TPS2045, TPS2055
CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS182 – 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
D
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 TPS2045 and TPS2055 power-distribution switches are intended for applications where heavy capacitive
loads and short circuits are likely. Each of these 135-mΩ N-channel MOSFET high-side power switches 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 TPS2045 and TPS2055 limit
the output current to a safe level by switching into a constant-current mode, pulling the overcurrent (OC
) 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 TPS2045 and TPS2055 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
TYPICAL SHORT-CIRCUIT
PACKAGED DEVICES
T
A
ENABLE
LOAD CURRENT
(A)
CURRENT LIMIT AT 25°C
(A)
SOIC
(D)
†
PDIP
(P)
–40°C to 85°C Active low 0.25 0.44 TPS2045D TPS2045P
–40°C to 85°C Active high 0.25 0.44 TPS2055D TPS2055P
†
The D package is available taped and reeled. Add an R suffix to device type (e.g., TPS2045DR)
Copyright 1999, Texas Instruments Incorporated
This document contains information on products in more than one phase
of development. The status of each device is indicated on the page(s)
specifying its electrical characteristics.
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
IN
EN
OUT
OUT
OUT
OC
TPS2045
D OR P PACKAGE
(TOP VIEW)
1
2
3
4
8
7
6
5
GND
IN
IN
EN
OUT
OUT
OUT
OC
TPS2055
D OR P PACKAGE
(TOP VIEW)
TPS2045, TPS2055
CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS182 – APRIL 1999
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TPS2045 functional block diagram
OUT
OC
IN
EN
GND
Current
Limit
Driver
UVLO
Charge
Pump
CS
Thermal
Sense
Power Switch
†
†
Current Sense
Terminal Functions
TERMINAL
NO.
TPS2045 TPS2055
EN 4 – I Enable input. Logic low turns on power switch.
EN – 4 I Enable input. Logic high turns on power switch.
GND 1 1 I Ground
IN 2, 3 2, 3 I Input voltage
OC 5 5 O Over current. Logic output active low
OUT 6, 7, 8 6, 7, 8 O Power-switch output
TPS2045, TPS2055
CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS182 – 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 OUT to IN and IN to OUT 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 (EN or EN)
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 EN (TPS2045) or a logic low is present
on EN (TPS2055). A logic zero input on EN or a logic high on EN 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 (OC)
The OC
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
An internal thermal-sense circuit shuts off the power switch when the junction temperature rises to
approximately 140°C. Hysteresis is built into the thermal sense circuit. After the device has cooled
approximately 20°C, the switch turns back on. The switch continues to cycle off and on until the fault is removed.
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.
TPS2045, TPS2055
CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS182 – 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 Note 1) –0.3 V to 6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output voltage range, V
O(OUT)
(see Note 1) –0.3 V to V
I(IN)
+ 0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, V
I(EN)
or V
I(EN)
–0.3 V to 6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous output current, I
O(OUT)
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
TPS2045 TPS2055
Input voltage, V
I(IN)
2.7 5.5 2.7 5.5 V
Input voltage, V
I(EN
)
or V
I(EN)
0 5.5 0 5.5 V
Continuous output current, I
O(OUT)
0 250 0 250 mA
Operating virtual junction temperature, T
J
–40 125 –40 125 °C
TPS2045, TPS2055
CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS182 – 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(EN)
= 0 V, V
I(EN)
= Hi (unless otherwise noted)
power switch
V
I(IN)
= 5 V,
IO = 0.25 A
TJ = 25°C,
80 95 80 95
Static drain-source on-state
resistance, 5-V operation
V
I(IN)
= 5 V,
IO = 0.25 A
TJ = 85°C,
90 120 90 120
V
I(IN)
= 5 V,
IO = 0.25 A
TJ = 125°C,
100 135 100 135
mΩ
DS(on)
V
I(IN)
= 3.3 V,
IO = 0.25 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 = 0.25 A
TJ = 85°C,
100 135 100 135
V
I(IN)
= 3.3 V,
IO = 0.25 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 EN or EN
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
TPS2045 V
I(EN)
= 0 V or V
I(EN)
= V
I(IN)
–0.5 0.5
TPS2055 V
I(EN
)
= V
I(IN)
or V
I(EN)
= 0 V
–0.5 0.5
µ
t
on
Turnon time CL = 100 µF, RL = 20 Ω 20 20 ms
t
off
Turnoff 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 enabled 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.
TPS2045, TPS2055
CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS182 – 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(EN)
= 0 V, V
I(EN)
= Hi (unless otherwise noted) (continued)
supply current
current,
No Load
V
I(EN)
= V
I(IN)
–40°C ≤ TJ ≤ 125°C
V
I(EN)
= V
I(IN)
–40°C ≤ TJ ≤ 125°C TPS2045 100
to ground
V
I(EN)
= 0 V –40°C ≤ TJ ≤ 125°C TPS2055 100
µ
Low-level input voltage 2 2.5 2 2.5 V
Hysteresis TJ = 25°C 100 100 mV
overcurrent OC
Sink current
†
VO = 5 V 10 10 mA
Output low voltage IO = 5 V, V
OL(OC)
0.5 0.5 V
Off-state current
†
VO = 5 V, VO = 3.3 V 1 1 µA
†
Specified by design, not production tested.
TPS2045, TPS2055
CURRENT-LIMITED POWER-DISTRIBUTION SWITCHES
SLVS182 – APRIL 1999
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
RL CL
OUT
t
r
t
f
90%
90%
10%
10%
50%
50%
90%
10%
V
O(OUT)
V
I(EN)
V
O(OUT)
VOLTAGE WA VEFORMS
TEST CIRCUIT
t
on
t
off
50%
50%
90%
10%
V
I(EN)
V
O(OUT)
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(OUT)
(2 V/div)
0123456
t – Time – ms
78910
V
I(IN)
= 5 V
TA = 25°C
CL = 0.1 µF
V
I(EN)
(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
O(OUT)
(2 V/div)
V
I(EN)
(5 V/div)