Why is current consumption high on my nRF9160 custom board?

Question

I made a custom board using nRF9160 and tested a very simple program.

However, it consumes high current compared to nRF9160 DK.
I measured current flowing on VCC line of nRF9160.

Custom board: 60uA
nRF9160 DK 0.8.5: 25~30uA

Can anybody give me advice to decrease the current consumption?

based on nrf9160_pca10090ns
nrf tag: v1.0.0

<main.c>

#include <zephyr.h>
#include <misc/printk.h>
#include <uart.h>

void disable_uart(){
        NRF_UARTE0->TASKS_STOPTX = 1;
        NRF_UARTE0->TASKS_STOPRX = 1;
}

void main(void)
{
        disable_uart();
        while(1){
                k_sleep(K_SECONDS(10));
        }
}

<prj.conf>

CONFIG_TRUSTED_EXECUTION_NONSECURE=y

CONFIG_GPIO=n
CONFIG_SERIAL=y
CONFIG_LOG=n

CONFIG_AT_HOST_LIBRARY=n

Håkon Alseth · Accepted Answer

Hi, 
 
 Try disabling serial (CONFIG_SERIAL=n), and configuring your board to be in the secure region "nrf9160_pca10090" (not " ns "), then run a very simple main: 
 k_sleep(1000);
while(1) k_cpu_idle(); 
 
 And see if the current consumption is still equal. Now, it should be < 10 uA, but if it is higher; it is most likely related to floating GPIOs. Make sure that each GPIO has a defined state in sleep, especially those where the level enables external ICs, like "WIFI_EN", "USART_RX_WIFI", and other signals that are controlled by the nRF. 
 
 Kind regards, 
 Håkon

Why is current consumption high on my nRF9160 custom board?

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