Figure 2. Application with Cirrus Logic Interface
MAX1602
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
V
CC
MAX1602
TO PC
CARD
SOCKET
GND
+3.3V
+5V
+12V
