RT9725A/B
Express Card Power Interface Switch
General Description
The RT9725A/B power distribution switches are designed
to fulfill power management requirements of Express Card
specification. The RT9725A/B supports systems with
single slot ExpressCard|34 and ExpressCard|54 socket.
The device distributes 3.3V, AUX and 1.5V to the Express
Card socket. Each power rail is protected with current
limit circuitry when output load exceeds over-current
threshold or short-circuits occurs. A thermal protection
circuit turns off switches to prevent the device from damage
when power dissipation is increased by continuous heavy
overloads or short-circuits in the switches. The
RT9725A/B is available in WQFN-20L 3x3 package.
Features
Meets Express Card Standard (ExpressCard|34 and
ExpressCard|54)
Compliant with the Express Card Compliance
Check Lists, Compliance ID : EC100328
Fully Satisfy the Express Card Implementation
Guidelines
Supports Systems with WAKE Function
TTL-Logic Compatible Input
Under-Voltage Lockout Protection
Over Current Protection
Over Temperature Protection
RoHS Compliant and Halogen Free
Ordering Information
RT9725A/B
Package Type
QW : WQFN-20L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
SYSRST Pull High Resistor
A : With Internal Resistor
B : Without Internal Resistor
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Applications
PCs
PDAs
Digital Cameras
TV and Set Top Boxes
Pin Configurations
(TOP VIEW)
SHDN
FLG
RCLKEN
AUXIN
NC
20 19 18 17 16
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
STBY
3.3VIN
3.3VOUT
NC
NC
1
2
3
4
5
6
7
8
9
10
15
14
GND
21
13
12
11
AUXOUT
NC
NC
1.5VIN
1.5VOUT
WQFN-20L 3x3
DS9725A/B-01 April 2011
SYSRST
GND
PERST
CPUSB
CPPE
www.richtek.com
1
RT9725A/B
Typical Application Circuit
3.3V
100k
RT9725A/B
15
17 AUXIN
AUXOUT
4.7µF
AUXOUT
22µF
FLG
3.3V
19 FLG
2 3.3VIN
4.7µF
3.3VOUT
3
22µF
3.3VOUT
1.5VOUT
11
22µF
1.5VOUT
1.5V
12 1.5VIN
4.7µF
20
SHDN
PERST
CPPE
8
10
9
PERST
CPPE
SHDN
STBY
SYSRST
1
STBY
6
SYSRST
CPUSB
CPUSB
18
RCLKEN
RCLKEN
7, Exposed Pad (21)
GND
Functional Pin Description
Pin No.
1
2
3
4, 5, 13, 14, 16
6
Pin Name
STBY
3.3VIN
3.3VOUT
NC
SYSRST
Input pin for 3.3V output voltage.
Switched output that delivers 0V,3.3V or high impedance to card.
No Internal Connection.
System reset input-active low, logic level signal, Internal pulled up to AUXIN for
RT9725A or floating for RT9725B.
Ground.
The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
A logic level power good to slot (with delay).
Card present input for USB cards, Internal pulled up to AUXIN.
Card present input for PCI cards, Internal pulled up to AUXIN.
Switched output that delivers 0V,1.5V or high impedance to card.
Input pin for 1.5V output voltage.
Switched output that delivers 0V,AUX or high impedance to card.
AUX input for AUXOUT and chip power.
Reference Clock Enable signal. As an output, a logic power good to host for slot
(no delay-open drain). As an input, if kept inactive(low) by the host, prevents
PERST from being de-asserted. Internal pulled up to AUXIN
Over current or over temperature status output for slot (open drain)
Shutdown input-active low, logic level signal. Internal pulled up to AUXIN
Pin Function
Standby input-active low, logic level signal, Internal pulled up to AUXIN.
7, 21 (Exposed Pad) GND
8
9
10
11
12
15
17
18
19
20
PERST
CPUSB
CPPE
1.5VOUT
1.5VIN
AUXOUT
AUXIN
RCLKEN
FLG
SHDN
www.richtek.com
2
DS9725A/B-01 April 2011
RT9725A/B
Function Block Diagram
AUXIN
Current
Limit
3.3VIN
Current
Limit
1.5VIN
Current
Limit
Power
Good
AUXOUT
3.3VOUT
1.5VOUT
UVLO
FLG
CPUSB
CPPE
STBY
SHDN
Delay
Charge
Pump
Oscillator
GND
OTP
AUXIN
RCLKEN
Gate
Control
AUXIN
PERST
RT9725A Only
SYSRST
DS9725A/B-01 April 2011
www.richtek.com
3
RT9725A/B
Operation
Table 1. Truth Table for Voltage Outputs
Input Power (1)
AUXIN
Off
On
On
On
On
On
On
On
On
3.3VIN
X
X
X
Off
ON >> Off
On
On
1.5VIN
X
X
X
SHDN
X
0
1
1
1
1
1
Logic Input
STBY
X
X
X
1
1
0
1
Output (2)
CPXX (4) AUXOUT 3.3VOUT 1.5VOUT
X
Off
Off
Off
X
1
1 >> 0
0
0
0
GND
GND
Off
On
On
On
GND
GND
Off
Off
Off
On
GND
GND
Off
Off
Off
On
Mode (3)
Off
Shutdown
No Card
Off
Standby (5)
Standby
Card Inserted
(1) For Power Input :
“On”
means the respective input voltage is higher than its turn on threshold voltage;
“Off”
means
the input voltage is lower than its UVLO falling threshold voltage. (for AUX input,
“Off ”
means the voltage is close to
0V).
(2) For Output :
“On”
means the respective power switch is turned on, so that the input is connected to the output;
“Off”
means the power switch and its output discharge FET are both off;
“GND ”
means the powers switch is off but the
output discharge FET is on, so that the voltage on the output is pulled down to 0V.
(3) Mode assigns each set of input conditions and respective output voltage results to a different name. These modes are
referred to as input conditions in the following
“Truth
Table” for Logic Outputs.
(4) CPXX = 1 when both CPUSB and CPPE signals are logic high, or CPXX = 0 when either CPUSB or CPPE is low.
(5) The card is inserted prior to the removal of the Primary or Secondary power (either 3.3VIN or 1.5VIN or both) at the
input of the ExpressCard power switch, then only the Primary and Secondary power (both 3.3VOUT and 1.5VOUT)
are removed and the auxiliary power is sent to the ExpressCard slot.
(6)
“X”
means
“Don'st
Care”.
Table 2. Truth Table for Logic Output
Input Conditions
Mode
OFF
Shutdown
No Card
Standby
0
Card Inserted
0
1
1
Hi-Z
0
Hi-Z
0
0
0
1
0
1
0
1
0
X
X
0
0
SYSRST
RCLKEN (1)
Logic Outputs
PERST
RCLKEN (2)
(1) RCLKEN acts as a logic input in this column. RCLKEN is an I/O pin and it can be driven low externally, left open, or
connected to high-impedance terminals, such as the gate of a MOSFET. It must not be driven high externally.
(2) RCLKEN acts as a logic output in this column.
www.richtek.com
4
DS9725A/B-01 April 2011
RT9725A/B
Absolute Maximum Ratings
(Note 1)
Supply Voltage (AUXIN, 3.3VIN) -----------------------------------------------------------------------------------
−0.3V
to 5V
Supply Voltage 1.5VIN -----------------------------------------------------------------------------------------------
−0.3V
to 2.5V
Logic Input/Output Voltage ------------------------------------------------------------------------------------------
−0.3V
to 5V
Power Dissipation, P
D
@ T
A
= 25°C
WQFN-20L 3x3 -------------------------------------------------------------------------------------------------------- 1.667W
Package Thermal Resistance (Note 2)
WQFN-20L 3x3,
θ
JA
--------------------------------------------------------------------------------------------------- 60°C/W
WQFN-20L 3x3,
θ
JC
-------------------------------------------------------------------------------------------------- 7.5°C/W
Junction Temperature ------------------------------------------------------------------------------------------------- 150°C
Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260°C
Storage Temperature Range ----------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV
MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
(Note 4)
Supply Voltage (AUXIN, 3.3VIN) ----------------------------------------------------------------------------------- 3V to 3.6V
Supply Voltage (1.5VIN) --------------------------------------------------------------------------------------------- 1.35V to 1.65V
Junction Temperature Range ----------------------------------------------------------------------------------------
−40°C
to 100°C
Ambient Temperature Range ----------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
(3.3VIN)
= V
(AUXIN)
= 3.3V, V
(1.5VIN)
= 1.5V, V
SHDN
= V
STBY
= V
SYSRST
=3.3V, V
CPPE
= V
CPUSB
= 0V, PERST, FLG, RCLKEN are open,
all output voltage are unloaded; T
A
= 25°C, unless otherwise specified)
Parameter
Power Switch
Symbol
Test Conditions
3.3VIN to 3.3VOUT,
I
OUT
= 1300mA
1.5VIN to 1.5VOUT,
I
OUT
= 650mA
AUXIN to AUXOUT,
I
OUT
= 275mA
V
SHDN
= 0V, I
Discharge
= 1mA
Output power into a short
Min
Typ
Max
Unit
R
DS(ON)_33
Switch On Resistance
R
DS(ON)_15
R
DS(ON)_AUX
Discharge Resistance
(3.3V/1.5V/AUX Output)
R
Discharge
--
--
--
100
1350
670
275
--
--
--
--
--
--
90
90
120
300
2000
1000
450
25
25
250
5
5
280
120
120
160
500
2500
1300
600
30
30
280
10
10
310
μA
μA
mA
Ω
mΩ
I
SC_33
Output Short-Circuit Current
I
SC_15
(steady state value)
I
SC _AUX
Total Input Quiescent
Current (Normal Operation)
I
Q_33
I
Q_15
I
Q _AUX
Total Input Quiescent
Current (Shutdown Mode)
I
SHDN_33
I
SHDN_15
I
SHDN _AUX
Output are unloaded (Include CPPE
and CPUSB logic pull-up current)
V
CPPE
= V
CPUSB
= V
SHDN
= 0V,
discharge FETs are on (Include
CPPE, CPUSB and SHDN pull-up
current)
To be continued
DS9725A/B-01 April 2011
www.richtek.com
5
Analogue and Mixed Signal
京公网安备 11010802033920号
EEWORLD
