground to the load ground. 14 CCI Current-Balance Compensation. Connect a 470pF capacitor between CCI and FB (see the CurrentBalance Compensation (CCI) section). 15 FB Feedback Input.
PAGE 16
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 Pin Description (continued) PIN NAME FUNCTION 31 PGND 32 DLS Secondary Low-Side Gate-Driver Output. DLS swings from PGND to VDD. DLS is forced high after the MAX1519/MAX1545 power down. 33 DHS Secondary High-Side Gate-Driver Output. Swings LXS to BSTS. 34 LXS Secondary Inductor Connection. LXS is the internal lower supply rail for the DHS high-side gate driver.
PAGE 17
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 Table 1. Component Selection for Standard Multiphase Applications* DESIGNATION MAX1519/MAX1545 2-PHASE DESKTOP P4 MAX1519/MAX1545 4- PHASE DESKTOP P4 Circuit of Figure 1 Circuit of Figure 12 Input Voltage Range 7V to 24V 7V to 24V VID Output Voltage (D4–D0) 1.5V (CODE = GND, D4–D0 = 01110) 1.
PAGE 18
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies R11 100kΩ C1 2.2µF R10 10Ω C2 1µF POWERGOOD VDD VCC MAX1519 MAX1545 VROK D0 D1 D2 D3 D4 DAC INPUTS GND (DESKTOP P4) SUSPEND INPUTS (FOUR-LEVEL LOGIC) ON OFF U1 CODE S0 S1 SHDN 5V BIAS SUPPLY BST DIODES V+ BSTM INPUT* 7V TO 24V CIN CBST1 0.22µF DHM NH1 TIME CCCV 47pF COUT LXM DLM NL1 PGND R2 1kΩ ±1% GND RTIME 64.9kΩ RSENSE1 1.0mΩ L1 CMN CMP OAIN+ OAIN- R3 1kΩ ±1% R6 1.
PAGE 19
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 SHDN DO NOT CARE VID (D0–D4) SOFT-SHUTDOWN 1LSB PER 4 RTIME CYCLES SOFT-START 1LSB PER RTIME CYCLE VCORE VROK tVROK(START) 3ms, TYP Figure 2. Power-Up and Shutdown Sequence Timing Diagram Table 2. Component Suppliers MANUFACTURER PHONE WEBSITE BI Technologies 714-447-2345 (USA) www.bitechnologies.com Central Semiconductor 631-435-1110 (USA) www.centralsemi.com Coilcraft 800-322-2645 (USA) www.
PAGE 20
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies Table 3. Operating Mode Truth Table SHDN SUS SKIP OFS OUTPUT VOLTAGE GND x x x GND Low-Power Shutdown Mode. DL_ is forced high, DH_ is forced low, and the PWM controller is disabled. The supply current drops to 1µA (typ). VCC GND VCC GND or REF D0–D4 (no offset) Normal Operation. The no-load output voltage is determined by the selected VID DAC code (CODE and D0–D4, Table 4).
PAGE 21
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 D0–D4 DECODER D0 D1 D2 D3 D4 IN OUT CODE 0 SUSPEND MUX SEL S0–S1 DECODER S0 S1 IN OUT SEL 1 OUT DAC SEL SUS 2.5V SUS 3-LEVEL DECODER 1.0V Figure 3. Internal Multiplexers Functional Diagram independent suspend-mode output voltage codes set by the four-level S0–S1 inputs and the three-level SUS input.
PAGE 22
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies SUS 1 LSB PER RTIME CYCLE VDAC OUTPUT SET BY D0–D4 OUTPUT SET BY SUS AND S0–S1 tSLEW tBLANK = 24 CLKS tSLEW tBLANK = 24 CLKS TIME CLOCK VROK VROK BLANKING VROK BLANKING Figure 4. Suspend Transition than the current limit set by ILIM.
PAGE 23
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies CODE = VCC CODE = GND D4 D3 D2 D1 D0 OUTPUT VOLTAGE (V) 0 0 0 0 0 1.750 0 0 0 0 0 1.850 0 0 0 0 1 1.700 0 0 0 0 1 1.825 0 0 0 1 0 1.650 0 0 0 1 0 1.800 0 0 0 1 1 1.600 0 0 0 1 1 1.775 0 0 1 0 0 1.550 0 0 1 0 0 1.750 0 0 1 0 1 1.500 0 0 1 0 1 1.725 0 0 1 1 0 1.450 0 0 1 1 0 1.700 0 0 1 1 1 1.400 0 0 1 1 1 1.675 0 1 0 0 0 1.
PAGE 24
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies Table 5. Suspend Mode DAC Codes LOWER SUSPEND CODES UPPER SUSPEND CODES SUS* S1 S0 OUTPUT VOLTAGE (V) High GND GND 0.675 REF GND GND 1.075 High GND REF 0.700 REF GND REF 1.100 High GND OPEN 0.725 REF GND OPEN 1.125 High GND VCC 0.750 REF GND VCC 1.150 High REF GND 0.775 REF REF GND 1.175 High REF REF 0.800 REF REF REF 1.200 High REF OPEN 0.
PAGE 25
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies On-Time One-Shot (TON) The core of each phase contains a fast, low-jitter, adjustable one-shot that sets the high-side MOSFETs on-time. The one-shot for the main phase varies the ontime in response to the input and feedback voltages. The main high-side switch on-time is inversely proportional to the input voltage as measured by the V+ input, and proportional to the feedback voltage (VFB): t ON(MAIN) = K (VFB + 0.
PAGE 26
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies BSTS CSN DHS SECONDARY PHASE DRIVERS CSP LXS DLS ILIM Q 19R CMP TRIG Gm ON-TIME ONE-SHOT R CMN CCI MINIMUM OFF-TIME CMP Q CSN TRIG Gm ONE-SHOT CMN FB VCC ON-TIME ONE-SHOT CSP V+ TON REF REF (2.0V) Q TRIG Q T Q SHDN MAIN PHASE DRIVERS R Q GND DHM S LXM S Q CMP CCV R CMN Gm BSTM 1.5mV VDD REF 1.
PAGE 27
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies For loads above the critical conduction point, where the dead-time effect is no longer a factor, the actual switching frequency (per phase) is: fSW = (VOUT + VDROP1) tON (VIN + VDROP1 - VDROP2 ) where VDROP1 is the sum of the parasitic voltage drops in the inductor discharge path, including synchronous rectifier, inductor, and PC board resistances; VDROP2 is the sum of the parasitic voltage drops in the inductor charge path, incl
PAGE 28
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies Table 7. SKIP Settings* SKIP CONNECTION MODE OPERATION High (3.3V or VCC) Two-phase forced-PWM The controller operates with a constant switching frequency, providing low-noise forced-PWM operation. The controller disables the zero-crossing comparators, forcing the low-side gatedrive waveform to constantly be the complement of the high-side gate-drive waveform.
PAGE 29
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 UNDEFINED REGION ∆i VBATT - VOUT = ∆t L IPEAK 100 INDUCTOR CURRENT OUTPUT OFFSET VOLTAGE (mV) 200 0 -100 0.8 -200 0 0.5 ILOAD = IPEAK/2 1.2 1.0 1.5 0 2.0 ON-TIME TIME OFS VOLTAGE (V) Figure 7. Pulse-Skipping/Discontinuous Crossover Point reverse under light loads, providing fast, accurate negative output voltage transitions by quickly discharging the output capacitors.
PAGE 30
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies the input voltage due to the typically low duty cycles. The total load current at the PFM/PWM crossover threshold (ILOAD(SKIP)) is approximately: CBYP VDD DBST BST  K  V -V V ILOAD(SKIP) = η TOTAL  OUT   IN OUT   L   VIN  where ηTOTAL is the number of active phases, and K is the on-time scale factor (Table 6).
PAGE 31
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies C  VGS(TH) < VIN  RSS   CISS  Lot-to-lot variation of the threshold voltage can cause problems in marginal designs. Typically, adding a 4700pF between DL and power ground (CNL in Figure 9), close to the low-side MOSFETs, greatly reduces coupling. Do not exceed 22nF of total gate capacitance to prevent excessive turn-off delays.
PAGE 32
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies response vs. output noise. Low-inductor values provide better transient response and smaller physical size, but also result in lower efficiency and higher output noise due to increased ripple current. The minimum practical inductor value is one that causes the circuit to operate at the edge of critical conduction (where the inductor current just touches zero with every cycle at maximum load).
PAGE 33
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies RESR ≤ VRIPPLEL (2VIN − ηTOTAL VOUT )t ON − ηTOTAL VOUT t TRIG where ηTOTAL is the total number of active phases, tON is the calculated on-time per phase, and tTRIG is the trigger delay between the master’s DH rising edge and the slave’s DH rising edge. The trigger delay must be less than 1/(fSW × ηTOTAL) for stable operation.
PAGE 34
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies Input Capacitor Selection The input capacitor must meet the ripple current requirement (IRMS) imposed by the switching currents. The multiphase Quick-PWM controllers operate out-ofphase, while the Quick-PWM slave controllers provide selectable out-of-phase or in-phase on-time triggering. Out-of-phase operation reduces the RMS input current by dividing the input current between several staggered stages.
PAGE 35
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 CMN CMP MAIN PHASE L1 MAX1519 MAX1545 RSENSE RA RB PC BOARD TRACE RESISTANCE OAIN+ RFBS ERROR COMPARATOR CPU SENSE POINT OAINPC BOARD TRACE RESISTANCE RF FB RA SECOND PHASE L2 RB RSENSE CSP CSN Figure 10.
PAGE 36
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies Current-Balance Compensation (CCI) The current-balance compensation capacitor (CCCI) integrates the difference between the main and secondary current-sense voltages. The internal compensation resistor (RCCI = 20kΩ) improves transient response by increasing the phase margin. This allows the dynamics of the current-balance loop to be optimized.
PAGE 37
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies KMIN = 3µs for fSW = 300kHz tOFF(MIN) = 400ns VVPS = 3mV/A × 30A = 90mV VDROP1 = VDROP2 = 150mV (30A load) 3) 4) h = 1.5 and ηOUTPH = 2  1.4 V − 90mV + 150mV  VIN(MIN) = 2 x    1 − 2 x (0.4 µs x 1.5 / 3.0µs  + 150mV − 150mV + 90mV = 4.96V Calculating again with h = 1 gives the absolute limit of dropout:  1.4 V − 90mV + 150mV  VIN(MIN) = 2 x    1 − 2 x (0.4 µs x 1.0 / 3.0µs  + 150mV − 150mV + 90mV = 4.
PAGE 38
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies 2) 3) 38 Group the gate-drive components (BST diodes and capacitors, VDD bypass capacitor) together near the controller IC. Make the DC-to-DC controller ground connections as shown in the Standard Application Circuits.
PAGE 39
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies MAX1519/MAX1545 KELVIN SENSE VIAS UNDER THE SENSE RESISTOR (REFER TO EVALUATION KIT) CPU MAIN PHASE SECONDARY PHASE OUTPUT COUT RSENSE COUT COUT COUT COUT COUT RSENSE INDUCTOR INDUCTOR CIN CIN CIN CIN CIN CIN POWER GROUND INPUT PLACE CONTROLLER ON BACK SIDE WHEN POSSIBLE, USING THE GROUND PLANE TO SHIELD THE IC FROM EMI VIAS TO POWER GROUND CONNECT THE EXPOSED PAD TO ANALOG GND VIAS TO ANALOG GROUND POWER G
PAGE 40
MAX1519/MAX1545 Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies R11 100kΩ C1 2.2µF R10 10Ω C2 1µF POWERGOOD VDD VCC MAX1519 MAX1545 VROK D0 D1 D2 D3 D4 DAC INPUTS GND (DESKTOP P4) SUSPEND INPUTS (FOUR-LEVEL LOGIC) ON OFF U1 CODE S0 S1 SHDN 5V BIAS SUPPLY BST DIODES V+ BSTM INPUT* 7V TO 24V CIN CBST1 0.22µF DHM NH1 TIME CCCV 47pF COUT LXM DLM NL1 PGND R2 1kΩ ±1% GND RTIME 64.9kΩ RSENSE1 1.5mΩ L1 CMN CMP OAIN+ OAIN- R3 1kΩ ±1% R6 3.
PAGE 41
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies R12 10Ω DBST3 POL BST OUTPUT COMP CCOMP1 RCOMP1 270pF 20kΩ INPUT* 7V TO 24V CIN V+ D1 1N4148 DH CBST3 0.22µF NH3 RSENSE3 1.5mΩ L3 R17 200kΩ U2 LX MAX1980 DL OUTPUT COUT NL3 ILIM PGND R18 49.
PAGE 42
C10 1µF R19 10Ω VDD VCC C11 0.22µF DBST4 POL BST OUTPUT COMP CCOMP2 RCOMP2 270pF 20kΩ INPUT* 7V TO 24V CIN V+ D2 1N4148 DH CBST4 0.22µF NH4 RSENSE4 1.5mΩ L4 R24 200kΩ U3 LX MAX1980 DL OUTPUT COUT NL4 ILIM PGND C14 100pF R25 49.
PAGE 43
Dual-Phase, Quick-PWM Controllers for Programmable CPU Core Power Supplies QFN THIN 6x6x0.8.EPS D2 D CL D/2 b D2/2 k E/2 E2/2 E (NE-1) X e CL E2 k L e (ND-1) X e CL CL L L e A1 A2 e A PACKAGE OUTLINE 36,40L QFN THIN, 6x6x0.8 mm C 21-0141 COMMON DIMENSIONS 1 2 EXPOSED PAD VARIATIONS D2 E2 PKG. CODES MIN. NOM. MAX. MIN. NOM. MAX. T3666-1 3.60 3.70 3.80 3.60 3.70 3.80 T4066-1 4.00 4.10 4.20 4.00 4.10 4.20 NOTES: 1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.