4
LTC3738
3738f
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V
OUTEN
= V
SS
= 5V unless otherwise noted.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
× 34°C/W)
Note 3: The IC is tested in a feedback loop that includes the differential
amplifier driving the VID DAC into the error amplifier and servoing the
resultant voltage to the midrange point for the error amplifier (V
ITH
= 1.2V).
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 5: The minimum on-time condition corresponds to an inductor peak-
to-peak ripple current of ≥40% of I
MAX
(see minimum on-time
considerations in the Applications Information Section).
Note 6: ATTEN
ERR
specification is in addition to the output voltage
accuracy specified at VID code 110101.
Note 7: 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.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
PLLFLTR
= 1.2V 325 365 415 kHz
f
LOW
Lowest Frequency V
PLLFLTR
= 0V 190 220 250 kHz
f
HIGH
Highest Frequency V
PLLFLTR
= 2.4V 480 550 630 kHz
R
FCB
FCB Clock
Input Threshold 1.2 V
I
PLL LPF
Phase Detector Output Current
Sinking Capability f
PLLIN
< f
OSC
20 µA
Sourcing Capability f
PLLIN
> f
OSC
20 µA
R
RELPHS
Controller 2-Controller 1 Phase 120 Deg
Controller 3-Controller 1 Phase 240 Deg
No_CPU Detection
t
NOCPU
No-CPU Shutdown Latency After All VID Bits = “1” 0.5 1 µs
Differential Amplifier
A
V
Differential Gain 1.000 V/V
V
OS
Input Offset Voltage IN
+
= IN
–
= 1.2V, Input Referred 0.5 mV
CM Common Mode Input Voltage Range 0 5 V
CMRR Common Mode Rejection Ratio 0V < IN
+
= IN
–
< 5V,
Input Referred 70 dB
GBP Gain Bandwidth Product 2 MHz
V
O(MAX)
Maximum High Output Voltage V
CC
– 0.8 V
R
IN
Input Resistance Measured at IN
+
Pin 160 kΩ
Active Voltage Positioning
I
SINK
Sinking Current Ability of AVP Pin IN
+
= 1.2V 0.250 mA
I
SOURCE
Sourcing Current Ability of AVP Pin IN
+
= 1.2V 1.4 mA
V
AVP
– V
O(MAX)
Max Voltage Drops V
AVP
to VO IN
+
= 1.2V, V
IN
= 60mV 180 mV
Thermal Detection
V
INT
Thermal Comparator Trip Threshold 1.67 V
V
INT_HYS
Hysteresis 0.21 V
V
TH_TH
Internal Detection Enable Threshold 3.4 V
CC
– 1 V
