Figure 2. Application with Cirrus Logic Interface

Single-Channel CardBus and PCMCIA VCC/VPP

Power-Switching Network

10

______________________________________________________________________________________

independent of resistive and capacitive loads (see rise-

time photos in the

Typical Operating Characteristics).

Fall times are a function of loading, and are compensat-

ed by internal circuitry.

Power savings is automatic: internal charge pumps draw

very low current when the VCC switches are static.

Standby mode reduces switch supply current to 11µA.

Operating Modes

The MAX1602 is compatible with the Cirrus

CL-PD67XX, Databook DB86184, and Intel 82365SL PC

Card Interface Controllers (PCIC). Four control inputs

select the internal switches’ positions and the operating

modes according to the input code. Select the proper

code format for the chosen controller with the CODE

input pin (see

Pin Description and Tables 1, 2, and 3).

CODE reconfigures the logic decoder to one of three

interface controllers:

Low = Standard “Intel” code (Figure 3)

High = “Cirrus” code (Figure 2)

Mid-supply = “Databook” code (Figure 4)

An additional 1µA (3µA max) of VY supply current will

flow if CODE = mid-supply (VY/2).

The MAX1602 has two operating modes: normal and

standby. Normal mode supplies the selected outputs

with their appropriate supply voltages. Standby mode

places all switches at ground, high impedance, or a

combination of the two.

Overcurrent Protection

Peak detecting circuitry protects both the VCC and VPP

switches against overcurrent conditions. When current

through any switch exceeds the internal current limit

(4A for VCC switches and 200mA for VPP switches) the

switch turns off briefly, then turns on again at the con-

trolled rise rate. If the overcurrent condition lasts more

than 2µs, the

FAULT output goes low. FAULT is not

latched. A continuous short-circuit condition results in a

pulsed output current and a pulsed

FAULT output until

thermal shutdown is reached.

FAULT is open-drain and

requires an external pull-up resistor.

Thermal Shutdown

If the IC junction temperature rises above +150°C, the

thermal shutdown circuitry opens all switches, including

the GND switches, and

FAULT is pulled low. When the

temperature falls below +130°C, the switches turn on

again at the controlled rise rate. If the overcurrent con-

dition remains, the part cycles between thermal shut-

down and overcurrent.

Undervoltage Lockout

If the VX switch input voltage drops below 1.9V, the

associated switch turns off and

FAULT goes low. For

example, if VY is 3.3V and VX is 0V, and if the interface

controller selects VY, the VCC output will be 3.3V. If VX

is selected, VCC changes to a high-impedance output

and

FAULT goes low.

When a voltage is initially applied to 12IN, it must be

greater than 8V to allow the switch to operate.

Operation continues until the voltage falls below 2V

(the VPP output is high impedance).

When VY drops to less than 2.6V, all switches are

turned off and the VCC and VPP outputs are high

impedance.

__________Applications Information

Supply Bypassing

Bypass the VY, VX, and 12IN inputs with ceramic 0.1µF

capacitors. Bypass the VCC and VPP outputs with a

0.1µF capacitor for noise reduction and ESD protection.

VY

VY

VX

12IN

CODE

A:VPP_VCC

A:VPP_PGM

A:VCC_5

A:VCC_3

A0VPP

A1VPP

A0VCC

A1VCC

VCC

TO PC CARD SOCKET

SOCKET

INTERFACE

CIRRUS LOGIC

CL-PD6720

CL-PD6722

CL-PD6729

GND

VPP

MAX1602

TO PC

CARD

SOCKET

GND

+3.3V

+5V

+12V