Micrel
MIC2172/3172
Typical Characteristics MIC2172 (cont)
Parameter
Oscillator Section
Frequency (f
O
)
Duty Cycle [δ(max)]
Sync Coupling Capacitor
Required for Frequency
Lock
Minimum Operating
Voltage
Quiescent Current (I
Q
)
Supply Current Increase
(∆I
IN
)
3V
≤
V
IN
≤
40V, V
COMP
= 0.6V, I
SW
= 0
∆I
SW
= 1A, V
COMP
= 1.5V
V
PP
= 3.0V
V
PP
= 40V
88
85
80
22
2.2
100
89
51
4.7
112
115
95
120
10
kHz
kHz
%
pF
pF
Condition
Min
Typ
Max
Units
Input Supply Voltage Section
2.7
7
9
3.0
9
20
V
mA
mA
Electrical Characteristics MIC3172
Note 1, 3. Unless otherwise specified, V
IN
= 5V.
Parameter
Reference Section
Feedback Voltage (V
FB
)
Feedback Voltage Line
Regulation
Feedback Bias Current
(I
FB
)
Error Amplifier Section
Transconductance
(∆I
COMP
/∆V
FB
)
Voltage Gain
(∆V
COMP
/∆V
FB
)
Output Current
Output Swing
Compensation Pin
Threshold
Output Switch Section
ON Resistance
Current Limit
I
SW
= 1A, V
FB
= 0.8V
Duty Cycle = 50%, T
J
≥
25°C
Duty Cycle = 50%, T
J
< 25°C
Duty Cycle = 80%,
Note 2
3V
≤
V
IN
≤
40V
I
SW
= 5mA
1.25
1.25
1
65
75
0.76
1
1.1
3
3.5
2.5
Ω
Ω
A
A
A
V
∆I
COMP
= ±25µA
0.9V
≤
V
COMP
≤
1.4V
V
COMP
= 1.5V
High Clamp, V
FB
= 1V
Low Clamp, V
FB
= 1.5V
Duty Cycle = 0
3.0
2.4
500
125
100
1.8
0.25
0.8
0.6
3.9
800
175
2.1
0.35
0.9
6.0
7.0
2000
350
400
2.3
0.52
1.08
1.25
µA/mV
µA/mV
V/V
µA
µA
V
V
V
V
3V
≤
V
IN
≤
40V
Condition
Pin 2 tied to pin 3
1.224
1.214
1.240
0.07
310
750
1100
1.264
1.274
V
V
%/V
nA
nA
Min
Typ
Max
Units
Breakdown Voltage (BV)
April 2006
5
M9999-041806
(408) 955-1690
MICREL [ MICREL SEMICONDUCTOR ]
