MAX8792ETD+T Maxim Integrated Products, MAX8792ETD+T Datasheet - Page 10

• Manufacturer Part Number: MAX8792ETD+T
• Description: IC PWM CONTROLLER 14TDFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX8792ETD+T

• Applications: PWM Controller
• Voltage - Input: 2 ~ 26 V
• Current - Supply: 700µA
• Operating Temperature: -40°C ~ 80°C
• Mounting Type: Surface Mount
• Package / Case: 14-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Single Quick-PWM Step-Down
Controller with Dynamic REFIN
10
______________________________________________________________________________________
PIN
10
11
12
13
1
2
3
4
5
6
7
8
9
NAME
REFIN
TON
SKIP
ILIM
V
BST
REF
V
DH
EN
DL
LX
FB
DD
CC
Shutdown Control Input. Connect to V
its 2µA shutdown state. When disabled, the MAX8792 slowly ramps down the target/output voltage to
ground and after the target voltage reaches 0.1V, the controller forces both DH and DL low and
enters the low-power shutdown state. Toggle EN to clear the fault-protection latch.
Supply Voltage Input for the DL Gate Driver. Connect to the system supply voltage (+4.5V to +5.5V).
Bypass V
Low-Side Gate Driver. DL swings from GND to V
overvoltage fault is detected, overriding any negative current-limit condition that may be present. The
MAX8792 forces DL low during V
Inductor Connection. Connect LX to the switched side of the inductor as shown in Figure 1.
High-Side Gate Driver. DH swings from LX to BST. The MAX8792 pulls DH low whenever the
controller is disabled.
Boost Flying-Capacitor Connection. Connect to an external 0.1µF 6V capacitor as shown in Figure 1.
The MAX8792 contains an internal boost switch/diode (see Figure 2).
Switching Frequency-Setting Input. An external resistor between the input power source and TON
sets the switching period (T
where C
drops below 10µA, the MAX8792 shuts down, and enters a high-impedance state.
TON is high impedance in shutdown.
Feed b ack V ol tag e- S ense C onnecti on. C onnect d i r ectl y to the p osi ti ve ter m i nal of the outp ut cap aci tor s
for outp ut vol tag es l ess than 2V as show n i n Fi g ur e 1. For fi xed - outp ut vol tag es g r eater than 2V ,
connect RE FIN to RE F and use a r esi sti ve d i vi d er to set the outp ut vol tag e ( Fi g ur e 4) . FB senses the
outp ut vol tag e to d eter m i ne the on- ti m e for the hi g h- si d e sw i tchi ng M OS FE T.
Current-Limit Threshold Adjustment. The current-limit threshold is 0.05 times (1/20) the voltage at
ILIM. Connect ILIM to a resistive divider (from REF) to set the current-limit threshold between 20mV
and 100mV (with 0.4V to 2V at ILIM).
External Reference Input. REFIN sets the feedback regulation voltage (V
using the resistor-divider connected between REF and GND. The MAX8792 includes an internal
window comparator to detect REFIN voltage transitions, allowing the controller to blank PGOOD and
the fault protection.
2V Reference Voltage. Bypass to analog ground using a 470pF to 10nF ceramic capacitor. The
reference can source up to 50µA for external loads.
Pulse-Skipping Control Input. This four-level input determines the mode of operation under normal
steady-state conditions and dynamic output-voltage transitions.
5V Analog Supply Voltage. Internally connected to V
to analog ground using a 1µF ceramic capacitor.
V
REF (2V) = pulse-skipping mode with forced-PWM during transitions.
Open (3.3V)= ultrasonic mode (without forced-PWM during transitions).
GND = pulse-skipping mode (without forced-PWM during transitions).
DD
(5V) = forced-PWM operation.
TON
DD
to power ground with a 1µF or greater ceramic capacitor.
= 16.26pF and V
SW
FB
= 1 / f
= V
CC
T
SW
REFIN
UVLO and REFOK lockout conditions.
SW
DD
=
) according to the following equation:
C
for normal operation. Pull EN low to place the controller into
TON
under normal operating conditions. If the TON current
FUNCTION
(
R
TON
DD
. The controller pulls DL high when an output
+
DD
6 5 . Ω
through an internal 20Ω resistor. Bypass V
k
)
⎛
⎜
⎝
V
V
OUT
FB
⎞
⎟
⎠
FB
Pin Description
= V
REFIN
) of the MAX8792
CC