LM3485_15 Datasheet, PDF (7/24 Pages) Texas Instruments – Hysteretic PFET Buck Controller

LM3485
www.ti.com
SNVS178G – JANUARY 2002 – REVISED FEBRUARY 2013
Typical Performance Characteristics (continued)
Unless otherwise specified, T_J = 25°C
Output Ripple Voltage
vs
Input Voltage
(V_OUT = 3.3V, I_OUT = 1A, C_OUT(ESR) = 80mΩ, C_ff = 100pF)
80
Operating Frequency vs
Output Load Current
(L = 22µH, C_OUT(ESR) = 45mΩ, C_ff = 100pF)
400
L=10PH
60
L=15PH
300
12VIN / 5.0VOUT
12VIN / 3.3VOUT
40
L=22PH
20
200
12VIN / 1.242VOUT
4.5VIN / 1.242VOUT
100
0
4
12
20
28
36
4.5VIN / 3.3VOUT
0
0
200 400 600 800 1000
INPUT VOLTAGE (V)
OUTPUT CURRENT LOAD (mA)
Feed-Forward Capacitor (Cff) Effect
(V_OUT = 3.3V, L = 22µH, I_OUT = 500mA)
300
300
Operating Frequency
250
250
200
150
100
50
0
4
@Cff=100p ²⁰⁰
150
@no Cff
Ripple Voltage
100
@no Cff ₅₀
@Cff=100p
0
12
20
28
36
INPUT VOLTAGE (V)
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