MAXIM INTEGRATED PRODUCTS Dual PCI Express, Hot-Plug Controller MAX5946 Data Sheet User Manual

19-3483; Rev 0; 11/04

EVALUATION KIT AVAILABLE

Dual PCI Express, Hot-Plug

Controller

General Description Features

The MAX5946 dual hot-plug controller is designed for PCI Express Compliant

PCI Express™ applications. The device provides hot-

Hot Swaps 12V, 3.3V, and 3.3V Auxiliary for 2

plug control for 12V, 3.3V, and 3.3V auxiliary supplies of

PCI-E Slots

two PCI express slots. The MAX5946’s logic inputs/out-

Integrated Power MOSFET for Auxiliary Supply

puts allow interfacing directly with the system hot-plug

Rails

management controller or through an SMBus™ with an

external I/O expander. An integrated debounced atten- Controls d I/dt and d V/dt

tion switch and present-detect signals are included to Active Current Limiting Protects Against simplify system design. Overcurrent/Short-Circuit Conditions The MAX5946 drives four external n-channel MOSFETs Programmable Current-Limit Timeout to control the 12V and 3.3V main outputs. The 3.3V aux-

PWRGD Signal Outputs with Programmable

iliary outputs are controlled through internal 0.3Ω

Power-On Reset (POR) (160ms Default)

n-channel MOSFETs. Internal charge pumps provide

Latched FAULT Signal Output after Overcurrent

gate drive for the 12V outputs while the gate drive of

or Overtemperature Fault

the 3.3V output is driven by the 12V input supply. The

3.3V auxiliary outputs are completely independent from Attention Switch Inputs/Outputs with 4ms the main outputs with their own charge pumps. Debounce At power-up, the MAX5946 keeps all of the external Present-Detect Inputs

MOSFETs off until the supplies rise above their respec- Forced-On Inputs Facilitates Testing tive undervoltage lockout (UVLO) thresholds. The

Thermal Shutdown

device keeps the internal MOSFETs off only until the

auxiliary input supply rises above its UVLO threshold. Allows Control through SMBus with an I/O 3. 3G PO RA DJ Expander

Upon a turn-on command, the MAX5946 enhances the

external and internal MOSFETs slowly with a constant FA UL TA PG ND

PW RG DA GN Ordering Information

gate current to limit the power-supply inrush current.

3. 3V AU XO VI

The MAX5946 actively limits the current of all outputs at

3. 3V AU XI IN PU T1

PART TEMP RANGE PIN-PACKAGE

all times and shuts down if an overcurrent condition

3. 3V AU XO OU TP UT

persists for longer than a programmable overcurrent MAX5946AETX -40°C to +85°C 36 Thin QFN

PW RG DB OU TP UT

timeout. Thermal-protection circuitry also shuts down all

FA UL TB IN PU T2 MAX5946LETX -40°C to +85°C 36 Thin QFN

outputs if the die temperature exceeds +150°C. After an 3. 3G TI overcurrent or overtemperature fault condition, the

MAX5946L latches off while the MAX5946A automatical- Pin Configuration

ly restarts after a restart time delay. The device is avail- able in a 36-pin (6mm × 6mm) thin QFN package and

TOP VIEW

operates over the -40°C to +85°C temperature range.

Applications

PRES-DETA PRES-DETB1

Servers

FONA FONB

Desktop Mobile Server Platforms ONA ONB AUXONA AUXONB

Workstations

12SA+ MAX5946 12SB+

12SA- 12SB-

Embedded Devices

12GA 12GB 3.3SA+ 3.3SB+ 3.3SA- 3.3SB-

Typical Application Circuit appears at end of data sheet.

SMBus is a trademark of Intel Corp.

THIN QFN

PCI Express is a trademark of PCI-SIG Corp.

Maxim Integrated Products

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.