a8837 Allegro MicroSystems, Inc., a8837 Datasheet - Page 4

• Manufacturer Part Number: a8837
• Description: Photoflash Capacitor Charger With Igbt Driver
• Manufacturer: Allegro MicroSystems, Inc.

A8837
ELECTRICAL CHARACTERISTICS
Supply Voltage*
Supply Current
Primary Side Current Limit
(ILIM clock input at CHARGE pin)
SW On Resistance
SW Leakage Current*
SW Maximum Off-Time
SW Maximum On-Time
CHARGE Input Current
CHARGE Input Voltage*
ILIM Clock High Time at
CHARGE Pin
ILIM Clock Low Time at
CHARGE Pin
Total ILIM Setup Time
¯ D ¯ ¯ O ¯ ¯ N ¯ ¯ E ¯ Output Leakage Current*
¯ D ¯ ¯ O ¯ ¯ N ¯ ¯ E ¯ Output Low Voltage*
FB Voltage Threshold*
FB Input Current
UVLO Enable Threshold
UVLO Hysteresis
IGBT Driver
IGBTDRV On Resistance to VIN
IGBTDRV On Resistance to GND
TRIGGER Input Current
TRIGGER Input Voltage*
Propagation Delay, Rising
Propagation Delay, Falling
Output Rise Time
Output Fall Time
Minimum dV/dt for
ZVS Comparator
*Guaranteed by design and characterization over operating temperature range, –40°C to 85°C.
Characteristics
V
V
V
V
R
V
R
R
I
TRIGGER(H)
t
V
I
TRIGGER(L)
CHARGE(H)
I
CHARGE(L)
DONELKG
Symbol
t
t
I
I
I
I
I
I
I
I
OFF(Max)
t
TRIGGER
DS(On)SW
I
CHARGE
UVLOHYS
DS(On)I-G
ON(Max)
t
ILIM(SU)
V
DS(On)I-V
SWLIM1
SWLIM2
SWLIM3
SWLIM4
SWLIM5
SWLIM6
SWLIM7
SWLIM8
ILIM1(H)
t
T
SWLKG
DONE(L)
dV/dt
ILIM(H)
ILIM(L)
V
A
V
UVLO
I
I
t
t
FB
IN
Dr
Df
t
t
FB
IN
r
f
= 25°C and V
Charging
Charging done
Shutdown (V
V
V
V
Initial pulse
Subsequent pulses
32 μA into ¯ D ¯ ¯ O ¯ ¯ N ¯ ¯ E ¯ pin
V
V
V
V
V
R
R
R
R
Measured at SW pin
Photoflash Capacitor Charger with IGBT Driver
IN
SW
CHARGE
FB
IN
IN
IN
TRIGGER
gate
gate
gate
gate
= 3.3 V, I
rising
= 3.3 V, V
= 3.3 V, V
= 1.205 V
IN
= 35 V
=12 Ω, C
=12 Ω, C
=12 Ω, C
=12 Ω, C
= 3.3 V (unless otherwise noted)
= V
= V
D
IN
CHARGE
IN
IGBTDRV
IGBTDRV
LOAD
LOAD
LOAD
LOAD
= 800 mA
= 6500 pF, V
= 6500 pF, V
= 6500 pF, V
= 6500 pF, V
Test Conditions
= 0 V, V
= 1.5 V, V
= 1.5 V, V
TRIGGER
TRIGGER
TRIGGER
IN
IN
IN
IN
= 3.3 V
= 3.3 V
= 3.3 V
= 3.3 V
= 0 V)
= V
= 0 V
IN
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
1.187 1.205 1.223
2.55
Min.
1.8
0.2
0.2
20
3
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
2
–
–
–
–
–
–
–
–
–
2
–
–
–
–
–
–
–120
0.01
0.86
0.27
2.65
Typ.
150
1.5
2.0
1.8
1.6
1.4
1.2
0.7
18
18
54
30
30
70
70
30
–
1
1
–
–
–
–
–
–
–
–
–
5
6
–
–
–
Max. Units
2.75
100
5.5
2.2
0.8
0.8
10
–
1
–
–
–
–
–
–
–
–
1
–
–
1
–
–
–
–
–
1
–
–
–
–
1
–
–
–
–
–
–
V/μs
mV
mV
mA
μA
μA
μA
μs
μs
μA
μs
μs
μs
μs
μA
nA
μA
ns
ns
ns
ns
V
Ω
V
V
V
V
Ω
Ω
V
V
A
A
A
A
A
A
A
A
4