TPS2046, TPS2056
DUAL CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS183 – APRIL 1999
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
features
D
135-mΩ -Maximum (5-V Input) High-Side
MOSFET Switch
D
250 mA Continuous Current per Channel
D
Independent Short-Circuit and Thermal
Protection With Overcurrent Logic Output
D
Operating Range . . . 2.7-V to 5.5-V
D
Logic-Level Enable Input
D
2.5-ms Typical Rise Time
D
Undervoltage Lockout
D
10 µA Maximum Standby Supply Current
D
Bidirectional Switch
D
Available in 8-pin SOIC and PDIP Packages
D
Ambient Temperature Range, –40°C to 85°C
D
2-kV Human-Body-Model, 200-V
Machine-Model ESD Protection
typical applications
D
Notebook, Desktop and Palmtop PCs
D
Monitors, Keyboards, Scanners, and
Printers
D
Digital Cameras, Phones, and PBXs
D
Hot-Insertion Applications
description
The TPS2046 and TPS2056 dual power-distribution switches are intended for applications where heavy
capacitive loads and short circuits are likely. These devices incorporate in single packages two 135-mΩ
N-channel MOSFET high-side power switches for power-distribution systems that require multiple power
switches. Each switch is controlled by a logic enable compatible with 5-V and 3-V logic. Gate drive is provided
by an internal charge pump that controls the power-switch rise times and fall times to minimize current surges
during switching. The charge pump requires no external components and allows operation from supplies as low
as 2.7 V.
When the output load exceeds the current-limit threshold or a short is present, the TPS2046 and TPS2056 limit
the output current to a safe level by switching into a constant-current mode, pulling the overcurrent (OCx
) logic
output low. When continuous heavy overloads and short circuits increase the power dissipation in the switch
causing the junction temperature to rise, a thermal protection circuit shuts off the switch in overcurrent to prevent
damage. Recovery from a thermal shutdown is automatic once the device has cooled sufficiently. Internal
circuitry ensures the switch remains off until valid input voltage is present.
The TPS2046 and TPS2056 are designed to limit at 0.44-A load. These power distribution switches, available
in 8-pin small-outline integrated circuit (SOIC) and 8-pin plastic dual-in-line packages (PDIP), operate over an
ambient temperature range of –40°C to 85°C.
AVAILABLE OPTIONS
RECOMMENDED
PACKAGED DEVICES
T
A
ENABLE
LIMIT AT 25°C
(A)
SOIC
(D)
†
PDIP
(P)
–40°C to 85°C Active low 0.25 0.44 TPS2046D TPS2046P
–40°C to 85°C Active high 0.25 0.44 TPS2056D TPS2056P
†
The D package is available taped and reeled. Add an R suffix to device type (e.g., TPS2046DR)
Copyright 1999, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
1
2
3
4
8
7
6
5
GND
IN
EN1
EN2
OC1
OUT1
OUT2
OC2
TPS2046
D OR P PACKAGE
(TOP VIEW)
1
2
3
4
8
7
6
5
GND
IN
EN1
EN2
OC1
OUT1
OUT2
OC2
TPS2056
D OR P PACKAGE
(TOP VIEW)
TPS2046, TPS2056
DUAL CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS183 – APRIL 1999
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TPS2046 functional block diagram
†
Current sense
Thermal
Sense
Driver
Current
Limit
Charge
Pump
UVLO
CS
†
Driver
Current
Limit
CS
†
Thermal
Sense
Charge
Pump
Power Switch
GND
EN1
IN
EN2
OC1
OUT1
OUT2
OC2
Terminal Functions
TERMINAL
NO.
TPS2046 TPS2056
EN1 3 – I Enable input. Logic low turns on power switch, IN-OUT1.
EN2 4 – I Enable input. Logic low turns on power switch, IN-OUT2.
EN1 – 3 I Enable input. Logic high turns on power switch, IN-OUT1.
EN2 – 4 I Enable input. Logic high turns on power switch, IN-OUT2.
GND 1 1 I Ground
IN 2 2 I Input voltage
OC1 8 8 O Overcurrent. Logic output active low, for power switch, IN-OUT1
OC2 5 5 O Overcurrent. Logic output active low, for power switch, IN-OUT2
OUT1 7 7 O Power-switch output
OUT2 6 6 O Power-switch output
TPS2046, TPS2056
DUAL CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS183 – APRIL 1999
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
detailed description
power switch
The power switch is an N-channel MOSFET with a maximum on-state resistance of 135 mΩ (V
I(IN)
= 5 V).
Configured as a high-side switch, the power switch prevents current flow from OUTx to IN and IN to OUTx when
disabled. The power switch can supply a minimum of 250 mA per switch.
charge pump
An internal charge pump supplies power to the driver circuit and provides the necessary voltage to pull the gate
of the MOSFET above the source. The charge pump operates from input voltages as low as 2.7 V and requires
very little supply current.
driver
The driver controls the gate voltage of the power switch. T o limit large current surges and reduce the associated
electromagnetic interference (EMI) produced, the driver incorporates circuitry that controls the rise times and
fall times of the output voltage. The rise and fall times are typically in the 2-ms to 4-ms range.
enable (ENx or ENx)
The logic enable disables the power switch and the bias for the charge pump, driver, and other circuitry to reduce
the supply current to less than 10 µA when a logic high is present on ENx (TPS2046) or a logic low is present
on ENx (TPS2056). A logic zero input on ENx or logic high on ENx restores bias to the drive and control circuits
and turns the power on. The enable input is compatible with both TTL and CMOS logic levels.
overcurrent (OCx)
The OCx
open-drain output is asserted (active low) when an overcurrent or overtemperature condition is
encountered. The output will remain asserted until the overcurrent or overtemperature condition is removed.
current sense
A sense FET monitors the current supplied to the load. The sense FET measures current more efficiently than
conventional resistance methods. When an overload or short circuit is encountered, the current-sense circuitry
sends a control signal to the driver. The driver in turn reduces the gate voltage and drives the power FET into
its saturation region, which switches the output into a constant current mode and holds the current constant
while varying the voltage on the load.
thermal sense
The TPS2046 and TPS2056 implement a dual-threshold thermal trip to allow fully independent operation of the
power distribution switches. In an overcurrent or short-circuit condition the junction temperature rises. When
the die temperature rises to approximately 140°C, the internal thermal sense circuitry checks to determine which
power switch is in an overcurrent condition and turns off that switch, thus isolating the fault without interrupting
operation of the adjacent power switches. Hysteresis is built into the thermal sense, and after the device has
cooled approximately 20 degrees, the switch turns back on. The switch continues to cycle off and on until the
fault is removed. The (OCx
) open-drain output is asserted (active low) when overtemperature or overcurrent
occurs.
undervoltage lockout
A voltage sense circuit monitors the input voltage. When the input voltage is below approximately 2 V , a control
signal turns off the power switch.
TPS2046, TPS2056
DUAL CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS183 – APRIL 1999
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
†
Input voltage range, V
I(IN)
(see Note1) –0.3 V to 6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output voltage range, V
O(OUTx)
(see Note1) –0.3 V to V
I(IN)
+ 0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, V
I(ENx)
or V
I(ENx)
–0.3 V to 6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous output current, I
O(OUTx)
internally limited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous total power dissipation See Dissipation Rating Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating virtual junction temperature range, T
J
–40°C to 125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range, T
stg
–65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead temperature soldering 1,6 mm (1/16 inch) from case for 10 seconds 260°C. . . . . . . . . . . . . . . . . . . . . . .
Electrostatic discharge (ESD) protection: Human body model MIL-STD-883C 2 kV. . . . . . . . . . . . . . . . . . . . .
Machine model 0.2 kV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
†
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: All voltages are with respect to GND.
DISSIPATION RATING TABLE
PACKAGE
TA ≤ 25°C
POWER RATING
DERATING FACTOR
ABOVE TA = 25°C
TA = 70°C
POWER RATING
TA = 85°C
POWER RATING
D 725 mW 5.8 mW/°C 464 mW 377 mW
P 1175 mW 9.4 mW/°C 752 mW 611 mW
recommended operating conditions
TPS2046 TPS2056
Input voltage, V
I(IN)
2.7 5.5 2.7 5.5 V
Input voltage, V
I(ENx
)
or V
I(ENx)
0 5.5 0 5.5 V
Continuous output current, I
O(OUTx)
0 250 0 250 mA
Operating virtual junction temperature, T
J
–40 125 –40 125 °C
TPS2046, TPS2056
DUAL CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS183 – APRIL 1999
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating junction temperature range, V
I(IN)
= 5.5 V,
I
O
= rated current, V
I(ENx)
= 0 V, V
I(ENx)
= Hi (unless otherwise noted)
power switch
V
I(IN)
= 5 V,
IO = 0.1 A
TJ = 25°C,
80 95 80 95
Static drain-source on-state
resistance, 5-V operation
V
I(IN)
= 5 V,
IO = 0.1 A
TJ = 85°C,
90 120 90 120
V
I(IN)
= 5 V,
IO = 0.1 A
TJ = 125°C,
100 135 100 135
mΩ
DS(on)
V
I(IN)
= 3.3 V,
IO = 0.1 A
TJ = 25°C,
85 105 85 105
Static drain-source on-state
resistance, 3.3-V operation
V
I(IN)
= 3.3 V,
IO = 0.1 A
TJ = 85°C,
100 135 100 135
V
I(IN)
= 3.3 V,
IO = 0.1 A
TJ = 125°C,
115 150 115 150
V
I(IN)
= 5.5 V,
CL = 1 µF,
TJ = 25°C,
RL = 20 Ω
2.5 2.5
V
I(IN)
= 2.7 V,
CL = 1 µF,
TJ = 25°C,
RL = 20 Ω
3 3
V
I(IN)
= 5.5 V,
CL = 1 µF,
TJ = 25°C,
RL = 20 Ω
4.4 4.4
V
I(IN)
= 2.7 V,
CL = 1 µF,
TJ = 25°C,
RL = 20 Ω
2.5 2.5
†
Pulse-testing techniques maintain junction temperature close to ambient temperature; thermal effects must be taken into account separately.
enable input ENx or ENx
V
IH
High-level input voltage 2.7 V ≤ V
I(IN)
≤ 5.5 V 2 2 V
4.5 V ≤ V
I(IN)
≤ 5.5 V 0.8 0.8 V
VILLow-level input voltage
2.7 V≤ V
I(IN)
≤ 4.5 V 0.4 0.4
TPS2046 V
I(ENx
)
= 0 V or V
I(ENx)
= V
I(IN)
–0.5 0.5
TPS2056 V
I(ENx)
= V
I(IN)
or V
I(ENx)
= 0 V –0.5 0.5
µ
t
on
Turn-on time CL = 100 µF, RL = 20 Ω 20 20 ms
t
off
Turn-off time CL = 100 µF, RL = 20 Ω 40 40
current limit
I
OS
Short-circuit output current
V
I(IN)
= 5 V, OUT connected to GND,
Device enable into short circuit.
0.345 0.44 0.525 0.345 0.44 0.525 A
†
Pulse-testing techniques maintain junction temperature close to ambient temperature; thermal effects must be taken into account separately.
TPS2046, TPS2056
DUAL CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS183 – APRIL 1999
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating junction temperature range, V
I(IN)
= 5.5 V,
I
O
= rated current, V
I(ENx)
= 0 V, V
I(ENx)
= Hi (unless otherwise noted) (continued)
supply current
PARAMETE
current,
No Load
V
I(ENx)
= V
I(IN)
–40°C ≤ TJ ≤ 125°C
V
I(ENx)
= V
I(IN)
–40°C ≤ TJ ≤ 125°C TPS2046 100
to ground
V
I(ENx)
= 0 V –40°C ≤ TJ ≤ 125°C TPS2056 100
µ
IN = high
V
I(ENx
)
= 0 V
Low-level input voltage 2 2.5 2 2.5 V
Hysteresis TJ = 25°C 100 100 mV
overcurrent OCx
Sink current
†
VO = 5 V 10 10 mA
Output low voltage IO = 5 mA, V
OL(OCx)
0.5 0.5 V
Off-state current
†
VO = 5 V, VO = 3.3 V 1 1 µA
†
Specified by design, not production tested.
TPS2046, TPS2056
DUAL CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS183 – APRIL 1999
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
RL CL
OUTx
t
r
t
f
90%
90%
10%
10%
50%
50%
90%
10%
V
O(OUTx)
V
I(ENx)
V
O(OUTx)
VOLTAGE WA VEFORMS
TEST CIRCUIT
t
on
t
off
50%
50%
90%
10%
V
I(ENx)
V
O(OUTx)
t
on
t
off
Figure 1. Test Circuit and Voltage Waveforms
Figure 2. Turnon Delay and Rise Time
with 0.1-µF Load
Figure 3. Turnoff Delay and Fall Time
with 0.1-µF Load
V
O(OUTx)
(2 V/div)
0123456
t – Time – ms
78910
V
I(IN)
= 5 V
TA = 25°C
CL = 0.1 µF
V
I(ENx)
(5 V/div)
0 1000 2000 3000
t – Time – ms
4000 5000
V
I(IN)
= 5 V
TA = 25°C
CL = 0.1 µF
V
I(ENx)
(5 V/div)
V
O(OUTx)
(2 V/div)