LTC3617_15 Datasheet, PDF (3/20 Pages) Linear Technology – 6A Monolithic Synchronous Step-Down Regulator for DDR Termination

LTC3617
Electrical Characteristics The l denotes the specifications which apply over the full operating junction
temperature range, otherwise specifications are at T_A = 25°C. PV_IN = SV_IN = 3.3V, RT = SV_IN unless otherwise specified (Notes 1, 2, 8).
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
∆V_FB(LINEREG) Feedback Voltage Line Regulation
SV_IN = PV_IN = 2.25V to 5.5V,
l
VDDQIN = 1.5V (Notes 3, 4)
0.2
%/V
∆V_FB(LOADREG) Feedback Voltage Load Regulation
ITH from 0.5V to 0.9V (Notes 3, 4)
V_ITH = SV_IN (Note 5)
0.25
%
0.25
%
I_Q
Input DC Supply Current
Active Mode
V_FB = 0.6V, VDDQIN = 1.5V (Note 6)
Shutdown
SV_IN = PV_IN = 5.5V, V_RUN = 0V
1100
µA
0.1
1
µA
R_DS(ON)
Top Switch On-Resistance
PV_IN = 3.3V
35
 
mΩ
Bottom Switch On-Resistance
PV_IN = 3.3V
25
mΩ
I_LIM
Top Switch Positive Peak Current Limit Sourcing (Note 7), V_FB = 0.5V
Top Switch Negative Peak Current Limit Sinking (Note 7)
8
10
14
A
–12
–8
–5
A
g_m(EA)
I_EAO
Error Amplifier Transconductance
–5µA < I_ITH < 5µA (Note 4)
Error Amplifier Maximum Output Current (Note 4)
200
µS
±30
µA
t_SS
Internal Soft-Start Time
V_FB from 0.075V to 0.675V,
VDDQIN = 1.5V
0.4
0.85
2
ms
f_OSC
f_SYNC
Oscillator Frequency
Internal Oscillator Frequency
Synchronization Frequency Range
R_T = 370k
V_RT = SV_IN
l
0.8
1
1.2
MHz
l
1.8
2.25
2.7
MHz
0.3
4
MHz
V_SYNC
SYNC Input Threshold High Voltage
SYNC Input Threshold Low Voltage
1.2
V
0.3
V
I_SW(LKG)
Switch Leakage Current
SV_IN = PV_IN = 5.5V, V_RUN = 0V
 
0.1
1
µA
PGOOD
Power Good Voltage Windows
VDDQIN = 1.5V, Entering Window
V_FB Ramping Up
–3.5
–5
%
V_FB Ramping Down
3.5
5
%
t_PGOOD
R_PGOOD
Power Good Blanking Time
Power Good Pull-Down On-Resistance
VDDQIN = 1.5V, Leaving Window
V_FB Ramping Up
V_FB Ramping Down
Entering and Leaving Window
8
10
%
–8
–10
%
70
105
140
µs
8
17
33
Ω
V_RUN
RUN voltage
Input High
Input Low
l
1
l
V
0.4
V
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3617 is tested under pulsed load conditions such that
T_J ≈ T_A. The LTC3617E is guaranteed to meet performance specifications
over the 0°C to 85°C operating junction temperature range. Specifications
over the –40°C to 125°C operating junction temperature range are
assured by design, characterization and correlation with statistical process
controls. The LTC3617I is guaranteed to meet specifications over the
full –40°C to 125°C operating junction temperature range. Note that
the maximum ambient temperature is determined by specific operating
conditions in conjunction with board layout, the rated package thermal
resistance and other environmental factors. The junction temperature
(T_J, in °C) is calculated from the ambient temperature (T_A, in °C) and
power dissipation (P_D, in watts) according to the formula:
T_J = T_A + (P_D • θ_JA), where θ_JA (in °C/W) is the package thermal
impedance.
Note 3: This parameter is tested in a feedback loop which servos V_FB to
the midpoint for the error amplifier (V_ITH = 0.75V).
Note 4: External compensation on ITH pin.
Note 5: Tying the ITH pin to SV_IN enables the internal compensation.
Note 6: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 7: In sourcing mode the average output current is flowing out of the
SW pin. In sinking mode the average output current is flowing into the SW
Pin.
Note 8: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
3617fa
3