1
dc1899af
DEMO MANUAL DC1899A
DESCRIPTION
LTC4228-1/LTC4228-2
Dual Ideal Diode and
Hot Swap Controller
Demonstration circuit 1899A controls two independent
power rail circuits each with Hot Swap™ and ideal diode
functionality provided by the LTC4228-1/LTC4228-2 dual
ideal diode and Hot Swap controller.
DC1899A facilitates evaluation of LTC4228 performance
in different operation modes such as supply ramp-up,
power supply switchover, steady state, and overcurrent
faults. Power supply switchover mode can be realized as
either an ideal diode or as a prioritizer.
Each DC1899A circuit is assembled to operate with a
12V supply and 9A maximum current load. The main
components of the board are the LTC4228 controller, two
MOSFETs operating as ideal diodes, two MOSFETs operat-
ing as Hot Swap devices, two current sense resistors, two
jumpers for independently enabling each rail, six LEDs to
L
, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
PERFORMANCE SUMMARY
indicate status, power good and fault conditions separately
for each channel, and input voltage snubbers. There are
pads for optional RC circuits for each Hot Swap MOSFET
gate in order to adjust output voltage slew rate. In addition
to this there are jumpers allowing monitoring of supply
undervoltage conditions at either IN or SENSE+ pins.
The standard configuration (as DC1899A populated by
default) places the ideal diode MOSFET ahead of the Hot
Swap MOSFET. The board also has pads for an alternative
configuration with the Hot Swap MOSFET located ahead
of the ideal diode MOSFET.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at T
A
= 25°C
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IN
Input Supply Range
2.9
18
V
V
INTVCC(UVL)
Internal V
CC
Undervoltage Lockout
INTV
CC
Rising
2.1
2.2
2.3
V
V
INTVCC(HYST)
Internal V
CC
Undervoltage Lockout Hysteresis
30
60
90
mV
Ideal Diode Control
ΔV
FWD(REG)
Forward Regulation Voltage (V
IN
– V
OUT
)
10
25
40
mV
ΔV
DGATE
External N-Channel Gate Drive
(V
DGATE
– V
IN
)
ΔV
FWD
= 0.1V
IN < 7V
IN = 7V to 18V
5
10
7
12
14
14
V
V
I
CPO(UP)
CPO Pull-Up Current
CPO = IN = 2.9V
CPO = IN = 18V
–60
–50
–95
–85
–120
–110
μA
μA
I
DGATE(FPU)
DGATE Fast Pull-Up Current
ΔV
FWD
= 0.2V, ΔV
DGATE
= 0V, CPO = 17V
–1.5
A
I
DGATE(FPD)
DGATEn Fast Pull-Down Current
ΔV
FWD
= –0.2V, ΔV
DGATE
= 5V
1.5
A
Hot Swap Control
ΔV
SENSE(CB)
Circuit Breaker Trip Sense Voltage
(V
SENSEEn
+
– V
SENSEEn
–
)
47.5
50
52.5
mV
ΔV
SENSE(ACL)
Active Current Limit Sense Voltage
(V
SENSEEn
+
– V
SENSEEn
–
)
55
65
75
mV
I
HGATE(UP)
External N-Channel Gate Pull-Up Current
Gate Drive On, HGATE = 0V
–7
–10
–13
μA
I
HGATE(DN)
External N-Channel Gate Pull-Down Current
Gate Drive Off, OUT = 12V, HGATE = OUT + 5V
150
300
500
μA
I
HGATE(FPD)
External N-Channel Gate Fast Pull-Down Current
Fast Turn-Off, OUT = 12V, HGATE = OUT + 5V
100
200
300
mA
