2 A, High-Side P-Channel Switch with
a
FEATURES
2 A Load Current
45 m⍀ On Resistance
User-Settable Current Limit
12 A Typical Quiescent Current
10 nA Typical Shutdown Current
40 nA Typical Switch Off Leakage
Short-Circuit Protection
Thermal Shutdown
FAULT Output
Small, 16-Lead QSOP Package
APPLICATIONS
Desktop Computers
Palmtop Computers
Notebook Computers
Hand-Held Instruments
Universal Serial Bus (USB)
Current Limit and Thermal Shutdown
ADM869L
GENERAL DESCRIPTION
The ADM869L is a logic controlled P-channel switch with low
on resistance, capable of sourcing up to 2 A from supply voltages
between 2.7 V and 5.5 V. A user-settable current limit allows
the trip current to be set between 400 mA and 2 A with an
accuracy of ± 21%. This allows the system power supply to be
protected against short circuits and surge currents in peripheral
loads powered via the ADM869L. Over-current and overtemperature conditions are signalled by a FAULT output.
The ADM869L also offers low quiescent current of typically
12 µA and shutdown current of typically 10 nA.
FUNCTIONAL BLOCK DIAGRAM
IN
(2.7V TO 5.5V)
ON
MIRROR FET
ADM869L
ON
TEMPERATURE
SENSOR AND
CONTROL
CIRCUITRY
MAIN FET
OVERTEMP
MIRROR
AMPLIFIER
ON
CURRENT
LIMIT
AMPLIFIER
ON
1.24V
BANDGAP
REFERENCE
ON
SET
FAULT
GND
OUT
0.1F22F
V
PULLUP
0 TO 5.5V
R
R
SET
PULLUP
10k⍀ TO 100k⍀
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2000
ADM869L–SPECIFICATIONS
(VCC = 3.0 V, TA = –40ⴗC to +85ⴗC1, unless otherwise noted.)
Parameter Min Typ Max Unit Test Conditions/Comments
Operating Voltage Range 2.7 5.5 V
Quiescent Current 12 20 µAV
= 5 V, ON = GND, I
IN
OUT
= 0 A,
0°C to 85°C
12 25 µAV
= 5 V, ON = GND, I
IN
OUT
= 0 A,
–40°C to +85°C
Shutdown Supply Current 0.01 2 µA ON = VIN = V
Off-Switch Current 0.04 2 µA ON = V
= VCC, V
IN
OUT
= 5.5 V
= 0 V
OUT
Undervoltage Lockout 2.0 2.3 2.6 V Rising Edge, 1% Hysteresis
On Resistance 38 70 mΩ VIN = 4.75 V
45 90 mΩ V
Nominal Current-Limit Setting Range 0.4 2.4 A R
Current-Limit Amplifier Threshold 1.178 1.240 1.302 V V
I
OUT/ISET
ON Input Low Voltage, V
ON Input High Voltage, V
Current Ratio 810 955 1100 A/A I
IL
IH
2.0 V VIN = 2.7 V to 3.6 V
0.8 V VIN = 2.7 V to 5.5 V
2.4 V V
ON Input Leakage 0.01 ± 1 µAV
Current-Limit Amplifier Input Bias Current 0.05 ± 3 µAV
FAULT Logic Output Low Voltage 0.4 V I
FAULT Output High Leakage Current 0.05 1 µAV
Slow Current-Loop Response Time 10 µs 20% Current Overdrive, V
= 3.0 V
IN
= 1% Tolerance
SET
Required to Turn Off Switch
SET
= 1 A, V
OUT
= 4.5 V to 5.5 V
IN
= 5.5 V
ON
= 1.24 V, I
SET
= 1 mA, V
SINK
FAULT
OUT
= 5.5 V, V
> 1.6 V
= 0 A
OUT
= 1.4 V
SET
SET
2
= 1 V
IN
= 5 V
Fast Current-Loop Response Time 4 µs
Turn-On Time 100 300 µsV
200 µsV
Turn-Off Time 1 2 30 µsV
NOTES
1
Specifications to –40°C are guaranteed by design, not tested.
2
Guaranteed by design. Derived from the I
3
Tested with I
Specifications subject to change without notice.
= 200 mA and V
OUT
SET
current ratio, current-limit amplifier and external set resistor accuracies.
SET
adjusted until (VIN – V
) 艌 0.8 V.
OUT
= 5 V, I
IN
= 3 V, I
IN
= 5 V, I
IN
= 500 mA
OUT
= 500 mA
OUT
= 500 mA
OUT
3
–2–
REV. A
ADM869L
ABSOLUTE MAXIMUM RATINGS*
(TA = 25°C unless otherwise noted)
IN to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +6 V
ON, FAULT to GND . . . . . . . . . . . . . . . . . . . –0.3 V to +6 V
SET, OUT to GND . . . . . . . . . . . . . . –0.3 V to (V
+ 0.3 V)
IN
Maximum Continuous Switch Current . . . . . . . . . . . . . . . 3 A
Continuous Power Dissipation (T
= 70°C) . . . . . . . 667 mW
A
QSOP (Derate 8.3 mW/°C above 70°C)
Operating Temperature Range
Industrial (A Version) . . . . . . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . 300°C
ESD Rating (Outputs) . . . . . . . . . . . . . . . . . . . . . . . . . . 15 kV
(Other Pins) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 kV
*This is a stress rating only; functional operation of the device at these or any other
conditions above those indicated in the operation sections of this specification is
not implied. Exposure to absolute maximum rating conditions for extended
periods of time may affect reliability.
THERMAL CHARACTERISTICS
16-Lead QSOP Package:
= 50°C/W, θ
θ
JA
= 10°C/W
JC
ORDERING GUIDE
Temperature Package Package
Model Range Description Option
ADM869LARQ –40°C to +85°C 16-Lead QSOP RQ-16
PIN CONFIGURATION
16
15
14
13
12
11
10
9
IN
OUT
OUT
IN
IN
OUT
FAULT
SET
OUT
OUT
OUT
ON
GND
IN
IN
IN
1
2
3
4
ADM869L
TOP VIEW
5
(Not to Scale)
6
7
8
PIN FUNCTION DESCRIPTIONS
Pin Mnemonic Function
1, 4, 5, 12, 13, 16 IN Input to P-Channel MOSFET Source and Supply to Chip Circuitry. Bypass IN with a 22 µF
capacitor to ground.
2, 3, 6, 11, 14, 15 OUT Output from P-Channel MOSFET Drain. Bypass OUT with a 0.1 µF capacitor to ground.
7 ON Digital Input. Active-low switch enable (logic 0 turns the switch on).
9 SET Current Limit Setting Input. A resistor from set to ground sets the current limit. Refer to
Current Limit section.
10 FAULT Open-Drain Digital Output. FAULT goes low when the current limit is exceeded or the die
temperature exceeds 135°C. During startup, FAULT remains low for the turn-on time + 50 µs.
REV. A
–3–
ADM869L–Typical Performance Characteristics
60
55
50
45
40
35
30
25
20
15
QUIESCENT CURRENT – A
10
5
0
–5
0612 4 53
INPUT VOLTAGE – Volts
TPC 1. Quiescent Current vs. Input Voltage
13.0
12.5
12.0
11.5
45
40
35
30
25
20
CURRENT – nA
15
10
5
0
–40
–20 0 20 40 60 80
TEMPERATURE – ⴗC
OFF-SWITCH
CURRENT
TPC 4. Off-Switch Current vs. Temperature
1.3
1.2
1.1
ON
1.0
RESISTANCE
CURRENT – A
11.0
10.5
10.0
–40
–20 0 20 40 60 80
TEMPERATURE – ⴗC
TPC 2. Quiescent Current vs. Temperature
9
7
5
3
CURRENT – nA
1
–1
–20 0 20 40 60 80
–40
TEMPERATURE – ⴗC
CURRENT
TPC 3. Off-Supply Current vs. Temperature
0.9
NORMALIZED R
0.8
0.7
–40
–20 0 20 40 60 80
TEMPERATURE – ⴗC
TPC 5. Normalized On Resistance vs. Temperature
1300
1250
1200
1150
1100
RATIO
1050
SET
/I
I
1000
OUT
950
900
850
800
0.4
TPC 6. I
VIN = 5V
VIN = 3V
0.8 2.42.01.61.2
0.6 1.0 1.4 1.8 2.2
OUT/ISET
I
– A
SWITCH
Ratio vs. Switch Current
–4–
REV. A
1.4
TEMPERATURE – ⴗC
t
ON
– s
0
–40
VIN = 3V
–20 0 20 40 60 80
50
100
150
200
250
300
350
VIN = 5V
1.2
1.0
0.8
0.6
0.4
NORMALIZED OUTPUT CURRENT
0.2
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE
TPC 7. Normalized Output Current vs. Output Voltage
5
ADM869L
TPC 8. Turn-On Time vs. Temperature
4
3
– s
OFF
t
2
VIN = 3V OR 5V
1
0
–20 0 20 40 60 80
–40
TEMPERATURE – ⴗC
TPC 9. Turn-Off Time vs. Temperature
REV. A
–5–
ADM869L
V
FAULT
V
OUT
I
OUT
V
IN
TPC 10. Fast Current-Limit Response
V
FAULT
V
OUT
I
OUT
V
IN
TPC 11. Slow Current-Limit Response
, 5V/DIV
1
, 5V/DIV
2
, 4A/DIV
3
, 5V/DIV
4
CH1 5.00V CH2 5.00V M 20.0s CH3 120mV
, 5V/DIV
1
T
, 5V/DIV
2
, 2A/DIV
T
3
, 5V/DIV
T
4
CH1 5.00V CH2 5.00V M 50.0s CH3
CH3
B
100mV CH4
W
5.00V
C
C
R
= 100F
IN
OUT
LOAD
= 0.1F
= 1.0⍀
64mV
1
2
3
4
CH1 5.00V CH2 5.00V M 50.0s CH1 2.2V
B
CH3
50.0mV CH4
5.00V
W
TPC 13. Switch Turn-On Time
T
1
T
2
T
3
T
4
CH1 5.00V CH2 5.00V M 1.00s CH1 2.5V
CH3
100mV CH4
5.00V
TPC 14. Switch Turn-Off Time
V
ON
V
OUT
I
OUT,
V
FAULT
V
ON
V
OUT
I
OUT,
V
FAULT
0.5A/DIV
0.5A/DIV
I
= 0mA TO
OUT
1A, 0.5A/DIV
3
RIPPLE,
V
OUT
100mV/DIV,
AC COUPLED
2
CH2
CH3
B
100mV M 10.0s CH2 –52mV
50.0mV
W
B
W
TPC 12. Load Transient Response
T
T
1
T
T
2
3
T
4
CH1 5.00V CH2 2.00V M 500s CH1 3.1V
CH3
100mV CH4
2.00V
TPC 16. USB Circuit Output Fall Time
T
1
T
2
T
3
4
T
CH1 5.00V CH2 2.00V M 500s CH1 3.1V
CH3
100mV CH4
2.00V
TPC 15. USB Circuit Output Rise Time
V
ON
V
OUT
I
0.5A/DIV
OUT,
V
FAULT
V
ON
V
OUT
I
OUT,
V
FAULT
0.5A/DIV
–6–
REV. A
ADM869L
FUNCTIONAL DESCRIPTION
The ADM869L comprises a high-current P-channel switch controlled by an active-low logic input ON (Pin 7). When ON is
low, the internal circuitry of the ADM869 is powered up and the
output of the current-limit amplifier is low, providing gate drive
to the switching FET. When ON is high, the internal circuitry is
powered down and the current consumption is typically 100 nA.
It should be noted that the ADM869L is not a bidirectional
switch, so V
must always be higher than V
IN
OUT
.
CURRENT LIMIT
When the switch is turned on, a smaller mirror switch passes a
proportionate current equal to I
/955. The mirror amplifier
OUT
maintains this relationship by keeping the drain of the mirror
FET at the same voltage as the main FET, and drives the mirror
current through the current-limit resistor RSET, which is
connected between the noninverting input of the current limit
amplifier and ground. An on-chip bandgap reference of 1.24 V
is connected to the inverting input of the current-limit amplifier.
When the load current exceeds the preset limit, the voltage
across R
exceeds 1.24 V, and the output voltage of the
SET
current-limit amplifier rises, reducing the gate drive to the FETs.
If, for example, a 1 A current limit is required, R
1.047 mA = 1.184 kΩ. Note that I
OUT/ISET
varies depending on
= 1.24 V/
SET
current so please refer to TPC 6.
I
LIMIT
955
SET
ADM869L
1.24V
R
SET
V
PULLUP
R
PULLUP
INT
FAULT
ADM869L
Figure 2. Wire Or’ing
FAULT
ADM869L
FAULT
ADM869L
FAULT
Outputs
During startup, the FAULT output goes low for the turn-on time
plus 50 µs.
APPLICATIONS INFORMATION
INPUT FILTERING
To prevent the input voltage being pulled below the minimum
operating voltage under transient short-circuit conditions, before
the current limit has had time to operate, a reservoir capacitor
should be connected from IN to GND. This does not need to be
large, but should have a low ESR. A 22 µF ceramic type is
suitable. Larger values will reduce the voltage drop still further.
OUTPUT CAPACITANCE
A 0.1 µF capacitor should be connected between OUT and
GND to prevent the back e.m.f. of parasitic inductance from
pulling OUT below ground during turn-off. For Universal Serial
Bus (USB) applications, C
should be at least 120 µF. This
OUT
causes the output rise and fall times to be longer, as shown in
the typical operating characteristics, but does not affect the
turn-off time of the ADM869L itself.
Figure 1. Setting the Current Limit
THERMAL SHUTDOWN
The thermal shutdown operates when the die temperature
exceeds 135°C, turning off the switch. The thermal shutdown
circuit has built-in hysteresis of 10°C, so the switch will not turn
on again until the die temperature falls to 125°C. If the fault
condition is not removed, the switch will pulse on and off as the
temperature cycles between these limits.
FAULT OUTPUT
If either the current limit or the thermal shutdown is activated,
FAULT will pull low. This is an open-drain output and requires
a pull-up resistor of between 10 kΩ and 100 kΩ. Several FAULT
outputs may be wire-OR’d to form a common interrupt line, as
shown in Figure 2 or FAULT may be wire-OR’d to an existing
interrupt line that has a resistive pull-up.
LAYOUT CONSIDERATIONS
Printed circuit board tracks to and from the ADM869L should be
as thick and as short as possible to minimize parasitic inductance
and take full advantage of the fast response time of the switch. It is
recommended that all input lines be connected together, close to
the device. This ensures equal current distribution in all legs. If
this is not possible, then all traces should be of equal width and
length. The same rules apply for all output lines. Input and output
capacitors should be placed as close to the device as possible (less
than 5 mm).
THERMAL CONSIDERATIONS
Under normal operating conditions, the worst-case power dissipation will be 518 mW with the highest specified on resistance
and 3 V supply (W = 2.4 A × 0.9 V). The package is capable of
handling and dissipating this power, but heat dissipation can
further be improved by providing a large area of copper in contact with the device pins, particularly IN and OUT.
REV. A
–7–
ADM869L
0.157 (3.99)
0.150 (3.81)
0.059 (1.50)
MAX
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
16-Lead QSOP Package
(RQ-16)
0.197 (5.00)
0.189 (4.80)
16 9
0.244 (6.20)
1
PIN 1
0.228 (5.79)
8
0.069 (1.75)
0.053 (1.35)
C01037–0–7/00 (rev. A)
0.010 (0.25)
0.004 (0.10)
0.025
(0.64)
BSC
0.012 (0.30)
0.008 (0.20)
SEATING
PLANE
0.010 (0.20)
0.007 (0.18)
8ⴗ
0ⴗ
0.050 (1.27)
0.016 (0.41)
–8–
PRINTED IN U.S.A.
REV. A
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