Data Sheet

High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
5
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
OVERCURRENT CHARACTERISTICS (continued)
Fault Enable (FAULT_EN Pin) Delay
9
t
FED
Set FAULT_EN to low, V
OC
= 0.25 × V
CC
,
C
OC
= 0 F; then run a DC I
P
exceeding the
corresponding overcurrent threshold; then
reset FAULT_EN from low to high and
measure the delay from the rising edge of
FAULT_EN to the falling edge of
¯
F
¯ ¯
A
¯
U
¯¯
L
¯ ¯
T
¯
– 15 – µs
Overcurrent Fault Response Time t
OC
FAULT_EN set to high for a minimum
of 20 µs before the overcurrent event;
switchpoint set at V
OC
= 0.25 × V
CC
;
delay from I
P
exceeding overcurrent
fault threshold to V
¯
F
¯ ¯
A
¯
U
¯¯
L
¯ ¯
T
¯
< 0.4 V, without
external C
OC
capacitor
– 1.9 – µs
Overcurrent Fault Reset Delay t
OCR
Time from V
FAULTEN
< V
IL
to
V
FAULT
> 0.8 × V
CC
, R
PU
= 330 kΩ
– 500 – ns
Overcurrent Fault Reset Hold Time t
OCH
Time from V
FAULTEN
pin < V
IL
to reset of
fault latch; see Functional Block Diagram
– 250 – ns
Overcurrent Input Pin Resistance R
OC
T
A
= 25°C, VOC pin to GND 2 – – MΩ
VOLTAGE REFERENCE CHARACTERISTICS
Voltage Reference Output V
ZCR
T
A
= 25 °C – 0.5 × V
CC
– V
Voltage Reference Output Load Current I
ZCR
Source current 3 – – mA
Sink current 50 – – µA
Voltage Reference Output Drift ∆V
ZCR
– ±10 – mV
1
Devices are trimmed for maximum accuracy at V
CC
= 5 V. The ratiometry feature of the device allows operation over the full V
CC
range; however, accuracy
may be slightly degraded for V
CC
values other than 5 V. Contact the Allegro factory for applications that require maximum accuracy for V
CC
= 3.3 V.
2
R
F(INT)
forms an RC circuit via the FILTER pin.
3
This parameter can drift by as much as 0.25% over the lifetime of this product.
4
This parameter can drift by as much as 0.3% over the lifetime of this product.
5
Calculated using the formula f
3dB
= 0.35 / t
r
.
6
See page 8 on how to set overcurrent fault switchpoint.
7
Switchpoint can be lower at the expense of switchpoint accuracy.
8
This error specification does not include the effect of noise. See the I
NCOMP
specification in order to factor in the additional influence of noise on the
fault switchpoint.
9
Fault Enable Delay is designed to avoid false tripping of an Overcurrent (OC) fault at power-up. A 15 µs (typical) delay will always be needed, every
time FAULT_EN is raised from low to high, before the device is ready for responding to any overcurrent event.
COMMON OPERATING CHARACTERISTICS (continued) Valid at T
A
= –40°C to 150°C, V
CC
= 5 V, unless otherwise specified
Characteristic Symbol Test Conditions Min. Typ. Max. Units