CS5171, CS5172, CS5173, CS5174
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4
ELECTRICAL CHARACTERISTICS (2.7 V< V
CC
< 30 V; Industrial Grade: −40°C < T
J
< 125°C;
Commercial Grade: 0°C < T
J
< 125°C; For all CS5171/2/3/4 specifications unless otherwise stated.)
Characteristic UnitMaxTypMinTest Conditions
Power Switch
Switch Saturation Voltage
I
SWITCH
= 1.5 A, (Note 3)
I
SWITCH
= 1.0 A, 0°C ≤ T
J
≤ 85°C
I
SWITCH
= 1.0 A, −40°C ≤ T
J
≤ 0°C
I
SWITCH
= 10 mA
−
−
−
−
0.8
0.55
0.75
0.09
1.4
−
−
0.45
V
V
V
V
Switch Current Limit 50% duty cycle, (Note 3)
80% duty cycle, (Note 3)
1.6
1.5
1.9
1.7
2.4
2.2
A
A
Minimum Pulse Width FB = 0 V or NFB = 0 V, I
SW
= 4.0 A, (Note 3) 200 250 300 ns
DI
CC
/ DIV
SW
2.7 V ≤ V
CC
≤ 12 V, 10 mA ≤ I
SW
≤ 1.0 A
12 V < V
CC
≤ 30 V, 10 mA ≤ I
SW
≤ 1.0 A
2.7 V ≤ V
CC
≤ 12 V, 10 mA ≤ I
SW
≤ 1.5 A, (Note 3)
12 V < V
CC
≤ 30 V, 10 mA ≤ I
SW
≤ 1.5 A, (Note 3)
−
−
−
−
10
−
17
−
30
100
30
100
mA/A
mA/A
mA/A
mA/A
Switch Leakage V
SW
= 40 V, V
CC
= 0V − 2.0 100
mA
General
Operating Current
I
SW
= 0 − 5.5 8.0 mA
Shutdown Mode Current V
C
< 0.8 V, SS = 0 V, 2.7 V ≤ V
CC
≤ 12 V
V
C
< 0.8 V, SS = 0 V, 12 V ≤ V
CC
≤ 30 V
−
−
12
−
60
100
mA
Minimum Operation Input Voltage V
SW
switching, maximum I
SW
=
10 mA − 2.45 2.70 V
Thermal Shutdown (Note 3) 150 180 210 °C
Thermal Hysteresis (Note 3) − 25 − °C
3. Guaranteed by design, not 100% tested in production.
PACKAGE PIN DESCRIPTION
Package
Pin #
Pin
Symbol
Function
1 V
C
Loop compensation pin. The V
C
pin is the output of the error amplifier and is used for loop compensation,
current limit and soft start. Loop compensation can be implemented by a simple RC network as shown in the
application diagram on page 2 as R1 and C1.
2
(CS5171/3
only)
FB Positive regulator feedback pin. This pin senses a positive output voltage and is referenced to 1.276 V. When
the voltage at this pin falls below 0.4 V, chip switching frequency reduces to 20% of the nominal frequency.
2
(CS5172/4)
3
CS5171/3)
Test These pins are connected to internal test logic and should either be left floating or tied to ground. Connection
to a voltage between 2 V and 6 V shuts down the internal oscillator and leaves the power switch running.
3
(CS5172/4)
NFB Negative feedback pin. This pin senses a negative output voltage and is referenced to −2.5 V. When the
voltage at this pin goes above −0.65 V, chip switching frequency reduces to 20% of the nominal frequency.
4 SS Synchronization and shutdown pin. This pin may be used to synchronize the part to nearly twice the base
frequency. A TTL low will shut the part down and put it into low current mode. If synchronization is not used,
this pin should be either tied high or left floating for normal operation.
5 V
CC
Input power supply pin. This pin supplies power to the part and should have a bypass capacitor connected to
AGND.
6 AGND Analog ground. This pin provides a clean ground for the controller circuitry and should not be in the path of
large currents. The output voltage sensing resistors should be connected to this ground pin. This pin is
connected to the IC substrate.
